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Viana, José Marcelo Soriano. "Breeding strategies for recurrent selection of maize". Pesquisa Agropecuária Brasileira 42, nr 10 (październik 2007): 1383–91. http://dx.doi.org/10.1590/s0100-204x2007001000003.
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The objectives of this work were to analyze theoretical genetic gains of maize due to recurrent selection among full-sib and half-sib families, obtained by Design I, Full-Sib Design and Half-Sib Design, and genotypic variability and gene loss with long term selection. The designs were evaluated by simulation, based on average estimated gains after ten selection cycles. The simulation process was based on seven gene systems with ten genes (with distinct degrees of dominance), three population classes (with different gene frequencies), under three environmental conditions (heritability values), and four selection strategies. Each combination was repeated ten times, amounting to 25, 200 simulations. Full-sib selection is generally more efficient than half-sib selection, mainly with favorable dominant genes. The use of full-sib families derived by Design I is generally more efficient than using progenies obtained by Full-Sib Design. Using Design I with 50 males and 200 females (effective size of 160) did not result in improved populations with minimum genotypic variability. In the populations with lower effective size (160 and 400) the loss of favorable genes was restricted to recessive genes with reduced frequencies.
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Esmailizadeh, A. K., A. Baghizadeh i M. Ahmadizadeh. "Genetic mapping of quantitative trait loci affecting bodyweight on chromosome 1 in a commercial strain of Japanese quail". Animal Production Science 52, nr 1 (2012): 64. http://dx.doi.org/10.1071/an11220.
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This study was conducted to identify quantitative trait loci (QTL) affecting growth on chromosome 1 in quail. Liveweight data were recorded on 300 progeny from three half-sib families created from a commercial strain of Japanese quail. Three half-sib families were genotyped for nine microsatellite loci on chromosome 1 and QTL analysis was conducted applying the least-squares interval mapping approach. Significant QTL affecting bodyweight at 3, 4, 5 and 6 weeks of age, average daily gain, and Kleiber ratio, an indirect criterion for feed efficiency, were mapped at 0–23 cM on chromosome 1. The detected QTL segregated in two of the three half-sib families and the size of the QTL effect ranged from 0.6 to 1.1 in unit of the trait standard deviation. This is the first report of liveweight QTL segregating in a commercial strain of Japanese quail.
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Liang, Yongshu, Chao Yan, Xiaojian Qin, Wenbin Nan i Hanma Zhang. "Construction of three half-sib SSR linkage maps derived from overwintering cultivated rice and segregation distortion loci mapping". Genome 63, nr 4 (kwiecień 2020): 239–51. http://dx.doi.org/10.1139/gen-2019-0160.
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Segregation distortion is a common phenomenon that has been observed in genetics and plant breeding; however, the mechanism of segregation distortion is unknown. In the present study, three half-sib F2 populations derived from three japonica overwinter (perennial) rice varieties (W1, W2, and W3) crossed to the indica rice variety Minghui725 (MH725) were developed to construct three half-sib linkage maps. We established linkage map lengths of 2032.8, 2317.4, and 2108.7 cM with average intervals of 20.1, 20.5, and 19.7 cM using 101, 113, and 107 SSR markers in W1/MH725, W2/MH725, and W3/MH725, respectively. Discrepancies in marker order and genetic linkage distance occurred in the three half-sib linkage maps due to segregation distortion. A total of 88 markers exhibited segregation distortion across the three linkage maps at P < 0.01 level, 42 segregation distortion loci (SDLs) were detected across the three half-sib populations and exhibited variable LOD value that ranged from 3.2 (SDL2f) to 30.1 (SDL5d), and 13 of the 42 SDLs were repeatedly located at the same chromosomal regions of the previously published hybrid sterility quantitative trait loci. Data from this study provide an extensive archive for investigating the genetic characteristic of overwintering cultivated rice and the future exploration and innovation of overwintering rice breeding.
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Marcu, Nicu, Marius Budeanu, Ecaterina Nicoleta Apostol i Raul Gheorghe Radu. "Valuation of the Economic Benefits from Using Genetically Improved Forest Reproductive Materials in Afforestation". Forests 11, nr 4 (27.03.2020): 382. http://dx.doi.org/10.3390/f11040382.
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The research objective was to demonstrate the economic impact of using, in afforestation, forest reproductive materials (FRMs) obtained from seed trees selected in the most valuable Norway spruce populations of the FGRs’ (forest genetic resources’) category. The values obtained for the main growth traits (diameter at breast height (Dbh), tree height (Th), and tree volume (Tv)), both in the FGR and in the closest population (with the same age and growth in similar environmental conditions), were compared. Three comparative trials were analyzed, each belonging to different breeding levels: Open-pollinated (Breţcu, 40 years old), half-sib (Măneciu, 25 years), and full-sib (Comandău, 23 years). The difference in volume/hectare between the FGR and an unimproved neighbor population was economically quantified (€), based on the average price per cubic meter (m3) of spruce wood in Romania; the profit at the end of the rotation period (110 years) was projected taking into account the genetic gain that will result from the use of FRM collected from the FGRs. The average FGR growth results were superior to the unimproved neighbor populations, with 8%–13%, 14%–25%, and 26%–79% for Dbh, Th, and volume/ha, respectively, and the differences increased if the best 10% seed trees of the trials were used. For Th, a five times higher family mean heritability was registered for the pendula trees (compared to pyramidalis) in the half-sib trial, while in the full-sib experiment, the pendula trees (both full and half pendula) again registered higher heritability, but for Dbh, which recommends the pendula selection for different traits in the two trials. These results have led to a rate of profitability between 540 and 3366 €/ha, a value that is predicted to increase until the end of the rotation period, when the genetic gain could generate a profit of 7560 €/ha.
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Gomez-Raya, L. "Biased Estimation of the Recombination Fraction Using Half-Sib Families and Informative Offspring". Genetics 157, nr 3 (1.03.2001): 1357–67. http://dx.doi.org/10.1093/genetics/157.3.1357.
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Abstract A maximum-likelihood method to estimate the recombination fraction and its sampling variance using informative and noninformative half-sib offspring is derived. Estimates of the recombination fraction are biased up to 20 cM when noninformative offspring are discarded. In certain scenarios, the sampling variance can be increased or reduced up to fivefold due to the bias in estimating the recombination fraction and the LOD score can be reduced up to 5 units when discarding noninformative offspring. Comparison of the estimates of recombination fraction, map distance, and LOD score when constructing a genetic map with 251 two-point linkage analyses and six families of Norwegian cattle was carried out to evaluate the implications of discarding noninformative offspring in practical situations. The average discrepancies in absolute value (average difference when using and neglecting noninformative offspring) were 0.0146, 1.64 cM, and 2.61 for the recombination fraction, map distance, and the LOD score, respectively. A method for simultaneous estimation of allele frequencies in the dam population and a transmission disequilibrium parameter is proposed. This method might account for the bias in estimating allele frequencies in the dam population when the half-sib offspring is selected for production traits.
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Kuhlman, E. G., i F. R. Matthews. "Variation in virulence among single-aeciospore isolates from single-gall isolates of Cronartiumquercuum f.sp. fusiforme". Canadian Journal of Forest Research 23, nr 1 (1.01.1993): 67–71. http://dx.doi.org/10.1139/x93-011.
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Single aeciospores from single-gall isolates of Cronartiumquercuum (Berk.) Miyabe ex Shirai f.sp. fusiforme previously shown to have virulence toward resistant half-sib loblolly pine (Pinustaeda L.) families 10-5, 11-20, or 29R were propagated in the asexual uredial stage on leaves of oak seedlings. Only 80 of 1086 single aeciospores from a single-gall isolate with virulence towards family 10-5 produced symptoms of infection on the oaks, and 17 infections produced telia directly. Thirty-two single-aeciospore isolates were propagated from the 63 uredinia. Half-sib progeny of 10-5 were inoculated with each of the 32 isolates, and after 9 months incidence of seedlings with galls varied from 46 to 93%. Six isolates produced galls on more than 90% of the seedlings. Average gall length ranged from 30 to 56 mm among the 32 isolate treatments. Similarly, 20 single-aeciospore isolates propagated from two single-gall isolates with virulence towards family 11-20 caused galls on 19–59% of 11-20 progeny. Finally, 12 single-aeciospore isolates propagated from a single-gall isolate with virulence towards family 29R produced galls on 38–91% of the half-sib progeny of 29R. Thus, in three separate experiments virulence among single-aeciospore isolates toward a resistant source ranged from normal to very high.
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Gonzalez-Benecke, C. A., T. A. Martin, A. Clark i G. F. Peter. "Water availability and genetic effects on wood properties of loblolly pine (Pinus taeda)". Canadian Journal of Forest Research 40, nr 12 (grudzień 2010): 2265–77. http://dx.doi.org/10.1139/x10-162.
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We studied the effect of water availability on basal area growth and wood properties of 11-year-old loblolly pine ( Pinus taeda L.) trees from contrasting Florida (FL) (a mix of half-sib families) and South Carolina coastal plain (SC) (a single, half-sib family) genetic material. Increasing soil water availability via irrigation increased average whole-core specific gravity (SG) and latewood percentage (LW%) by 0.036 and 6.93%, respectively. Irrigation did not affect latewood SG or wood stiffness, but irrigated FL and SC trees had more latewood due to a 29 day longer growing season. Irrigation did not affect the length of corewood production, but irrigated trees had earlier transition ages, producing outerwood ~3 years before rainfed trees. The increase in whole-core SG and LW% was moderate because irrigation promoted earlywood growth in corewood formed before canopy closure, but after year 7, rain-fed and irrigated trees had similar earlywood growth but irrigated trees had more latewood growth, increasing ring SG and LW%. The SC half-sib family had higher SG and greater LW% than trees from FL independent of irrigation due to greater yearly latewood growth. Thus, absence of soil water stress extended seasonal diameter cessation date but did not change latewood SG or wood stiffness.
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Zhao, Xiyang, Yanyan Pan, Xiaona Pei, Fuwei Wang, Chenglu Wang, Lili Shao, Lihu Dong i Guan-Zheng Qu. "Forward, backward selection and variation analysis of growth traits in half-sib Larix kaempferi families". Silvae Genetica 68, nr 1 (1.01.2019): 1–8. http://dx.doi.org/10.2478/sg-2019-0001.
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Abstract Tree height and diameter at breast height of 30 half-sib Larix kaempferi families were analyzed at different ages. Analysis of variance revealed a significant difference in growth among different families. Phenotypic variation coefficients of the traits tree height and diameter at breast height among families of different ages ranged from 11.04 % to 31.74 % and 19.01 % to 19.83 %, respectively. Average heritability of tree height and diameter at breast height ranged from 0.87 to 0.96 and 0.93 to 0.96, respectively. Significant positive correlations were observed among all traits at different ages. By the method of multiple-traits comprehensive, six families (L18, L12, L8, L3, L25 and L20) were selected as being elite using a 20 % selection ratio at 12 years of age. Average values of these elite families were 11.15 % and 16.83 % higher than the total average for height and diameter at breast height, and genetic gains were 10.53 % and 15.79 %, respectively. Forty five elite individual plants were selected using a 5 % selection ratio which were 23.47 % and 24.90 % higher than the overall average for height and diameter at breast height, respectively.
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Maliondo, S. M., i H. H. Krause. "Genotype and soil fertility interaction in the growth of black spruce progeny from a central New Brunswick population". Canadian Journal of Forest Research 15, nr 2 (1.04.1985): 410–16. http://dx.doi.org/10.1139/x85-066.
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Seedlings representing 10 half-sib families from a black spruce (Piceamariana (Mill.) B.S.P.) stand in central New Brunswick were raised in a greenhouse on three different soils, each with two levels of fertility. Seedling growth varied significantly with soil, fertility, and half-sib family. After 7 months mean dry weights, for example, ranged from 0.292 to 0.755 g with soil, 0.174 to 0.936 g with level of fertility, and 0.370 to 0.657 g with family. With soil and fertility considered fixed variables, the family and family–fertility interaction accounted for approximately 3 and 20% of the phenotypic variation in mean seedling dry weight, respectively. Similar variance components were observed for shoot and root weights, and root collar diameter. Based on the family – soil fertility interaction, the population was divided into groups of (i) broadly adapted families showing average performance through the full range of fertility environments, (ii) strong responders, i.e., families performing below average at low fertility, but showing a large fertilization response, and (iii) weak or nonresponders, i.e., families performing poorly in all fertility environments.
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Barrera-Irigoyen, Cesar Augusto, Aureliano Peña-Lomelí, Natanael Magaña-Lira, Jaime Sahagún-Castellanos i Mario Pérez-Grajales. "Study of inbreeding in tomatillo (Physalis ixocarpa Brot. ex Horm.)". Revista Chapingo Serie Horticultura 27, nr 3 (2021): 185–98. http://dx.doi.org/10.5154/r.rchsh.2021.03.006.
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Only intervarietal and interfamilial hybridization can be carried out in tomatillo. Therefore, the objective was to study the effect of inbreeding in families of four varieties of tomatillo obtained through three generations of mating by fraternal and plant-to-plant crosses. The varieties studied were Tecozautla, Diamante, Manzano and Morado, each represented by three maternal half-sib families (Generation 1). In 2018, plant-to-plant and fraternal crosses were made in selected plants within each family, resulting in full-sib (FSF) and maternal half-sib (MHSF) families, respectively (Generation 2). In 2019, the process was repeated in Generation 2 families, and another generation of FSFs and MHSFs (Generation 3) was obtained. Field evaluation was conducted in 2020. A randomized complete block design with four replications was used, and yield per plant was evaluated in two harvests and total yield per plant, as well as fruit weight, volume and bulk density, in each harvest and average of harvests. Inbreeding depression occurred among generations. Fruit yield, size and volume in the first harvest decreased over generations. The Tecozautla and Diamante varieties showed greater inbreeding depression. The type of cross had a different effect depending on the variety. Fruit size was lower in plant-to-plant crosses in Tecozautla, Diamante and Morado; that is, they generated greater inbreeding depression than the fraternal crosses.
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Tran, Thi Phuong Dung, Hong Loc Nguyen, Hoang Thong Nguyen, Hoang Khoi Nguyen Le i Van Sang Nguyen. "The application of microsatellite markers for parentage analysis in selective population of striped catfish (Pangasianodon hypophthalmus)". Ministry of Science and Technology, Vietnam 64, nr 2 (25.02.2022): 48–53. http://dx.doi.org/10.31276/vjst.64(2).48-53.
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The research used ten newly developed microsatellites markers set which were assigned offsprings to their parents on the first generation of selection on striped catfish. The result shows: (1) When analysing 50 samples of parents (G0) and 50 samples of offsprings (G1), the PCR ratio was from 98-100%, the allele number (NA) ranged from 5-14 per locus. The average Polymorphic Information Content (PIC) of microsatellites on G0 and G1 were 0.71 and 0.67, respectively. The average observed heterozygosity (HO) and expected heterozygosity (HE) all over loci were 0.73, 0.76, and 0.73, 0.71, respectively. Ten microsatellites are stable and polymorphic that are suitable for parentage analysis. (2) After makers screening, parentage analysis on 50 selective families, the initial set of nine microsatellites (excluded Pahy-02) for parentage analysis was effective with 93.4% of offspring allocated unambiguously to their parental pairs, of which families with the father not having half-sib, 93.0% of offspring was allocated unambiguously to their parental pairs and families with the father having half-sib, 94.0% of offspring allocated unambiguously to their parental pairs. The results show that the maker set with nine microsatellites can be used in parentage analysis for the breeding program on striped catfish.
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Brka, M., N. Reinsch i E. Kalm. "Is there linkage between supernumerary teats in cattle and BTA3 markers?" Archives Animal Breeding 45, nr 5 (10.10.2002): 429–32. http://dx.doi.org/10.5194/aab-45-429-2002.
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Abstract. From 1997 to 1999 1005 new born German Holstein calves were investigated for the incidence of supernumerary teats. Age at inspection varied from 1 to 4 weeks. In total 110 affected calves (20 male and 90 female) and their 21 sires were genotyped for five chromosome 3 microsatellites. The average size of half-sib families was 5.2 ranging from 2 to 17. A non-parametric multipoint linkage analysis showed no evidence for linkage.
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Basyuni, Mohammad, Shigeyuki Baba, Hirosuke Oku, Ridha Wati i Annisa Fitri. "Microsatellite analysis of the mating system of Bruguiera gymnorrhiza and Kandelia obovata". MATEC Web of Conferences 197 (2018): 06003. http://dx.doi.org/10.1051/matecconf/201819706003.
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Microsatellite loci were used for estimating mating system for three populations of B. gymnorrhiza and K. obovata (Rhizophoracea) in Okinawa, Japan. Mother trees and thirty offspring of individual samples representing the population of both species were genotyped at five microsatellites. The mating system was examined using two approaches: a mixed mating model of multilocus testing, implemented by MLTR program and outcrossing rate from the level of inbreeding. Mating system analysis showed multilocus outcrossing rates (tm) for both species was 0.850-1.000 and 0.780-0.938 respectively. By contrast, according to inbreeding level, tm was lower than MLRT: 0.495-1.028 and 0.480-0.612 of both species respectively. However, biparental inbreeding (tm- ts) was diverse from zero both species for all three populations, showing that cross-fertilization events may ensue between the relatives both species. This data as well means the genetic relatedness (r) for B. gymnorrhiza and K. obovata were 0.108±0.025 and 0.032±0.09 respectively. Average relatedness was below 0.25, the value for a half-sib relationship. These results suggest that postulation of a half-sib relationship among progeny of open-pollinated families is opposed for both mangrove tree species.
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Khan, Mueen Alam, Fei Tong, Wubin Wang, Jianbo He, Tuanjie Zhao i Junyi Gai. "Using the RTM-GWAS procedure to detect the drought tolerance QTL-allele system at the seedling stage under sand culture in a half-sib population of soybean [Glycine max(L.) Merr.]". Canadian Journal of Plant Science 99, nr 6 (1.12.2019): 801–14. http://dx.doi.org/10.1139/cjps-2018-0309.
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Soybean crops face drought as one of their major yield barriers. Dissecting the complete genetic architecture of drought tolerance (DT) is an ongoing challenge for soybean breeders. A half-sib population with 404 lines consisting of two recombinant inbred line (RIL) populations with M8206 as the joint parent (M8206 × TongShan and ZhengYang × M8206) was established and tested for their DT under sand culture. The population was sequenced using RAD-seq (restriction-site-associated DNA sequencing) filtered with minor allele frequency (MAF) ≥ 0.01, and 55 936 single nucleotide polymorphisms (SNPs) were obtained and organized into 6137 SNPLDBs (SNP linkage disequilibrium blocks). The innovative RTM-GWAS (restricted two stage multi-locus genome-wide association study) identified 46 novel QTLs with 107 alleles on an average of 38.67% of the phenotypic variance (PV) collectively for relative plant length (RPL) and relative plant dry weight (RPDW). The identified quantitative trait loci (QTLs) with their corresponding alleles for RPL and RPDW were structured into QTL-allele matrices, showing the DT genetic architecture of the three parents and half-sib population. From the matrices, the possible best genotype was predicted to have their weighted average value (WAV) over two indicators 1.663, while the top 10 optimal crosses among RILs with 95thpercentile WAV was 0.872–0.960, transgressive over the parents (0.469–0.675) but much less than 1.663, depicting further pyramiding potential. From the detected QTL-allele system, 63 potential candidate genes collectively for both RPL and RPDW indicators explaining on average of 26.94% PV were annotated and χ2-tested as a DT potential candidate gene system involving nine biological processes, endorsing the genetic complexity of DT.
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Brito, Orlando Gonçalves, Valter Carvalho de Andrade Júnior, Alcinei Mistico de Azevedo, Luan Mateus Silva Donato, Lidiane Rodrigues Silva i Marcos Aurélio Miranda Ferreira. "Study of repeatability and phenotypical stabilization in kale using frequentist, Bayesian and bootstrap resampling approaches". Acta Scientiarum. Agronomy 41, nr 1 (24.05.2019): 42606. http://dx.doi.org/10.4025/actasciagron.v41i1.42606.
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The aim of this study was to obtain information for the genetic improvement of kale through repeatability and phenotypic stabilization studies and to compare methodologies that represent the reliability of the estimated parameters. Thirty-three half-sib progenies were evaluated in a randomized block design with three replicates and six plants per plot. Eight harvests were evaluated in terms of the yield of fresh leaves, number of shoots, number of leaves and average mass of leaves. Then, a phenotypic repeatability and stabilization study was performed, estimating the genetic parameters σ2a, σ²g, σ²e, and the coefficient of environmental variation and repeatability using the frequentist and Bayesian methodologies. To evaluate the reliability of these estimates, intervals were obtained using the frequentist, Bayesian and bootstrap methods. It was verified that the reliable selection of progenies of half-sib of kale can be achieved in four harvests that were realized between 95 and 170 days after planting. It was observed that the frequentist and Bayesian methodologies are better suited to obtain reliable estimates of the genetic parameters evaluated, as the last one provided smaller amplitudes for the obtained intervals. The bootstrap methodologies are not recommended for phenotypic repeatability and stabilization studies in kale.
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TILQUIN, P., I. VAN KEILEGOM, W. COPPIETERS, E. LE BOULENGÉ i P. V. BARET. "Non-parametric interval mapping in half-sib designs: use of midranks to account for ties". Genetical Research 81, nr 3 (czerwiec 2003): 221–28. http://dx.doi.org/10.1017/s0016672303006256.
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In QTL analysis of non-normally distributed phenotypes, non-parametric approaches have been proposed as an alternative to the use of parametric tests on mathematically transformed data. The non-parametric interval mapping test uses random ranking to deal with ties. Another approach is to assign to each tied individual the average of the tied ranks (midranks). This approach is implemented and compared to the random ranking approach in terms of statistical power and accuracy of the QTL position. Non-normal phenotypes such as bacteria counts showing high numbers of zeros are simulated (0–80% zeros). We show that, for low proportions of zeros, the power estimates are similar but, for high proportions of zeros, the midrank approach is superior to the random ranking approach. For example, with a QTL accounting for 8% of the total phenotypic variance, a gain from 8% to 11% of power can be obtained. Furthermore, the accuracy of the estimated QTL location is increased when using midranks. Therefore, if non-parametric interval mapping is chosen, the midrank approach should be preferred. This test might be especially relevant for the analysis of disease resistance phenotypes such as those observed when mapping QTLs for resistance to infectious diseases.
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Masoni, Alberto, Alessandro Calamai, Lorenzo Marini, Stefano Benedettelli i Enrico Palchetti. "Constitution of Composite Cross Maize (Zea mays L.) Populations Selected for the Semi-Arid Environment of South Madagascar". Agronomy 10, nr 1 (31.12.2019): 54. http://dx.doi.org/10.3390/agronomy10010054.
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In many African countries, such as Madagascar, a large part of the population is currently estimated to be undernourished, and self-subsistence agriculture represents the primary source of food available for the family. Smallholder farmers cultivate crops with limited agricultural input and use old landraces or obsolete hybrid varieties, with a total country-wide production that is far from being able to sustain the national food demand. In this study, we have developed two maize composite cross populations (CCPs) of different kernel colors, through a selection process among 30 half-sib lines, chosen both for their agronomic performance and their environmental adaptability to a Malagasy farm context. The best half-sib lines, identified through field tests, were clustered as a parental group for open-pollinated crosses. The new CCP created, after two years of seed multiplication in an open field, showed promising yields compared with the hybrids, parental varieties, and local landraces, with average values of 2.7 t/ha for the white CCP and 3.5 t/ha for the yellow one. The seeds produced were then distributed among 15 local farmers to begin a participatory breeding program. Our approach represents an innovative step to improve and stabilize maize yields, employing populations adapted to the cultivation environment and able to cope with different stresses, thereby helping farmers’ life conditions.
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Blumenthal, MJ, K. Prakash, A. Leonforte, PJ Cunningham i HI Nicol. "Characterisation of the Kangaroo Valley ecotype of perennial ryegrass (Lolium perenne)". Australian Journal of Agricultural Research 47, nr 7 (1996): 1131. http://dx.doi.org/10.1071/ar9961131.
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A breeding program commenced in 1992 to produce perennial ryegrass (Lolium perenne) cultivars based on the Kangaroo Valley perennial ryegrass (KVPR) ecotype with improved winter and late season growth, disease resistance, and persistence. Perennial ryegrass plants (9000) were collected from 45 sites within the Kangaroo Valley and Shoalhaven flood plain in August 1992. Using principal component analysis, site differences were greatest for N percentage, Mg and Na concentration, and A1 saturation. Collections were space planted along with standard cultivars (Banks, Ellett, Embassy, Grasslands Lincoln, and Vedette) at Berry, New South Wales (34�48'S), and Timboon, Victoria (38'32'S), with 50 treatments and 10 replicates. Plants were visually scored for seasonal yield, rust incidence, greenness, leafiness, persistence, habit, and tiller density at both sites. At Berry, leaf angle, leaf width, and heading date were determined. Despite the differences in moisture, temperature, and growth indices between the 2 test sites, seasonal yield scores (mean of 100 plants) at Berry and Timboon were highly genetically correlated (r = 0.79-0.99). Standard cultivars were higher yielding with higher tiller density but with a greater rust incidence than collections (P < 0.01). Collections originating from the Shoalhaven flood plain were higher yielding with greater tiller density than plants from the Kangaroo Valley (P < 0.01), although differences were not as great as site of origin differences would suggest. Selections have been made for polycross half-sib formation, and half-sib evaluation will take place at a number of sites to determine the average general combining ability of parent selections for synthetic cultivar production.
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Liu, M. F., M. Makarechian i R. T. Berg. "Distributional characteristics of phenotypic variation within paternal half sib groups for postweaning average daily gain in two beef cattle populations of different origins". Journal of Animal Breeding and Genetics 108, nr 1-6 (12.01.1991): 35–40. http://dx.doi.org/10.1111/j.1439-0388.1991.tb00153.x.
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Wang, Xinhua, Xiaomu Yu, Jianxin Feng, Qin Zhang, Changyi Qu, Qingshan Liu, Jingou Tong i Wenyan Xu. "Estimation of the Heritabilities for Body Shape and Body Weight in Yellow River Carp (Cyprinus carpio haematopterus) Based on a Molecular Pedigree". Journal of Applied Ichthyology 2023 (24.06.2023): 1–8. http://dx.doi.org/10.1155/2023/9326728.
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Estimation of the heritability for a given phenotype would provide basic information for potential breeding programs. As one of the most precious common carp strains, Yellow River carp was subject to selection for fast growth and a slender body to meet market demands. In the present study, heritabilities for body shape (body length, BL and body height, BH) and body weight (BW) were estimated based on a molecular parentage assignment for 750 progenies from 58 half-sib and full-sib Yellow River carp families. Eight highly polymorphic microsatellites were used for the construction of the molecular pedigree, and the average observed heterozygosity (Ho), expected heterozygosity (He), and the polymorphism information content (PIC) were 0.841, 0.792, and 0.763, respectively. All 750 progenies were successfully assigned to single parental pairs with 100% accuracy. Using the linear mixed model, the heritabilities were estimated to be 0.268, 0.338, and 0.340 for BL, BH, and BW, respectively. High phenotypic (0.831–0.927) and genetic (0.952–0.987) correlations among these three traits suggested that selection for BW could also largely affect the body shape and vice versa. Moderate heritabilities and high genetic corrections revealed by this study strongly indicate substantial potentials for genetic improvement of both growth rate and body formation in Yellow River carp breeding programs.
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Maiorano, Amanda M., Alula Assen, Piter Bijma, Ching-Yi Chen, Josineudson Augusto II Vasconcelos Silva, William O. Herring, Shogo Tsuruta, Ignacy Misztal i Daniela A. L. Lourenco. "Improving accuracy of direct and maternal genetic effects in genomic evaluations using pooled boar semen: a simulation study1". Journal of Animal Science 97, nr 8 (25.05.2019): 3237–45. http://dx.doi.org/10.1093/jas/skz207.
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Abstract Pooling semen of multiple boars is commonly used in swine production systems. Compared with single boar systems, this technique changes family structure creating maternal half-sib families. The aim of this simulation study was to investigate how pooling semen affects the accuracy of estimating direct and maternal effects for individual piglet birth weight, in purebred pigs. Different scenarios of pooling semen were simulated by allowing the same female to mate from 1 to 6 boars, per insemination, whereas litter size was kept constant (N = 12). In each pooled boar scenario, genomic information was used to construct either the genomic relationship matrix (G) or to reconstruct pedigree in addition to G. Genotypes were generated for 60,000 SNPs evenly distributed across 18 autosomes. From the 5 simulated generations, only animals from generations 3 to 5 were genotyped (N = 36,000). Direct and maternal true breeding values (TBV) were computed as the sum of the effects of the 1,080 QTLs. Phenotypes were constructed as the sum of direct TBV, maternal TBV, an overall mean of 1.25 kg, and a residual effect. The simulated heritabilities for direct and maternal effects were 0.056 and 0.19, respectively, and the genetic correlation between both effects was −0.25. All simulations were replicated 5 times. Variance components and direct and maternal heritability were estimated using average information REML. Predictions were computed via pedigree-based BLUP and single-step genomic BLUP (ssGBLUP). Genotyped littermates in the last generation were used for validation. Prediction accuracies were calculated as correlations between EBV and TBV for direct (accdirect) and maternal (accmat) effects. When boars were known, accdirect were 0.21 (1 boar) and 0.26 (6 boars) for BLUP, whereas for ssGBLUP, they were 0.38 (1 boar) and 0.43 (6 boars). When boars were unknown, accdirect was lower in BLUP but similar in ssGBLUP. For the scenario with known boars, accmat was 0.58 and 0.63 for 1 and 6 boars, respectively, under ssGBLUP. For unknown boars, accmat was 0.63 for 2 boars and 0.62 for 6 boars in ssGBLUP. In general, accdirect and accmat were lower in the single-boar scenario compared with pooled semen scenarios, indicating that a half-sib structure is more adequate to estimate direct and maternal effects. Using pooled semen from multiple boars can help us to improve accuracy of predicting maternal and direct effects when maternal half-sib families are larger than 2.
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Blazier, Michael A., Michael C. Tyree, Mary Anne Sword Sayer, Dipesh KC, Wilson G. Hood i Bradley S. Osbon. "Gas Exchange and Productivity in Temperate and Droughty Years of Four Eastern, Elite Loblolly Pine Genotypes Grown in the Western Gulf Region". International Journal of Agronomy 2018 (3.12.2018): 1–10. http://dx.doi.org/10.1155/2018/3942602.
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Loblolly pine plantations in the western portion of the species’ range are sometimes planted with genotypes from the eastern portion of its range to improve plantation productivity. Advances in loblolly pine breeding have led to the development of clonally propagated genotypes with higher potential growth rates and better form than more commonly planted half-sib genotypes. At a site in the western portion of the loblolly pine range, four genotypes from the eastern portion of the loblolly pine range were established. Two genotypes (HS756 and HS8103) were half-sib, and two genotypes (V9 and V93) were varieties. The V93 genotype was propagated from the HS756 genotype. The objective of this study was to determine the effects of genotype on seasonal trends in gas exchange parameters at the leaf and crown levels, growth, and biomass allocation patterns. During the two-year study, one year had precipitation and temperature trends similar to the long-term average and one year had extreme drought, with record heat. The HS756, V9, and V93 genotypes had the highest height growth throughout the study. The V93 genotype was sensitive to the drought; its leaf- and crown-levelAsatandgs, declined during the drought more markedly than those of the other genotypes. Although itsAsatandgswere affected by drought, height growth productivity of V93 may have been sustained during the drought by its biomass partitioning pattern of allocating higher proportions of its root biomass to small and fine roots and its aboveground biomass to foliage. These results suggest that a variety such as V93 could be more susceptible to changes in C fixation and water uptake with recurrent drought.
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Cano, E. M., S. Debenedetti, M. Abad, D. Allain, H. R. Taddeo i M. A. Poli. "Chromosomal segments underlying quantitative trait loci for mohair production in Angora goats". Animal Genetic Resources Information 45 (październik 2009): 107–12. http://dx.doi.org/10.1017/s1014233909990423.
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SummaryThis study reports the results obtained in the search of chromosomal regions affecting fleece traits in a population of Angora goats in the Argentinean Patagonia. Six hundred thirty-four offspring from 14 parental half-sib families were used. Nine phenotypic fleece traits were recorded at 4 and 11 months of age. A genome examination using 85 informative molecular markers was conducted. A linkage analysis was performed using a regression interval analysis. Our study identified 10 genomic regions affecting the average fibre diameter, coefficient of variation of the average fibre diameter, percentage of fibres with diameters over 30 µm, greasy fleece weight, staple length, average curvature of fibres, percentage of continuous medullated fibres and percentage of kemp fibres located on five goat chromosomes (1, 2, 5, 13 and 19). These results show that the average size of the quantitative trait loci effect was 1.6 phenotypic standard deviations for different traits and families. The aims of quantitative trait loci detection is the potential use of these molecular markers to increase accuracy in predicting the genetic merit of breeding and its implementation in animal breeding schemes through marker-assisted selection.
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Hayatgheibi, Haleh, Mats Berlin, Matti Haapanen, Katri Kärkkäinen i Torgny Persson. "Application of Transfer Effect Models for Predicting Growth and Survival of Genetically Selected Scots Pine Seed Sources in Sweden". Forests 11, nr 12 (16.12.2020): 1337. http://dx.doi.org/10.3390/f11121337.
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We used a regression model approach to examine transferability of the 1.5-generation Swedish Scots pine orchard plus trees using the estimated coefficients of the transfer models recently developed for growth and survival of unimproved Scots pine in Sweden and Finland. Differences between observed and predicted values obtained for height and survival of 3214 plus tree progenies, tested at 58 progeny trials, were regressed on latitudinal transfers (∆LAT). In order to evaluate rates of improvement in height and survival of selected progenies over unimproved trees, average percentage differences in performances (∆g%) between the tree groups were calculated. Results indicate that the adopted models can further predict performances of more advanced-generation orchard trees, as there was no evidence of any systematic pattern in the slope of regression functions. Overall, ∆g% estimates obtained for height of progenies were greater than those of survival, suggesting Swedish Scots pine breeding activities are generating gain in the height growth. Moreover, ∆g% estimates obtained for height and survival of half-sib progenies were higher than those of full-sib ones, as a result of response to higher selection intensity applied in the reselection of their parents. This indicates that, in addition to the gain in growth, a gain in survival is also achievable from 1.5-generation seed orchards, depending on the intensity of selection and intended deployment site.
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KADARMIDEEN, HAJA N., YONGJUN LI i LUC L. G. JANSS. "Gene–environment interactions in complex diseases: genetic models and methods for QTL mapping in multiple half-sib populations". Genetical Research 88, nr 2 (15.09.2006): 119–31. http://dx.doi.org/10.1017/s0016672306008391.
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An interval quantitative trait locus (QTL) mapping method for complex polygenic diseases (as binary traits) showing QTL by environment interactions (QEI) was developed for outbred populations on a within-family basis. The main objectives, within the above context, were to investigate selection of genetic models and to compare liability or generalized interval mapping (GIM) and linear regression interval mapping (RIM) methods. Two different genetic models were used: one with main QTL and QEI effects (QEI model) and the other with only a main QTL effect (QTL model). Over 30 types of binary disease data as well as six types of continuous data were simulated and analysed by RIM and GIM. Using table values for significance testing, results show that RIM had an increased false detection rate (FDR) for testing interactions which was attributable to scale effects on the binary scale. GIM did not suffer from a high FDR for testing interactions. The use of empirical thresholds, which effectively means higher thresholds for RIM for testing interactions, could repair this increased FDR for RIM, but such empirical thresholds would have to be derived for each case because the amount of FDR depends on the incidence on the binary scale. RIM still suffered from higher biases (15–100% over- or under-estimation of true values) and high standard errors in QTL variance and location estimates than GIM for QEI models. Hence GIM is recommended for disease QTL mapping with QEI. In the presence of QEI, the model including QEI has more power (20–80% increase) to detect the QTL when the average QTL effect is small (in a situation where the model with a main QTL only is not too powerful). Top-down model selection is proposed in which a full test for QEI is conducted first and then the model is subsequently simplified. Methods and results will be applicable to human, plant and animal QTL mapping experiments.
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Magnussen, S., i C. W. Yeatman. "Early testing of jack pine. I. Phenotypic response to spacing". Canadian Journal of Forest Research 17, nr 6 (1.06.1987): 453–59. http://dx.doi.org/10.1139/x87-078.
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Six-year results of stem and branch size, stem form, and branch angle in four local jack pine seed lots showed the expected changes caused by variations in available growing space. Spacing, age, and their interaction had significant effects on all traits examined. Tree height was the only variable in which seed lot differences were of practical importance. Offspring from a bulked plus-tree seed lot were significantly taller than offspring from average trees. This difference was more pronounced and persistent among dominant trees in the trial. Statistically significant, but practically unimportant, seed lot × spacing interactions were seen in the diameters of stem and branches. More pronounced interactions are expected to exist among for example half-and full-sib progenies. Juvenile spacing trials are recommended in forest tree breeding programs as they allow assessment under conditions comparable to those in older trials.
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LIU, M. F., i M. MAKARECHIAN. "COMPARISON OF PHENOTYPIC VARIATION WITHIN PATERNAL HALF SIB FAMILIES FOR WEANING WEIGHT IN A PUREBRED AND A SYNTHETIC BEEF CATTLE POPULATION". Canadian Journal of Animal Science 70, nr 2 (1.06.1990): 703–6. http://dx.doi.org/10.4141/cjas90-083.
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Records of 1487 adjusted weaning weights expressed as deviations from year means in a multibreed Beef Synthetic and a purebred Hereford population raised and managed together under the same selection program from 1968 to 1978 were used to examine the behavior of the phenotypic variation within sire families in the two populations and to further test the conventional common error variance assumption imposed on a sire model. The results indicated that on the average there was no difference in the phenotypic variation within sire families between the purebred and the synthetic populations. Within-sire standard deviations in the two populations were also normally and similarly distributed. Within-sire variances were not heterogeneous. The results suggested that the conventional common error variance assumption imposed on a sire model would be a reasonable approximation applicable to the two populations of different origins. Key words: Beef cattle, variation among half-sibs, weaning weight
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Fu, Yong-Bi, G. Peter Y. Clarke, Gene Namkoong i Alvin D. Yanchuk. "Incomplete block designs for genetic testing: statistical efficiencies of estimating family means". Canadian Journal of Forest Research 28, nr 7 (1.07.1998): 977–86. http://dx.doi.org/10.1139/x98-072.
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A half-sib progeny trial with single-tree plots on one test site of various environmental variations is simulated to examine the relative statistical efficiencies of randomized incomplete block designs (ICBs) over their corresponding randomized complete block design (RCB) in estimating family means. The ICBs with full constraint (FC), half constraint (HC), and no constraint (NC) over replicates and an alpha design (Alpha) are considered. A geostatistical spatial model is employed, which allows specifications of patchy and systematic environmental variations across the test site and estimations of block and error components with SAS PROC MIXED. The simulation shows that Alpha is the most efficient ICB in the 21 scenarios of patchy and systematic site variations, followed by NC and HC, and these ICBs (except FC) are generally more efficient than RCB in terms of the average variance of a family mean contrast. The gains in statistical efficiencies with implementations of Alpha and NC (rather than RCB) in forest genetic testing can be high, depending largely on the nature (and level) of spatial environmental variation. Practical implications of these simulated results for forest genetic trials are discussed.
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Boujenane, I., i M. Kerfal. "Estimates of genetic and phenotypic parameters for growth traits of D'Man lambs". Animal Science 51, nr 1 (sierpień 1990): 173–78. http://dx.doi.org/10.1017/s0003356100005274.
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ABSTRACTThe heritability of growth traits from birth to 6 months of age and the genetic and phenotypic correlations among them were determined from paternal half-sib analyses of 1689 records of D'man lambs. Heritability estimates were 0·34 (s.e. 0·08), 0·23 (s.e. 0·06), 0·52 (s.e. 0·10) and 0·43 (s.e. 0·09) for weights at birth, 30 days, 90 days and 180 days, respectively. Heritabilities for average daily gains from birth to 30 days and from 30 to 90 days were estimated to be 0·12 (s.e. 0·05) and 0·56 (s.e. 0·11), respectively. Genetic and phenotypic correlations among growth traits were all positive and of high magnitude. The former estimates varied from 0·66 to 0·98, the latter estimates ranged from 0·23 to 0·92. Selection for high weight at 90 days would be expected to have large effect on other growth traits as a result of their large positive genetic correlations.
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Apostol, Ecaterina, i Marius Budeanu. "Adaptability of Narrow-Crowned Norway Spruce Ideotype (Picea abies (L.) Karst. pendula Form) in 25 Years Half-Sib Comparative Trials in the Eastern Carpathians". Forests 10, nr 5 (6.05.2019): 395. http://dx.doi.org/10.3390/f10050395.
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This study analysed the stability of the narrow-crowned Norway spruce (pendula form) compared with the classic form of spruce (pyramidalis form) in two half-sib field trials located in the Romanian Carpathians. From eight natural populations, representative of three of the four large spruce spread areas in Romania, open-pollinated seeds from 48 trees (24 pendula ideotype and 24 pyramidalis form) were collected to install the Maneciu and Soveja trials. In these trials, at age 25 years, measurements were performed for the following traits: tree height, breast height diameter, crown diameter, number of branches per whorl and dominant branch diameter. Some important traits were calculated: average volume per tree, trees’ slenderness, crown slenderness and branches’ finesse. Pearson’s simple correlations between the analysed traits were calculated and also the correlations between traits and geographic and climatic gradients of provenances’ origin. In addition, cores were collected to compare the wood density of the two forms of spruce. In both trials, but especially in the limitative environmental conditions of the Soveja trial, the narrow crowned form of Norway spruce (Picea abies f. pendula) presented more favourable average results than the normal crown spruce form for the most important stand stability traits: trees’ slenderness, wood density, branches’ diameter and branches’ finesse. Between spruce crown forms, in both trials, no significant differences were observed for the growth traits, but between trials, higher results resulted in optimal environmental conditions of the Măneciu test (+89% for the trees’ volume). The trees from different provenances and with specific forms of the crown reacted differently to the changing of the testing site, which required the adoption of maximum caution for decisions regarding the transfer of forest reproductive materials. The correlations between the analysed traits converge towards the adoption of a two-step breeding strategy, starting by selection of narrow crowned trees after stability traits.
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Besliu, Emanuel, Marius Budeanu, Ecaterina Nicoleta Apostol i Raul Gheorghe Radu. "Microenvironment Impact on Survival Rate, Growth and Stability Traits, in a Half-Sib Test of Pendula and Pyramidalis Varieties of Norway Spruce". Forests 13, nr 10 (14.10.2022): 1691. http://dx.doi.org/10.3390/f13101691.
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Norway spruce (Picea abies) is a tree species with low resistance to wind storms and breakage from snow. In this study, we analyzed the microenvironmental impact on the survival rate (Sr), growth, and stability traits of 25-year-old narrow (pendula)- and normal-crowned (pyramidalis) spruce varieties in the Măneciu half-sib trial. The replication factor had a highly significant influence (p < 0.001) on the growth and stability traits and a significant influence (p < 0.05) on the Sr, which confirms the microenvironmental impact. The average Sr was 85% and was 5% higher for the pendula variety (p < 0.05). For normal-crowned trees, a negative correlation (r = −0.26***) between the crown diameter and Sr was found, while for pendula trees, the correlations were 31% lower, suggesting the pendula variety’s high adaptation potential to a denser planting scheme. The edge effect affected the Sr of both varieties almost equally, with a 3% superiority for pendula. The Sr variations in relation to the slope position indicated that the narrow-crowned variety was less affected by the slope position, while the normal variety showed significant slope variation. The pendula variety of Norway spruce could be promoted in afforestation because of its high adaptation plasticity to a denser planting scheme.
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Mussmann, S. M., M. R. Douglas, W. J. B. Anthonysamy, M. A. Davis, S. A. Simpson, W. Louis i M. E. Douglas. "Genetic rescue, the greater prairie chicken and the problem of conservation reliance in the Anthropocene". Royal Society Open Science 4, nr 2 (luty 2017): 160736. http://dx.doi.org/10.1098/rsos.160736.
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A central question in conservation is how best to manage biodiversity, despite human domination of global processes (= Anthropocene). Common responses (i.e. translocations, genetic rescue) forestall potential extirpations, yet have an uncertain duration. A textbook example is the greater prairie chicken (GRPC: Tympanuchus cupido pinnatus ), where translocations (1992–1998) seemingly rescued genetically depauperate Illinois populations. We re-evaluated this situation after two decades by genotyping 21 microsatellite loci from 1831 shed feathers across six leks in two counties over 4 years (2010–2013). Low migration rates (less than 1%) established each county as demographically independent, but with declining-population estimates (4 year average N = 79). Leks were genetically similar and significantly bottlenecked, with low effective population sizes (average N e = 13.1; 4 year N e / N = 0.166). Genetic structure was defined by 12 significantly different family groups, with relatedness r = 0.31 > half-sib r = 0.25. Average heterozygosity, indicating short-term survival, did not differ among contemporary, pre- and post-translocated populations, whereas allelic diversity did. Our results, the natural history of GRPC (i.e. few leks, male dominance hierarchies) and its controlled immigration suggest demographic expansion rather than genetic rescue. Legal protection under the endangered species act (ESA) may enhance recovery, but could exacerbate political–economic concerns on how best to manage ‘conservation-reliant’ species, for which GRPC is now an exemplar.
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Bian, Liming, Jisen Shi, Renhua Zheng, Jinhui Chen i Harry X. Wu. "Genetic parameters and genotype–environment interactions of Chinese fir (Cunninghamia lanceolata) in Fujian Province". Canadian Journal of Forest Research 44, nr 6 (czerwiec 2014): 582–92. http://dx.doi.org/10.1139/cjfr-2013-0427.
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Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is the most commercially important conifer in China, and the Nanjing Forestry University – Fujian Province Chinese fir Cooperation (NJFU – Fujian Cooperation) breeding program has advanced it into the third cycle of selection and breeding. In this paper, we estimated genetic parameters from four sites for 80 half-sib families and summarized previous estimates of genetic parameters in Chinese fir with an objective to propose optimal breeding strategy. Heritability averaged 0.20 and 0.14 for height and diameter at breast height (DBH), respectively, for the four sites. A significant genotype–environment interaction (G × E) for growth was also observed among the four sites, with the greatest interactions between a marginal site and the three central sites in the Fujian Province Chinese fir plantation region. The average estimated type-B genetic correlation between the marginal site and the three central sites was 0.08 for height and –0.09 for DBH. However, the highly productive families were among the most stable across the four sites. The results from this study in combination with summarized genetic parameters from literature were used to discuss and propose an optimal breeding strategy for the third generation of the breeding program for Chinese firs in Fujian Province.
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Waldron, Blair L., Kevin B. Jensen, Michael D. Peel i Valentin D. Picasso. "Breeding for Resilience to Water Deficit and Its Predicted Effect on Forage Mass in Tall Fescue". Agronomy 11, nr 11 (20.10.2021): 2094. http://dx.doi.org/10.3390/agronomy11112094.
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Resilience is increasingly part of the discussion on climate change, yet there is a lack of breeding for resilience per se. This experiment examined the genetic parameters of a novel, direct measure of resilience to water deficit in tall fescue (Lolium arundinaceum (Schreb.) Darbysh.). Heritability, genetic correlations, and predicted gain from selection were estimated for average productivity, resilience, and stability based on forage mass of a tall fescue half-sib population grown under a line-source irrigation system with five different water levels (WL). Resilience was both measurable and moderately heritable (h2 = 0.43), with gains of 2.7 to 3.1% per cycle of selection predicted. Furthermore, resilience was not correlated with average response over environments and negatively correlated with stability, indicating that it was not a measure of responsiveness to more favorable environments. Genetic correlations among WL ranged from 0.87 to 0.56, however in contrast, resilience was either not or slightly negatively genetically correlated with WL except for moderate correlations with the ‘crisis’ WL. Thus, breeding for improved resilience was predicted to have little effect on forage mass at any given individual water deficit environment. Overall, results indicated that this novel metric could facilitate breeding for improved resilience per se to water deficit environments.
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Wehner, Todd C. "446 PB 259 GAIN FROM RECURRENT SELECTION IN FOUR FRESH-MARKET CUCUMBER POPULATIONS". HortScience 29, nr 5 (maj 1994): 495b—495. http://dx.doi.org/10.21273/hortsci.29.5.495b.
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Several major traits (yield, earliness, quality) of interest to cucumber (Cucumis sativus L.) breeders are quantitatively inherited. The objective of this study was to determine the progress made on such traits using recurrent selection in 4 fresh-market cucumber populations (NCWBS, NCMBS, NCES1, NCBA1). During population improvement, 1 to 2 replications of 200 to 335 half-sib families were evaluated for 5 traits: total, early and marketable fruits per plot, a quality rating, and a simple weighted index (=.2Total/2 + .3Early + .2%Marketable/10 + .3Quality). Families from each population were intercrossed in an isolation block during each summer using remnant seeds of the best 10% selected using the index. Progress was evaluated using a split-plot treatment arrangement in a randomized complete block design with 32 replications in each of 2 seasons (spring and summer). Whole plots were the 4 populations, and subplots were the 11 cycles (cycles 0-9 plus checks). Greatest gains were made for the NCBA1 population, with an average of 45% gain from cycle 0 to 9 over the 5 traits, and for early yield, with an average of 58% gain from cycle 0 to 9 over the 4 populations. Populations were improved for performance in a selected (spring season) as well as a non-selected environment (summer season).
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Laviola, Bruno Galvêas, Alexandre Alonso Alves, Fábio de Lima Gurgel, Tatiana Barbosa Rosado, Rodrigo Barros Rocha i Julio Cesar Albrecht. "Estimates of genetic parameters for physic nut traits based in the germplasm two years evaluation". Ciência Rural 42, nr 3 (marzec 2012): 429–35. http://dx.doi.org/10.1590/s0103-84782012000300008.
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In spite of increasingly widespread interest in planting physic nut, breeding efforts are still in its infancy. In that context, an important resource recently established aiming future breeding efforts was the assembly of a germplasm bank with near 200 accessions. The objective of this study was to estimate genetic parameters, repeatibility coefficients and genetic correlation between seven traits, measured in 110 accessions (half sib families) of this germplasm bank in different stages of development. The results show that higher relative values of additive variance were only found for yield and height, and the existence of low environmental variation (either of temporary or permanent nature) among plots within blocks. Given the high repeatibility values found for all traits, on average three measurements are necessary to predict, accurately and efficiently, the true breeding value of an individual. Based on the results of genetic correlations, breeding effort should initially be use track trees with increased stem diameter, elevated number of branches and canopy volume so as to increase the chances of finding an exceptionally highly productive tree.
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Wehner, Todd C., Richard L. Lower, Jack E. Staub i Greg E. Tolla. "Convergent-Divergent Selection for Cucumber Fruit Yield". HortScience 24, nr 4 (sierpień 1989): 667–69. http://dx.doi.org/10.21273/hortsci.24.4.667.
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Abstract A heterogeneous cucumber (Cucumis sativus L.) population (mostly gynoecious) was evaluated at five locations for single-plant fruit yield at the mature-fruit stage in 1981. Seeds from the highest-yielding plants were then harvested, combined, and partitioned into five lots. Seeds were combined such that each location received only the superior genotypes from the other four locations. This procedure was continued for an additional four cycles using two types of selection: single-plant selection for fruit number at the mature-fruit stage (1981–82) and half-sib family selection at the once-over harvest stage (1983–84). In 1985, yield improvement from selection was measured by compositing the seeds of the selected plants or families from each of the four cycles and five locations and planting them at the five locations. No progress was made for total, marketable, or early yield. Percentage of culls was reduced an average of 0.7% per cycle. Genotype by environment interaction among the diverse locations may have prevented progress for yield.
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Visser, C., i E. van Marle-Koster. "Genetic variation of the reference population for quantitative trait loci research in South African Angora goats". Animal Genetic Resources Information 45 (październik 2009): 113–19. http://dx.doi.org/10.1017/s1014233909990435.
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SummaryThe South African Angora goat industry makes the largest contribution to global mohair production. Mohair is a luxury fibre and production of a high quality clip is essential. For many years genetic improvement of Angoras in South Africa was based on quantitative selection. Genome mapping efforts provided new avenues for improvement and a quantitative trait loci (QTL) study was initiated to identify QTL associated with mohair traits. The aim of this study was to describe the genetic diversity of the reference population using the available stud and commercial herds with full phenotypic records. The most appropriate QTL design was identified based on the population structure with regard to the families and number of bucks available for breeding. Four herds, consisting of 1067 pure bred goats in 12 half-sib families, were included. Blood samples were obtained from the herds, 94 markers were tested and diversity parameters were estimated. The average number of alleles per marker varied between 5.4 and 7.2 amongst the herds, whereas the observed heterozygosity varied between 0.59 and 0.67. The genetic structure of these herds was found appropriate for use as a reference population as they showed sufficient genetic variability.
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Liu, Guangjin, Zuwei Tian, Hongyan Jia, Wenhui Shen, Zuhe Li, Li Tang, Hongpeng Zhao i Jianmin Xu. "Genetic Parameter Estimates for the Growth and Morphological Traits of Castanopsis hystrix Families and the Genotype × Environment Interaction Effects". Forests 14, nr 8 (11.08.2023): 1619. http://dx.doi.org/10.3390/f14081619.
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Castanopsis hystrix, a timber resource from Southeast Asia, is characterized by rapid growth and high yield, but plantation quality and efficiency improvements are required. Twenty-year-old C. hystrix experimental forests in Yulin, Liuzhou, and Pingxiang in Guangxi Province, China, comprising 21 open-pollinated half-sib families, were used in this study. Genetic variations in the growth (tree height, diameter at breast height (DBH), and volume (V)) and morphological (height to live crown base (HCB), crown width (CW), and branch angle) traits were assessed, and the genetic parameters were estimated to clarify the genotype × environment interaction effects. The average values for the tree height, DBH, V, HCB, CW, and branch angle were 16.33 m, 17.25 cm, 0.21 m3, 6.68 m, 2.15 m, and 45.45°, respectively. The most important sources of variance for the tree height, DBH, V, and HCB were the block and family, whereas the location, family, and family × location had significant impacts on the tree height, DBH, V, and HCB (p < 0.01). The family heritability for each trait was 0.35, 0.38, 0.62, and 0.19, respectively. Excellent families with strong adaptability and genetic stability were identified using BLUP–GGE biplots for single and multiple traits. The results provide a theoretical basis for the efficient cultivation of C. hystrix in South China.
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Azizi, Ahmad, Mahmood Maniati, Hadis Ghanbari-Adivi, Zeinab Aghajari, Sedigheh Hashemi, Bahareh Hajipoor, Asma Rabiee Qolami, Maryam Qolami i Amirabbas Azizi. "Usability Evaluation of Hospital Information System According to Heuristic Evaluation". Frontiers in Health Informatics 10, nr 1 (26.03.2021): 69. http://dx.doi.org/10.30699/fhi.v10i1.271.
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Introduction: There are various applications and health information systems which have been developed to promote the effective retrieval of patient information, statistics, research, and education. Therefore, there is a need to design them in consistency with scientific principles of usability. To this end, the usability of hospital information sub-systems employed at the hospitals of Ahvaz were compared using heuristic evaluation method. The objective of the study was to assess the usability of hospital information system according to heuristic evaluation.Material and Methods: Six trained evaluators, independently determined the ADT subsystem, HIM subsystem, and NIS according to Nielsen’s 10 Heuristic Principles. Since more than half of the hospitals (about 54%) employed Sib application, no specific sampling method was used. After combining the usability problems, the average severity ratings of the problems were calculated, and then the subsystems were compared.Results: The number of the usability problems of the ADT information subsystem, HIM subsystem, and NIS were 40, 39, and 37, respectively. After merging the problems, the features of “user control and freedom” with 20 cases and “flexibility and efficiency of use” with six cases had the highest and the lowest inconsistencies with usability principles. The average severity ratings of the problems also varied between 1.7 and 3.Conclusion: Heuristic evaluation method is regarded as one of the approaches appropriate to identify usability problems in health information systems. Thus, it is advisable to utilize this method to modify the design of the systems and to improve their efficiency before their implementation in order to increase user satisfaction.
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Wehner, Todd C., i Christopher S. Cramer. "Ten Cycles of Recurrent Selection for Fruit Yield, Earliness, and Quality in Three Slicing Cucumber Populations". Journal of the American Society for Horticultural Science 121, nr 3 (maj 1996): 362–66. http://dx.doi.org/10.21273/jashs.121.3.362.
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Fruit yield, earliness, and quality have low to moderate heritability, but are traits of major importance in cucumber (Cucumis sativus L.). The objective of this study was to determine the changes made in those traits using recurrent selection in three slicing cucumber populations (NCMBS, NCES1, and NCBA1). During population improvement, one or two replications of 200 to 335 half-sib families were evaluated in the spring season for five traits: total, early, and marketable fruit per plot, fruit shape rating, and a simple weighted index (SWI = 0.2(total yield)/2 + 0.3(early yield) + 0.2(% marketable)/10 + 0.3(fruit shape). Families from each population were intercrossed in an isolation block during the summer season using remnant seeds of the best 10% selected using the index. Response was evaluated using a split-plot treatment arrangement in a randomized complete block design with 32 replications in each of two seasons (spring and summer). Whole plots were the three populations, and subplots were the 11 cycles (cycles 0 to 9 plus checks). We measured improvement in performance of the populations in a selected (spring) and unselected environment (summer). Significant gains were made for all traits in all populations over the 9 to 10 cycles of recurrent selection. Greatest progress was made for the NCMBS population, with an average of 37% gain from cycle 0 to 9 over all five traits. The trait where most progress was made was early yield, with an average of 63% gain from cycle 0 to 9 over the three populations.
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Mrode, R. A., i B. W. Kennedy. "Genetic variation in measures of food efficiency in pigs and their genetic relationships with growth rate and backfat". Animal Science 56, nr 2 (kwiecień 1993): 225–32. http://dx.doi.org/10.1017/s0003356100021309.
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AbstractData on 3783 Yorkshire, 2842 Landrace and 937 Duroc littermate pairs of boars, station tested between 1976 and 1989, were used to measure genetic parameters of average daily gain (ADG) from 30 to 90 kg, live backfat at 90 kg (BF), estimated lean growth rate (LGR), average daily food intake, food conversion ratio (FCR) and lean food conversion ratio (LFCR), as well as measures of residual daily food intakes over and above requirements for growth and lean growth. A method was developed to obtain restricted maximum likelihood estimates of genetic variances and covariances under an animal model when observations are on the means of sib pairs. Heritabilities of ADG, BF, LGR, FCR and LFCR were 0·43, 0·59, 0·39, 0·28 and 0·34, respectively. Heritability of daily food intake was 0·45, and heritability of measures of residual daily food intake ranged from 0·30 to 0·38. About half of the variation in daily food intake was residual (0·48 to 0·56). Genetic correlations of ADG with daily food intake, FCR and LFCR were 0·80, −0·28 and −0·09, respectively, and were small and positive (0·18 to 0·34) with measures of residual daily food intake. Backfat had genetic correlations of 0·42, 0·24 and 0·52 with daily food intake, FCR and LFCR, respectively, and genetic correlations between backfat and measures of residual daily food intake ranged from 0·15 to 0·61. Selection against residual food intake may be a useful means of improving efficiency of food utilization.
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De Moraes, Pedro L. R., Reinaldo Monteiro i Roland Vencovsky. "Genetic differentiation and diversity of natural populations of Cryptocarya spp. (Lauraceae) from the Brazilian Atlantic rain forest". Lundiana: International Journal of Biodiversity 3, nr 2 (1.06.2002): 99–109. http://dx.doi.org/10.35699/2675-5327.2002.21803.
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The genetic variability and structure of ten populations of Cryptocarya spp. (Lauraceae) were investigated by means of isozymes. Leaf samples of adult individuals of C. aschersoniana, C. moschata, and Cryptocarya sp., from two regions of São Paulo state, Brazil, were collected. Seeds from 35 families of C. moschata and juveniles of three populations from diaspores dispersed by “muriquis”, Brachyteles arachnoides (Primates - Cebidae), were also collected. From twenty loci analysed, the expected average heterozygosity of progenies, juveniles, and adults of C. moschata was respectively 0.313, 0.227, and 0.351, whereas it was 0.258 and 0.393 for C. aschersoniana and Cryptocarya sp., respectively. Results indicated that a greater variability occurred within populations for all categories analysed. For adult populations of C. moschata, the divergence obtained through GST estimates suggests the existence of significant genetic drift and/or natural selection effects between regions. The level of gene differentiation (GST = 0.107) was relatively high, and comparable to what would be expected for groups of plants having a half-sib family structure in a single generation. For juvenile populations, the genetic differentiation was also high (GST = 0.084). This could be explained by differential feeding behaviour of “muriquis” within their home range, allied to the distance among sites of seed dispersion. Nei’s average genetic distance (D) between pairs of C. moschata adult populations was 0.07, indicating again a pronounced genetic differentiation. Present values obtained from isozymes support morphological and wood anatomy evidences that C. moschata and C. aschersoniana are closely related species.
Keywords: Cryptocarya aschersoniana, C. moschata, Genetic distance, Genetic structure, Genetic variability, Population differentiation, Lauraceae
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Mudawamah, Mudawamah, M. Z. Anwar i Sumartono Sumartono. "Estimation of Repeatability and Most Probable Producing Ability (MPPA) of Sapudi Sheep Based on Daily Body Weight Gain of Lambs from Birth to Pre-weaning and Weaning". Jurnal Sain Peternakan Indonesia 17, nr 3 (29.09.2022): 149–54. http://dx.doi.org/10.31186/jspi.id.17.3.149-154.
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This research aimed to estimate the repeatability and MPPA values of Sapudi ewes based on the lamb’s daily gain from birth to pre-weaning and weaning. Using recorded data in a pedigree of lamb, 53 data with half-sib relationship came from 14 ewes which included the record of body weight gain of Sapudi lambs from birth to pre-weaning and weaning. The data were analyzed by descriptive method with a quantitative approach. The study showed that the average daily gain of pre-weaning and weaning was 007 kg/day. The repeatability value of pre-weaning and weaning daily gain was 0.636 in the high category and 0.377 in the medium category. The MPPA daily gain values for pre-weaning and weaning ranged from -0.032 to 0.018 and -0.016 to 0.009. The research concluded that the Sapudi sheep ewes based on the MPPA daily gain pre-weaning were six heads with four rankings, while the daily weight gain weaning was ten heads with ranking of five. The highest rank of Sapudi ewes in pre-weaning and weaning daily gain was ear tag 094 with MPPA values of 0.018 and 0.009. It is recommended that further research can be conducted to estimate the repeatability value of quantitative periodically as the basis for the selection and culling of livestock.
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Atkins, KD, JI Murray, AR Gilmour i AL Luff. "Genetic variation in liveweight and ultrasonic fat depth in Australian Poll Dorset sheep". Australian Journal of Agricultural Research 42, nr 4 (1991): 629. http://dx.doi.org/10.1071/ar9910629.
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Genetic and phenotypic variances and covariances were estimated for liveweight and ultrasonic fat depth in the Australian Poll Dorset. The data were obtained from the New South Wales Meatsheep Testing Service between 1983 and 1986, and involved 28 159 records from 50 stud flocks. A total of 681 sires were used to derive the half-sib genetic parameters. The data were further grouped according to average age at measurement, so that parameters were estimated for animals within age ranges of 4-6 months, 7-11 months and 12-16 months. Heritabilities for liveweight were between 0.21 and 0.31, with the highest value obtained in the oldest age group. Heritabilities for fat depth varied between 0.26 and 0.31, with the highest value again obtained in the oldest age group. Genetic correlations between liveweight and fat depth were about 0.4 except in 4-6-month-old animals where the estimate was about 0.7. The implications of these parameters to breed improvement programmes are discussed. In particular, the scope for genetic response in producing faster growing, leaner animals at a constant liveweight is highlighted. Information on sire-son generation intervals and apparently limited between-flock genetic variation is reported. The results indicate the need to improve the evaluation procedures for sires within the breed at both the between- and within-flock level.
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Ivkovich, Milosh, Gene Namkoong i Mathew Koshy. "Genetic variation in wood properties of interior spruce. II. Tracheid characteristics". Canadian Journal of Forest Research 32, nr 12 (1.12.2002): 2128–39. http://dx.doi.org/10.1139/x02-139.
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In this study we investigated quantitative genetic variation in tracheid characteristics in two genetic tests of British Columbia's interior spruce (the common name for white spruce, Picea glauca (Moench) Voss; Engelmann spruce, Picea engelmanni Parry ex Engelm.; and their hybrids). The study included 88 half-sib families from the East Kootenay and Prince George regions. We have developed a technique for quantitative assessment of tracheid characteristics by measuring cross-sectional dimensions. We obtained cell size, wall thickness and their ratio in early-, transition-, and late-wood classes within a growth ring. Tracheid length and microfibril angle were measured in the transition wood. A number of tracheid characteristics showed significant genetic variation, but heritability, phenotypic, and genetic correlation estimates varied across test sites within and outside regions of origin of parental trees. Ring width was determined, both phenotypically and genetically, by the number of tracheids and to a lesser extent by the by their mean size. On average, rings with larger tracheids did not have significantly thicker walls. Wider rings had lower mean wall to tracheid size ratio. Faster growth did not result in shorter tracheids in the transition wood. Longer tracheids had lower micro fibril angle. There were no particular benefits from considering the anatomical component traits for breaking the negative genetic correlation between growth and wood density.
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Liu, Detuan, Jiajun Yang, Lidan Tao, Yongpeng Ma i Weibang Sun. "Seed Germination and Seedling Growth Influenced by Genetic Features and Drought Tolerance in a Critically Endangered Maple". Plants 12, nr 17 (31.08.2023): 3140. http://dx.doi.org/10.3390/plants12173140.
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Understanding the adaptation of plant species will help us develop effective breeding programs, guide the collection of germplasm, and improve the success of population restoration projects for threatened species. Genetic features correlate with species adaptation. Acer yangbiense is a critically endangered plant species with extremely small populations (PSESP). However, no information was available on its seed germination and seedling growth in populations with different genetic characteristics. In this study, we investigated seed germination and compared the performance of 566 seedlings in 10 maternal half-sib families cultivated in Kunming Botanical Garden. The results showed that A. yangbiense seeds required an average of 44 days to start germinating, with a 50% germination rate estimated to take about 47–76 days, indicating slow and irregular germination. There is a trade-off between the growth and survival in A. yangbiense seedlings, with fast growth coming at the cost of low survival. Groups that were able to recover from a recent bottleneck consistently had higher relative growth rates. High genetic diversity and low levels of inbreeding are likely to be responsible for their improved survival during drought conditions and rapid growth under optimal environmental conditions. Our results suggest that maternal genetic traits might be used as indicators for conservation and population restoration. These findings provide us with new information that could be applied to support ex situ conservation and reintroduction of threatened species.
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Li, Weijian, Rongyang Li, Yinghui Wei, Xueqing Meng, Binbin Wang, Zengkai Zhang, Wangjun Wu i Honglin Liu. "Effect of MSTN Mutation on Growth and Carcass Performance in Duroc × Meishan Hybrid Population". Animals 10, nr 6 (28.05.2020): 932. http://dx.doi.org/10.3390/ani10060932.
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The Meishan pig is a traditional Chinese native breed, known for its excellent reproduction performance that is widely used in commercial pig production through two-way or three-way crossbreeding systems. However, the lean meat yield of Meishan crossbred pigs is still very low and cannot meet the market demand. To evaluate the lean meat yield of Meishan crossbred pigs, six wild-type Meishan sows were artificially inseminated by using the MSTN+/− Duroc boar semen in this experiment. Some reproductive performance-related traits of Meishan sows were recorded to ensure that semen from MSTN knockout Duroc boar did not affect offspring production, including total births, live births, sex, and litter weight. In total, 73 piglets were obtained and 63 were alive. Male to female ratio was close to 1: 1. because of factors such as disease, only 43 pigs were utilized, including 28 MSTN mutant pigs (MSTN+/−) and 15 MSTN homozygous pigs (MSTN+/+). We compared the growth performance and carcass performance of these full or half-sib populations and found that there were no differences between MSTN+/− and MSTN+/+ genotypes for live animal measures including average daily gain (ADG), body dimensions, or ultrasonic measurement of fat thickness when pigs were harvested after 120 days of feeding. Conversely, the MSTN+/− pigs had higher dressing percentage and lean meat percentage, lower level of carcass fat, larger longissimus muscle area, less percentage of skin and skeleton, thinner average backfat thickness, and lower intramuscular fat (IMF) content than MSTN+/+ pigs. In conclusion, the production of MSTN+/− mutant progeny from Meishan females resulted in improved carcass composition, providing a feasible solution to improve the lean meat yield of Chinese local fat-type pig breeds.
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Suhada, Hary, Sumadi (Sumadi) i Nono Ngadiyono. "Estimasi Parameter Genetik Sifat Produksi Sapi Simmental di Balai Pembibitan Ternak Unggul Sapi Potong Padang Mengatas, Sumatera Barat (Estimation of Genetic Parameters of Production Characteristics on Simmental Cattle at Balai Pembibitan Ternak Unggulan". Buletin Peternakan 33, nr 1 (23.02.2012): 1. http://dx.doi.org/10.21059/buletinpeternak.v33i1.127.
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<p>The objectives of this research were to estimate the genetic parameters of production characteristics, breeding value (BV), weaning weight ratio (WWR) correlation with BV and most probable producing ability (MPPA) of Simmental cattle reared at Balai Pembibitan Ternak Unggul Sapi Potong Padang Mengatas. Research was based on records of birth weight (BW), weaning weight (WW), post weaning average daily gain (ADG) and yearling weight (YW) from 2002 to 2007. Heritability value (h2) was estimated for BV, WW, ADG and YW using paternal-half sib correlation and repeatability value (r) of characteristics of both using intra class correlation. The genetic correlation (rG) of BW-WW, WW-YW, WW-ADG, WW-YW, WW-ADG and YW-ADG were analyzed by variance and covariance. BV and MPPA estimation was base on record of weaning weight. The h2 value of BW, WW, YW and ADG were 0.11±0.09; 0.39±0.16; 0.43±0.19; and 0.46±0.20, respectively. The r of BW, WW, YW and ADG, were 0.25±0.16; 0.32±0.18; 0.25±0.22; and 0.34±0.16, respectively. The genetic correlation value of BW-WW, WW-YW, WW-ADG, WW-YW, WW-ADG and YW-ADG were 0.29±0.37; 0.46±0.33; 0.2 ±0.39; 0.68±0.16; 0.006±0.30 and 0.57±0.21, respectively. From 18 Bulls, 10 bulls (55.56%) had the BV higher then average population value, 142.21 kg and the remaining 8 bulls (44.44%) was lower then average population value. Frequency of the BV of prospective male and female with WW higher than WW average was 210 calves (44.68%); whereas, 260 calves (55.32%) had WW lower than average population corrected with parent age (130.21 kg). Range of absolute BV was from 112.77 kg to 155.91 kg. The BV of male had average frequency higher than that of female, i.e. 149 males (66.22%) compared to 61 female (24.90%). The MPPA with above the average WW of the population was 150 cows (41.67%) and the rest of cows (210 head or 58.33%) were under the<br />average. The WWR had positive and significant correlation (1.00**) with the NP. It means that, if the cattle have a high WWR, they will also have a high NP, so that they can be used as the criteria of selection.</p><p>(Key words: Simmental cattle, Genetic parameters, Breeding value, Most probable producing ability, Weaning weight ratio)<br /><br /></p>
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Souza, Ana Raquel Ribeiro e., Glauco Vieira Miranda, Messias Gonzaga Pereira i Leandro Vagno de Souza. "Predicting the genetic gain in the Brazilian white maize landrace". Ciência Rural 39, nr 1 (luty 2009): 19–24. http://dx.doi.org/10.1590/s0103-84782009000100004.
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The objectives of this research were to evaluate the genetic variability and predict genetic gain in the white maize landrace rescued in Barbacena, Minas Gerais, Brazil. The Brazilian maize landraces have economic and social importance for certain areas in Brazil, and research on this germplasm is very important for local food security. Three experiments were carried out with 100 half-sib progenies, in Campos dos Goytacazes, RJ, Coimbra and Barbacena, Minas Gerais, Brazil. These sites were chosen for their soil and climatic differences. An analysis of variance was significant among the progeny for all characters, indicating the presence of genetic variability between the three populations. In Campos dos Goytacazes and Coimbra, the genetic variation of the white maize landrace was responsible for most of the phenotypic variance in grain yield and can be used in selection cycles. There was no significant genetic variance in grain yield in Barbacena. For the white maize landrace it was concluded that: the characters of the component of productivity such as plant density and number of plants with kernels can produce indirect genetic gain for grain yield and are suitable for breeding; prebreeding of the maize landrace is necessary before being used directly in the elite germplasm; the population contains high genetic variability and opportunities for genetic gain; the average agronomic traits are suitable only for traditional production systems with few inputs, and polyculture; the difference between environments produces specific responses in the progeny i.e. there is a progeny x environment interaction.