Field evaluation of 33 Bambara groundnut lines were carried out to estimate genetic variability, heritability and genetic advance. One-way analysis of variance (ANOVA) result showed significant differences for 14 of the 17 agronomic traits studied. The results on the variance components revealed that phenotypic variance had values (vigour index 2.30, pod length 10.09, seed length 1.64) that were slightly higher than the respective genotypic variance (vigour index 1.68, pod length 9.88, seed length 0.26). Similarly, the values (number of branches 41.91, number of nodes 68.72, internode length 59.02) of phenotypic coefficient of variation (PCV) were slightly higher than the corresponding genotypic coefficient of variation (GCV) (number of branches 40.11, number of nodes 66.98, internode length 57.31), suggesting a substantial genetic variability that can serve as a base for Bambara groundnut improvement. High estimates of heritability were observed for most characters like number of branches (95.70%), number of nodes (97.46%), internode length (97.10%), pod length (97.91%), and seed length (93.79%). Likewise, genetic advance values for most traits were high, pod length (201), number of nodes (200), internode length (200), number of branches (197) and seed yield (195), implying that improvement of seed yield in Bambara groundnut can be achieved through direct selection.
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Leafspot is one of the major diseases of peanut (
objective
of this study was to identify and map quantitative trait loci (QTLs) for resistance to leafspot disease. An F2:6 recombinant inbred line (RIL) population, derived from a released cultivar Tamrun OL07 and a highly tolerant breeding line Tx964117, were used as a mapping population. A total of 90 RILs were planted for disease phenotyping in Yoakum, Texas in 2010 and 2012. A genetic map spanning the 20 linkage groups was developed using 1,211 SNP markers based on double digest restriction-site associated DNA sequencing (ddRAD-seq). A total of six quantitative trait loci (QTLs) were identified, with LOD score values of 3.2–5.0 and phenotypic variance explained ranging from 11%–24%. Major QTLs identified in this study may be used as potential targets for peanut improvement to leafspot disease through molecular breeding.
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