Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Master of Science in Crop, Soil & Environmental Sciences (MS)

Degree Level

Graduate

Department

Plant Pathology

Advisor/Mentor

Chen, Pengyin

Committee Member

Mason, Richard E.

Second Committee Member

Gbur, Edward E. Jr.

Third Committee Member

Atungulu, Griffiths G.

Fourth Committee Member

Espinoza, Leonel

Keywords

Biological sciences; Association mapping; Edamame; Infrared heating; Protein; Seed weight; Sucrose

Abstract

Edamame is a specialty large-seeded soybean (Glycine max L. Merr.) harvested at an immature stage (R6) that has become the second largest consumed soyfood. Although United States is the largest soybean producer, majority of edamame is imported from Asia, highlighting the importance of developing new edamame varieties. Association mapping (AM) provides an alternative to bi-parental linkage mapping method to detect quantitative trait loci (QTL) adding higher resolution and broader germplasm information. Seed weight, sucrose, and protein are quantitative traits of value when selecting edamame lines. However molecular mechanisms controlling each of these traits are still inconclusive and have not been addressed using edamame accessions. Edamame has not reached its potential due to lack of diversity on edamame-based products. Information regarding edamame processing is limited. Therefore, the objectives were 1) to identify and validate seed weight, sucrose, and protein QTL using single nucleotide polymorphisms (SNP) in an association mapping population, and 2) to determine the kinetics of edamame under infrared heating and evaluate three heating intensity levels on the physicochemical attributes of edamame. For the first objective 378 edamame accessions of different maturity groups (000-IX) were grown in Stuttgart and Fayetteville, AR in 2014 and 2015. A total of 16 SNPs on ten chromosomes were found to be associated (-log P > 2.5) with seed weight. Validating 11 previously reported QTL and identifying three new regions on Gm04, Gm16, and Gm19. For sucrose content 13 SNPs were significantly associated, mainly in Gm08, but also in Gm04, and Gm06. For seed protein content six SNPs were found to be significant on four chromosomes, confirming previously reported QTLs. For the second objective one variety (8080) was used to establish the kinetics of edamame using three IR heating intensities. Temperature, weight, texture, green intensity, and peroxidase activity were measured. Across heating intensities, treating edamame for 100 and 120 seconds resulted on the best texture, weight reduction, and green intensity. Although 100% of peroxidase inactivation was not achieved, enzyme activity was reduced (62 %). Results indicate the potential of using IR treatment as a drying or pre-drying step in edamame product development.

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