Evaluation of Intergenotypic Competition with a Paired-Row Technique1
- W. R. Fehr2
A paired-row technique was developed to measure intergenotypic competition between soybean (Glycine max (L.) Merr.) cultivars. A paired-row plot consisted of two rows spaced 8 cm apart, the closest that we were able to grow soybeans in Iowa and still distinguish the individual rows at harvest. Different paired-row plots were grown 1 m apart. To evaluate the competitive interaction of two soybean cultivars, three paired-rows are needed per replication, one where the cultivars compete and one for each of the two cultivars in pure stand.
Intergenotypic competition in paired-rows was compared with that in a 1:1 blend grown in a single-row plot for nine cultivar pairs. A cultivar with tawny pubescence and a cultivar with gray pubescence were selected for each blend to permit separation of the cultivars at maturity. The individual cultivars were harvested separately in both the paired-rows and the 1:1 blend, and their yield performance was compared with that in a pure stand.
The paired-row technique was effective for determining the good and poor competitors in a blend for every cultivar pair tested. The percentage yield increase or decrease of each cultivar in competition generally was similar in the blend and the paired-rows. The data suggested, however, that growing cultivars in rows only 8 cm apart did not perfectly simulate the competitive interactions that occur in a 1:1 blend.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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