Seed Quality and Yield of Early-Planted, Short-Season Soybean Genotypes
- W. L. Mayhew and
- C. E. Caviness
A new soybean [Glycine max (L.) Merr.] production system, in which early-maturing indeterminate cultivars are planted in early April, has been used by some growers in Arkansas and other Southern states. The intent is to escape late-season moisture deficits. This research was conducted to measure seed yield and seed quality (as determined by seed germination and viability) of Maturity Group (MG) III and IV genotypes planted in early April of 1989 and 1990 under nonirrigated conditions at three locations in Arkansas (approximately 34° to 36° N lat). Yields across the six environments averaged 1816 and 1992 kg ha−1 for four MG HI and four MG IV cultivars, respectively. ‘Williams 82’ produced the highest average yield (2072 kg ha−1) in MG III and ‘Competitor’ produced the highest (2110 kg ha−1) in MG IV. Seed germination was 32 and 39% for MG III and IV, respectively (average of six environments). Poor seed germination was associated with infection with Phomopsis longicolla T.W. Hobbs, one of the causal organisms of phomopsis seed decay (PSD). PI 417479 had significantly less PSD-infected seed than the other genotypes in three environments and averaged only 4% infection when all environments were included. Yield of early-planted, nonirrigated MG III and IV indeterminate cultivars was = 16% greater than for nonirrigated conventional cultivars, but the seed produced had low germination and viability. Highyielding, early-maturing cultivars with resistance to PSD need to be developed if this new production system is to be a viable management option for growers in the soybean production region of the U.S. South.
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