Use of Small-seeded Soybean Parents for the Improvement of Large-seeded Cultivars1
- J. A. Bravo,
- W. R. Fehr and
- S. Rodriguez de Cianzio2
We studied the segregation for seed size in two- and three-way crosses of soybeans [Glycine max (L.) Merr.] involving adapted small- and large-seeded parents. Three lines with small seeds (15.3 to 19.8 g/100 seeds) were crossed to one of two large-seeded cultivars (25.6 to 28.2 g/100 seeds), and the F1, was crossed to a third parent with intermediate seed size (22.1 to 23.0 g/100 seeds). Seed size of 60 F2-derived lines in F3 from three two-way and three three-way crosses were evaluated with the eight parents in two environments.
The observed population mean was closely predicted by either the arithmetic or geometric mean of the parents. The mean seed size of a three-way compared with its two-way cross was directly related to seed size of the third parent. Only four of the 360 F2-derived lines evaluated had a mean seed size within the confidence interval of the smallest or largest parent in the cross. Our results indicated that, utilization of small-seeded cultivars for improvement of large-seeded types will require special care in population development to obtain the desired frequency of large-seeded segregates.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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