Study On Genetic Diversity Of The Distant Hybridization Cotton Germplasms And Some Cotton Cultivars In Hubei Province

Utilization,exploitation and innovation of germplasm resources are fundamental work in new cultivars breeding.Wild Gossypieae are abundant in genetic diversities and comparatively possesses a lot of elite genes which can be utilized in cotton breeding. Furthermore,these potential elite characters can be transfered from wild Gossvpieae to the species of G.hisutum through distant hybridization,and may broaden upland cotton genetic diversities in some sense.In this study,97 cotton germplasms were collected,which derived from interspecific crosses between G.hirsutum and other wild species and involved 17 types of wild Gossypieae and upland cotton lines or cultivars.The Cluster Analysis based on 62 pairs of highly polymorphic SSR primers was used to analyze 97 cotton germplasms mentioned above and 28 cotton cultivars from Hubei province,and this analysis focused on their important agronomic traits,such as yield,fibre quality and resistance.223 polymorphic bands were produced among 97 cotton germplasm and 28 cotton cultivars from Hubei province by 62 SSR primers,and each primer amplified 2～10 polymorphic bands, averaging 3.6.Dendrograms based on Jaccard's genetic similarity coefficients were constructed by the unweighted pair group method of arithmetic average(UPGMA) using the NTSYS-pc version 2.11.The purposes of this paper were to evaluate the effect of germplasms innovation,to find a good method to broaden cotton germplasms resources and finally to select some cotton germplasms can be applied to cotton breeding.The results of this study were as follows:1.There were 97 cotton germplasms which were classified into 4 groups by analysis of dendrograms construced by NTSYS-pc version 2.11 based on molecular markers technology related to 62 pairs SSR primers amplification.The cluster result can match its previously published pedigree of these germplasms at a great measure except a small part. The genetic similarity coefficients among all the germplasms ranged from 0.659 to 0.974 with an average of 0.833,which indicated that the genetics background of the germplasms was comparatively narrow.The cluster result cannot match its pedigree of the island cotton descent partially because the corresponding germplasms derived from different way of breeding involved with different parents.Interestingly,the germplasms unmatched the previous pedigree corresponded to the widest genetic similarity coefficients range.2.There were top 70 cotton germplasms among 97 cotton germplasms mentioned above that were classified into 6 groups and the squared euclidean distance ranged from 1.6 to 28.08 with an average of 5.24,which mainly based on the analysis of 13 agronomic traits.Germplasm 1(G..latifolium descent) and Germplasm 39(G.arboreum,G.anomaluc, G.hirsutum and G.barbadense descent) were classified into 2 corresponding groups respectively and the rest of the materials were classified into 4 corresponding groups respectively only due to its unique agronomic traits.There was a wider range of the squared euclidean distance compared the Germplasm 1 with the others.Finally,we got some conclusions that the genetics background of most germplasms were comparatively narrow and the genetic diversity were relatively poor.3.All the Germplasms analysis of the agronomic traits showed that the variation extent of yield traits and disease resistant trait was higher than of fiber quality traits,and indicated that the Germplasms preferred to fiber quality traits in terms of artificial selection.4.Compared with different descent germplasms on the effect of breeding improvement of fiber quality traits,G.anomalum and G.thurberi descent Germplasms played an important role in fiber strength,and G.anomalum played a great part in fiber length.The self-inbreded materials from hybridization between G.hirsutum and G. barbadense was excellent in fiber quality,but the other materials from bloodline of G. hirsutum behaved ordinary.The results showed that the contributed effect of different cotton gossypium or species on fiber quality was different,and the effect of the same cotton gossypium or species from different breeding pattern was also different.5.There were 5 cotton germplasms screened out that had good fibre quality.They derived from G.barbadense,G.armourianum,G.thurberi and G.anomalum descent germplasms,which indicated these cotton descent germplasms played an important role in good fiber quality traits.A batch of high yield germplasms were found,with a number of bolls per plant.6.A batch of cotton germplasms with Resistance to Fusarium wilt and Verpicillum Wilt were obtained,among which 6 germplasms were high resistant to both Fusarium wilt and Verpicillum Wilt,and 5 were resistant to Fusarium wilt and high resistant to Verpicillum Wilt,and 11 were tolerant to Fusarium wilt and resistant to Vertillium wilt, and 20 were sensitive to Fusarium wilt and tolerant to Vertillium wilt.The exogenic parents of these germplasms derived from G.thurberi,G.anomalum,G.arboreum, G.barbadense,G.herbaceum,G.stocksii,G.raimondii,G.armourianum,G.latifolium, G.bickii,G.tomentosum,G.somalense,G.Paimerii.It was indicated that these wild germplasms or cultivars of cotton germplasms possessed excellent characteristics with resistance to Fusarium wilt and Verpicillum Wilt.These results was consistent with previous studies.7.According to the clustering analysis of mainly 28 cotton cultivars from Hubei province,the 28 cotton cultivars were classified into 5 groups on the basis of the average similarity coefficient(0.882) among 28 cotton cultivars.The genetic similarity coefficients ranged from 0.73 to 0.955 with the average of 0.859,which indicated that the phylogenetic relationship was very similar among 28 cotton cultivars from Hubei province.8.According to the yield,the fiber quality and disease resistance analysis of 28 cotton cultivars related to different breeding periods from Hubei province,we got some interesting conclusions that the lint yield,boll weight,fiber strength and lint percentage had some various degrees of growth on all the previous renewed cultivar in Hubei province.The results indicated that these cultivars had good prolificacy and excellent fibre length,but their Mic value were too large and fiber strength were too low.So there was a lack of high quality cotton in good fibre quality traits.Most of the 28 cotton cultivars were the medium varieties,and their types of variety were poor.There were almost susceptible varieties during the early period cultivars in Hubei province,and afterwards,most of the cotton cultivars were resistant or tolerant to Fusarium wilt and Verpicillum Wilt.Recent years,the mixed growth of Fusarium wilt and Verpicillum Wilt is serious and threaten the cotton yield in Hubei province,therefore it is greatly necessary to breed new cotton cultivars and significantly strengthen the new cotton cultivars resistance to both Fusarium wilt and Verpicillum Wilt at the same time.