Date of Award
Master of Science
Vincent R. Pantalone
Fred Allen, Dennis West
Soybean is a remarkable crop that is used in many aspects of our everyday lives. The seed protein is used primarily for livestock feed, though it is becoming more available as a meat substitute for human consumption. Soybean oil is used in many products such as plastics, foods, and industrial products. Seed yield is the major trait that is selected for in a breeding program. A population of 239 F4 derived RIL from the cross of USG 5601T × U99-310255 was used to calculate heritability estimates by parent offspring regression and on an entry mean basis. This population was grown in 2009 as unreplicated F4:5 plant rows at the East Tennessee Research and Education Center (ETREC) in Knoxville, TN. In 2010, the F4:6 generation was grown as two replications with two locations, ETREC and Highland Rim Research and Education Center (HRREC) in Springfield, TN. In 2011, the F4:7 generation was grown at ETREC, HRREC, and at the Research and Education Center at Milan (RECMLN) in Milan, TN. Averaged over two years (2010 and 2011) and 5 environments exhibited a range of 1928.7 to 3033.6 kg ha-1 with a mean of 2325.7 kg ha-1for seed yield, 398.4 to 451.8 g kg-1 with a mean of 426.8 g kg-1 for seed protein concentration, and 201.1 to 224.6 g kg-1 with a mean of 213.7 g kg-1 seed oil concentration. On an entry mean basis, a heritability estimate of 0.85 for seed protein concentration was observed. However, a parent-offspring regression of F4:6 to F4:7 revealed an estimate of 0.43 (R2= 0.26). For seed oil concentration, heritability estimate on an entry mean basis was 0.78 and the parent-offspring regression was 0.11 (R2=0.01). Seed yield exhibited heritability estimates of 0.23 (R2=0.09) and 0.38 for parent-offspring regression and entry mean basis respectively. Genetic gains were calculated for all traits through selections for the top 5, 10, 15, and 20% of RILs for seed yield, seed protein, and seed oil concentration. Improvements in these traits were achieved singularly and could be selected for multiple traits when phenotypic correlations are considered.
Wiggins, Benjamin T., "Heritability and Genetic Gain of Seed Protein, Oil, and Yield among RIL of Soybean. " Master's Thesis, University of Tennessee, 2012.