Heading and spikelet fertility in cold tolerant rice genotypes as influenced by environments in high altitude area

Eighty-eight cold tolerant rice germplasm consisting of indica, japonica and javanica types were evaluated in direct seeded, rainfed, upland condition at three sowing dales (SD) in high altitude area of Garhwal Himalayas. Heading time was not significantly altered by the first (24 April) or the Second (28 May) SD, but very few lines flowered in the third SD (28 June). Heading time was reduced by 237 days in the third SD. About 64% lines showed head emergence while, 28% lines bore fertile spikelets. Japonica and Javanica types showed increased head emergence and spikelet fertility. Average spikelet fertility was, in general, more in the cloudy conditions during anthesis, as compared to that of the first SD (3.64%) indicating not only the possible role of low temperature in influencing this character but also of other factors as well. High spikelet sterility in some early maturing lines vindicated this fact further.