Effects of Water Deficit at Different Growth Stages on Development and Yield of Three Maize Cultivars
Kasetsart University, Chatuchak, Bangkok 10900
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The effects of water deficit at different growth stages on development and yield of DK 888 (strongly drought tolerant), Suwan 3 (moderately drought tolerant), and Suwan 1 (drought sensitive) maize cultivars were investigated in dry season (November 1995March 1996) at Khaohinson Research Station, Chachoengsao province. Four irrigation schemes were weekly irrigation, limited irrigation at vegetative stage (4 to 6 weeks after emergence), limited irrigation at tasselling (7 to 10 weeks after emergence), and limited irrigation at grain filling (9 to 12 weeks after emergence).
Water deficit at vegetative stage reduced plant height as well as ear height, number of leaves, 34.1% of leaf area index (LAI), shoot biomass, number of tasselled spikelets and delayed tasselling up to 4.8 days. However, water deficit during vegetative growth did not significantly reduce grain yield. Water deficit imposed during tasselling stage reduced number of florets, 61.7% of grain yield compared to that of the control (no limited or optimum) irrigation and delayed silking and physiological maturity up to 6.8 and 1.6 days, respectively. Water deficit during grain filling shortened physiological maturity duration. Grain size (1000 kernel weight) and ear size were also reduced due to low growth rate during grain development. Water deficit during grain filling had little effect on grain yield. As expected, DK 888 gave higher grain yield than Suwan 3 and Suwan 1 when subjected to water deficit during either vegetative or reproductive growth stages. The ability of DK 888 to have quick growth recovery from stress was more important to grain yield than the ability to tolerate stress.
Kingkan