Дисертації з теми "Crop and pasture improvement (incl. selection and breeding)"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-15 дисертацій для дослідження на тему "Crop and pasture improvement (incl. selection and breeding)".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Childerhouse, Emma. "The effect of a natural plant extract and synthetic plant growth regulators on growth, quality and endogenous hormones of Actinidia chinensis and Actinidia deliciosa fruit : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1052.
Повний текст джерелаStewart, Alan V. "Plant breeding aspects of ryegrasses (Lolium sp.) infected with endophytic fungi." Phd thesis, University of Canterbury. Lincoln College, 1987. http://theses.lincoln.ac.nz/public/adt-NZLIU20071005.172250/.
Повний текст джерелаLeeks, C. R. F. "Determining seed vigour in selected Brassica species." Lincoln University, 2006. http://hdl.handle.net/10182/1274.
Повний текст джерелаMoot, Derrick J. "Harvest index variability within and between field pea (Pisum sativum L.) crops." Lincoln University, 1993. http://hdl.handle.net/10182/1285.
Повний текст джерелаRaikar, S. V. "Protoplast fusion of Lolium perenne and Lotus corniculatus for gene introgression." Diss., Lincoln University, 2007. http://hdl.handle.net/10182/301.
Повний текст джерела(7718969), N. Smith. "Aspects of seed germination and early growth in rainforest cabinet timber species." Thesis, 2002. https://figshare.com/articles/thesis/Aspects_of_seed_germination_and_early_growth_in_rainforest_cabinet_timber_species/13426841.
Повний текст джерела(9847298), Zongjian Yang. "Resource allocation within plants: Some theoretical and practical implications for control of plant development." Thesis, 2003. https://figshare.com/articles/thesis/Resource_allocation_within_plants_Some_theoretical_and_practical_implications_for_control_of_plant_development/13424417.
Повний текст джерела(12298370), Alison S. Jensen. "Redefining pachymetra root rot management strategies and cultivar resistance in commercial sugarcane fields." Thesis, 2020. https://figshare.com/articles/thesis/Redefining_pachymetra_root_rot_management_strategies_and_cultivar_resistance_in_commercial_sugarcane_fields/19426862.
Повний текст джерела(9834818), Sachesh Silwal. "Comparative analysis of physiological and phenological traits of rice (Oryza sativa) under aerobic production systems in dry and wet tropics of Queensland, Australia." Thesis, 2017. https://figshare.com/articles/thesis/Comparative_analysis_of_physiological_and_phenological_traits_of_rice_Oryza_sativa_under_aerobic_production_systems_in_dry_and_wet_tropics_of_Queensland_Australia/13452425.
Повний текст джерела(8797199), Blake A. Russell. "Trait Identification to Improve Yield and Nitrogen Use Efficiency in Wheat." Thesis, 2020.
Знайти повний текст джерелаWheat is a major source of calories and protein for humans worldwide. Wheat is the most widely grown crop, with cultivation areas and production systems on every continent. The cultivated land area is vast because of its importance and adaptability to various environmental conditions. Global wheat production has not kept up with the growing population, provoking the need to develop new methods and techniques to increase genetic gains. The first research chapter of this Ph.D. dissertation involves performing genome-wide association studies (GWAS) to identify and examine transferability of marker-trait associations (MTAs) across environments. I evaluated yield and yield components traits among 270 soft red winter (SRW) wheat varieties. The population consists of experimental breeding lines adapted to the Midwestern and eastern United States and developed by public university breeding programs. Phenotypic data from a two-year field study and a 45K-SNP marker dataset were analyzed by FarmCPU model to identify MTAs for yield related traits. Grain yield was positively correlated with thousand kernel weight, biomass, and grain weight per spike while negatively correlated with days to heading and maturity. Sixty-one independent loci were identified for agronomic traits, including a region that with –logP of 16.35, which explained 18% of the variation in grain yield. Using 12 existing datasets from other states and seasons, in addition to my own data, I examined the transferability of significant MTAs for grain yield and days to heading across homogenous environments. For grain yield and days to heading, I only observed 6 out of 28 MTAs to hold up across homogenous environments. I concluded that not all marker-trait associations can be detected in other environments.
In the second research chapter of this Ph.D. dissertation, I dissected yield component traits under contrasting nitrogen environments by using field-based low-throughput phenotyping. I characterized grain yield formation and quality attributes in soft red winter wheat. Using a split-block design, I studied responses of 30 experimental lines, as sub-plot, to high nitrogen and low nitrogen environment, as main-plot, for two years. Differential N environments were imposed by the application, or lack thereof, of spring nitrogen application in a field, following a previous corn harvest. In this study, I measured agronomic traits, in-tissue nitrogen concentrations, nitrogen use efficiency, nitrogen harvest index and end-use quality traits on either all or subset of the germplasm. My data showed that biomass, number of spikes and total grain numbers per unit area were most sensitive to low nitrogen while kernel weight remained stable across environments. Significant genotype x N-environment interaction allowed me to select N-efficient germplasm, that can be used as founding parents for a potential breeding population specifically for low-N environments. I did this selection on the basis of superior agronomic traits and the presence of the desirable gluten quality alleles such as Glu-A1b (2*) and Glu-D1d (5+10).
(9852200), BJ King. "Molecular techniques for the identification of triploid citrus." Thesis, 1995. https://figshare.com/articles/thesis/Molecular_techniques_for_the_identification_of_triploid_citrus/13424915.
Повний текст джерела(8086352), Xiaochen Xu. "IDENTIFICATION AND MAPPING OF ANTHRACNOSE RESISTANCE GENES IN SORGHUM [SORGHUM BICOLOR (L.) MOENCH]." Thesis, 2019.
Знайти повний текст джерелаColletotrichum sublineolum is the causal agent of sorghum anthracnose, a very common and destructive fungal disease in warm and humid areas, especially in West and Central Africa. Use of host plant resistance is considered as the most important and effective control option for sorghum diseases. To achieve this goal, identification and mapping resistance genes is essential. In this study, we used an isolate of C. sublineolum, CsGL1, to screen our sorghum germplasm and identified a resistant inbred line, P9830. We developed a mapping population from a cross between P9830 and a susceptible line, TAM428, for this research. The population was advanced to the F6 generation. Progenies were phenotyped at F2, F3 and F6 generations for disease resistance against the pathogen, CsGL1. In the F2 generation, 460 individuals showed resistance and 149 individuals showed susceptibility to CsGL1. This result fits the 3:1 segregation pattern expected for resistance controlled by a single gene. Bulked segregant analysis with next generation sequencing was used on selected F6 recombinant inbred lines. A significant peak containing 153 SNPs was observed on the distal end of the long arm of chromosome 8. To verify resistance to CsGL1 was controlled by genes in this region, indel and SNP markers were used between 59.4Mbp and 60.6Mbp on chromosome 8 to fine map the resistance locus. One SNP marker located in the gene Sobic.008G166400 co-segregated with resistance, and another two indel markers were discovered to be tightly linked to the resistance locus. These three PCR-based SNP markers would be useful for marker-assisted selection for improving anthracnose resistance against CsGL1. Two candidate genes, Sobic.008G166400 and Sobic.008G166550, were found in the locus. Both of the genes encode LRR proteins implicated in plant disease defense response. The identity of DNA sequence between these two candidate genes is 94.1%, possibly the result of tandem duplication. Another possible ortholog in the region is Sobic.008G167500. Quantitative PCR analysis showed that the expression level of Sobic.008G166400 didn’t change significantly in a resistant RIL, 17-12 but was induced in a susceptible RIL, 13-31, after CsGL1 infection. In conclusion, we mapped two candidate genes conferring resistant to CsGL1 on chromosome 8, and Sobic.008G166400 is more likely of the two to be determined as the gene controlling resistance to CsGL1.
(8797730), Rupesh Gaire. "GENOTYPIC AND PHENOTYPIC CHARACTERIZATION OF PURDUE SOFT RED WINTER WHEAT BREEDING POPULATION." Thesis, 2020.
Знайти повний текст джерела(7371827), Miguel A. Lopez. "Developing the Yield Equation for Plant Breeding Purposes in Soybean (Glycine max L. Merr)." Thesis, 2019.
Знайти повний текст джерелаDissecting the soybean grain yield (GY) to approach it as a sum of its associated processes seems a viable approach to explore this trait considering its complex multigenic nature. Monteith (1972, 1977) first defined potential yield as the result of three physiological efficiencies: light interception (Ei), radiation use efficiency (RUE) and harvest index (HI). Though this rationality is not recent, few works assessing these three efficiencies as strategies to improve crops have been carried out. This thesis approaches yield from the perspective of Ei, RUE, and HI to better understand yield as the result of genetic and physiological processes. This study reveals the phenotypic variation, heritability, genetic architecture, and genetic relationships for Ei, RUE, and HI and their relationships with GY and other physiological and phenological variables. Similarly, genomic prediction is presented as a viable strategy to partially overcome the tedious phenotyping of these traits. A large panel of 383 soybean recombinant inbred lines (RIL) with significant yield variation but shrinkage maturity was evaluated in three field environments. Ground measurements of dry matter, photosynthesis (A), transpiration (E), water use efficiency (WUE), stomatal conductance (gs), leaf area index (LAI) and phenology (R1, R5, R8) were measured. Likewise, RGB imagery from an unmanned aircraft system (UAS) were collected with high frequency (~12 days) to estimate the canopy dynamic through the canopy coverage (CC). Light interception was modeled through a logistic curve using CC as a proxy and later compared with the seasonal cumulative solar radiation collected from weather stations to calculate Ei. The total above ground biomass collected during the growing season and its respective cumulative light intercepted were used to derive RUE through linear models fitting, while apparent HI was calculated through the ratio seeds dry matter vs total above-ground dry matter. Additive-genetic correlations, genome wide association (GWA) and whole genome regressions (WGR) were performed to determine the relationship between traits, their association with genomic regions, and the feasibility of predicting these efficiencies through genomic information. Our results revealed moderate to high phenotypic variation for Ei, RUE, and HI. Additive-genetic correlation showed a strong relationship of GY with HI and moderate with RUE and Ei when the whole data set was considered, but negligible contribution of HI on GY when just the top 100 yielding RILs were analyzed. High genetic correlation to grain yield (GY) was also observed for A (0.87) and E (0.67), suggesting increase in GY can be achieved through the improvement of A or E. The GWA analyses showed that Ei is associated with three SNPs; two of them located on chromosome 7 and one on chromosome 11 with no previous quantitative trait loci (QTLs) reported for these regions. RUE is associated with four SNPs on chromosomes 1, 7, 11, and 18. Some of these QTLs are novel, while others are previously documented for plant architecture and chlorophyll content. Two SNPs positioned on chromosome 13 and 15 with previous QTLs reported for plant height and seed set, weight and abortion were associated with HI. WGR showed high predictive ability for Ei, RUE, and HI with maximum correlation ranging between 0.75 to 0.80. Both directed and undirected multivariate explanatory models indicate that HI has a strong relationship with A, average growth rate of canopy coverage for the first 40 days after planting (AGR40), seed-filling (SFL), and reproductive length (RL). According to the path analysis, increase in one standard unit of HI promotes changes in 0.5 standard units of GY, while changes in the same standard unit of RUE, and Ei produce increases on GY of 0.20 and 0.19 standard units. This study presents novel genetic knowledge for Ei, RUE, HI and GY along with a set of tools that may contribute to the development of new cultivars with enhanced light interception, light conversion and optimized dry matter partitioning in soybean. This work not only complements the physiological knowledge already available with the genetic control of traits directly associated with yield, but also represents a pioneer attempt to integrate traditional physiological traits into the breeding process in the context of physiological breeding
(8744436), Liyang Chen. "Molecular identification of Phytophthora resistant genes in soybean." Thesis, 2021.
Знайти повний текст джерелаPhytophthora root and stem rot (PRSR), caused by oomycete Phytophthora sojae, is the most severe soil-borne disease of soybean (Glycine max (L.) Merr.) worldwide. The disease can be effectively managed by introducing resistance to P. sojae (Rps) genes into soybean cultivars by breeding, which requires continuous efforts on identification of resistance resources from soybean germplasm. Previously, two resistance genes, Rps2-cas (former name Rps2-das) and Rps14 (former name Rps1-f), were mapped by linkage analysis from soybean landraces, PI 594549 C and PI 340029, respectively. The resistance underlying PI 594592 also need further characterization given its broad resistance spectrum. In this study, Rps-2cas and Rps14 were further mapped, and Rps2-b, was identified and initial mapped from PI 594592. Thus, this thesis research was divided into three parts for three Rps genes.
The first part mainly focuses advances on Rps2-cas. Marker-assisted spectrum analysis was performed for Rps-2cas to confirm its potential in disease management. A high-quality genome assembly of PI 594549 C was generated, and KASP markers were developed based on comparison between new reference and Williams 82 reference genome. The gene was further mapped to a 32.67-kb region on PI 594549 C reference genome harboring three expressed NLRs by 24 recombinants screened from a large F4 population. Comparative genomics analysis suggests the only intact NBS-LRR gene in the fine mapping region is the best candidate gene for Rps2cas, and its function was validated by stable transformation. Evidences from other high-quality assembly genomes suggest Rps2-cas originated from an ancient unequal crossing over event.
In the second part, Rps14 was further mapped using 21 recombinants identified from a F3 population consisting of 473 plants. In commonly used Williams 82 reference genome, the assembly of fine mapping region was incomplete, and Rps14 region showed drastic variation in size and copy number of NLRs in 23 high-quality genome assemblies, suggesting the complexity of Rps14 region and high-quality reference sequence of donor line is required for isolation of Rps14 candidate genes. Marker assisted resistance test showed Rps14 had wider resistance spectrum to different P. sojae isolates comparing to other Rps genes on chromosome 3, and phylogenic analysis further supported the potential of Rps14 to be a novel resistance gene.
For the third part, an F2 population derived from a cross between PI 594592 and Williams was tested by P. sojae race 1. The 3:1 and 1:2:1 Mendelian segregation ratios were observed in F2 individuals and F2:3 families, respectively, suggesting a single dominant Rps gene in PI 594592. The gene was initially mapped to the distal end chromosome 16 overlapped with Rps2, and the gene was tentatively named as Rps2-b. Polymorphic SSR markers and InDel markers designed based on re-sequencing data of PI 594592 and Williams was used to genotyping all the F2:3 families, and a linkage map was constructed for Rps2-b. Rps2-b was mapped to a 461.8-kb region flanked by SSR marker Satt431 and InDel marker InDel3668 according to the reference genome (Wm82. a2). Marker-assisted resistance test showed Rps2-b hold a wide resistance spectrum.