Exploring the Bush yam (Dioscorea praehensilis Benth) as a Source of Agronomic and Quality Trait Genes in White Guinea yam (Dioscorea rotundata Poir) Breeding

Abstract

Yam (Dioscorea spp.) is an important food security crop in the tropics and subtropics. However, it is characterized by a narrow genetic base within cultivated and breeding lines for tuber yield, disease resistance, and postharvest traits, which hinders the yam breeding progress. Identification of new sources of desirable genes for these traits from primary and secondary gene pools is essential for this crop improvement. This study aimed at identifying potential sources of genes for yield and quality traits in a panel of 162 accessions of D. praehensilis, a semi-domesticated yam species, for improving the major yam species, D. rotundata. Significant differences were observed for assessed traits (p < 0.05), with D. praehensilis genotypes out-performing the best D. rotundata landraces for tuber yield (23.47 t ha−1), yam mosaic virus (YMV) resistance (AUDPC = 147.45), plant vigour (2.43) and tuber size (2.73). The study revealed significant genotypic (GCV) and phenotypic (PCV) coefficients of variance for tuber yield, YMV severity score, and tuber flesh oxidation. We had also a medium-to-high broad-sense heritability (H2b) for most of the traits except for the dry matter content and tuber flesh oxidation. This study identified some promising D. praehensilis genotypes for traits such as high yield potential (WNDpr76, CDpr28, CDPr7, EDpr14, and WNDpr63), resistance to YMV (WNDpr76, CDpr7, EDpr14, CDpr28, and EDpr13), high dry matter content (WNDpr76, CDpr28, and WNDpr24), low tuber flesh oxidation (WNDpr76, CDpr5, WNDpr31, CDpr40, and WNDpr94) and high number of tubers per plant (WNDpr76, CDpr7, CDpr68, CDpr29, and CDpr58). These genotypes could, therefore, be employed in breeding programmes to improve the white Guinea yam by broadening its genetic base.

Assessment of the Yam Landraces (Dioscorea spp.) of DR Congo for Reactions to Pathological Diseases, Yield Potential, and Tuber Quality Characteristics

“…Of the cultivated species, accessions of D. dumetorum, D. alata, and D. praehensilis had better tolerance than the popular preference species for consumption (D. rotundata) and, as such, can be considered in breeding programs for the improvement of D. rotundata, particularly D. praehensilis due to their similar genome information [38]. This corroborates the findings of Adewumi et al [39], who observed better tolerance of D. praehensilis genotypes over that of D. rotundata for YMV severity. Accessions of D. praehensilis and D. rotundata had the best genetic tolerance to YAD severity among the considered species while D. alata had the least tolerance.…”

Status of yam (Dioscorea spp.) in the Democratic Republic of Congo

“…Poor agronomic potential concerning yield (<10 ton/ ha) compared to other yamproducing countries (>10 ton/ha), tolerance to pathological diseases and insect pests of many landraces seasonally cultivated by local farmers (Adewumi et al, 2022;Agre, Dassou, et al, 2021;Jeancy et al, 2021) 4 Non-commitment to providing stake support for yam establishment (Adejumobi, Agre, Onautshu, Adheka, Cipriano, et al, 2022) 5…”

Genetic diversity of yam (Dioscorea sp.) through morphological and molecular markers

“…High positive correlations were observed for the tuber traits. Positive correlations for tuber traits were also observed in studies characterizing 100 D. alata accessions (Agre et al 2019), as well as D. praehensilis and D. rotundata accessions (Adewumi et al 2022). The correlations related to tuber descriptors are relevant, as tuber yield and quality traits are considered important for selection and breeding of yam varieties (Adewumi et al 2022).…”