Genetic Analyses On The Sterility Instability Of CMS Line Longtepu A

Longtepu A(LTA) is a favorable CMS line with high yield general combining and outcrossing abilities, while its instability in sterility is a main obstruct for its broader use. In order to improve the sterility stability of LTA , three maintainers (T55B~ T77B and T87B, designated as TB) and their corresponding CMS lines (T55A~ T77A and T87A, designated as TA) were bred by means of genetic improvement of Longtepu B(LTB). In this study, the LTA (LTB) and TA(TB) were used as parents to make up F1~. F2-. BC1 and BQ populations to study the inheritance of the sterility instability of LTA. The results were as follows:1.The sterility of LTA with a great various distribution of fertility was unstable, whilst, the sterility of Thwith a little fertile variation was stable.The extremely significant difference between LTA and TA in sterility was detected by t梩est. Among 慉p T77A and T87A had a little stabler sterility than T55A.Meanwhile, FIA(TA/LTB)also showed a stabler pollen sterility than LTA, suggesting that F1A would be some potential value in pra鐍tical use.2.The stable fertility of T77F1A(T77A/LTB) with a pollen fertility 3.79% was similar as that of its parent(T77A), the same tendency was observed in T87F1A(T87A/LTB) as well. These showed that the stable fertility of T77A and T87A was completely dominant over unstable fertility of LTA. However, The fertility of T55F1A was between that of their parents and biased T55A, which suggested that the genes controlling fertilitystability of T55A were characterized by partial dominance.3.The pollen fertility ofF2 and BC1 in three combinations during different heading dates presented a continuous multiple climax distribution, which indicated that the sterility instability of LTA was controlled by several major genes and modifiers . If the type of fertility was divided by the valley of fertile distribution, the segregation ratios of fertility in the F2(T87F2A ~. T77F2A) and BC1(T87BC1T77BC1)populations were 15(stable sterility): 1(unstable sterility) and 3(stable sterility):l(unstable sterility)respectively, indicating that the sterile stabilities in T87A and T77A were mastered by two pairs of overlap genes . On the other hand, the ratios of pollen fertility in the F2(T55F2A) and BC1(T55BC1) populations of T55A showed a satisfactory fit to 9:6:1 and 1:2:1 ,which revealed that the stable sterility in T55A was characterized by two pairs of genes with dosage effect...