The Effection Of Male Gamete Selection And Diversity Of Cytoplasmic Background On Segregation Distortion Chromosomes In Cotton

Cotton, one kind of economic crop, is one of the most important sources of nature fiber and edible oil. Upland cotton and Sea-island cotton are the most important cultivated species, which support97%of the whole yield of cotton. Upland cotton is widely cultivated for its high yield and adaptability. For its high quality of fiber, Sea-island cotton is an important source for high-grade textile, and Sea-island cotton also has a better ability of resistance for disease.Creating new varieties with high yield, high quality of fiber and better resistance for disease with the method of wide cross between Upland cotton and Sea-island is the research direction of many breeders. However, due to the genetic relationship between Upland cotton and Sea-island, species isolation appears and becomes the barrier of breeding by wide crossing with the phenomenon of severe segregation and the difficult of assembling good traits.The developing of molecular marker provides a new powerful and efficient method to study the mechanism of species isolation. This study based on the result of experiments finished in our laboratory. The object is to verify the effective of male gametes derived from two reciprocal cross and diversity of cytoplasm background on ChrO2, Chr16and Chr18. The markers on the3chromosomes presented severe and widespread segregation distortion on the linkage map constructed in our lab.The results as below:female gamete selection may cause more segregation distortion marker than male gamete selection on the3chromosomes in BC population; the diversity of molecular markers segregation mostly happened on part segment of Chr16in the two BC1populations which were constructed by two reciprocal cross F1as male parent and a same line as female parent; the effection of cytoplasm background on molecular segregation also focus on Chr16, and the diversity was significant; the result of analysis of average focus content in single plant of the populations indicate that more loci of3-79on Chr16and Chr18in the BC1population which was constructed by (E22x3-79)F1as male parent than in the BC1population which was constructed by (3-79xE22)F1as male parent; there were more koci of3-79on ChrO2and Chrl6in the F2population with cytoplasm background of3-79, but there was no diversity significant in the F2population with cytoplasm background of E22; analysis result of the cause of segregation distortion of the2F2populations shows the effect degree of gamete selection and zygote selection on ChrO2and Chr16is the same and zygote selection has more influence on Chrl8than gamete selection. This research can provide some reference for understanding of genetic mechanism of segregation distortion chromosomes and wide cross in cotton.