The Analysis To The Fluctuation Of Endogenous Hormones During Fiber Development, The Difference Of α-tubulin Gene And Blood Relationship Among Cotton Lines

In this paper, the fluctuation of the contents of endogenous hormones(IAA,GA1+2+3 and ABA) in ovules of cotton varieties(lines)were examined by using Enzyme Linked Immuno Sorbent Assay(ELISA). Sequence of α-tubulin, the gene which is correlative with fiber development, was analyzed with the means of linking PCR and sequencing from cotton varieties(lines) with different quality. Thirteen cotton varieties(lines) was studied using RAPD. The main results are as follows:⑴Endogenous hormones have an important effect on cotton fiber development. The increase of IAA helps to the differentiation of ovule epidermal cell and to the enhancement of fiber quantities on single seed at 0－3 days after anthesis, accordingly, increasing lint percentage and fiber length uniformity. GA1+2+3 stimulates the elongation of fiber after anthesis. GA1+2+3 with high contents is in favor of the thickening of fiber cell wall and abundant sediment of cellulose, thereby, heightening fiber strength. ABA restrains the elongation of fiber. The balance of above three endogenous hormones control the fiber development. ⑵Homology of α-tubulin of Zhongmian 12 and Lvxu 12, Shannongzong 01,Nongdazi 07 is respectively 94％,98％,98％. Therefore,α-tubulin havevery conservative,but there is a certain difference among different cotton varieties(lines).Comparing the sequence of α-tubulin DNA segment of four cotton materials with different quality and combining their quality and agronomic characters , we find that the change of α-tubulin affects the morphogenesis of the cotton fiber,controls the sediment manner of cellulose and the synthesis of glucan. In a word,α-tubulin has an important action on fiber elongation and secondary wall thickening. ⑶The difference of single base can be screened out by the combination of PCR and sequencing. Therefore, this method can detect gene mutant as a new molecular marker. It can directly detect the difference of different genus, species and varieties in the level of DNA and it is more convenient, direct and reliable than some other means.⑷Lvxu12,Shannongzong01,Nongdazi07 and other ten varieties(lines) belonging to Gossypium hirsutum L were analyzed by RAPD markers to determine their blood relationship. Of the 10 primers screened, eight primer showed consistent banding patterns and amplification and produced 51 bands with 33 polymorphic. The blood relationship of two color cotton lines and other10 cotton varieties(lines)is very large,so the former can be used in breeding of color cotton as one of parents. That of Nongdazi07 with good quality and other10 cotton varieties(lines)is the largest, and also can be used in breeding of cotton with good quality as one of parents.