Expression of Known Maturity Genes of Sorghum in Temperature and Tropical Environments1

In Texas, in the long days of summer (14.5 hr), combinations of dominant and recessive alleles at the four maturity gene loci in Sorghum bicolor (L.) Moench cause a spread in flowering from 40 to 100 days. In Puerto Rico in the short days of the winter (ll hr), the spread in flowering is 42 to 64 days. The maturity genotypes studied indicate that sorghums flower at about the same time in short days, but not in long days; and that flowering in long days can be explained in terms of a few genes. The maturity responses of sorghum in the tropics, under conditions described herein, are due to short days and not quantitative inheritance.