Abstract
The experiment was carried out in pot culture, using two indica varieties (Mas-24 and Muruga-kayan-302) to determine the effect of shading treatment given during the period of 3 weeks before heading or after heading on sterility in indica rice as a part of“studies on sterility of indica rice”in the Department of Agriculture, Peradeniya, Ceylon 1959.
Results obtained are summerized as follows :
1. Shading treatment given at this stage showed no effect on number of panicles per plant in both varieties.
2. The pre-heading shading caused a remarkable decrease in sterility percentage due to an elemination of excessive number of spikelets, particularly in Mas-24.
3. Post-heading shading caused a remarkable reduction in the carbohydrate production during after heading accompanied with very high sterility.
4. Combined pre-and post-heading shading gave an intermediate percentage of sterility between pre-heading treatment and post-heading treatment because effect of both treatments was was compensated with each other.
The results presented here suggest that high sterility percentage observed in general with some of the indica varieties might be attributable to the nature of the varieties capable of producing so many number of spikelets per panicle for the quantity of carbohydrate to be available.
