Reduction in Number of Motes in Bolls of Interspecific Hybrid Cotton by Backcross Pollination1
- Harbans L. Bhardwaj and
- James B. Weaver2
Motes are cotton (Gossypium spp.) ovules that fail to ripen into mature seeds but develop into aborted structures. These aborted ovules represent a loss in yield and cause imperfections in yarn and cloth quality by causing neps. The number of motes (percentage of ovules that failed to develop into seeds) was studied in interspecific hybrids (ISH) of cotton, which have a higher number of motes, for 3 years (1980-1982). A cytoplasmic male sterile ISH was hand-pollinated with pollen from its counterpart fertile-ISH and strains of parental species (Gossypium hirsutum and G. barbadense). The number of motes in seed-cotton produced as a result of these hand-pollinations was compared in 1980 and 1981. The results indicated that the number of motes was dependent upon the male parent used to pollinate the CMS-ISH. Pollinations with strains of G. hirsutum or G. barbadense resulted in approximately a 50% reduction in number of motes as compared to pollination with counterpart fertile-ISH. These findings provide an indirect evidence of cryptic structural differentiation in tetraploid species of cotton. During 1982, G. hirsutum backcross plants (grown from seed produced by hand-pollination in 1981), a fertile upland hybrid, and genotypes of parental species, when grown under open-pollination, had significantly lower number of motes than fertile-ISH plants. Out-crossing to parental species was observed to greatly reduce the number of motes in fertile-ISH. This is as expected because outcrossing to parental species is similar to backcrossing, which masks the effects of cryptic structural differentiation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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