Abstract: A series of fiber-specific mutants, or germplasms, have been recently used in the study of fiber development. In the current study, scanning electron microscopy (SEM) was used to investigate developmental differences in lint and fuzz initiation in different genotypes (Gossypium hirsutum) of upland cotton. These fiber mutants included dominant naked seed N1, recessive naked seed n2, Xuzhou-142 lintless-fuzzless (XZ142WX), Xinxiangxiaojilintless-fuzzless (XinWX), Xinxiangxiaojilinted-fuzzless (XinFLM), with TM-1, the cytogenetic and genetic experimental standard stock, as the control. Characteristics of fiber initiation were analyzed from –1 to +1 days post anthesis (dpa) and at 4 and 5 dpa for fuzz initiation. Our data suggested that lint initiation centered on day of anthesis (0 dpa), and elongated significantly at 1 dpa, while fuzz initiation began at 4 dpa, although the shape of fuzz protrusions differed from that of lint fibers. Fiber initiation occurred first on the ovule funicular crest. Compared to TM-1, there was a noted retardation in development and fiber protrusion in N1 and XinFLM. Microscopy data also demonstrated that lintless-fuzzless mutants (XZ142WX and XinWX) developed irregular protrusions during early developmental stages, which were unable to grow into fiber.

Key words: fiber development mutant, Gossypium hirsutum, initiation, scanning electron microscopy