Studies on water deficits on apical development and panicle initiation of grain sorghum (Sorghum bicolor L. Moench) incontrolled temperature glasshouse conditions

Controlled temperature glasshouse experiments were performed to determine the influence of water deficits, imposed during the period between seedling emergence and panicle initiation, on leaf primordium production, apex growth, and panicle initiation of grain sorghum (Sorghum bicolor L. Moench). The consequence of these water deficits on the duration of subsequent growth stages as well as grain yield was examined after transferring plants to an ordinary glasshouse at panicle initiation. Leaf primordium production was severely inhibited by periods of water deficit, with apparent cessation occurring around a dawn water potential of -1.0 MPa. Panicle initiation was delayed according to the duration of water deficit and the period of cessation of leaf primordium production. The duration of growth stages two and three were not altered appreciably by the treatments. Panicle initiation occurred earlier when plants were grown in 25/20 and 30/25 oC than in 20/15 and 35/30 oC day/night temperature regimens. Higher grain yields were obtained for plants previously grown at 20/15 and 35/30 oC compared with those grown at 25/20 and 30/25 oC. Ghana Jnl agric. Sci. Vol.30(2) 1997:161-16