Effects of tall alleles and to the dwarfing allele originating from 'Dee-geo-woo-gen' on yield and related traits on the genetic background of IR36 in rice.

originating from 'Dee-geo-woo-gen' has been utilized to develop short-culmed varieties adaptable to higher fertilizer-application. Its tall alleles and are harbored in and subspecies, respectively. The of IR36 was substituted with or by recurrent backcrossing with IR36, and two tall isogenic lines ("5867-36" and "Koshi-36") were developed. IR36, 5867-36 and Koshi-36 were grown in a paddy field in three years, and yield and related traits were measured, the effects of and on yielding ability and related characteristics were examined on the genetic background of IR 36. decreased panicle number per m but increased spikelet number per panicle, ripened-grain percentage and 1000-grain weight, compared with , resulting in the increase of yield. The increase of 1000-grain weight by , caused by the increases of length, width and thickness of grain, was due to the increases of the length and width of lemma. did not significantly affect yield, mainly because the decrease of panicle number per m was compensated by the enlarged 1000-grain weight owing to the increase of lemma length. Serious lodging was observed in long-culmed 5867-36, suggesting that is indispensable for breeding programs.