Seeding time on irrigated rice

Abstract

At six field experiments, seeded in October, November and December of 1978 and 1979, the rice blast disease (Pyricularia oryzae Cav.) and low temperature effects on the grain yield of the rice cultivars Bluebelle, EEA 406, IRGA 408, Dawn, and Caloro, were studied. The results showed that seeding time had effect on rice yield, and in the later seeding times, in December the yield was reduced simultaneously by the rice blast disease and cold. It was also determinated that the rice cultivars show differences on susceptibility to these factors, and that the early seeding, at October and November, gives the cultivation more chances for the rice crop lo escape from both blast and cold damages. The rice blast disease attack was more severe on the rice cultivars Caloro and EEA 406. On the other hand, the low temperatures injured more the rice cultivars IRGA 408 and Dawn. The Bluebelle, a short growth duration variety has more chances lo escape from these losses. No satisfactory correlation was obtained between the rice blast disease losses and the metheorological conditions.