Genetic Analysis and Primary Mapping of pms4, a Photoperiod-Sensitive Genic Male Sterility Gene in Rice (Oryza sativa)

To understand the genetic characteristics of a new photoperiod-sensitive genic male sterile line Mian 9S, some reciprocal crosses were made between Mian 9S and six indica rice materials, Yangdao 6, Luhui 602, Shuihui 527, Mianhui 725, Fuhui 838 and Yixiang 1B. Genetic analysis results suggested that the photoperiod-sensitive genic male sterility （PGMS） of Mian 9S was controlled by a single recessive nuclear gene. Thus, the F2 population derived from the cross of Yangdao 6/Mian 9S was used to map the PGMS gene in Mian 9S. By using SSR markers, the PGMS gene of Mian 9S was mapped on one side of the markers, RM6659 and RM1305, on rice chromosome 4, with the genetic distances of 3.0 cM and 3.5 cM, respectively. The gene was a novel PGMS gene and designated tentatively as pms4. In addition, the application of the pms4 gene was discussed.

Studies on the Photoperiod Sensitive Characters of Male Fertility Alteration of Peiai64S' Main Male Genic Sterile Gene

Peiai64S, an indica male sterile rice with a male fertility alteration under different environments, is selected from the offspring of indica rice crossed with Nongken58S. Nongken58S, a japonica pho-toperiod sensitive genie male sterile rice (PGMS), deriving from a natural mutant plant individual of normal japonica rice variety, Nongken58, is used as a male sterile gene donor of Peiai64S. But Peiai64S is not a typical PGMS rice, the male fertility is sensitive to temperature just as thermo-sensitive genie male sterile rice (TGMS). We have selected typical PGMS plants in F2 population of Peiai64S× Nongken58, whose ratio of fertile plants to sterile plants is nearly 3:1. The sterility inheritance conformed to one pair of gene segregation model. The result indicates the main male sterile gene in Peiai64S is not other than the PGMS gene, and comes from Nongken58S. The genetic background affects effective expression of the PGMS gene. This suggests that we ought to focus on optimizing the genetic background of the PGMS gene in PGMS rice breeding, and select an ideal genetic background as a transgenic background in molecular breeding.

Selection and Characterization of a Novel Photoperiod-Sensitive Male Sterile Line in Upland Cotton

Upland cotton （Gossypium hirsutum L.） shows strong heterosis. However, heterosis is not widely utilized owing to the high cost of hybrid seed production. Creation of a photoperiod-sensitive genetic male sterile line could substantially reduce the cost of hybrid seed production in upland cotton. Such a mutant with virescent marker was found by space mutation in near-earth orbit and its traits had been stable after 4 years of selection in Anyang and Sanya, China. This mutant was fertile with an 11-12.5 h photoperiod when the temperature was higher than 21.5 ℃ and was sterile with a 13-14.5 h photoperiod. Genetic analysis indicated that both traits were controlled by a single recessive gene or two closely linked genes. Also, the cytological observations and transcriptome profiling analysis showed that the degradation of pollen grain cytoplasm should be the primary reason why the mutant line were male sterile under long-day conditions.

三系细胞质在两系法杂种优势的利用探讨

本文在两系法育种进行了细胞质方面的探讨。为克服目前光、温敏核不育系育性不稳的问题,首次提出了利用对低温较敏感的质核互作雄性不育细胞质或者受细胞质控制的耐寒性雄性不育系作供体,借助恢复系为桥梁亲本,杂交 F_1与光敏核不育系杂交,分离选择。三个组合实验结果,F_2分离出不育株多,育性转换株少,不同组合间出现育性转换株频率差异大。这些选择的单株,育性转换明显,对低温不敏感,且光照较敏感,不育性好。可获得光周期效应大,温变性小,不育性似三系雄性不育系稳定的光敏核不育系。