| Abstrakt: |
The complex nuclear genomic and flower structures of sugarcane cultivars ( Saccharum hybrids spp., 2 n = 10 x = 100-130) render sugarcane a difficult subject for genetics research. Using a capillary electrophoresis- and fluorescence-labeling-based simple sequence repeat (SSR) genotyping platform, the segregation of a multi-allelic sugarcane SSR marker SMC336BS was investigated among single pollens of a sugarcane cultivar L 99-233 as well as its F progenies of a bi-parental cross between HoCP 00-950 (female) and L 99-233 (male). L 99-233 produced five reproducible SSR alleles, namely, 6- 154, 6- 167, 6- 169, 6- 171, and 6- 175, while HoCP 00-950 produced two SSR alleles, 6- 166 and 6- 169. Of these six parental alleles, 6- 167, 6- 169, 6- 171, and 6- 175 were detected in approximately half of the pollens indicating an independent Mendelian segregation. In addition, four alleles, namely, 6- 154, 6- 166, 6- 167, and 6- 175, were detected in approximately half of the F progenies, again an indication of independent Mendelian segregation. Twenty-two pollen genotypes were observed among 92 single pollens at frequencies varying from 1.08 to 11.83 % and 33 genotypes were observed among 162 F progenies at frequencies varying from 0.62 to 8.64 %. Although none of the 92 single pollens amplified all five parental alleles, one F progeny produced all the six parental alleles. Unexpected segregation patterns were also observed. Allele 6- 171, which was absent in HoCP 00-950, segregated at 3 presence:1 absence instead of expected 1:1. Allele 6- 169, which was detected in both cultivars and segregated at 1:1 among pollens, segregated at nearly1:0. These unexpected segregation patterns may be associated with the complexity of sugarcane genome and illustrate the needs of additional genetic studies in polyploid sugarcane. [ABSTRACT FROM AUTHOR] |
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