Phenotypic diversity and path analysis of seed yield in Bambara groundnut grown in rain forest agroecological zone

Abstract

Bambara groundnut is a reliable source of carbohydrates and protein in rainforest agroecology, but limited research had been done and few varieties commercialised. The magnitude of phenotypic variability, character association, and contribution of characters to seed yield were investigated among 50 accessions received from IITA, Nigeria. Field evaluation took place during the 2017 – 18 cropping seasons. The accessions were allocated to experimental plots using a Randomised Complete Block Design with three replicates. Data were collected on phenological, agronomic, and seed yield characters. The main effect showed significant (p ≤ 0.05) differences for phenological, vegetative, and reproductive characters. The year effect influenced agronomic and seed yield characters while accessions by year interaction were insignificant for all characters. The stepwise discriminant analysis identified three redundant characters. The leaflet length and width, canopy spread, leaf/plant, seeds/plant, and seed weight showed high discriminatory ability and are efficient for morphological characterisation and conservation. Hybridisation between accessions dispersed in quadrants 1, 2, and 4 may evolve early and medium maturity types with improved seed yield and biomass. The number of seeds/plant and pods/plant are indices for seed yield. The contribution of pods/plant to seed yield was masked by canopy spread, peduncle length, and pod width indicating competition for photo-assimilates. TVSu 17, TVSu 277, TVSu 271, and TVSu 278 are donor parents for earliness. TVSu 261 performed best for seed yield and yield component characters. Hybridisation among TVSu 261, TVSu 587, TVSu 275, and TVSu 17 will evolve medium maturing and high seed-yielding varieties for further evaluation.

Exploring phenotypic variation of diverse bambara groundnut (Vigna subterranea L) origin and development of mini‐core collection for future breeding

“…However, significant landrace x year effects for most of the studied traits have confirmed the need to test these landraces in multiple environments over different years to identify landraces that could be used for a breeding programme. Adeniji et al (2022) pointed out that the measurement of phenotypic traits across environments or years is imperative for identifying phenotypically stable and unstable traits…”

“…Therefore, a hybridization programme with clusters 3 and 1 would lead to the development of early maturing genotypes with improved yield. Cluster analysis has been used for the identification and selection of the best parent for hybridization by characterizing and grouping genotypes according to their genetic similarity and morphological characteristics in several crops like bambara groundnut (Adeniji et al, 2022; Khaliqi et al, 2021; Khan et al, 2020; Ntundu et al, 2006), common bean (Nadeem et al, 2020) and African yam bean (Olomitutu et al, 2022). The selection of a genotype requires the manipulation of many characters, which are correlated.…”

“…Genetic variability, germplasm assembly and evaluation, development of progeny, and maintenance are crucial components needed to design and release farmer-preferred varieties (Majola et al, 2021). The prospects of selecting bambara groundnut landraces with yield potentials have been reported by several researchers (Adeniji et al, 2022;Alake & Ayo-Vaughan, 2016;Gbaguidi et al, 2018;Khan et al, 2021) with a yield of 0.3 tons/ha under marginal conditions and up to 4.2 tons/ ha with improved varieties under optimum conditions (Madamba, 1995;Makanda et al, 2009). Assessment and characterization of bambara groundnut germplasm are vital for identifying of the best parents for its improvement (Khaliqi et al, 2021;Khan et al, 2021).…”