Adaptability of rice varieties to low light intensity
1989
Islam, M.S. | Haque, M.Z. (Bangladesh Rice Research Inst., Joydebpur, Gazipur (Bangladesh). Plant Physiology Div.)
A major cause of low yields in the aus season in Bangladesh is low light intensity at later growth stages, mostly at ripening. Five modern and five traditional varieties were seeded so that the ripening stage would occur at the same time, late in the aus season to avoid cloudy weather. Twenty-five day old seedlings were transplanted in pots fertilized at 40-80-60 kg NPK/ha were topdressed in modern varieties and traditional varieties, respectively. As soon as panicles began to emerge, the plants were covered with cloth screens to provide 22-26% of full sunlight for 28 d. Check plants were grown in full daylength. The experiment was in a randomized complete block with six replications. Grain yield in all varieties decreased significantly with low light exposure. Hashikalmi was least affected, followed by BR9 and Kataktara. BR9 had the highest yields at both light intensities, and was the least affected modern variety. The highest yield reduction was in BR6, followed by BR1. Field spikelets were more affected than 1,000 - grain weight.
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