The leafy hull sterile (Ihs) mutant is characterized by a deformed lemma and palea showing a leafy sheath structure and accompanied by various malformed floral organs, in the retarded panicle rp(t) mutant, panicle development is inhibited under low-temperature conditions. The neckleaf nl1 mutant has a bract leaf at the neck node of the panicle. We examined genie interactions among Ihs, rp(t), and nl1. Double mutants were produced in F_2 populations of crosses among three lines -- H-726 (Ihs), N-180 (rp(t)), and H-69 (nl1). A segregation ratio of 9:3:3:1 was observed in the respective populations. The double mutant Ihs rp(t) showed shoot-like spikelets, whereas the double mutant rp(t) nl1 showed shoot-like panicles. In contrast, the double mutant Ihsnl1showed Ihs-type spikelets and nl1-type bract leaves. Therefore, there is no genie interaction between Ihs and nl1. Two double mutants (Ihs rp(t) and rp(t) nl1), their parental lines, and cultivar Shiokari as the control were tested for rooting and vegetative growth ability from sterile spikelets and panicles. Only the double mutants Ihs rp(t) and rp(t) nl1 grew to independent plants from their shoot-like spikelets and panicles, respectively. These results indicated that the double mutants Ihs rp(t)and rp(t) nl1 inhibit the differentiation of floral organs, thus maintaining vegetative growth during spikelet and panicle development, respectively.
展开▼
