| Two elongated uppermost internode mutants were obtained from P(T)GMS line X07S by v -ray of 60Co irradiating it's dry seed. Genetics and breeding evaluation of the two mutants were studied, which included allelism test, plant height and internodes, growing traits, panicle exsertion, fertility altering character, floral and cross-fertilize characters, rice quality, analysis of combining ability and so on. The primary results were as following:1. Crossed with XQZeBl with euil and XQZeB2 with eui2 can know the two mutants are controlled by euil gene. The mutants were named as X07eSl-l and X07eSl-2 respectively.2. The pollen fertility of the mutants were the same as X07S. The result indicates that the expression of eui\ gene is independent of the male sterility gene. Moreover, the expression of euil gene does not affect pollen fertility. Compared with the original S line, X07eSl headed about l~2d earlier, the sterility period was longer about 5~9d.3. The plant height of X07eS1-l and X07eS1-2 were higher than control about 2.7-26.6cm and 1.8-16.1cm respectively. There hadn't significant difference of plant height between them in sterile period. After sterility alteration, X07eSl was higher as a significant level. The two mutants exhibited higher plant height because of elongation of uppermost and 2nd internodes. Because the uppermost sheath of X07eSl elongated 2.6-5.7cm more than that of X07S. The effect which euil gene getting rid of poor panicle exsertion wasn't significant in its sterile period. X07eSl released from panicle enclosure in fertilizable stage, whereas the panicle exsertion of X07S was about -6.1cm. During eight phases' survey, the two mutants were different slightly with control in dynamic expression of leaf age. The tiller ability of X07eSl seemed weak. The seedling height of X07eS1 was always higher after 10 days transplanted.4. X07eS1-1 and X07eS1-2 had increased remarkably about 20 spikilets per panicle. In addition, eS line had a tendency to increase its panicle and spikelet length as well as length-width ratio at a significant level. There didn't have significant difference among the three S lines in stigma vigor, they all losed stigma vigor at 7th day. They had low rate of stigma exsertion, the mutants were higher than X07S at some phases significantly. X07eS1-l and X07eS1-2 were inferior to X07S in flowering habit, they hadn't flowering peak apparently, and the total amounts of flowering spikelet were very few. The angles of opening spikelet among them had no significant difference. Opening periods of spikelet of the mutants were shorter.35. In hybrid seed production with X07eSl, using fewer GA3 had a satisfied result, that is to say, euil showed increased sensitivity to GA3. The quality of hybrid seed with eui\ was enhanced.6. Through incomplete diallel cross using 3 P(T)GMS lines and 6 restorer lines, combining ability was analyzed with 18 combinations. X07eSl-l and X07eSl-2 showed higher gca in plant height and filled grains per panicle. X07eSl-2 had greater gca in yield per plant. Using X07eSl-2 as female line could get higher yield, the increase of effective tillers per plant made the primary role. Plant height had close correlation with sea value. Yield per plant was related to sea, it seemed that the parents' gca were more important. The variances of gca were greater than those of sea in most characters of all combinations, indicating additive effect is dominant, the roles of dominant and epistatic effect are unimportant. The heriabilities of spikelets per spanicle, grains per panicle, ratio of seed setting and 1000-grain weight were large, which indicates the ability of transmitting from parents to offsprings is powerful.7. Milling qualities of X07eSl were better than that of X07S. They had more head rice. There was not regularity between the combinations whether concluding euil gene or not. All the three line's appearance qualities were inferior. The rate of chalky grain exceeded 80%. To get good appearance quality of combinations,...
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