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Development of New Cytoplasmic-Nuclear Male-Sterile Lines and Mapping Male Fertility Gene of NJCMS3A in Soybean

Author: LiShuGuang
Tutor: GaiJunZuo；ZhaoTuanJie
School: Nanjing Agricultural College
Course: Crop Genetics and Breeding
Keywords: soybean(Glycine max (L.) Merr.) cytoplasmic-nuclear male sterility inheritance gene mapping cytomorphology
CLC: S565.1
Type: Master's thesis
Year: 2009
Downloads: 49
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Abstract

Utilization of heterosis is one of the most important ways to increase crop yield quickly, however, it is still at primary stage for soybean. Up to now dozens of cytoplasmic-nuclear male-sterile (CMS) lines have been developed and many sets of "three lines" have been obtained in many different research institutions in China, and three soybean hybrid cultivars based on the "three lines" of CMS system have been released. Because of the poor outcrossing rate of the CMS lines under natural cultivation condition, it is very difficult to produce enough soybean hybrid seeds with cheap price for soybean production. The objectives of this thesis were to develop new CMS lines with different sterile cytoplasm sources and nuclear backgrounds, to reveal the genetic mode of CMS line NJCMS3A and map its male fertility gene through SSR marker technique, and to investigate the cytomorphology of nuclear male-sterile mutant NJS-1H in soybean. The main results were as follows:1. Some CMS progenies derived from N8855 and N21566 cytoplasm were obtained from National Center for Soybean Improvement, and five new CMS lines have been developed by three times of successive backcrossing with corresponding maintainer line. Among them, two possessed identical male-sterile cytoplasm (N21566):NJCMS 4A (BC8F1) and NJCMS (N21566/73-935) (BC3F1); the other three ones derived from the male-sterile cytoplasm (N8855):NJCMS5A (BC8F1), NJCMS(N8855/ 88-48) (BC4F1) and NJCMS (N8855/73-935) (BC3F1). On the other hand, NJCMS 4A/NJCMS 3A、NJCMS 5A/ NJCMS 1A were iso-nuclear lines with different sterile cytoplasm. The male sterility of these five CMS lines was stable among different years based on pollen dispersiveness and germination viability, as well as fertility performance at maturity stage.2. The cross between cytoplasmic and nuclear donor parents (N21566/N21249) of CMS line NJCMS3A was made, its F1 plants were fertile according to the pod-setting situation. The results of the fertility performance of (N21566/N21249) F2, (N21566/N21249//N21249) BC1F1 generations showed that the segregation ratio of two phenotypes, i.e. fertile and sterile plants, in the F2 and BC1F1 fit 3:1 and 1:1 expected ratios, respectively. It indicated that there might be one pair of gene for the male fertility of NJCMS3A, and the plants which had the dominant gene were fertile, vice versa, sterile. The above-mentioned F2 and BC1F1 populations were utilized to map male fertility gene of NJCMS3A with 793 SSR markers selected randomly from the soybean public genetic linkage map reported by Song et al.(2004). Three SSR markers, Satt331, CSSR133 and Satt477 in linkage group O, were found linked to the fertility gene Rf of NJCMS3A, the genetic distance were Satt331/8.1 cM, CSSR133/11.4 cM, Satt477/13.3 cM, respectively..3. It confirmed that the male fertility of a nuclear male-sterile mutant NJS-1H was controlled by a single recessive nuclear gene according to the fertility segregation data of the NJS-1H progenies (M8:9, M9:10 and M10:11). Nomal squash and acetocarmine dyeing observation indicated that the meiosis of pollen mother cells of NJS-1H sterile plants was highly irregular with chromosome asynapsis or desynapsis. There were univalent, chromosome lagging, unequal and asynchrony distribution among other phenomena during meiotic division. At tetrad stage, various malformed polyad with micronucleus can be observed, then, the degenerated microspores were empty, shrunken without cytoplasm at uninuclear microspore stage. The results showed that there appeared different sterility characters from initial stages of meiosis to pollen maturity, and the pollen abortion of NJS-1H occurred mainly at meiosis stage, and the disorder of chromosome synapsis at meiosis might cause the pollen degeneration after tetrad stage.

Development of New Cytoplasmic-Nuclear Male-Sterile Lines and Mapping Male Fertility Gene of NJCMS3A in Soybean

Abstract

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