The Influence of Cropping Season on the Growth and Yield of Inbred and Hybrid Sorghum [Sorghum bicolor (L.) Moench]
Eight sorghum inbred lines and eight F1 hybrids were grown at two locations in the fall cropping season of 1991 and spring cropping season of 1992. Several important agronomic characters were investigated and the grain yield was evaluated to compare the performance of inbreds and hybrids between different cropping seasons. Experimental results indicated that for all traits, significant difference was observed between two cropping seasons but not between the two locations. The investigation of growth duration showed that the days from emergence to flowering were less in the fall than in the spring season. On the contrary, the total growth period and the actual grain-filling period were longer in the fall crop season. In general, the hybrids grew faster than their respective parental inbred lines. For the comparison of the means of agronomic traits, significant differences were observed between the two cropping seasons for both the inbred lines and the hybrids for all traits with the only exception of 1,000-seed weight. The correlation between grain yield and growth duration was negative in the spring crop but positive in the fall crop.