Abstract:
White Guinea yam (Dioscorea rotundata Poir.) is an important
tuber crop grown extensively in tropical regions of West
African yam belt. Tuber yield, dry matter content, and tolerance to yam mosaic virus are key traits used for identification
and selection of superior varieties for commercial deployment.
In this study, we estimated genetic parameters for fresh tuber
yield, tuber dry matter content, and quantitative field tolerance
to yam mosaic virus in 49 clones grown in multi-environment
trials (METs). We conducted genomic prediction involving 6337
single nucleotide polymorphisms (SNPs) and phenotypic field
evaluation of data collected on the three traits from four sites.
Additive genetic and non-genetic factors contributed significantly to phenotypic variation of studied yam traits in METs
but to varying degrees. The non-genetic effects were relatively
high for most of the measured traits. Narrow-sense heritability
values were low (<0.30) for all studied traits. Further analysis of
the performance of the clones at test sites with additive main
effects and multiplicative interaction (AMMI) analysis exhibited
significant genotype by environment interactions (GEI) for the
three traits. The AMMI identified TDr10/00412, TDr11/00055,
and TDr09/00135 clones with lowest mean trait stability index
and outstanding performance for fresh tuber yield (t ha−1),
tuber dry matter, and mosaic virus resistance across sites. The
elite clones identified could serve as useful source of alleles for
the genetic improvement of the crop and possibly considered
for release to farmers.
