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A novel male-sterile maize mutant male sterility 39 (ms39) was obtained from offspring of the commercial hybrid Chuandan No. 9 that had been carried into outer space. A previous study demonstrated that ms39 is controlled by a single recessive nuclear gene, located on the long arm of chromosome 3. Here, we used 1073 mutant individuals derived from the (ms39 × Mo17) F2 population and sequentially developed new primers to identify markers supporting the fine mapping of ms39. A 365-kb region on chromosome 3 flanked by markers L8 and M30 at a genetic distance of 0.18 and 0.47 cM, respectively, was identified. According to the reference sequence of ZmB73_Ref-Gen_v4, 12 candidate genes were identified within the 365-kb mapping region. Based on cloning and sequence BLAST analysis of the 12 candidate genes, a four-base-pair deletion was found within the exon of Zm00001d043909, which encoded callose synthase12. This four-base-pair deletion resulted in a frameshift mutation in ms39, leading to the earlier termination of the coding protein, and ultimately caused abnormal performance of the callose synthase. Additionally, cytological observation was conducted on a sister cross population (ms39/ms39 × ms39/Ms39). These observations showed that the tapetum cells of the ms39 mutant appeared abnormal from the dyad stage, and aborted microspores were observed during pollen development. These results lay the foundation for the cloning of ms39 and exploration of the molecular mechanism underlying aborted pollen development in ms39 maize.

Two F2 populations with different kinds of spike derived from maize male sterility materials RP(3)195 (A) x S37 (inbred line) ,which had been sib-bred for many generations,were used for sterility analysis and gene location. There were 138 and 247 plants in the two F2 populations respectively. Among the 326 pairs of microsatellite primers selected,56 were found polymorphic. Linkage analysis of F2 populations with the 56 pairs of primers showed that microsatellite markers bnlg197 and umc1012 were linked with the male sterility gene. The genetic distance between marker bnlgl97 and the male sterility gene in the two different F2 populations were 7 cM and 14.5 cM respectively. The genetic distance between marker umc1012 and the male sterility gene in the 138 plants was 28.5 cM. Thus the male sterility gene was located on chromosome 3L.

Three sets of data for the P1, P2, F1, and F2 populations derived from three crosses between the normal fertility wheat (Triticum aestivum L.) cultivars with different ecotypes and the female sterile line (XND126) were used to investigate the inheritance of female fertility in wheat using mixed major gene plus polygenes inheritance model in 2005 and 2006. The results from the joint segregation analysis of the four generations showed that female fertility in wheat is controlled by two major genes plus polygenes, and the interaction between the two major genes is also detected.