| 8015s, a new sterile line of its fertility controlled by both day-length and temperature factors, has the characteristic of producing hybrid seed safely and multiplying itself easily, thus it has a well applying prospects. Its growth characteristic, fertility alteration, outcrossing habits, multiplication, and combining ability were systematically studied and discussed in this dissertation. The main results are as follows.1. 8015S had some good agronomic traits with dwarf plant height of 85cm, compact plant type, erect and peak green leaves of its life, upper 3 leaves with the long, erect, narrow, V-shape and thick characteristic, thickset culms, short internodes of bottom stem, strong tillering ability and big panicle of about 185 spikelets.2. Fertility initial temperature of 8015s was low in comparison to that of Peiai64s, and fertility alteration was co-controlled by dual factors. There was not the fertile period under the natural condition in Changsha in 2002 and 2003.After 8015s was treated with cold water of 22.0℃ for continuous 9 or 15 days respectively in Hunan Normal University, the results showed corresponding stainable pollen rate was 3.5% and 82.3%, and corresponding bagged seed setting rate was 0 and 59.6%. Obviously, it was rather safe to produce hybrid seed in Changsha.3. The average seed setting rate of being test-crossed with 4 testers was 81.0%, and the result showed that its wide compatibility was good.4. 8015s had good outcrossing habits. Its flowering habit was of early flowering time, obviously peak anthesis, spikelet opening angle of 32? , and spikelet opening time of about 180 mins. Length, width, area and bulk of stigma were 1.25mm, 0.46mm, 0.57mm2 and 0.168mm3 respectively, and the stigma exserting rate, single exserting rate and double exserting rate were 90.5%, 28.5% and 62.0% respectively. In addition, spraying "920" of 200g/hm2 could remove the "wrapping neck" phenomenon during heading rate of about 5 %.5. Initial flowering and blooming flowering time were corresponding late of 2 or 3days in comparison to initial heading and flourishing heading time, so it was feasible to adopt the seed production technique of "one period male parent". However, generally, the period from initial heading to heading time of male parent was shorter, and flowering time was more concentrated. Thus it was advantageous of meeting with the blooming flowering time of parents if the initial heading period of 8015s was early 2 or 3 days in comparison to that of male parent.6. Among these combinations combined with R288 and 6 different female parents, their analytical results of control superiority of main traits showed that 8015s/288 was with the biggest control superiority of panicle number per plant and total grain number per panicle, which were 4.94% and 15.36% respectively, and that the yield control superiority of 8015s/288 was 15.31 %, reaching the extremely significant level.7. The correlation analysis of main traits of these combinations, combined with 8015s, showed that yield was positive relation to panicle number per plant, grain number per panicle, seed setting rate and 1000-grain weight, and this kind correlation with 1000-grain weight reached significant level, and that plant height was significantly negative correlation with panicle number per plant, and it was significant correlation between seed setting rate and panicle length.8. 8015s pollen fertile percentage and bagged seed setting rate was respectively 79.9% and 60.5%, after it was running-irrigated with cold water ( its input-water temperature of 19.2 C, and outlet-water temperature of 21.5 C ), under natural short day-length condition from 1 st to 8th September in Changsha. It was feasible to treat with artificially creating photo-thermo-condition for 15 days in order to multiply 8015s, and was advantageous to multiply 8015s under the Hainan's climate condition if the fertility sensitive period was arranged in February and the heading and flowering was in warm March, the high-yield of multiplying itself...
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