对棕色棉细胞质雄性不育系和保持系的小孢子发生进行了细胞学观察。结果表明，棕色棉不育系小孢子发生败育的时期是在造孢细胞增殖至小孢子母细胞进行减数分裂的整个过程。造孢细胞和小孢子母细胞退化导致雄性不育的主要细胞形态学特征是：造孢细胞核仁增大、细胞质液泡化和细胞形状畸形，还有因核仁物质弥散而使整个细胞染色较深；核仁穿壁很普遍；多核仁、细胞核核膜消失、细胞质液泡化；染色体行为异常；不育系花药小孢子母细胞成半月形；小孢子母细胞互相粘连成巨型团块；小孢子母细胞胞壁消失，核高度液泡化；彩色棉细胞质雄性不育花药内的造孢细胞和小孢子母细胞的败育与绒毡层的过早退化密切相关。

对白色棉、棕色棉和绿色棉纤维进行了电镜观察，结果表明：三种颜色纤维的结构由外到内依次为初生壁、次生壁和中腔.在白色纤维的超微结构中未发现染色较深的物质；在绿色棉纤维中，纤维的次生壁内层存在大量染色深的条纹，这些条纹可能是色素沉积的结果，类似沉积的日轮；在棕色棉纤维的中腔内，存在大量染色深的物质，而且这些物质主要沉积在中腔壁上，这些染色较深的物质可能是棕色棉纤维的色素物质，同时发现棕色棉纤维具有分叉结构。与白色纤维比较，彩色纤维表现出的品质较差，可能与纤维素含量低及色素物质的沉积有关。

A mRNA preferentially expressed in cotton fiber was cloned from fiber total RNA of normal upland cotton TM-1 (wild-type) by using RT-PCR and corresponding cDNA (signed as TM-E6) was sequenced. TM-E6 gene had no intron and contained an open reading frame 771 bp long, and might encode a peptide of 246 amino acids. Other four genes, Fl-E6, Li-E6, N-E6 and Bl-E6, which were homologous to TM-E6 gene, also were isolated from four fiber mutants of Fiberless Xu-Zhou 142, Ligon lintless, Naked seed and Brown lint, respectively. Sequence analysis of each of these mutant genes revealed many variations in structure and nucleotide composition of gene when compared with sequence of TM-E6 gene. (1). There was a changeable repetitive segment in which GGCTCA (Gly-Ser) was repeated from three to five times between the 82nd and the 93rd codon in different mutant genes. Since the change of Gly-Ser repetitive segment occurred not only in the mutants but also in the wild-type cotton, the repeat frequency might be not associated with the mutation of fiber characteristics. (2). Among these four mutant genes, the percentage of changed codons was 7.05% in Fl-E6, 4.98% in Li-E6, and 4.15% in N-E6 and Bl-E6. It seems that the percentage of changed codons in E6 sequence was positively correlated to the degree of fiber morphological variation. (3). E6 polypeptides of Two long-fiberless mutants (Fiberless Xu-Zhou 142 and ligon lintless) contained high similar (99.4%) variation in the region of ~174 amino acids from N-terminus, and those of shor-fiberlees mutants (Fiberless Xu-Zhou and naked seed) revealed identical variation in the region from 116th to 220th amino acid. It also seems that there was a parallel relation between E6 protein variation and fiber phenotype mutation. (4). Li-E6 and Bl-E6 gene also expressed at low level in seed coat besides at high level in fiber.

In the present study, three types of color fiber cottons i.e. white, brown and green were compared for their fiber quality and yield. The comparison of fiber quality suggested that color fiber cotton was inferior as compared to white fiber cotton. To know the effect of cellulose, mineral elements (N, P and K) and pH of fiber cells on quality of fiber, these components were studied at different fiber cell development stages in all the three fiber cotton types. The cellulose content is closely associated with quality of fiber. The higher fiber quality of white fiber cotton might be due to the high cellulose content in it as compared to colored fiber cotton. A rapid and slow decrease in pH in white and colored cottons, respectively, might bring some effects in fiber elongation. Among the mineral contents, Potash (K) element positively correlated with the fiber quality traits. The pigment development in brown and green fiber cottons was not similar. In green fiber cotton it take more time to become deep as compared to brown fiber cotton. Ultimately, the possible strategy for improvement in quality of color fiber cotton was discussed. The results of heterosis in colored fiber cotton suggested that heterosis approach could improve yield and quality of colored fiber cotton. In the present study, the hybrid between ZJU12A

A glutathione S-transferase (GST) gene has been introduced into restorers of cytoplasmic male sterility in upland cotton (Gossypium hirsutum L.) using Agrobacterium-mediated transformation. A transgenic restorer, signed as 'Zheda strong restorer', which has strong restorability to male sterility, was selected from progeny plants of transformants. When compared with an American restorer 'DES-HAF277', the fertility restorability of 'Zheda strong restorer' to male sterility was been enhanced by 25.8% in the percentage of viable pollens of hybrid (sterile line