Intergenotypic Competition Between Determinate and Indeterminate Soybean Cultivars in Blends and Alternate Rows1
- Sumarno and
- Walter R. Fehr2
Two experiments were conducted to evaluate the role of plant height on intergenotypic competition of soybean [Glycine max (L.) Merr.] cultivars and to compare directly their response in blends and alternate rows. The nine entries in experiment I consisted of three indeterminate cultivars with different heights, ‘Chippewa 64’, ‘Provar’, and ‘Amsoy 71’, grown in pure stand and three pair-wise combinations of the cultivars in 1:1 blends and alternate rows. The 15 entries in experiment II consisted of one short determinate, ‘Elf’, and two taller indeterminate cultivars, ‘Cumberland’ and (‘Williams’, grown in pure stand and three pair-wise combinations of the cultivars in 1:3, 1:1, and 3:1 blends and alternate rows. Four replicates of plots containing four rows spaced 40 cm apart were used in six Iowa environments during 1977 and 1978. Data on yield, maturity, height, and lodging were recorded separately for each component in a blend or alternate rows.
Yields of cultivar combinations in blends and alternate rows were not significantly different from the weighted mean of the components in pure stand, except for the 1:1 blend of Chippewa 64-Amsoy 71. Differences between cultivars for plant height did not consistently determine yield response in blends and alternate rows. The yields of blends and alternate rows were not significantly different for any cultivar combination. Factors other than yield should be considered in the choice between blends and alternate rows to achieve genetic heterogeneity in a field. The strongest competitor of a cultivar combination usually was the tallest, but an exception was observed. Changes in maturity, height, and lodging due to intergenotypic competition were small and of little practical importance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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