Interspecific Hybrid Between Gossypium Hirsutum And G. Sturtianum And Its Polyploidy Induction

Cotton is an important economic crop, there are rich germplasm resources in Gossypium, Wild cotton species have many valuable agronomic traits, Introgress the valuable agronomic traits of wild cotton into G. hirsutum, it has the vital significance.In this study, G. hirsutum Zhong 12 was female parent, it was crossing with G. sturtianum, then hybrid F1 was obtained, but F1 was sterile. Hope to restore the fertility of hybrid F1, Designed the different concentrations of colchicine agar gel, in order to induce the polyploid. The results indicated that the best inducing parameter was 0.2% colchicine for 24 h. The survival rate of mutagenic plant was 55% and the inducing rate was 5%. Compared with the control plant, mutant plant showed bigger cotyledons, shorter internode, later euphylla appearing. Petiole of cotyledons and stem performed nodular. The mutant plant had a prolific growth with a thicker color leaf and a bigger, thinner flower. Chlorophyll content in leaf increased by 20.01% from 32.13 of contrast to 38.56 of mutant. compared with the control plant, mutant plant showed bigger stomatal, lower density. It was tested that the obtained mutant plant was polyploidy by elementary typical characteristics of morphology and morphology.Not only in meiosis observation of F1 pollen mother cells was observed, but also meiosis of pollen mother cell in mutant plant was observed. The results showed that in meiosis observation of F1 pollen mother cells, there were many abnormal behavior, such as chromosome fragment, lagging chromosomes and unequal separation, meanwhile, found the microspores frequency of 41.03%, the abnormal pollen grains frequency of 67.64%, while explaining the sterility of F1. The meiosis of pollen mother cell in mutant plant was also observed. The results showed that the meiosis of pollen mother cells in 17.4% was normal and the percentage of normal pollen grain was increased by 6.66% compared with that of control plant. These findings indicated that the fertility of the induced plant had a tendency for fertility restoration.