Use of Pod Width for Indirect Selection of Seed Weight in Soybeans1
- J. A. Bravo,
- W. R. Fehr and
- S. Rodriguez de Cianzio2
We evaluated the use of pod width for indirect selection of seed weight in soybeans [Glycine max (L.) Merrill], Each of three experimental lines with relatively small seed was crossed to one of two large-seeded cultivars, and each F1 was crossed to a different parent with intermediate seed weight. Width of the terminal pod cavity (suture-to-suture) and seed weight (g/100 seeds) were measured on individual plants and their progeny for the F1 of the three-way crosses, F2 and F3 of all crosses, the eight parents, and a control cultivar.
Selection for seed weight was more effective using pod width than was direct selection for seed weight per se on an individual-plant basis. The phenotypic correlations between the two characters were highly significant (P< 0.01) and ranged from 0.55 on an individual-plant basis to 0.64 on an entry-mean basis. The genotypic correlation on an entry-mean basis was 0.72. Heritabilities based on variance component estimates for pod width were 54% on a plant, 75% on a plot, and 92% on an entry-mean basis, and for seed weight were 27% on a plant, 41% on a plot, and 71% on an entry-mean basis. Average genetic response in seed weight obtained from individual plant selection of the top 25% of F1 F2, and F3 plants on the basis of pod width was 50% greater than for seed weight per se.
Use of pod width permits more efficient selection for seed weight in soybean cultivars development. Implications of the results in breeding for seed weight are discussed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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