Genetic variation and response to selection for storage root dry matter and associated traits in a population of yam bean (Pachyrhizus spp.) interspecies crosses

Abstract

The goal of yam bean improvement in Africa is to develop superior high yielding and high dry matter cultivars that are preferred for adoption. In this study, the estimates of variance components, heritability and response to selection were studied in F3 yam bean families selected from interspecies crosses targeting improvement of storage root dry matter and associated traits. Breeding populations were generated using North Carolina II (NC II) mating design involving high dry matter P. tuberosus chuin cultivar, low dry matter P. ahipa and the high yielding P. erosus yam beans. The progenies were advanced through selfing from F1 to F2 population and then exposed to selection at 10% selection intensity to obtain 83 high dry matter lines. The selected lines were evaluated in an F3 trial using a randomized complete block design (RCBD) with three replications at the National Crops Resources Research Institute (NaCRRI) Namulonge, in Central Uganda. The results revealed significant (P < 0.001) genetic variation for storage root dry matter (RDM), storage root fresh yield (RFY), storage root dry yield (RDY), vine yield (VNY), fresh biomass yield (FBY), harvest index (HI), starch (STA) and protein (PRO) content. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were obtained for VNY, RDY, FBY, RFY, RDM and STA. Narrow sense heritability was higher than 0.5 and response to selection was 15.5 to 33.1 for RDM, RFY, RDY, VNY, FBY and STA, indicating rapid genetic progress is achievable and early generation selection would be effective to improve these traits. Significant (P < 0.01) positive genetic correlations were observed between RDM, RDY, RFY, VNY, FBY and STA ranging from 0.422 to 0.963 implying that simultaneous improvement of these traits is possible in the current yam bean populations.

Predictive genotype-phenotype relations using genetic diversity in African yam bean (Sphenostylis stenocarpa (Hochst. ex. A. Rich) Harms)

“…The cost effectiveness of the RAD-Seq over other NGS based methods cannot be overemphasized as the use of restriction enzymes coupled with barcoding increases the efficiency of multiplexing allowing the genotyping of multiple or different populations at the same time [ 27 ]. In terms of breeding purposes and targeting the African continent, high dry matter content and associated traits has been defined as key traits [ 28 ] which greatly depends on the genetic background of AYB [ 29 ]. Higher contents of dry matter in AYB tubers would increase competitivity and adoption against other root and tuber crops especially cassava and yam.…”

Genetic gains for obtaining improved progenies of oil palm in Colombia

“…In general, plant breeding programs have marked success in their genetic variability and in selecting progenitors that offer an excellent genetic combination for the different traits of agronomic interest (Agaba et al 2021). In this sense, this research demonstrated the precise selection of female parents in oil palm, with good genetic combinations in their progenies and high values of genetic gain in different traits of interest for world palm cultivation.…”

Morphological characterization and genetic diversity assessment of accessions of Musa spp

“…However, the use of morphological parameters alone could result in over-or underestimation of the degree of relatedness among cultivars. Therefore, the use of a genomic approach for determining relatedness among available accessions is needed because this approach will enhance the understanding of accessions before e cient hybridization across germplasms occurs (Agaba et al 2021). Understanding the genetic diversity of different accessions of Musa species harboring diverse genomic constitutions can improve the e ciency of banana and plantain breeding programs.…”