| A two-line hybrid system using thermo-sensitive cytoplasmic male sterility fromAegilops kotschyi proposed as a means for seed multiplication and production of hybridwheat is crossed to a pollinator line during the normal wheat-growing season for productionof hybrid wheat seeds production and maintained through self-pollination when planted inanti-season（spring or summer）. This manuscript elaborates the anther development, fertilitychanges, abortive morphological characteristics and cytologyical performances of the sterileline KTP116A and its maintainer line TP116B at various temperature environment by usingartificial climate chamber. Meanwhile, we built four groups made up by3sterile lineincluding KTPA116, restorer line and maintainer line to investigate the frequency of haploid,the self-setting rate of parents and progenies, and analysis the sterility type and genetic modelof the sterile lines genetic model of this kind sterile line. Furthermore, group KTP116A//TP116B/WM5-5was chosen as mapping population to locate thermo-sensitive recessiverestoring gene,712pairs of SSR markers were used to locate themo-senstive recessiverestoring gene, do linkage map and explore the genetic mechanism of thermo-sensitivecytoplasmic cytoplasmic male sterile line. The results show that:1.The pollen mother cells of KTP116A can carry the normal meiosis and producemicrospore and develop into mature pollen grains under fertile environment. In sterileenvironment, only a few microspores can go through the second mitosis and produce twosperm cells, most of the them are arrested at binucleate pollen grain, abnormal pollen grainsand shell anthers without protoplast, no anther dehisencing and power loosing unsdr naturalconditions; two fertility sensitive periods of KTP116A were from meiosis to early microsporeand binucleate to trinucleate, tempreture response time is10days, corresponding to2-8dbefore heading and the3-5d before flowering.2. There were no haploid produced in this male sterile line and its progenies after1RSchromosome segment was substituted by1BS chromosome segment; it is a gametophytesterility due to its nuclear gene passing on mainly through female gamete, we should choosebackcross group when constructing genetic map, the number of sterile plants is45and thefrequency of sterile plants is22.7%, crresponding to two pairs genes controlling by χ2 text(χ2=0.5455＜χ0.05，12), in addition to the sterility distribution, we reached a conclusion thatits fertility is determined by two pairs of maingenes plus other microgenes.3. Polymorphism between the parents, the sterile and fertile DNA bulks ware detectedwith712SSR markers and16pairs of markers were polymorphic.8markers locals includingXgwm413, Xbarc137, Xgwm11and Xgwm18on1B, Xgwm614, Xwmc474, Xwmc644andXgwm294on2A amplified identical polymorphism after198BC1individuals were furtherconfirmed.4. Linkage ralationship between the SSR markers and destination genes was analyzedusing Mapmaker/Exp, version3.0and the linkage map was drawm by sofeware MapDrawV2.1. One gene named rfv1spfor the male sterility was mapped between the markersXgwm413and Xgwm11at a genetic distance of8.9and12.0cM on chromosome1B,respectively, The second gene named rfv2was located on chromosome2A, flanked by themarkers Xwmc474and Xwmc644at a genetic distance of23.9and13.7cM, respectively. Thedevelop of these markers have important values on fine mapping, map-based cloning andfurther study of thermo sensitive genes. |
