Date of Graduation

5-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Crop, Soil & Environmental Sciences (PhD)

Degree Level

Graduate

Department

Crop, Soil & Environmental Sciences

Advisor

Pengyin Chen

Committee Member

Terry Kirkpatrick

Second Committee Member

Jeremy Ross

Third Committee Member

Kris Brye

Fourth Committee Member

Ruben Morawicki

Keywords

Canning, Edamame, GWAS, Harvest

Abstract

Edamame is a food-grade soybean (Glycine max (L.) Merrill) that is either harvested immature (R6 stage) or after plant maturity (R8 stage). At R6, the premium product will have crescent- shaped large green pods and gray pubescence. At R8, the seed will either have stayed green or will have turned yellow, black, or brown. Edamame is a healthy snack with a sweet flavor and firm texture. The edamame market is growing in the United States, creating a need for more adapted varieties. The genetic diversity is low among adapted large-seeded breeding lines. Finding diverse accessions will help develop larger and more adapted varieties. Harvesting edamame at the R6 stage is challenging, as the harvest window can be <5 days. Research is needed to help define edamame breeding, production, and processing strategies. The objectives of this dissertation were to: i) discover quantitative trait loci (QTL) controlling seed weight and size traits in edamame-type germplasm; and compare the available diversity to large-seeded breeding lines from the University of Arkansas, ii) estimate the harvest window at the R6 stage; and evaluate the effects of planting date and variety on pod weight and color, and iii) improve shelf-stable edamame products by evaluating pasteurization methods of high moisture edamame. A total of 343 accessions and 31 breeding lines were used to discover QTLs and compare diversity of seed weight and size traits. Three varieties were planted in 12 environments to observe the optimum harvest date and harvest window at the R6 stage. A commercial edamame variety and three breeding lines with green, black, and brown seed were pasteurized in an acidic brine. Genetically, there were two main groups among the 343 accessions, and the accessions were genetically different than the breeding lines. A total of 59 single nucleotide polymorphisms (SNPs) associated with seed weight and size traits were discovered across nine chromosomes. Although the harvest window for edamame (for a specific planting date) at R6 is short (<5 – 7 days), the yearly harvest window for edamame at R6 can be from mid-August to early-mid October. The three varieties that are green, black, or brown at R8 had the best color after pasteurizing. The results of this dissertation will help define a breeding, production, and processing strategy for edamame.

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