ABSTRACT: Orange-fleshed sweetpotato (OFSP) is a biofortified food of Beta carotene that fights vitamin A deficiency and promotes nutritional security. The success to select and identify the superior genotype is limited by Genotype and Environment (G×E) interactions. The study was conducted to estimate the magnitude of G×E and to select stable and high yielding OFSP in three locations, and to identify the most discriminating test environments. Similarly, to characterized them according to similarities in traits. These genotypes were subjected to heatmap cluster analysis. The 35 OFSP genotypes were evaluated across 3 environments using a RCBD with three replications. The data were subjected to ANOVA using R package. The AMMI model analysis indicated that genotype (G) and environment(E) had significant effects on root yield and the contribution to the total sum of squares difference was 64.89% and 6.35%, respectively. The remaining 3.87 % of the variation resulted from GxE effects. G24, G35 and G34 exhibited high mean root yield across environments with high degree of stability. These hybrids have the potential for production across the test locations as well as others within the same agro-ecological zones. However, G3, G12 and G30 were not only low yielding but also among the least stable genotypes. The best genotype with respect to location include G15 and G14 which were best for Umudike (E1), while G34 and G4 were the best genotype for Igbariam (E1) area. G24 performed well in FUTO (E3). Among the locations, E1 was the most productive site in distinguishing genotypes and the most representative environment. The Cluster heatmap analysis grouped the 35 genotypes into 4 clusters with distinct features. Cluster I was recommended for high root girth, high root yield performance and high beta carotene content, while clusters II and IV were recommended for high dry matter and high starch. Cluster III was characterized with short vine length.
Keywords: G x E interaction, additive main effect and multiplicative interaction (AMMI), stability, heatmap cluster analysis, OFSP.

ABSTRACT: Understanding chromosomal variation among improved cowpea (Vigna unguiculata Walp.) varieties is crucial for advancing breeding strategies that aim to enhance yield stability and adaptability. This study employed cytogenetic analyses to characterise three improved cowpea varieties and evaluate their agronomic and breeding relevance. All varieties possessed a conserved diploid chromosome number (2n = 22; n = 11), confirming species identity. However, they differed in karyotype formulae: one variety exhibited 5 metacentric + 6 submetacentric (5M + 6SM) chromosomes, while another had 7M + 4SM. Notable variations were recorded in key karyological indices, including the coefficient of variation (CV), total form percentage (TF%), disparity index (DI), and intra- and inter-chromosomal asymmetry (A1 and A2). SAMPEA-19 showed the highest CV (14.59%), and SAMPEA-17 and SAMPEA-119 displayed the highest DI values (44.28%), indicating pronounced chromosomal asymmetry. SAMPEA-18 was cytogenetically distinct in its TF, divergence pattern, and karyotype structure. Cluster analysis grouped the varieties into two sub-varietal clusters, with SAMPEA-18 exhibiting the highest genetic divergence (similarity index = 60.59%). These findings underscore the utility of cytological data as a cost-effective tool for revealing intraspecific variation and informing varietal improvement in cowpea breeding programmes.
Keywords: Cowpea, Chromosome, FUAMPEA varieties, Variability, karyological properties

ABSTRACT: Fall armyworm (FAW) infestation poses a critical constraint to maize production across sub-Saharan Africa, with disproportionate impacts on extra-early maturing genotypes that are vital for ensuring food security in climate-sensitive and resource-constrained environments. This study provides the first systematic evaluation of extra-early Provitamin A Quality Protein Maize inbred lines for grain yield, biofortification traits, and FAW resistance under natural infestation. It employs multivariate analysis to integrate earliness, nutritional quality, and pest resilience for climate-smart maize breeding. Field evaluations were conducted during the 2023 and 2024 rainy seasons at Oke-Oyi, Nigeria, using a randomised complete block design. Multivariate analysis of variance revealed highly significant differences among inbred lines for key agronomic and nutritional traits. Notably, top-performing genotypes such as TZEEIORQ 14 exhibited grain yield advantages of 25.9% and 41.7% over standard checks. Multiple inbred lines surpassed the biofortification threshold of 12 µg/g for β-carotene and consistently demonstrated elevated tryptophan concentrations relative to the standard checks. Canonical discriminant analysis grouped the inbreds into distinct clusters, with grain yield, β-carotene, and tryptophan emerging as the primary discriminating traits. Conversely, leaf damage score and anthesis–silking interval were the most negative contributors to genotype separation. Inbreds TZEEIORQ 5, 10, 11, 14, and 18 emerged as promising candidates for breeding programmes aimed at enhancing FAW tolerance, nutritional quality, and grain yield. These findings demonstrate the effectiveness of multivariate tools in deciphering trait interrelationships and facilitating the selection of elite genotypes for sustainable maize improvement.
Keywords: Multivariate analysis, grain yield, Spodoptera frugiperda resistance, β-carotene, leaf damage score

ABSTRACT: A field experiment was carried out in 2023 cropping season at the Teaching and Research farm of Joseph Sarwuan Tarka University, Makurdi to study the relationship between yield and yield related traits of rice varieties at Makurdi. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Data were collected on the following parameters; plant height, number of tillers/plant, panicle exertion, leaf length, panicle length, days to 50% flowering, number of spikelet, number of seed per panicle, grain yield, and number of panicle. Grain yield showed highly significant and positive correlation with number of tillers, leaf length, panicle length, spikelet number, total seed per panicle, days to 50% flowering, and panicle number. In addition, phenotypic path coefficient analysis revealed that total number of seed per panicle, panicle number and number of tiller had appreciable positive direct effect on grain yield. This suggests that selection for total number of seed per panicle, tiller number, panicle number, and spikelet number would lead to simultaneous improvement of grain yield in rice. Hence, plant breeders are to prioritize genotypes with high panicle number and total seeds per panicle, as these exert the strongest direct effects on yield and to optimize leaf length and tiller number to exploit their indirect contributions.
Key Words: Rice, Grain Yield, Yield components, Correlation, Path Coefficient Analysis

ABSTRACT: Cytogenetic variability is essential for improving agronomic performance and informing effective breeding strategies in cowpea (Vigna unguiculata [L.] Walp). This study carried out detailed karyological analyses of four improved cowpea varieties to assess chromosomal differences and their relevance to genetic enhancement. All varieties exhibited a diploid chromosome number of 2n = 22; however, significant variation was observed in key karyological parameters, including arm ratio, centromeric index, total form percentage, disparity index, and symmetry indices. FUAMPEA-1 had the shortest total chromosome length (15.05 µm) and lowest R-value (0.61), yet recorded the highest arm ratio (1.63) and centromeric index (2.04). FUAMPEA-2 displayed the highest coefficient of variation (14.78%), total form percentage (52.55%), and disparity index (49.43%), indicating greater structural asymmetry. FUAMPEA-1, FUAMPEA-2, and FUAMPEA-3 shared a consistent karyotype formula of 6M + 5SM (six metacentric and five submetacentric chromosomes), while FUAMPEA-4 was distinct with a unique formula of 7M + 4SM. The chromosomal diversity observed among the varieties reflects a wide genetic base and offers valuable cytogenetic markers for selection and hybridisation in cowpea improvement programmes.

Keywords: Breeding, Cowpea, Chromosome, SAMPEA varieties, Variability.

ABSTRACT: This study assessed 16 groundnut (Arachis hypogaea L.) genotypes, including registered varieties and local landraces, under drought-stressed conditions to identify traits associated with resilience and yield stability. Significant variation (p ≤ 0.05) was observed for pod yield, while plants at harvest, pods per plant, and haulm yield showed highly significant differences (p ≤ 0.01). Mai Atamfa recorded the highest pod yield (980 kg ha⁻¹), Mai Bargo excelled in haulm yield (27,124 kg ha⁻¹), and Samnut 10 produced the largest kernels (107 g per 100 seeds). Correlation and regression analyses highlighted pods per plant (r = 0.88, R² = 0.84) as the most reliable determinant of pod yield, while a strong positive association between haulm yield and shelling percentage (r = 0.62, p < 0.01) indicated potential for simultaneous improvement of grain and fodder value. These findings underscore the importance of integrating landraces and improved varieties in breeding pipelines. Crossing high-yielding types with dual-purpose and large-seeded genotypes could accelerate the development of drought-resilient, farmer-preferred cultivars for stress-prone environments.
Keywords: drought stress, Arachis hypogaea, yield traits, landraces, breeding, Nigeria