A Study On The Inheritance Of Fertility Restoration Ability For CMS In Sinica Rice

1.The relationship between selfing seed-set rate and restoration ability was studied by using 68 plants in F₃ segregating generation of BT-Liuqianxin A/Xianjian 3 as male parents crossed with BT-Liuqianxin A or L-Pingrang 3 A.As shown by the results, when single F₃ plant was test-crossed with BT-Liuqianxin A?the selfing seed-set rate was basically equal to the restoring degree of its tF, (r=0.9130) ;when test-crossed with L-Pingrang 3 A,the situation was different (r=-0.0060) : among the 22 F₃ plants' tF, 21 showed a fertility restoration rate of 80% or more and the remainder 78.17% although the selfing seed-set rate of the 22 plants tested ranged from 16.63% to 95.99% This was becauseh type CMS lines were superior in restorable ability. The relationship between self ing- seed-set rate of F} plants and that of their F4 families was also investigated in the cross. The average selfing seed-set rate within F4 family was significantly positively correlated with selfing seed-set rate of Fj plants*2.The inheritance of fertility restoration ability for CMS in sinica rice was studied.The male - sterilelines(A) and maintainer lines(B) used were BT-Liuqian xin A?Liuqianxin B,L-Pingrang 3 A and Pingrang 3 B? The sinica restorer varieties(R) used were:Ninghui3-2 (restorer line in use commercially?from Jiangsu Province in China)>Hongke-Laoshuya(from Yunnan Province in China),CP23L(from America)?Arotamaro(from Italy), Honglinnuo39 (from Japan)*$ilimang,Huangdao( both from Tai Lake Valley in China).By crossing>backcross-ing and selfing.the following generations:?, (a/R) fBa (A//A/R) ,Bi' (A//B/R) >FZ F5 (both Fz and F3 contain sterile cytoplasm)were obtained in 14 combinations.Spi-kelet fertility was used as indicator of restoring-degree.As shown by the results, the 2 kinds of A lineswere gametephotic MS;Some restorer varieties have the saiiie restoration ability for both BT-Liuqianxin A and L-Pingrang 3 A# such as Ninghui 3-2 which could completely restore the fertility of the 2 kinds of A line; the others have different restoration ability for the2 kinds of A line* such as ArotamaroiNonglinnuo 39 which restore the fertility to ll-Q2c/o for L-Pingrang3 A.but only to 2O-54?b for BT-Liuqianxin A. Genetic analysis showed that the fertility restoration ability of Ninghui 3-2 for both BT-Liuqianxin ^ and L-Pingrang 3 A was controlled by one pair of dominant restoring genes;that of Nonglinnuo 39? Arotamaro and Cjr231 for L-?ingrang 3 A were also controlled by one pair of genes ? but CP231 was inferior to the other two varieties in restoration ability. The. restoration ability of Ho-ngke-Laoshuya for L—Pingrang 3 A?Arotamaro for BT-Liu qianxin A were controlled by one pair of major genes and some modifier genes. The restoration ability of CP 231.,Nonglinnua- 39? Yllimang, Huangdao for BT-Liuqianxin A were controlled by two pairs of weak restoring genes, and that of Huangdaq* lilimang for L-Pingrang 5 A werecontrolled by two and three pairs of weak restoring genes respectively. The weak restoring genes have dosage effect*3.The alleiism of the fertility restoring genes in the restorer varieties mentioned above*except Hingiaii 3-2 ? was also studied. The 6 restorer varieties were, crossed each otherfadding one reciprocal cross(Huangdao/Ydlimang)? altogether 16 R/R Fjcombinations were obtained. Then?the R/R F, s were test-crossed with. BT-Liuqianxin A and L-ping rang 3 A respectively. According to the- restoring degree variation of ti?i ?it was found that for BT-Liuqianxin A ? the fertility restoring genes in the 6 restorer varieties were not allelicrbecauce a certain ratio of male sterile plants and the plants which^er? still higher than the highest plant of tP, of parents in restoring degree apeared in the: R/R p, test-crossing generation. Un the other hand, far I*-Pingrang 3 A,the fertility restoring genes of Nongs-.. linnuo 39 was allelic with, that of Arataiuaro.,GP23t ?ad Hongke-LaQshuy,a?but aot allelic with that