Plant Sex Prediction Using Genetic Markers in Cultivated Yams (Dioscorea rotundata Poir.) in Benin

Abstract

Dioscorea rotundata Poir. is mainly dioecious but it also produces monoecious individuals. Recently two genetic markers were proposed to determine the sex in this species. We tested them in 119 individuals from 101 different cultivars of the national collection of Benin to verify whether they can predict the sex observed in the field. Among the analyzed individuals, 72 were male, 37 were female, 7 were monoecious and 3 were non-flowering. Our results showed that the marker sp16, associated with the W allele (female allele), was present in all female individuals but also in more than 42% of male individuals. Thus, while the absence of sp16 confirmed the male sex of the individuals, its presence did not allow sex discrimination. The marker sp1 allowed the identification of four genotypes (AA, AB, BB and AC) in the analyzed individuals with AA and AB being the most represented. Although AA was observed in 62.16% of female individuals and AB in 83.33% of male individuals, we did not observe a clear correlation between sp1 genotypes and sex identity. We concluded that the tested markers did not allow a clear sex discrimination in Beninese Dioscorea rotundata cultivars. Our results also suggest that Beninese D. rotundata cultivars have adopted a male XX/XY heterogametic system that is undergoing reorganization.

Genome-Wide Association Studies for Sex Determination and Cross-Compatibility in Water Yam (Dioscorea alata L.)

“…Previous reports demonstrated an involvement of chromosome 6, and secondary chromosomes 1 and 11, on D. alata flowering and sexual reproduction [ 3 , 5 ]. As hypothesized by Denadi et al [ 20 ], Dioscorea spp. flowering and sex might be controlled by several genes as our results also supported.…”

“…Tamiru et al [ 9 ] also identified a DNA marker, sp1, linked to the putative Z-linked region predicting maleness. Using these markers to predict sex at earlier growth phases among D. rotundata accessions has been reported [ 10 , 20 ]. However, these markers’ prediction accuracy is not always perfect in yam sex identification at the seedling stage.…”

“…However, no report exists on its practical application for identifying flower sex at the seedling stage in D. alata . Sex determination in yam plants could be controlled by more than one locus [ 20 ], and thus, identifying more sex markers is encouraged. Besides, the instability of the sexual phenotype across generations and environments is another indication that sex expression in yam is a polygenic trait [ 21 ].…”

Floral Biology and Pollination Efficiency in Yam (Dioscorea spp.)

“…However, the sp16 marker only predicts the likelihood of femininity and may not be transferable to other species. Dinadi et al [72] showed that although the absence of sp16 marker confirms the male sex of the individuals, its presence does not allow sex discrimination. From their study, it appeared that the best determinant of stable male cultivars is the absence of the sp16 marker and that the best determinant of stable female cultivars is the AA genotype of the sp1 marker.…”

“…From their study, it appeared that the best determinant of stable male cultivars is the absence of the sp16 marker and that the best determinant of stable female cultivars is the AA genotype of the sp1 marker. Further investigations are encouraged as sex determination in white Guinea yam would be controlled by more than one locus [72]. Electrochemical sex determination of D. zingiberensis and D. bulbifera plants using polydopamine-functionalized graphene sheets has been successful [73].…”