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1
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.
2
Melo, Dheyne Silva, César Augusto Brasil Pereira Pinto, Leandro Santos Peixouto, Diogo Gonçalves Neder i Josiane Cristina de Assis. "Early selection of full-sib potato families". Ciência e Agrotecnologia 35, nr 6 (grudzień 2011): 1101–9. http://dx.doi.org/10.1590/s1413-70542011000600009.
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Clonal selection is the preferred breeding method used in potatoes (Solanum tuberosum L.). However this selection procedure is only efficient for more advanced generations and shows no good results when applied in the seedling up to the second clonal generation. This study assessed the feasibility of selection in early generations of full-sib potato families and compares the selection method among and within families with the combined selection under different selection intensities. Six experiments were conducted from the first (C1) until the third clonal generation (C3). In C1 a randomized complete block design with four replications of 25 plants was used. In the remaining generations RCB was employed with three replications of 10 plants. Genetic variances were lower between families than within families, for all traits, but the heritabilities between families were almost always larger. The expected gains from selection between and within families were superior to gains from the combined selection in any intensity of selection. The selection of families should have weaker intensity than selection among clones within families. The selection of families was more efficient when based on the average of environments.
3
Mullin, T. J. "Genotype–nitrogen interactions in full-sib seedlings of black spruce". Canadian Journal of Forest Research 15, nr 6 (1.12.1985): 1031–38. http://dx.doi.org/10.1139/x85-167.
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Genotype–environment interactions were investigated in 40 full-sib black spruce (Piceamariana (Mill.) B.S.P.) families grown in a greenhouse for 25 weeks under three levels of nitrogen fertility. Large general combining ability components of variance indicated that much of the genetic variance was additive. Heritability estimates were also high, with narrow-sense heritabilities of 0.35 for 25-week height growth and 0.15 for ovendry weight. Specific combining ability, reciprocal, and maternal effects were negligible for all but very early seed and growth characters. Statistically significant family × nitrogen interaction components were detected for all growth variables. Stability analysis using regression suggested that these interactions were due more to differences in degree of expression of genetic variation than to extreme changes in rank. Generally, the families that ranked in the top 10% at the highest nitrogen level were above average at all other levels.
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Fu, Yong-Bi, Alvin D. Yanchuk i Gene Namkoong. "Incomplete block designs for genetic testing: some practical considerations". Canadian Journal of Forest Research 29, nr 12 (15.12.1999): 1871–78. http://dx.doi.org/10.1139/x99-176.
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Full-sib progeny and clonal trials to evaluate family and clone performance were simulated on a test site with various patterns of environmental variation to examine the effectiveness of randomized incomplete block designs (ICBs) under different design parameters (constant block size, variable block size, block shape and orientation, and family size). Simulations showed that blocks of fixed size 5-20 were effective in removing most site variation in a test with 120 full-sib families of three seedlings per family. Slight variations in block size did not affect the precision of mean estimations much when blocks were considered random. Square blocks were more effective than either column or row blocks in removing both patchy variation and gradients in one direction. With blocks of fixed size 10, increasing family size from 3 to 12 (at the expense of family number, which dropped from 120 to 30) reduced the average variance of family mean contrasts by 75%; most of this reduction (>50%) was achieved at 6 seedlings per family. The differences in precision of mean estimation between full-sib progeny and clonal trials were small with respect to the design parameters and patterns of site variation examined.
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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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Mielenz, N., V. Nurgiartiningsih, M. Schmutz i L. Schüler. "Schätzung von Varianzkomponenten mit Gruppenmittelwerten am Beispiel von Legehennen, gehalten in Gruppenkäfigen". Archives Animal Breeding 46, nr 5 (10.10.2003): 491–98. http://dx.doi.org/10.5194/aab-46-491-2003.
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Abstract. Title of the paper: Estimation of variance components from group mean records of laying hens housed in group cages Two models are presented to estimate variance components if only group mean records are available. The first model accounts for additive genetic relationships and full-sib group effects (SIMIANER and GJERDE, 1991) and the second model contains the additive genetic effects of all animals from one cage by using modified design matrices. Estimates of the genetic parameters were obtained by the MIVQUE-method (RAO, 1971; LAMOTTE, 1973). The variances of the estimated heritabilities were derived from the information matrix. Estimations from individual records and from average records (cage average) were compared in a small application on laying hen data. The analysed trait was single egg weight measured on hens housed in group cages. It could be shown: If cage variance is negligible, than for the estimation of the heritabilities full-sib data can be used successfully. The application of the modified animal model is suggested, because this model can take into account more complex relationships between the animals of one cage.
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Caballero, Armando, Alison M. Etheridge i William G. Hill. "The time of detection of recessive visible genes with non-random mating". Genetical Research 60, nr 3 (grudzień 1992): 201–7. http://dx.doi.org/10.1017/s0016672300030950.
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SummaryExpressions for the probability and average time of detection of a recessive visible gene in populations where there is partial selfing or partial full-sib mating are presented. A small increase in the proportion of inbred matings greatly reduces the average time until detection and increases the proportion detected. Unless the proportion of inbred matings or the population size is very small, the time and proportion detected are approximately independent of the population size.
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Li, Peng, Louis Parrot i Jean Bousquet. "Introduction of black walnut in southern Quebec: evaluation of 21-year-old full-sib families". Canadian Journal of Forest Research 22, nr 8 (1.08.1992): 1201–7. http://dx.doi.org/10.1139/x92-160.
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Black walnut (Juglansnigra L.) was introduced in the Québec City area 110 years ago. In the present study, we investigated performance of five full-sib families from controlled crosses among five selected cold-hardy parent trees of the introduced population. The number of seeds set per pollination bag averaged three, and seed germination was high (90%). At one fertile site close to the original plantation, the families showed normal growth, high survival rate, and good adaptability, as indicated by minimal frost damage. The average height was 3.1 m at 11 years, and 8.7 m at 21 years, reaching the height observed in native stands of black walnut. Therefore, the parent trees and their progenies could be used to produce seed for planting on similar sites. The results of this study demonstrated the importance of cold hardiness when introducing species into the northern temperate climatic zone.
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Maze, Jack, Satindranath Banerjee i Yousry A. El-Kassaby. "Variation in growth rate within and among full-sib families of Douglas-fir (Pseudotsuga menziesii)". Canadian Journal of Botany 67, nr 1 (1.01.1989): 140–45. http://dx.doi.org/10.1139/b89-021.
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Variation in growth rate in the four uppermost lateral branches of seedlings of Pseudotsuga menziesii (Mirb.) Franco was greatest among individuals within full-sib families. These results are consistent with those from other studies on conifers indicating there is much more within- than among-intraspecific group variation. Since these seedlings were grown in a common garden, it is assumed that the among-individual variation has a genetic basis. The greatest growth rate was in seedlings produced by crossing trees that had the highest average increments of growth; the lowest growth rate was in seedlings produced by crossing trees that had the lowest average increments of growth. However, the seedlings with the lowest growth rate were similar to those produced by crosses between trees with high average increments of growth. This implies that phenotypically superior trees, as assessed in a natural situation, do not necessarily produce superior offspring in their second year of growth. The high within-family variation coupled with the ontogenetic events associated with growth rate implies a complex multigenic control of growth rate. The genetic complexity of an apparently simple developmental event such as growth in length implies that evolutionary or developmental models based on a small portion of the genome may be inadequate.
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Beaulieu, J., i M. Bernier-Cardou. "Comparison of early height growth between white spruce seedlings and rooted cuttings". Canadian Journal of Forest Research 36, nr 12 (1.12.2006): 3246–50. http://dx.doi.org/10.1139/x06-170.
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Early height growth of eastern white spruce (Picea glauca (Moench) Voss) rooted cuttings was compared with that of seedlings using annual measurements collected over 5 years in a farm field test replicated on three sites. The experiment included 148 full-sib families obtained from controlled crossings of superior trees selected for a white spruce breeding population in Quebec. Fifteen additional seedlots were used as controls. The average growth rate of seedlings (37.3 cm·year–1) was slightly larger than that of rooted cuttings (36.2 cm·year–1). The yearly growth rate increased over the test period, and it did so at a somewhat higher rate for the seedlings. The relative size of the estimated variance components and the moderate rank correlations of full-sib family height growth features between the two propagule types suggest that tree breeders should favour seedlings over rooted cuttings to rank families for selection purposes, but vegetative propagation would prove useful for bulking up scarce valuable genotypes.
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Kumar, Satish, i D. J. Garrick. "Genetic response to within-family selection using molecular markers in some radiata pine breeding schemes". Canadian Journal of Forest Research 31, nr 5 (1.05.2001): 779–85. http://dx.doi.org/10.1139/x01-009.
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Marker-assisted selection (MAS) provides an opportunity to increase the efficiency of within-family selection in forest tree breeding. Within-family MAS involves selection decisions first made on conventional breeding values and quantitative trait loci (QTL) information used for within-family selection. In this study genetic response obtained by using MAS was compared with conventional methods for three options: "full-sib family forestry," "clonal forestry," and "forward selection for deployment." This comparison was undertaken using stochastic simulation for a locus that explained 10 or 20% of the genetic variance. In the full-sib family forestry scenario, markers were used to select genotypes (among juvenile individuals in a family) for vegetative propagation. Markers were used to preselect genotypes for clonal testing in clonal forestry option. In case of forward selection for deployment option, offspring that have favourable marker haplotype and a superior phenotype were selected from each family. The comparison between the MAS and the conventional strategy was evaluated in genetic terms based on comparison of the average genetic merit of the genotypes used for deployment in production plantations. The relative genetic gain (%) using MAS were found to be 48% and 23% higher compared with conventional strategy for full-sib family forestry and clonal forestry options, respectively. In case of forward selection for deployment option, MAS was generally found to be providing higher genetic gain only when the heritability is low.
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Hawkins, B. J., i M. Stoehr. "Growth, phenology, and cold hardiness of 32 Douglas-fir full-sib families". Canadian Journal of Forest Research 39, nr 10 (październik 2009): 1821–34. http://dx.doi.org/10.1139/x09-092.
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Thirty-two full-sib families of coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) with a range of predicted breeding values were monitored for growth rate, phenology, and cold hardiness over 2 years on two sites to investigate if other traits are being selected when family selection is based on height. Significant differences among families existed in most phenological, growth, and cold-hardiness traits. On average, taller families burst bud later but did not have significantly different growth rates or length of growing period than other families. We found no significant correlations between family date of bud burst and cold hardiness in late spring or between duration of shoot growth or height and autumn freezing damage. Family differences in freezing tolerance were greatest in September and October. In these months, family current-year leaf nitrogen was positively correlated with cold hardiness. Families that were most hardy in the autumn were not the most hardy families in spring. We conclude that, for the studied breeding series, selection based on height does not have a significant impact on cold hardiness. We found no consistent relationships between phenological, growth, or cold-hardiness parameters and final height that could explain family ranking by height. Relationships between grandparent elevation and dates of bud burst and cold hardiness were observed.
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Jones, Grace, Mateusz Liziniewicz, Stergios Adamopoulos i Johan Lindeberg. "Genetic Parameters of Stem and Wood Traits in Full-Sib Silver Birch Families". Forests 12, nr 2 (28.01.2021): 159. http://dx.doi.org/10.3390/f12020159.
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This study investigated heritability of stem and wood traits to improve Swedish silver birch (Betula pendula Roth.) through breeding. Birch is 12% of Sweden’s forest area but mainly used for low value pulp or firewood. This paper applied non-destructive test (NDT) methods, and estimated traits’ heritability (h2), to help breed birch for high value solid wood products. Two trials of 22 families were assessed at age 19 for stem diameter (DBH), stem straightness, rough brown bark height (BH), grain angle (GA), Pilodyn penetration depth (Pilo) and acoustic velocity (AV). X-ray densitometry was performed on a subsample of radial cores taken at 1.3 m from the ground to get an average benchmark density. The h2 values were moderate for GA (0.20 and 0.21) and Pilo (0.53 and 0.48) at the two sites, but the h2 values for AV were low (0.05 and 0.30). There were moderate genotypic correlations between BH and DBH (0.51–0.54). There were low genotypic and phenotypic correlations between NDT measurements and other traits so including NDT in birch breeding efforts should not inadvertently reduce size, stem or wood quality. The high genetic correlations between sites suggest that GA, Pilo and AV values were determined more by genotype than by environment.
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DeBuse, Carolyn J., Douglas V. Shaw i Theodore M. DeJong. "Response to Inbreeding of Seedling Traits in a Prunus domestica L. Breeding Population". Journal of the American Society for Horticultural Science 130, nr 6 (listopad 2005): 904–11. http://dx.doi.org/10.21273/jashs.130.6.904.
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Controlled pollinations were made using 20 elite selections from the University of California, Davis, Prunus domestica (european plum) breeding program as parents. These parents were used to generate 11 self-pollinated progenies with an inbreeding coefficient (F) of 0.5, 10 full-sibling progenies (F = 0.25), and 11 progenies from among nonrelated parents (F = 0). Seven additional progenies were chosen as a random-mating control set within the parental group; progenies in the control set had accumulated a range of current inbreeding coefficients (average F = 0.23) over two to five generations with intervening cycles of selection. Survival percentages were 85, 82, and 74 for the full-sib progeny, control set progeny, and selfed progeny, respectively, relative to nonrelated progeny. Two months after germination the percent decrease in the growth trait means for the selfed progeny compared to the nonrelated progeny ranged from 14% to 30% whereas growth trait means for full-sib progeny decreased from 1% to 9% compared to nonrelated progeny. The percent decrease for growth trait means of the selfed progeny after completing one season of growth in the field (10 months) was similar to that observed after 2 months, ranging from 14% to 28% compared to nonrelated progeny, whereas the decrease in full-sib progeny trait means was somewhat greater, ranging from 6% to 20%. Regression analysis of all growth traits on current-generation rates of inbreeding indicated a significant negative linear relationship (P = 0.0011 to 0.0232). No significant relationships were found between accumulated Fs and growth trait means of the control set progenies and the nonrelated progenies after 2 months in the greenhouse or one season growing in the field, suggesting that selection between breeding cycles decreased inbreeding depression.
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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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Stelzer, H. E., G. S. Foster, V. Shaw i J. B. McRae. "Ten-year growth comparison between rooted cuttings and seedlings of loblolly pine". Canadian Journal of Forest Research 28, nr 1 (1.01.1998): 69–73. http://dx.doi.org/10.1139/x97-193.
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Rooted cuttings and seedlings of loblolly pine (Pinus taeda L.) were established in a central Alabama field trial. Five, full-sib families, with an average number of six clones per family, were evaluated. Mean cutting/seedling height ratios revealed that despite initial differences in size, relative growth rates of both propagule types stabilized and were equal by age 7 years. Through age 10 years, results show virtually no difference in height, diameter at breast height, volume, or stem taper between the rooted cuttings and seedlings.
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Mrdakovic, Marija, Vesna Peric-Mataruga, Larisa Ilijin, Milena Vlahovic, Dajana Todorovic, Vera Nenadovic i Jelica Lazarevic. "Effects of tannic acid on trypsin and leucine aminopeptidase activities in gypsy moth larval midgut". Archives of Biological Sciences 65, nr 4 (2013): 1405–13. http://dx.doi.org/10.2298/abs1304405m.
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The effects of allelochemical stress on genetic variations in the specific activities of gypsy moth digestive enzymes (trypsin and leucine aminopeptidase) and relative midgut mass (indirect measure of food consumption), as well as variability in their plasticity, were investigated in fifth instar gypsy moths originating from two populations with different trophic adaptations (oak and locust-tree forests). Thirty-two full-sib families from the Quercus population and twenty-six full-sib families from the Robinia population were reared on an artificial diet with or without supplementation with tannic acid. Between population differences were observed as higher average specific activity of trypsin and relative midgut mass in larvae from the Robinia population. Significant broad-sense heritabilities were observed for the specific activity of trypsin in the control state, and for specific activity of leucine aminopeptidase in a stressful environment. Significantly lower heritability for relative midgut mass was recorded in larvae from the Robinia population reared under stressful conditions. Significant variability of trypsin plasticity in larvae from both populations and significant variability of leucine aminopeptidase plasticity in larvae from the Robinia population point to the potential for the evolution of enzyme adaptive plastic responses to the presence of stressor. Non-significant across-environment genetic correlations do not represent a constraint for the evolution of enzyme plasticity.
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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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Santiago, E., i A. Caballero. "Effective size of populations under selection." Genetics 139, nr 2 (1.02.1995): 1013–30. http://dx.doi.org/10.1093/genetics/139.2.1013.
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Abstract Equations to approximate the effective size (Ne) of populations under continued selection are obtained that include the possibility of partial full-sib mating and other systems such as assortative mating. The general equation for the case of equal number of sexes and constant number of breeding individuals (N) is Ne = 4N/[2(1 - alpha I) + (Sk2 + 4Q2C2) (1 + alpha I + 2 alpha O)], where Sk2 is the variance of family size due to sampling without selection, C2 is the variance of selective advantages among families (the squared coefficient of variation of the expected number of offspring per family), alpha I is the deviation from Hardy-Weinberg proportions, alpha O is the correlation between genes of male and female parents, and Q2 is the term accounting for the cumulative effect of selection on an inherited trait. This is obtained as Q = 2/[2 - G(1 + r)], where G is the remaining proportion of genetic variance in selected individuals and r is the correlation of the expected selective values of male and female parents. The method is also extended to the general case of different numbers of male and female parents. The predictive value of the formulae is tested under a model of truncation selection with the infinitesimal model of gene effects, where C2 and G are a function of the selection intensity, the heritability and the intraclass correlation of sibs. Under random mating r = alpha I = -1/(N - 1) and alpha O = 0. Under partial full-sib mating with an average proportion beta of full-sib matings per generation, r approximately beta and alpha O approximately alpha I approximately beta/(4 - 3 beta). The prediction equation is compared to other approximations based on the long-term contributions of ancestors to descendants. Finally, based on the approach followed, a system of mating (compensatory mating) is proposed to reduce rates of inbreeding without loss of response in selection programs in which selected individuals from the largest families are mated to those from the smallest families.
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Wilcox, P. L., S. D. Carson, T. E. Richardson, R. D. Ball, G. P. Horgan i P. Carter. "Benefitcost analysis of DNA marker-based selection in progenies of Pinus radiata seed orchard parents". Canadian Journal of Forest Research 31, nr 12 (1.12.2001): 2213–24. http://dx.doi.org/10.1139/x01-144.
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The financial viability of DNA marker-based within-family selection (MBS) compared with full-sib family forestry was evaluated for Pinus radiata Donn. ex D. Don. Two traits were investigated: wood density (WD) and diameter at breast height (DBH, 1.4 m). Assuming 20 biallelic loci of equal additive effect controlling trait variation in 15 unrelated top full-sib families of P. radiata, marginal costs of quantitative trait loci (QTL) detection and selection were estimated based on an average of slightly less than five loci per family. We assumed a program where 10 genotypes per family per year were deployed over a 5-year period, and each replicated 100 000 times via fascicle cuttings methods. Estimated marginal costs were NZ$32 and NZ$72 per 1000 plants for WD and DBH, respectively. Genotyping costs were the single largest component for both traits. Genetic gains were estimated by modifying predicted log volumes (DBH) or proportion of structural-grade timber (WD) with and without pruning. Estimated genetic gains ranged from 3.2 to 3.4%. Net present values (assuming a 9.5% discount rate) ranged from an average of NZ$51 to NZ$621/ha. Results showed that MBS for DBH was more profitable than for WD, despite markedly higher costs of QTL detection. All trait-silviculture combinations showed financial gains with internal rates of return of 9% or greater, even when estimated revenues were decreased 70% from forecast revenues. While this analysis is based on a large number of assumptions, it is robust and the results show that significant financial gains from MBS are possible even when selection is based upon DNA markers linked to a few loci each of relatively small effect.
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Flanagan, Lawrence B., i Kurt H. Johnsen. "Genetic variation in carbon isotope discrimination and its relationship to growth under field conditions in full-sib families of Piceamariana". Canadian Journal of Forest Research 25, nr 1 (1.01.1995): 39–47. http://dx.doi.org/10.1139/x95-005.
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Measurements of the stable carbon isotope composition of leaf tissue were made on Piceamariana (Mill.) B.S.P trees from four full-sib families grown on three different field sites at the Petawawa National Forestry Institute, Ontario, Canada. The four families chosen exhibited genetic variation for growth characteristics. Genetic variation was also observed for carbon isotopic discrimination (Δ) among the families of P. mariana. In addition, a strong correlation occurred between Δ values measured on trees in 1991 and 1992, two years that had very different precipitation and temperature conditions during the growing season, indicating that the ranking of individual trees remained almost constant between years. A strong, negative correlation was observed between average carbon isotope discrimination and average tree height for the four families on the driest, least productive site, as was expected based on leaf photosynthetic characteristics. There was no significant correlation, however, between Δ values and growth on the other two study sites, where productivity was higher.
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Dieters, M. J., T. L. White i G. R. Hodge. "Genetic parameter estimates for volume from fuil-sib tests of slash pine (Pinus elliottii)". Canadian Journal of Forest Research 25, nr 8 (1.08.1995): 1397–408. http://dx.doi.org/10.1139/x95-152.
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Data from 171 full-sib tests of slash pine (Pinuselliottii Engelm. var. elliottii) measured at multiple ages between 4 and 15 years, were used to obtain restricted maximum likelihood (REML) estimates of variance components. These tests included over 2100 full-sib families, from more than 700 first-generation parents, represented by some 170 000 individuals. Analyses were completed of each test, and using standardized data, of all possible pairs of connected tests (tests with five or more common parents). Heritability, proportion of dominance variance, type B genetic correlations (which examine genotype × environment interactions), and age-age genetic correlations were estimated from the REML variance component estimates. The average heritability of volume was 0.07 at 5 years, which increased to 0.12 at 11 and 14 years of age. These heritability estimates are similar to, though slightly smaller than, previous estimates obtained from open-pollinated tests. There was approximately 1.6 times as much additive variance as dominance variance at 5 years of age, increasing to more than 2 times at 11 or more years of age. Although the relative importance of dominance variance in tree volume apparently declines with age, the existence of dominance variance may warrant some changes to the current breeding strategy. Estimates of type B genetic correlations increased from around 0.6 at 5 years to over 0.8 at 14 years, and so the importance of genotype × environment interaction appears to decline with age. These estimates of type B genetic correlations and also the estimates of age-age genetic correlations are similar to estimates from open-pollinated tests.
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Dean, C. A., D. E. Welty i G. E. Herold. "Performance and Genetic Parameters of Somatic and Zygotic Progenies of Coastal Douglas-fir at 71/2-Years across Washington and Oregon, USA". Silvae Genetica 58, nr 1-6 (1.12.2009): 212–19. http://dx.doi.org/10.1515/sg-2009-0027.
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Abstract Five genetic tests involving 37 somatic clones of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were planted March 2000 in Weyerhaeuser plantations across western Washington and Oregon States, USA. Four of the tests are in Longview, Twin Harbors and Vail regions of Washington, and one test is in Springfield, Oregon. Each test is based on single-tree plots with 12 randomized complete-blocks. The 37 coastal Douglas-fir clones were propagated by somatic embryogenesis from four full-sib families. Zygotic seedlings from two of these full-sib families were planted across all five tests to allow comparison between somatic and zygotic trees of the same pedigree. Results are reported for survival, stem height, diameter at breast-height (DBH), volume and stem sinuosity at 71/2- years. On average the total population of 37 somatic clones had less stem sinuosity, but grew more slowly than zygotic trees across the five tests studied. However, the best 20% of somatic clones for growth produced 25% greater stem volume at 71/2-years than the zygotic fullsib families. Height had a clonal heritability of 0.61 ± 0.09, DBH 0.64 ± 0.06, volume 0.58 ± 0.08 and stem sinuosity 0.26 ± 0.06. The clonal genetic correlation between height and DBH at 71/2-years was 0.98 ± 0.01, while stem sinuosity was adversely genetically correlated with growth. Clonal performance for growth and stem sinuosity was stable across tests with overall between-test correlations of 0.96 to 0.98. This clonal stability resulted in little variance due to clone x test interactions.
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Ernst, S. G., J. W. Hanover i D. E. Keathley. "Assessment of natural interspecific hybridization of blue and Engelmann spruce in southwestern Colorado". Canadian Journal of Botany 68, nr 7 (1.07.1990): 1489–96. http://dx.doi.org/10.1139/b90-189.
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In a partial diallel mating design among 20 blue and 20 Engelmann spruce parents, the interspecific crosses were successful only with Engelmann spruce as the female parent. No viable seed were obtained from the reciprocal cross among the 60 full-sib families attempted. Under the conditions of artificial pollination and a controlled germination environment, an average of 0.3% of the seed germinated on a total seed basis across all 20 Engelmann spruce females. Many abnormalities were observed among the germinating hybrid seed, suggesting hybrid inviability also contributes to the low crossability between these two species. Isozyme analysis was used to confirm the interspecific hybrids between blue and Engelmann spruce based on the unique genotypic compositions of the hybrids relative to the two species. No natural F1 hybrids between blue and Engelmann spruce were observed in this study based on isozyme analysis of mature individuals or their seedling progeny. Analyses included samples of open-pollinated seed from blue and Engelmann spruce females located in an area where both species are present in close proximity, often side-by-side, and where pollen shed and female strobilus receptivity in the two species are coincident. In addition, there was evidence of possible gametic selection or hybrid inviability among the full-sib progeny based on deviations of observed from expected segregation ratios for progeny isozyme genotypes. Deviations tended to favor the allele more common to both species rather than the allele unique or more common to only one species. Also, the elevationally allopatric blue and Engelmann spruce subpopulations were less divergent genetically than the sympatric subpopulations.
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Ceballos, H., S. Pandey, E. B. Knapp i J. V. Duque. "Tolerancia a suelos ácidos en poblaciones tropicales de maíz del CIMMYT". Agronomía Mesoamericana 5 (15.06.2016): 96. http://dx.doi.org/10.15517/am.v5i0.25070.
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Currently, five tropical maize populations from CIMMYT are being bred for tolerance to acid soils through a full-sib recurrent selection scheme. Three cycles of selection from each population were evaluated in a split-plot design, with a varied number of replications under five environments (with normal soils, and the remaining four with varying degrees of soil stress). The observed genetic gains from these populations were highly significant: 4.72 % per cycle at all environments, 4.90% per cycle in acid soil environments (LSA), and 4.21 % per cycle for the normal soil location (LNA). The results suggest adequate genetic variability and high heritability for tolerance to soil acidity. In comparative trials, these populations yielded an average of 2.29 and 6.25 t/ha in the three LSA and two LNA environments, respectively. Under the same environments, the controls used (Tuxpeño, Pool 26 and Suwan-1) yielded an average of 1.28 and 5.56 t/ha.
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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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Wang, Jiang, Zheng, Xiao, Zhang, Wang, Li i in. "An SNP-Based Genetic Map and QTL Mapping for Growth Traits in the Red-Spotted Grouper (Epinephelus akaara)". Genes 10, nr 10 (12.10.2019): 793. http://dx.doi.org/10.3390/genes10100793.
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The red-spotted grouper (Epinephelus akaara) is one of the most commercially important aquatic species in China. However, its seedstock has low larval survival rates, and its stability is confronted with the danger of overexploitation. In this study, a high-density genetic map was constructed using 3435 single nucleotide polymorphisms (SNPs) from 142 first generation (F1) full-sib offspring and two parents of a red-spotted grouper population. The total genetic length of the map was 2300.12 cM with an average intermarker distance of 0.67 cM. Seventeen genome-wide significant quantitative trait loci (QTLs) for growth-related traits were detected on 24 linkage groups, including 5 QTLs for full length, 7 QTLs for body length, and 5 QTLs for body weight. The contribution values of explained phenotypic variance ranged from 10.7% to 12.9%. Moreover, 13 potential candidate genes for growth-related traits were identified. Collectively, these findings will be useful for conducting marker-assisted selection of the red-spotted grouper in future studies.
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Farias Neto, Austeclínio Lopes, i José Branco de Miranda Filho. "Genetic correlation between traits in the ESALQ-PB1 maize population divergently selected for tassel size and ear height". Scientia Agricola 58, nr 1 (marzec 2001): 119–23. http://dx.doi.org/10.1590/s0103-90162001000100018.
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Full-sib and selfed (S1) progenies were obtained from sub-populations of ESALQ-PB1, divergently selected for tassel size (T+ and T-) and ear height (E+ and E-), and used for estimating genetic and phenotypic correlation coefficients between traits. The analyzed traits were: EW- total ear weight (g/plant), PH- plant height (cm), EH- ear height (cm), TB- tassel branch number and TL- tassel length. The highest genetic (rG) and phenotypic (rF) correlation was observed for the combination PH x EH, as expected, with average of 0.800 and 0.778, respectively over sub-populations and locations. It is apparent that divergent selection for tassel size did not affect greatly the correlation between PH and EH in the full sib progenies, but in the inbred progenies the correlation was smaller in the sub-population selected for larger tassels. Genetic correlation between PH and EH with tassel traits was always positive but ranged from 0.020 to 0.668 in Piracicaba and from 0.06 to 0.309 in Rio Verde. Genetic correlation between PH and EH with yield (EW) also was positive in the range of 0.087 to 0.503. EH showed higher correlation with EW in relation to PH x EW and differences were larger in the sub-populations divergently selected for ear height. Correlation between tassel traits with other traits was positive in most of instances and a lack of consistency was observed among sub-populations. Generally the coefficients of genetic and phenotypic correlation differed substantially from the estimates in the base population ESALQ-PB1 before divergent selection for tassel size and ear placement. Divergent selection affected the correlation between traits under unpredicted and varying magnitudes.
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Wadenbäck, J., D. Clapham, G. Gellerstedt i S. von Arnold. "Variation in content and composition of lignin in young wood of Norway spruce". Holzforschung 58, nr 2 (15.03.2004): 107–15. http://dx.doi.org/10.1515/hf.2004.015.
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Abstract Lignin content and composition are important traits in several tree breeding programs, but very little is known about their natural variation. This study compares the lignin content in 1-year-old plants and 9-year-old trees of Norway spruce belonging to the same full-sib families. It is shown that the lignin content, according to the modified acetyl bromide method, does not vary significantly within or among the different full-sib families either as plants or as young trees. There is, however, on average 4.0% higher lignin content (31.4% versus 27.4%) and lower standard error for the trees than for the plants. The number of C9-units g−1 lignin, analyzed by thioacidolysis, ranges from 516 to 1186 μmmol C9-units g−1 lignin in plants and from 716 to 953 μmmol C9-units g−1 lignin in trees, with no significant differences among the families. However, the extent of change in C9-units g−1 lignin varies among the families with age. The ratio of erythro and threo stereoisomers does not vary significantly among the families. However, the ratio changes differently with age among the families similar to the C9-units g−1 lignin. Additionally, the content of p-hydroxyphenyl (H) lignin is 0.6% higher in the trees than in the plants (1.4% versus 0.8%), estimated indirectly from GC-MS data by a novel subtractive technique, indicating a higher degree of compression wood in the young trees. In conclusion, the amount and composition of lignin does not vary within or among the families at the same age. However, the amount of lignin increases with age while the change in lignin composition varies between family and age.
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Crawford, A. M., K. G. Dodds, A. J. Ede, C. A. Pierson, G. W. Montgomery, H. G. Garmonsway, A. E. Beattie, K. Davies, J. F. Maddox i S. W. Kappes. "An autosomal genetic linkage map of the sheep genome." Genetics 140, nr 2 (1.06.1995): 703–24. http://dx.doi.org/10.1093/genetics/140.2.703.
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Abstract We report the first extensive ovine genetic linkage map covering 2070 cM of the sheep genome. The map was generated from the linkage analysis of 246 polymorphic markers, in nine three-generation full-sib pedigrees, which make up the AgResearch International Mapping Flock. We have exploited many markers from cattle so that valuable comparisons between these two ruminant linkage maps can be made. The markers, used in the segregation analyses, comprised 86 anonymous microsatellite markers derived from the sheep genome, 126 anonymous microsatellites from cattle, one from deer, and 33 polymorphic markers of various types associated with known genes. The maximum number of informative meioses within the mapping flock was 222. The average number of informative meioses per marker was 140 (range 18-209). Linkage groups have been assigned to all 26 sheep autosomes.
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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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Zhang, Yaqun, Chuantao Zhang, Na Yao, Jingxian Huang, Xiangshan Sun, Bingran Zhao i Hengde Li. "Construction of a high-density linkage map and detection of sex-specific markers in Penaeus japonicus". PeerJ 9 (29.10.2021): e12390. http://dx.doi.org/10.7717/peerj.12390.
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Penaeus japonicus is one of the most important farmed shrimp species in many countries. Sexual dimorphism is observed in P. japonicus, in which females grow faster and larger than males; therefore, a unisexual female culture of P. japonicus could improve the efficiency of productivity. However, the genetic mechanisms underlying sex determination in P. japonicus are unclear. In this study, we constructed a high-density genetic linkage map of P. japonicus using genotyping-by-sequencing (GBS) technology in a full-sib family. The final map was 3,481.98 cM in length and contained 29,757 single nucleotide polymorphisms (SNPs). These SNPs were distributed on 41 sex-averaged linkage groups, with an average inter-marker distance of 0.123 cM. One haplotype, harboring five sex-specific SNPs, was detected in linkage group 1 (LG1), and its corresponding confidence interval ranged from 211.840 to 212.592 cM. Therefore, this high-density genetic linkage map will be informative for genome assembly and marker-assisted breeding, and the sex-linked SNPs will be helpful for further studies on molecular mechanisms of sex determination and unisexual culture of P. japonicus in the future.
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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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Mosseler, A., L. Zsuffa, M. U. Stoehr i W. A. Kenney. "Variation in biomass production, moisture content, and specific gravity in some North American willows (Salix L.)". Canadian Journal of Forest Research 18, nr 12 (1.12.1988): 1535–40. http://dx.doi.org/10.1139/x88-235.
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Biomass production and quality in seedlings and coppices of Salixamygdaloides Anderss., S. eriocephala Michx., S. exigua Nutt., and S. lucida Muhl. were investigated in a full-sib family test. Between 65 and 77% of the variation in plant biomass was due to species, while less than 5% was due to families. Approximately 39% of the variation in moisture content and 37% of the variation in specific gravity was due to species differences, while only 3 and 14%, respectively, was due to families. Salixeriocephala produced the highest yields, with an average 1-year coppice production of almost 1 kg/plant (dry matter) and had the lowest moisture content and highest specific gravity of the four species. There was a strong positive correlation between seedling and coppice productivity for all species, with S. eriocephala and S. lucida producing the most vigorous regrowth from coppice.
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Diter, A., R. Guyomard i D. Chourrout. "Gene segregation in induced tetraploid rainbow trout: genetic evidence of preferential pairing of homologous chromosomes". Genome 30, nr 4 (1.08.1988): 547–53. http://dx.doi.org/10.1139/g88-092.
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Gene segregation at six protein loci was analysed in progeny from tetraploid males and females obtained by suppression of first mitosis. The triploid full-sib families from five tetraploid males and the diploid gynogenetic lines from four tetraploid females were examined. The proportions of heterozygous gametes (0.83 on the average) were significantly higher than expected from tetrasomic inheritance (0.667) at all the loci studied. This was explained by preferential pairing of homologous chromosomes. The proportions of heterozygous gametes were significantly different between loci, but the variations were not correlated with the gene–centromere distances. Our results showed that, at least for one locus, the homozygous gametes mainly resulted from pairing of homoeologous chromosomes rather than from pairing of homologous chromosomes, quadrivalent formation, and chromatin exchanges between homoeologous chromosomes.Key words: Salmo gairdneri richardson, induced tetraploidy, gene segregation, electrophoresis.
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Katoh, Masaya, i David W. Foltz. "Biochemical evidence for the existence of a null allele at the leucine aminopeptidase-2 (Lap-2) locus in the oyster Crassostrea virginica (Gmelin)". Genome 32, nr 4 (1.08.1989): 687–90. http://dx.doi.org/10.1139/g89-499.
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The existence of a null activity allele at the leucine aminopeptidase-2 (Lap-2) locus in the oyster Crassostrea virginica (Gmelin) was previously inferred from anomalous segregation patterns observed in offspring from pair crosses, and from the occurrence of individuals lacking Lap-2 bands on gels (presumed null homozygotes). The present research was done to determine whether leucine aminopeptidase specific activity was significantly reduced in oysters presumed from breeding experiments to be heterozygous for a Lap-2 null allele. Approximately thirty 4-month-old oysters from each of two crosses were analyzed. In each cross, LAP specific activity was significantly reduced (P < 0.001) in active/null heterozygotes, compared with full-sib oysters that were active/active heterozygotes. On average, active/null heterozygotes had 57% of the activity of the corresponding active/active heterozygotes.Key words: oysters, null allele, leucine aminopeptidase.
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Padmakar, B., C. Kanupriya, P. Madhavi Latha, C. Vasugi, M. R. Dinesh, D. Sailaja i C. Aswath. "Enrichment of Genetic Linkage Maps and Mapping QTLs Specific to Seed Strength-Hardness/Softness-In Guava (Psidium guajava L.)". Journal of Horticultural Sciences 11, nr 1 (30.06.2016): 13–20. http://dx.doi.org/10.24154/jhs.v11i1.96.
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The present research focuses mainly on molecular mining and morphological evaluation of guava genome within a full-sib population and, thereby, mapping of quantitative trait loci related to fruit quality traits, viz., seed strength (hardness/softness) and average fruit weight. Linkage maps were enriched for both parental lines, 'Kamsari' and 'Purple Local' using a set of 60 RAPD markers following the pseudo-testcross strategy on a panel of 94 progeny. A total of 480 scorable markers were identified, of which 131 were specific to 'kamsari' and 28 to 'Purple Local', segregating as test cross markers, and, 321 showing intercross pattern common to both. 'Kamsari' spanned a total length of 1959.1cM with average marker interval distance of 3.93cM, while 'Purple Local' spanned a length of 1537.9cM with average marker interval distance of 3.29cM, by forming 11 linkage groups. Estimated genome length observed was 93.02% and 92.77% in 'Kamsari' and 'Purple Local', respectively. Composite Interval Mapping (CIM) was computed at significance of 0.05 and LOD threshold greater than 3.0, which led to detection of one major QTL for the trait of average fruit weight, and, four QTLs for the trait of seed strength (hardness/softness). Of these, two were major and two minor QTLs. Our study provides molecular mapping information on marker-assisted selection for improvement of guava in a breeding program.
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Ehiobu, NG, i ME Goddard. "Heterosis in F2-Generations of Drosophila-Melanogaster". Australian Journal of Zoology 37, nr 6 (1989): 609. http://dx.doi.org/10.1071/zo9890609.
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Three crosses among inbred lines of Drosophila melanogaster generated by eight generation full-sib mating, three Australasian population crosses, and two Australian/English population crosses were raised to the F2 generation, to examine evidence of hybrid breakdown. Inbred line crosses produced F2 generations that retained, on average, 54% of the F1 heterosis, which was not significantly different from the retention of 50% F1 heterosis expected under a dominance model of heterosis. Australasian population crosses produced F2 generations with significantly less than 50% of the F1 heterosis, while crosses between Australian and English populations produced a F2 generation that generally performed worse than midparent purebred populations. These results imply epistatic gene action. Because inbred lines contain random combinations of genes, recombination does not necessarily produce hybrid breakdown. However, in crosses between natural populations, recombination is likely to disrupt co-adapted gene combinations leading to poor F2 performance. Populations which rarely exchange migrants are more likely to have alternative gene combinations and to show hybrid breakdown than populations which regularly exchange migrants. The implications of these findings for livestock crossbreeding programs is discussed.
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A. Al-Homaidi, Eissa, Karrar Khalaf Allamy, Anwar Ahmad i Mosab I. Tabash. "The extent of voluntary disclosure in the annual reports of Islamic banks: empirical evidence from Yemen". Banks and Bank Systems 15, nr 1 (26.03.2020): 167–84. http://dx.doi.org/10.21511/bbs.15(1).2020.16.
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This article aims to measure the level of voluntary disclosure in the published annual reports of Yemeni Islamic banks. Four full-fledged Islamic banks from Yemen are selected for the current study. A disclosure checklist covering 266 items is prepared and a 10-year period, 2005–2014, is taken. The disclosure index items were classified into seven groups, such as basic information on Islamic banks, financial ratios, corporate governance information, financial statements data, corporate social disclosure, Zakat information, and other information that has been taken as an important attribute of voluntary disclosure. The obtained results show that the amount of voluntary disclosure that Yemeni Islamic banking institutions publish in their annual reports has gradually increased over the ten years examined. The results revealed that the highest average disclosure index score over the ten years was achieved by Tadhamon Islamic International Bank (TIIB), the second highest average disclosure score was obtained by Saba Islamic Bank (SIB), and the lowest average voluntary disclosure rating score during the ten years surveyed was achieved by Shamil Bank of Yemen &amp; Bahrain in Yemen during the study period. Substantially, the result of voluntary disclosure scores indicates that the degree of voluntary disclosure by Yemeni Islamic financial institutions has relatively expanded during the ten years investigated. The findings provide new evidence for voluntary disclosure, particularly, Islamic disclosure items. The survey findings can be useful for regulators in Yemen to improve overall disclosure practices by Islamic banks operating in Yemen.
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Wu, Shu-Biao, Graham Collins i Margaret Sedgley. "A molecular linkage map of olive (Olea europaea L.) based on RAPD, microsatellite, and SCAR markers". Genome 47, nr 1 (1.01.2004): 26–35. http://dx.doi.org/10.1139/g03-091.
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An integrated molecular linkage map of olive (Olea europaea L.) was constructed based on randomly amplified polymorphic DNA (RAPD), sequence characterized amplified region (SCAR), and microsatellite markers using the pseudo-testcross strategy. A mapping population of 104 individuals was generated from an F1 full-sib family of a cross between 'Frantoio' and 'Kalamata'. The hybridity of the mapping population was confirmed by genetic similarity and nonmetric multidimensional scaling. Twenty-three linkage groups were mapped for 'Kalamata', covering 759 cM of the genome with 89 loci and an average distance between loci of 11.5 cM. Twenty-seven linkage groups were mapped for 'Frantoio', covering 798 cM of the genome with 92 loci and an average distance between loci of 12.3 cM. For the integrated map, 15 linkage groups covered 879 cM of the genome with 101 loci and an average distance between loci of 10.2 cM. The size of the genomic DNA was estimated to be around 3000 cM. A sequence characterized amplified region marker linked to olive peacock disease resistance was mapped to linkage group 2 of the integrated map. These maps will be the starting point for studies on the structure, evolution, and function of the olive genome. When the mapping progeny pass through their juvenile phase and assume their adult characters, mapping morphological markers and identification of quantitative trait loci for adaptive traits will be the primary targets.Key words: genome mapping, RAPD, SSR, SCAR, Olea europea, peacock disease resistance.
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Chavarrías, David, Carlos López-Fanjul i Aurora García-Dorado. "The Rate of Mutation and the Homozygous and Heterozygous Mutational Effects for Competitive Viability: A Long-Term Experiment With Drosophila melanogaster". Genetics 158, nr 2 (1.06.2001): 681–93. http://dx.doi.org/10.1093/genetics/158.2.681.
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Abstract The effect of 250 generations of mutation accumulation (MA) on the second chromosome competitive viability of Drosophila melanogaster was analyzed both in homozygous and heterozygous conditions. We used full-sib MA lines, where selection hampers the accumulation of severely deleterious mutations but is ineffective against mildly deleterious ones. A large control population was simultaneously evaluated. Competitive viability scores, unaffected by the expression of mutations in heterozygosis, were obtained relative to a Cy/L2 genotype. The rate of decline in mean ΔM ≈ 0.1% was small. However, that of increase in variance ΔV ≈ 0.08 × 10-3 was similar to the values obtained in previous experiments when severely deleterious mutations were excluded. The corresponding estimates of the mutation rate λ ≥ 0.01 and the average effect of mutations E(s) ≤ 0.08 are in good agreement with Bateman-Mukai and minimum distance estimates for noncompetitive viability obtained from the same MA lines after 105 generations. Thus, competitive and noncompetitive viability show similar mutational properties. The regression estimate of the degree of dominance for mild-to-moderate deleterious mutations was ∼0.3, suggesting that the pertinent value for new unselected mutations should be somewhat smaller.
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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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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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Stoehr, M. U., N. K. Ukrainetz, L. K. Hayton i A. D. Yanchuk. "Current and future trends in juvenile wood density for coastal Douglas-fir". Canadian Journal of Forest Research 39, nr 7 (lipiec 2009): 1415–19. http://dx.doi.org/10.1139/x09-059.
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Increment cores from 10 full-sib families in each of three planting series were collected on 22 test sites per series (a total of 7063 samples across 63 sites). Juvenile wood density for individual test sites ranged from 0.378 to 0.481. Stepwise multiple linear regression analysis with wood density as the dependent variable and a battery of annual and monthly climate variables as independent variables was used to model the current distribution of wood density across the landscape in coastal British Columbia. Differences in the average temperature between the coldest month and the warmest month, precipitation in July, and the mean annual precipitation were the only significant variables predicting wood density, accounting for 47% of the total variation across all sites. Using two future climate change models (CGCM2 A2x and HADCM3 A2x) to predict changes in the three climate variables, wood density was mapped. Wood density will be reduced generally in the present range of coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii ), especially on southern Vancouver Island and along the coastlines of southern British Columbia. This may have implications for the future utility of Douglas-fir as a structural wood species, as well as for breeding and deployment.
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Yoshikawa, Sota, Masaomi Hamasaki, Kazushi Kadomura, Toshiyuki Yamada, Hisashi Chuda, Kiyoshi Kikuchi i Sho Hosoya. "Genetic Dissection of a Precocious Phenotype in Male Tiger Pufferfish (Takifugu rubripes) using Genotyping by Random Amplicon Sequencing, Direct (GRAS-Di)". Marine Biotechnology 23, nr 2 (18.02.2021): 177–88. http://dx.doi.org/10.1007/s10126-020-10013-4.
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AbstractThe novel non-targeted PCR-based genotyping system, namely Genotyping by Random Amplicon Sequencing, Direct (GRAS-Di), is characterized by the simplicity in library construction and robustness against DNA degradation and is expected to facilitate advancements in genetics, in both basic and applied sciences. In this study, we tested the utility of GRAS-Di for genetic analysis in a cultured population of the tiger pufferfish Takifugu rubripes. The genetic analyses included family structure analysis, genetic map construction, and quantitative trait locus (QTL) analysis for the male precocious phenotype using a population consisting of four full-sib families derived from a genetically precocious line. An average of 4.7 million raw reads were obtained from 198 fish. Trimmed reads were mapped onto a Fugu reference genome for genotyping, and 21,938 putative single-nucleotide polymorphisms (SNPs) were obtained. These 22 K SNPs accurately resolved the sibship and parent–offspring pairs. A fine-scale linkage map (total size: 1,949 cM; average interval: 1.75 cM) was constructed from 1,423 effective SNPs, for which the allele inheritance patterns were known. QTL analysis detected a significant locus for testes weight on Chr_14 and three suggestive loci on Chr_1, Chr_8, and Chr_19. The significant QTL was shared by body length and body weight. The effect of each QTL was small (phenotypic variation explained, PVE: 3.1–5.9%), suggesting that the precociousness seen in the cultured pufferfish is polygenic. Taken together, these results indicate that GRAS-Di is a practical genotyping tool for aquaculture species and applicable for molecular breeding programs, such as marker-assisted selection and genomic selection.
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Magnussen, S., i C. W. Yeatman. "Height growth components in inter- and intra-provenance jack pine families". Canadian Journal of Forest Research 19, nr 8 (1.08.1989): 962–72. http://dx.doi.org/10.1139/x89-148.
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Duration (D), rate of shoot elongation (RSE), number of stem units (NSU), and mean stem unit lengths (MSUL) of current year's (1987) leaders were analyzed in 18 jack pine (Pinusbanksiana Lamb.) full-sib progenies from nine inter- and nine intra-provenance crosses. The parent material consisted of selected "plus" trees from Ontario, Quebec, Wisconsin, and Michigan provenances. The average within-family variance (phenotypic) of D was on the average 186 days or twice as large as the among-family variance of 90 days. Duration was positively correlated with the number of growing degree-days at the place of parental origin. Tree height and height growth of several crosses significantly exceeded a local check lot, and the provenance effects on heights were predominantly additive (but not the luxuriance of hybrids). In determining annual height growth, it was discovered that D and RSE were roughly equally important, but large differences in RSE were observed among families with almost equal growth duration. The superior height growth of two interprovenance families was attributed to higher growth rates rather than a longer growth period. Although NSU was more important than MSUL in determining final shoot length, a negative correlation between NSU and MSUL complicated the overall significance of NSU. It was concluded that jack pine had sufficient variation in the examined height growth components to facilitate genetic improvement in height growth without adverse effects on periodicity. The provenance hybrids produced sufficiently promising results and additional exploitable phenotypic variation to warrant continued hybridization efforts.
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Cappa, Eduardo Pablo, A. D. Yanchuk i C. V. Cartwright. "Estimation of genetic parameters for height using spatial analysis in Tsuga heterophylla full-sibling family trials in British Columbia". Silvae Genetica 64, nr 1-6 (1.12.2015): 59–73. http://dx.doi.org/10.1515/sg-2015-0005.
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AbstractNon-spatial and spatial analyses were carried out to study the effects on genetic parameters in ten-year height growth data across two series of 10 large second-generation full-sib progeny trials of western hemlock [Tsuga heterophylla (Raf.) Sarg.] in British Columbia. To account for different and complex patterns of environmental heterogeneity, spatial single trial analyses were conducted using an individual-tree mixed model with a two-dimensional smoothing surface with tensor product of B-spline bases. The spatial single trial analysis, in all cases, showed sizeable lower Deviance Information Criterion values relative to the non-spatial analysis. Also, fitting a surface displayed a consistent reduction in the posterior mean as well as a decrease in the standard deviations of error variance, no appreciable changes in the additive variance, an increase of individual narrow-sense heritability, and accuracy of breeding values. The tensor product of cubic basis functions of B-spline based on a mixed model framework does provide a useful new alternative to model different and complex patterns of spatial variability within sites in forest genetic trials. Individual narrow-sense heritabilities estimates from the spatial single trial analyses were low (average of 0.06), but typical of this species. Estimated dominance relative to additive variances were unstable across sites (from 0.00 to 1.59). The implications of these estimations will be discussed with respect to the western hemlock genetic improvement program in British Columbia.
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McKay, Steven J., James M. Bradeen i James J. Luby. "Prediction of Genotypic Values for Apple Fruit Texture Traits in a Breeding Population Derived from ‘Honeycrisp’". Journal of the American Society for Horticultural Science 136, nr 6 (listopad 2011): 408–14. http://dx.doi.org/10.21273/jashs.136.6.408.
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The commercially successful apple (Malus pumila Mill.) cultivar Honeycrisp is known for its high degrees of crispness and juiciness. This cultivar has been incorporated into numerous breeding programs in an effort to duplicate its desirable texture traits in conjunction with such other traits as reduced postharvest disorders, disease resistance, and improved tree vigor. This study characterizes variability and estimates heritability for several apple fruit texture traits within a large breeding population over several years. Five full-sib families, all sharing ‘Honeycrisp’ as a common parent, were assayed with respect to crispness, firmness, and juiciness using sensory evaluation panels and total work required to fracture tissue using instrumental methods. The incomplete block design of the sensory panels, coupled with best linear unbiased prediction, facilitated the evaluation of a large number of genotypes with small numbers of fruit per genotype while accounting for individual sensory panelist effects. Broad-sense heritability estimates exceeded 0.70 for all four traits. Principal component analysis, applied to the phenotypic data, characterized ‘Honeycrisp’ as having average crispness and low firmness (53rd percentile relative to its offspring) but also as being a relatively extreme example of high juiciness and low work to fracture (first percentile). The improved characterization of desired fruit texture phenotypes and the high levels of broad-sense heritability provide valuable tools for the further development of new, high-quality apple cultivars.
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Johnsen, Øystein, i Tore Skrøppa. "Genetic variation in plagiotropic growth in a provenance hybrid cross with Piceaabies". Canadian Journal of Forest Research 22, nr 3 (1.03.1992): 355–61. http://dx.doi.org/10.1139/x92-046.
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Plagiotropism (angle departure from orthotropic growth) was measured on 360 Norway spruce (Piceaabies (L.) Karst.) clones propagated in 2 subsequent years. The clones were members of 20 full-sib families (18 clones per family) from a provenance hybrid factorial cross involving 10 parents of Norwegian (N) and 10 parents of east-European (EE) origin. The clones from the EE × EE crosses showed an average of 17° and 20° in plagiotropism, those from the N × N group showed 3° and 7° in plagiotropism, while the hybrids (EE × N and N × EE) showed 8° and 13° in plagiotropism in 1988 and 1989, respectively. A large family variation was found in the EE × EE and the hybrid groups (11 and 8.5% of total variation, respectively), but variation was small (3.5%) in the N × N group. The clonal component accounted for 10, 12, and 8.5% of total variation in EE × EE, hybrids, and N × N, respectively. Among the plagiotropic clones, some were heterogeneous with a large within-clone variation and others were homogeneous. The year × family and year × clone components were rather large in EE × EE (5 and 9% of total variation, respectively) but smaller in the hybrids and smallest in N × N. The clones with best growth were not among those with the worst plagiotropic growth. The clonal material is ideal for use in future studies on the genetic and physiological regulation of maturation.
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MENDES, UDENYS CABRAL. "YIELD POTENTIAL AND GENETIC VARIABILITY OF SEMIEXOTIC MAIZE POPULATIONS AS A BASIS FOR SELECTION". Revista Brasileira de Milho e Sorgo 19 (16.11.2020): 19. http://dx.doi.org/10.18512/rbms2020v19e1187.
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In order to verify the genetic and agronomic value, yield potential and inbreeding depression of synthesized composites, as well as quantifying the population variability and incorporating new sources of semiexotic germplasm in maize genetic improvement programs, four populations, identified as NAP-FA x HG-71 (P1), NAP-FL x HG-49 (P2), NAP-FB x HG-49 (P3), and NAP-DB x HG-49 (P4), with two levels of inbreeding (S0 and S1), were evaluated in three locations. From the P1 and P4 populations, 100 full-sib progenies were evaluated in only one location. Plant and ear height, lodging, breakage, ear length and diameter, resistance to diseases, ears with chalky kernels and grain yield were evaluated. The grain yield of the S0 and S1 populations varied between 5.50 and 6.65 t ha-1 and 3.8 and 4.58 t ha-1, respectively, with an average inbreeding depression between 23.9% and 38.0%. Considering all the locations, the grain yields of the non-inbreeding populations varied between 64.4% and 78.0% in relation to commercial hybrids (witnesses), indicating a good yield potential for start of improvement program. In the P1 and P4 populations, sufficient genetic variability was identified in most of the characters, which accredits them for recurrent selection. Gains of 13.7% and 17.8% for grain yield and 31.64% and 29.9% for ears with chalky kernels were estimated.