Effects of a Single Height Gene (DW3 of Sorghum on Certain Agronomic Characters1

Abstract

Results of a study, to determine more closely the degree of dominance of the Dwa gene of sorghum [Sorghum bicolor (L.) Moench] and to investigate further the relationships between height and other agronomic traits, are reported. Isogenic lines of ‘Martin,’ ‘Plainsman,’‘Redlan,’ and ‘Tx403,’ homozygous for the dominant and recessive allele of Dws were compared with heterozygous lines produced from crosses of each short line to its tall counterpart.Data were collected and analyzed for culm height, grain yield, test weight, kernel weight, panicles/plant, peduncle length, and node number. Height genotype influenced total yield, test weight, panicles/plant, and kernel weight, as well as culm height. Cultivar ✕ height interactions were observed for height, test weight, and kernel weight. Height appeared to be partially dominant. The degree of dominance recorded for Martin, Plainsman, and Redlan was 0.70, 0.70, and 0.82, respectively. Yields of the heterozygous lines were not significantly different from those of the corresponding homozygous tall lines. In general, heterozygous lines had test weights and kernel weights equal to those of the tall homozygous fines and higher than those of the short parents. Heterozygous lines tended to have more panicles/plant than did either the tall or short lines.