Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Multi-environment evaluation of winter pea genotypes for winter survival and yield stability(Montana State University - Bozeman, College of Agriculture, 2024) Poudel, Amrit; Chairperson, Graduate Committee: Kevin McPhee; This is a manuscript style paper that includes co-authored chapters.Winter pea can be grown as a rotational crop for soil moisture conservation and nutrient recycling in the wheat-growing region of Montana. Development of winter hardy cultivars would increase seed yield and expand the area of adaptation of this crop. Harsh winter conditions present a significant challenge to the production of winter peas. The objective of this study was to screen pea germplasm and breeding lines for winter survival and identify genotypes with good winter hardiness for future crop production. Field trials were conducted to evaluate genotypes at Bozeman, Havre, Huntley, and Moccasin, MT in 2021, 2022, and 2023. These lines included elite winter cultivars and several checks. Winter hardiness was evaluated as the percentage of surviving plants and by agronomic performance including yield. Genotypes were evaluated based on the GGE biplot method. This analysis captured multiple variables including yield, protein content, seed size, and their overall stability across multiple years and locations of study to aid in selecting lines. Differential winter survival was observed across locations and years. Higher winter survival was seen in Bozeman and Havre. Few lines were identified as having high seed yield and stable production over years and locations. Breeding lines had higher mean yield with few good lines having stable production of greater than 2500 kg/ha. Germplasm lines showed better winter survival than breeding lines. Protein content ranged from 20% to 31%. Larger seeds were observed in Moccasin, whereas Havre had the highest protein content. Mega- environment differentiation helped to select specific genotypes based on the trait of interest for a particular environment. Several European and US lines used in the experiments having high winter hardiness record performed better for seed yield and resistance to stress. The lines identified as having high levels of cold tolerance can be used as a prospective genetic resource in pea breeding programs. Genotypes having high and stable seed yield can be considered for release as a variety and made available to producers.Item Screening field pea (Pisum sativum L.) for tolerance to high salinity conditions(Montana State University - Bozeman, College of Agriculture, 2020) Tracy, Jacob D.; Chairperson, Graduate Committee: Kevin McPheeField pea (Pisum sativum L.) is an important salt-sensitive crop utilized in rotation with cereals in semi-arid cropping systems in the Northern Great Plains (NGP). Saline soils (EC > 4 dS m -1) negatively impact over 10.8 million acres in Montana, the second largest producer of field pea in the US. Despite its global importance, few studies have explored field pea response to high salinity conditions outside of germination testing and even fewer have looked at tolerance to sodium sulfate (Na 2SO 4), the dominant salt affecting plant growth in the NGP. In this study, 311 accessions comprising the genetically diverse USDA Pisum single plant (PSP) core collection were screened under high Na 2SO 4 conditions in germination and seedling experiments. Germination screening was conducted in petri dishes within a dark growth chamber. Accessions received H 2O (control) or 16 dS m -1 Na 2SO 4 (highly saline) solution for 8 days. The mean percent germination compared to the control was used as the indicator for tolerance. A preliminary greenhouse concentration series experiment using 7 levels of Na 2SO 4 (0, 3, 6, 9, 12, 15, and 18 dS m -1), supported screening seedlings at 9 dS m -1 Na 2SO 4. Greenhouse screening was conducted in plastic pots of coarse sand media. Accessions received a nutrient solution (control) or 9 dS m -1 Na 2SO 4 and nutrient solution daily. Salinity symptom scores were assessed on days 21, 28, 35, and 38 post-sowing using a visual growth response scale of 1-9 (healthy-dead). Phenotypic measurements and the Area Under the Injury Curve (AUIC) were used as indicators for tolerance. A Genome Wide Association Study (GWAS) was conducted using the phenotypic data collected and a large dataset of 68,222 Single Nucleotide Polymorphisms developed from the USDA PSP plus core collection. Potential candidate breeding germplasm conferring high salinity tolerance at the germination and seedling growth stages was identified. Significant marker-trait associations were discovered for all traits measured, providing potential Marker-Assisted Selection (MAS) opportunities.