1990 Volume 40 Issue 1 Pages 33-45
Yukara dwarf and Fukei 71 are dwarf mutants of different origins, which are characterized by a strong lodging resistance. Genetic experiments in this study indicated that the dwarf gene of Fukei 71 is the same as or allelic to d-12 of Yukara dwarf. A specific response to high temperature was observed in both Fukei 71 and the d-12 isoline (recurrent parent is a cultivar, 'Shiokari'): the internode elongation was depressed when average temperatures exceeded 26°C. Through the effect of d-12, the third (from the uppermost) to fifth internodes were markedly shortened, resulting in lower positions for the developing panicles of the d-12 isoline than for those of Shiokari. When cool weather occured, the developing panicles of the d-12 isoline were protected under the surface of the irrigation water warmer than the air while the most of the spikelets of Shiokari became sterile owing to the cool air. Under a normal condition, however, the yield of the d-12 isoline was somewhat lower than that of Shiokari owing to the decrease in the number of spikelets per panicle.
