Effect of water deficit at different growth stages on development and yield of three maize cultivars
1998
Kingkarn Kongjuntuk
Effect of water deficit at different growth stages on development and yield of three maize cultivars was investigated in dry season (November 1995 - March 1996) at Khaohinson Research Station, Chachengsao Province using a strip block design. Four irrigation schemes were the main plot; i.e. weekly irrigation, limited irrigation supply at vegetative stage (4 to 7 weeks after emergence), limited irrigation supply at tasselling (7 to 10 weeks after emergence) and limited irrigation supply at grain filling (9 to 12 weeks after emergence). The sub plot comprised of three maize cultivars; i.e. DK 888 (strongly drought tolerant), Suwan 3 (moderately drought tolerant) and Suwan 1 (drought sensitive). Water deficit at vegetative stage reduced plant and ear height, number of leaf, 34.1 percent of leaf area index (LAI), shoot biomass, number of tasselled spikelet and delayed tasselling by up to 4.8 days. Water deficit during vegetative growth did not significantly veduce grain yield. Water deficit imposed during tasselling stage reduce number of floret, 61.7 percent of grain yield compared to the irrigated control and delayed silking and physiological maturity by up to 6.8 and 1.6 days, respectively. Water deficit during grain filling shortened duration for physiological maturity. Grain size (1000-kernel-weight) and ear size were also reduced due to small growth rate during grain development. Water deficit during grain filling had little effect on grain yield. A comparison of yield potential between three contrasting maize cultivars (DK 888, Suwan 3 and Suwan 1) showed that DK 888 had 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 recover quickly from stress showed its acclimation potential and was more important to grain yield than the ability to tolerate stress.
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