Simulated Selection for Superior Yielding Soybean Lines in Conventional vs. Double-Crop Nursery Environments
- D. M. Panter and
- F. L. Allen *
Soybean [Glycine max. (L.) Merr.] is grown throughout the southeastern USA as both a single, full-season crop and as a second crop following small grains. Cultivars currently grown in both systems were developed under conventional, single-crop conditions. Since genotype ✕ environment interactions are known to be important in soybean production, the question arises as to whether cultivars selected for performance in single-crop culture will be the best cultivars for double-cropping. Twenty-five determinate and 25 indeterminate F4-derived soybean lines were evaluated for seed yield in conventional and double-crop nursery environments to determine if: (i) relative rankings of lines for yield was similar in the two systems, and (ii) indeterminate lines were higher yielding than determinate lines under double-crop conditions. The tests were conducted at 16 location-year combinations from 1982 to 1986. The 50 lines were separated into two groups based on overall means: (i) a superior group of 17 lines that yielded above the mean in both types of nursery environments, and (ii) a nonsuperior group of all other lines. Line ✕ nursery environment interactions were significant (P ≤ 0.01) for both groups, but the magnitude of interaction was twice as great for the nonsnperior group. Simulated selection of the top lines from combinations of one, two, three, and four conventional or double-crop tests in 1985 produced up to 67% of the superior lines. The best line was selected in every case. eterminates yielded significantly (P ≤ 0.01) more in double-crop tests, but there was no difference in conventional tests. These results indicate there is no immediate need to maintain separate breeding programs to enhance the development of soybean cultivars adapted to double cropping.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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