Yield Compensation for Stand Deficiencies by Determinate and Indeterminate Growth-Habit Soybean
- G. E. Pepper and
- J. T. Walker
Soybean [Glycine max (L.) Merr.] stands that emerge poorly are often replanted without taking into consideration the yield compensating ability of the plant in the field. This study was done to determine if compensation for yield in deficient soybean stands is influenced by the growth habit (determinate versus indeterminate). Gaps imposed at or before stage V2 were used to generate stand deficiencies. Compensation for yield in stands having gaps of fixed sizes was measured in the indeterminate cultivar Cumberland and the determinate cultivars Gnome, Sprite, and Pixie in 1981 and 1982. Three seeding dates were used in trials conducted on a Flanagan silt loam (Aquic Argiudoll) at Urbana, IL, and on a Cisne silt loam (Mollic Albaqualf) at Brownstown, IL. Compensation in yield for missing plants was found in both the rows with gaps and in adjacent full rows. Grain yields in gapped rows, having stand reductions equal to 63%, averaged 1614 kg/ha, or 55% of the control plot yield of 2923 kg/ha. Yields in adjacent full rows increased as much as 19% in response to the 63% stand reduction in gapped rows. In 1983, the determinate cultivar Sprite and the indeterminate, Asgrow A3127, were compared under farm field conditions where random gaps of various size were imposed as treatments. A single timely seeding was used. High levels of yield compensation for missing plants were again measured. Grain yields resulting from 60% stand reductions were only 25% less than those of full stands. Analysis of variance was used to evaluate gap x cultivar responses. The lack of a cultivar × gap interaction found in the analysis of variance suggested compensation for irregular or gap-filled stands was not influenced by the growth habit of the soybean.
Copyright © . .