Performance and Use of Seedcoat Mutants in Soybean
Soybean [Glycine max (L.) Merr.) mutants with solid (i) or saddleshaped (/k) seedcoat color patterns occur as the result of natural mutations at the I locus. These mutant isolines may be useful in determining effects of environmental factors, such as diseases, on resistance genes that could be backcrossed into one of the isolines. Prior to such uses, the productivity of the isolines would have to be determined. The first objective of this study was to evaluate the agronomic performance of seedcoat mutants in several cultivars in comparison with the normal (ii) isoline. A second objective was to determine the frequency of these in harvested seed from 1:1 blends with the normal isolines. Normal and mutant seedcoat isolines of six maturity Group II and III cultivars and blends of the two isolines were evaluated for 2 years in four-replicate tests at Lafayette, IN. In a second test, performance of ii, ik, and i isolines of ‘lCentury’ were evaluated for 2 years at the same location. There were no differences in seedling emergence, maturity date, lodging, mature plant height, or seed yield among isolines of the differnet cultivars except for a 9% difference in seedling emergence for one cultivar and a 1- and 2-day difference in maturity date for two cultivars in these tests. The 2-year average frequency of normal seeds in the blends varied from 51 to 53% based on a 400-seed count of harvested seed from each replication. Chi-square analyses of the frequency of normal and mutant seeds harvested from the blends indicated a significantly higher reproductive rate for the ii than for the i allele. The use of seedcoat mutants to study effects of environmental factors, such as diseases, on isolines of specific cultivars was discussed.
Copyright © . .