|dc.description.abstract||MOLECULAR ANALYSIS OF ABIOTIC STRESS IN LENTIL
(Lens culinaris Medik.)
by Md Nurul Amin, Ph.D.
Washington State University
Chair: Rebecca McGee
Lentil (Lens culinaris Medik.) is an important legume crop in cereal-based cropping systems due to its nitrogen-fixing ability and its utility in breaking disease and weed cycles. Additionally, lentil is an inexpensive source of protein, fiber, folates, and minerals. Lentils are often grown in marginal hot, dry areas where other crops fail to thrive. These areas include the arsenic contaminated regions of the Ganges delta where lentils produce seeds with toxic concentrations of arsenic and are a source, along with other foodstuffs, of chronic arsenic poisoning. Identifying biomarkers would allow the most rapid breeding of improved lentil cultivars with tolerance to high temperature and drought stress and have minimal concentrations of arsenic. Therefore, the objectives of this research were to identify the genomic regions of yield, components of yield and arsenic concentration in lentil under high temperature, drought, and arsenic stress conditions. Two association mapping panels consisting of either 308 or 150 lentil accessions were phenotyped for Days to flowering (DTF), seed weight (HSW), total biomass (BMP), seed yield (SYP), and seed size (SZ) under high temperature and drought stress. The experiment was grown at Central Ferry and near Pullman (West Whitlow and Spillman Research Farms), Washington, USA as an RCBD with three replications in 2015 and as an augmented design (with four checks) in 2016. To phenotype for As accumulation, 200 accessions of the mapping panel were planted in 2017 in arsenic prone areas of Jashore and Faridpur, Bangladesh using an augmented design. Lentil shoots and seeds were harvested at maturity, dried and ground for analysis of arsenic concentration using ICP-MS. The mapping panels were genotyped using a modified Poland’s Genotyping by Sequencing (GBS) approach with PstI and MspI restriction enzymes. 10,647 single nucleotide polymorphisms were identified using Stacks with a reference genome. The FARM CPU R package was used to perform the genome-wide association study with the 10,674 SNPs and three subpopulations of lentil. DTF, BMP, SYP, HSW, SZ, and arsenic concentration traits were significantly associated with SNP markers in fourteen chromosomal regions and will be useful for marker-assisted selection in the lentil breeding program.||en_US