Effects of Hybrid x Irrigation x Seeding Date on Grain Sorghum in the Midsouth.

Grain sorghum (Sorghum bicolor L. Moench) is seldom grown in the Midsouth using irrigation. Seeding is done usually the latter half of May. Four commercial hybrids were planted in May 2016 April 2017 and mid-June 2016-2017. A split-split plot design replicated twice was used with whole-plots as furrow irrigated vs. dryland treatments; planting dates as sub-plots; and hybrids as sub-sub plots replicated trice within sub-plots. Like in previous research irrigation had no effect on seed yields. Yields were greater (P≤0.05) in 2016 (4803.8 kg ha^-1) than 2017 (3867.2 kg ha^-1) and earlier seedings greater (5539.7 kg ha^-1) than June plantings (3131.3 kg ha^-1). The hybrid P38P17 tended to have higher seed yields than most other hybrids except for the June 2017 planting where no differences were observed. Fewer heads m^-1 were produced in June plantings than in earlier seedings. Kernels per head were greater (P≤0.05) for early seedings (2420) than June plantings (2008) and 2016 seedings (2862) greater than 2017 (1565). By contrast weights of 1000 kernels were greater (P≤0.05) in June seedings (24.4 g) than earlier ones (23.2 g) and in 2017 (28.2 g) than 2016 (19.4 g).