1. College of Life Sciences, Guizhou University, Guiyang, 550025;
2. College of Life Science and Technology, Guangxi University, Naning, 530005;
3. Haide Institute of Tropical Agricultural Resources (HITAR), Sanya, 572025
* These authors contributed equally to this work
Cotton Genomics and Genetics, 2010, Vol. 1, No. 1
Received: 20 Jun., 2010 Accepted: 10 Sep., 2010 Published: 01 Jan., 1970
This article was first published in Fenzi Zhiwu Yuzhong (Molecular Plant Breeding) in Chinese, and here was authorized to translate and publish the paper in English under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
In present study, the four cotton germplasms with significant differences in fiber traits, Bollgard DP 99B (full haired seed, upland cotton, Gossypium hirsutum L.), ZYS20 (fuzzless seed, upland seed, G. hirsutum L.), FLS2123 (fuzzless-lintless seeds or bare seeds, upland cotton, G. hirsutum L.), and VH8 (fuzzless seed, sea island cotton, G. barbardense L.) were employed as the experimental materials of cotton to develop the genetic populations by making four crosses, their hybrid combinations were: DP99B×FLS123, DP99B×ZYS20, ZYS20×FLS123, and DP99B×VH8. In February of 2007, we harvested their F1 hybrid seeds of four combinations planted in the October of 2006, and F2 segregating generation seeds harvested in the May of 2007. The fiber traits of F1 seeds and F2, seeds were phenotyped in order to figure out the genotypes conferring differentiation and development of of cotton fibrils on lint and fuzz.
Based on the results of F1 fiber phenotypes and F2 fiber segregating phenotypes, we presumed that the lint genotypes of the tested four parents as follows: the genotype of DP99B could be LiALiA or LiA liA and LiDLiD or LiD liD; as well as the genotype of ZYS20: LiALiA or LiA liA and LiDLiD or LiD liD; the genotype of FLS2132: liA liA liD liD; the genotype of VH8: LiALiA or LiA liA and LiDLiD or LiD liD. The results showed that cotton lint length showed a good normal distributions in all tested F2 populations, which implied that the development of cotton lint should be controlled by complex quantitative trait loci. For the genotypes of fuzz in the F2 populations of the four crosses, there were no any segregating photypes in the crosses of ZYS20×FLS2132 and DP99B×VH8, the F2 population derived from ZYS20×FLS2132 were only the phenotype of fuzzless seed, while the F2 population derived from DP99B×VH8 were only the phenotype of full haired seed. Whereas the F2 generations derived from the crosses of DP99B×FLS2132 and DP99B×ZYS20 were segregated in differences. Therefore the fuzz genotypes of the four parental germplasms were presumed as follows, the possible fuzz genotypes of DP99B could be ii, susu, Ft1Ft1, Ft2Ft2, Ft3Ft3, FcFc and ii, susu, Ft1Ft1, Ft2ft2, Ft3ft3, Fcfc, as well as the possible fuzz genotypes of VH8: Ii, Susu, Ft1Ft1, Ft2Ft2, Ft3Ft3, FcFc and Ii, susu, Ft1Ft1, Ft2Ft2, Ft3Ft3, FcFc, the possible fuzz genotypes of ZYS20: Ii, Susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc, Ii, susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc and ii, Susu, ft1ft1, ft2ft2, Ft3Ft3, fcfc, the possible fuzz genotypes of FLS2132: II, SuSu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc and Ii, Susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc. These results implied that the loci controlling the fibril differentiation of fuzz and lint might be located on different genomes of cotton.
Meanwhile, we further inferred that the genotypes of the F1 fibrils of fuzz as follows, the genotype of the F1 derived from DP99B×VH8 combination could be as ii, susu, Ft1Ft1, Ft2Ft2, Ft3Ft3, FcFc, which generate full haired seed of F1 seeds and no phenotype of fuzz segregating in the F2 generation. The genotype of the F1 derived from DP99B×ZYS20 combination could be as ii, susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc or ii, Susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc, which generate full haired seed of F1 seeds and phenotype of fuzz segregating in the F2 generation The genotype of the F1 derived from DP99B×FLS2132 combination could be as Ii, Susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc or Ii, susu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc, which generate fuzzless seed of F1 seeds and phenotype of fuzz segregating in the F2 generation. The genotype of the F1 derived from ZSY20×FLS2132 combination could be as II, SuSu, Ft1ft1, Ft2ft2, Ft3ft3, Fcfc, which generate fuzzless seed of F1 and no phenotype of fuzz segregating in the F2 generation.
According to statistical analysis of the data for the lint length and fuzz density of cotton seeds a for statistical analysis, there was a correlationship between the density of fuzz and lint length of cotton, that is in case of both of lint and fuzz existing in the cotton seed, the longer of the lint length and the greater the lint density they are, the greater of the fuzz density and distribution are. It can be confirmed that once the differentiation of fuzz cell came out from the ovule, the development of fuzz and lint might be synchronous and be controlled by a series of common genes.
The study concluded that there are significant interactions exsiting between the genes controlling development of lint and fuzz. The genes controlling the lint development might have some epistatic genetic effects on the genes controlling fuzz development. When the ovule epidermal cells differentiate into whatever types of cotton fibers, then the development of cotton fiber elongation will be controlled by the same serial genes. Once the fuzz fiber cells are differentiated, while the genes cotrolling the lint will simultaneous regulate the distribution and density of fuzz.