Assessment of Flowering Response in Traditional Rice Varieties of Karnataka to Photo Period

Photoperiod influences several aspects of plant growth. The overall growth and development of plants and flowering are dependent on sunlight. The transition from vegetative to reproductive phase (flowering) is one of the most important decisions a plant has to take in order to guarantee the success of its offspring. Rice is sensitive to photoperiod; hence, a study was undertaken to know the flowering responses of 324 traditional rice varieties (TRV’s) of Karnataka to photoperiod, during two distinct season’s viz., kharif (2011) and summer (2012) at ZARS V.C Farm Mandya. The results of the study showed that, all the 324 TRV’s flowered during kharif with a wide range for 50% flowering (65 to 124 days). The same set of TRV’s after discarding duplicates was raised during summer and the results showed that, 64 TRV’s did not flower; 225 flowered with a wide range for days to 50% flowering (71 to 124 days). The study clearly establishes the fact that, flowering in rice cultivars exhibit a wide range of variation in their degree of sensitivity to photoperiod.