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Evaluation of Rice Lines Tolerant to Heat during Flowering Stage

Masuduzzaman ASM, Ahmad HU, Haque M and Ahmed MME

Excess temperature hampers the normal physiological activities of rice. Therefore, breeding for improving heat tolerance in rice cultivars is a major objective throughout the tropical areas of Asia in the face of recent climatic changing situation. Screening for heat tolerance is one of the important issues to find out additional sources of tolerance to heat. An experiment was conducted following split-plot design. Temperature data will be recorded and best heat tolerant materials were selected based on yield, spikelet fertility and high grain filling under high temperature. Yield level and spikelet fertility of the entries are ranged from 11.92 to 32.8 g/plant and 61% to 86%, respectively. The highest yield was found in IR 86991-146-2-1-1 (20.02 g/plant.) followed by IR 87606-109-2-2 (19.35 g/plant). Highest spikelet fertility was observed in IR 88268-107-1-1 (86%) followed by IR 88268-124-2-3 (84%). The lowest pollen sterility was found in IR 86991-146-2-1-1(0-20%). IR 86991-146-2-1-1 was found as more tolerant to heat at flowering stage having higher yield/plant, higher number of filled grains/panicle and lower pollen sterility (0-20%). These materials could be used in crossing program to develop improved rice varieties with tolerance to heat for extreme heat prone rice areas of south-east Asia.