Novel Centromeric and Subtelomeric Repetitive DNA Sequences for Karyotyping the Bambara Groundnut (Vigna subterranea L. Verdc.)

Bambara groundnut (<i>Vigna subterranea</i> L. Verdc.) is an un­derutilized minor legume crop with climate resilience and great potential use in world agriculture. This study aimed to cytogenetically characterize the genome and chromosome properties of Bambara groundnut. We cloned, sequenced, and mapped a 50-bp centromere-specific tandem repeat on all chromosomes. In addition, a 400-bp subtelomeric repeat was discovered and mapped on a single pair of chromosomes. A Bambara groundnut karyotype was constructed using these novel repeats along with ribosomal RNA genes (45S and 5S) and telomeric DNA sequences. This study provides the first analysis of the genome and chromosome properties of Bambara groundnut. We discuss our findings in relation to genetic improvement of Bambara groundnut and centromere evolution in legume species.

Allelopathic effects of Androstachys johnsonii Prain on germination and growth of Zea mays L. and Vigna subterranea (L.) Verdc.

Allelopathic effects of the donor plants are mostly regarded as harmful to target plants such as traditional crops. Traditional crops play pivotal role as staple food for rural communities and hence ensuring food security. Study of the allelopathic effects of Androstachys johnsonii Prain on the germination and growth of Zea mays L. and Vigna subterranea (L.) Verdc was conducted. Different plant leachates concentrations of 0.675%, 1.25%, 2.5% and 5% were prepared through serial dilutions. Germination bioassays were arranged in a complete randomized setup of three replicates for each treatment for seven days. Germination rates were calculated, radicle and hypocotyl lengths were also measured. Germination rates of Z. mays L. and V. subterranea (L.) Verdc. ranged from 50 - 100% and 18 - 76%, respectively. Significant differences of P< 0.005 were noticed from the germination rates of V. subterranea (L.) Verdc subjected to high concentrations of different extracts used. Statistically there was no significant differences between germination rates of Z. mays L. treated with all concentrations of leaf leachates against germination rates of the seeds treated with distilled water. Outstandingly, the germination rate and early growth of Z. mays L. were promoted by less concentrated extracts of leaf, root, stem bark and soil which then suggest future use of allelochemicals from Androstachys johnsonii Prain for promotion of maize plant productions. Based on the beneficial attributes of allelochemicals from Androstachys johnsonii on the germination and growth of Z. mays L., planting of Androstachys johnsonii Prain in maize fields is highly recommended.

Path-coefficient and correlation analysis in Bambara groundnut (Vigna subterranea [L.] Verdc.) accessions over environments

In a breeding program, studies of genotypic and phenotypic relationships among agricultural crop traits are useful to design, evaluate, and develop selection criteria for desirable traits. Using path coefficient analysis, the present study was executed to estimate the phenotypic, genotypic, and environmental correlation coefficients between yield and yield-related traits and to determine the direct and indirect effects of yield-related traits on yield per plant. A total of 30 genotypes of Vigna subterranea were studied under tropical conditions at two sites over two planting seasons (considered as four environments). The experiment at each site used a randomized complete block design with three replicates. Data were collected on vegetative and yield component attributes. Based on analysis of variance, pooled results showed that there were positive and highly significant differences (p ≤ 0.01) among the 30 genotypes for all attributes studied. Highly significant and positive strong correlation at phenotypic level was observed for dry seed weight (0.856), hundred seed weight (0.754), fresh pod weight (0.789), and total pod weight (0.626) with yield in kg per hectare, while moderate positive correlations were observed for harvest cut (0.360) and days to maturity (0.356). However, a perfect positive correlation was observed for the dry weight of pods with seed yield. In contrast, days to 50% flowering (− 0.350) showed a negative significant relationship with yield per hectare. The dried pod weight attribute (1.00) had a high positive direct effect on yield. Fresh pod weight had the greatest indirect effect on yield per hectare, followed by the number of total pods by dry pod weight. As a result, dry pod weight, hundred seed weight, number of total pods, and fresh pod weight could be used as selection criteria to improve the seed yield of Bambara groundnut (Vigna subterranea).

Development of Selection Indices for Improvement of Seed Yield and Lipid Composition in Bambara Groundnut (Vigna subterranea (L.) Verdc.)

The underutilised grain legume bambara groundnut (Vigna subterranea) has the potential to contribute significantly to nutritional security. However, the lack of commercial cultivars has hindered its wider adoption and utilisation as a food source. The development of competitive cultivars is impeded by (1) lack of systematic data describing variation in nutritional composition within the gene pool, and (2) a poor understanding of how concentrations of different nutritional components interact. In this study, we analysed seed lipid and protein concentration and lipid composition within a collection of 100 lines representing the global gene pool. Seed protein and lipid varied over twofold with a normal distribution, but no significant statistical correlation was detected between the two components. Seed lipid concentration (4.2–8.8 g/100 g) is primarily determined by the proportion of oleic acid (r2 = 0.45). Yield and composition data for a subset of 40 lines were then used to test selection parameters for high yielding, high lipid breeding lines. From five selection indices tested using 15 scenarios, an index based on the seed number, seed weight, and oleic acid yielded a > 50% expected increase in each of the mean values of seed number, pod dry weight, seed dry weight, and seed size, as well as an expected 7% increase in seed lipid concentration.

AMMI and GGE biplot analysis for yield performance and stability assessment of selected Bambara groundnut (Vigna subterranea L. Verdc.) genotypes under the multi-environmental trails (METs)

The stability and high yielding of Vigna subterranea L. Verdc. genotype is an important factor for long-term development and food security. The effects of G × E interaction on yield stability in 30 Bambara groundnut genotypes in four different Malaysian environments were investigated in this research. The experiment used a randomized complete block design with three replications in each environment. Over multiple harvests, yield component traits such as the total number of pods per plant, fresh pods weight (g), hundred seeds weight (g), and yield per hectare were evaluated in the main and off-season in 2020 and 2021. Stability tests for multivariate stability parameters were performed based on analyses of variance. For all the traits, the pooled analysis of variance revealed highly significant (p < 0.01) variations between genotypes, locations, seasons, and genotypes by environment (G × E interaction). A two-dimensional GGE biplot was generated using the first two principal components (axis 1 and axis 2), which accounted for 94.97% and 3.11% difference in GEI for yield per hectare, respectively. Season and location were found to be the most significant causes of yield heterogeneity, accounting for 31.13% and 14.02% of overall G + E + G × E variation, respectively, according to the combined study of variance. The GGE biplot revealed that the three winning genotypes G1, G3, and G5 appear across environments whereas AMMI model exposed genotypes viz G18, G14, G7, G3, G1, and G5 as best performer. Based on ideal genotype ranking genotype G1 was the best performer, with a high mean yield and high stability in the tested environment. According to the AEC line, genotypes G1 and G3 were extremely stable, while genotypes G2 and G4 were low stable, with a high average yielding per hectare. A GGE and AMMI biplot graphically showed the interrelationships between the tested environment and genotypes, classified genotypes into three categories as well as simplifying visual evaluations, according to this investigation. According to our results, breeding could improve yield production, and the genotypes discovered could be recommended for commercial cultivation.

Effect of Nitrogen and Phosphorus Fertilizers on Growth, Yield, Nodulation and Nutritional Composition of Bambara Groundnut [Vigna subterranea (L.) Verdc.]

Background: Bambara groundnut is an edible legume that is highly nutritious. This study was carried out to find the effect of nitrogen (N) and phosphorus (P) fertilizers on the growth, yield, nodulation, the proximate and nutritional composition of bambara groundnut [Vigna subterranea (L.) Verdc.]. Methods: During the period of 2018, a glasshouse experiment was conducted in a randomized complete block design (RCBD) at Ladang 15, Faculty of Agriculture, Universiti Putra Malaysia. Different rates of N and P fertilizer were used. Kjeldahl method and HPLC, respectively, determined the protein and amino acid content in seed. Result: N and P fertilizer were found to play a dominating role in increasing the vegetative growth and yield of the plant. Plant height (20.65a), pod number (45.75a) and harvest index (41.61a) increased significantly with the application of N30 + P60 kg ha-1. Application of N30P60 kg ha-1 significantly influenced nodulation and nitrogen yield. Protein, fibre, Mg and amino acid content increased with N30P60 kg ha-1. The application of N30P60 mg kg-1 has increased the growth, yield, nodulation, proximate and nutritional composition of bambara groundnut.

Morphological Characterization of Bambara Groundnut [Vigna subterranea (L.) Verdc.] Landraces in Kenya

Background: Bambara groundnut [Vigna subterranea (L.) Verdc.], an indigenous drought tolerant crop of African origin is one of most important leguminous crop in Sub-Saharan Africa. Small-scale farmers continue cultivating unimproved landraces over the production areas in Kenya. Bambara exist variously as mixtures of seeds, which contain variable types of seed morphology which need to be agronomically and phenotypically differentiated. The study aimed at characterizing Bambara groundnuts collected in Kenya using morphological markers. Methods: One hundred and five germplasm assembled from four major growing agro-ecologies (Busia, Kakamega, Bungom and Vihiga Counties) and Kenya National Gene bank, were evaluated at the Kenya Agricultural and Livestock Research Organization (KALRO) - Alupe (0.4347° N, 34.2422° E) in a randomized complete block design with three replications in the long and short rains of 2015. Nineteen quantitative traits and seven qualitative traits were observed and measured at different growth stages and during harvesting. Result: Many landraces displayed pointed, round and yellowish pod, with grooved and oval seeds. About 49.4% had round leaves, 21.5% had elliptical leaves, while 55.7% were heterogeneous for leaf shape. Quantitative traits were significant (p≤0.05) except for seed weight, seed number per plant and number of stems. The first four principal components accounted for a total of 73.1% of the variations. germplasm were divided into two distinct clusters. Leaf morphology variations could be used as a reliable phenotypic marker in Bambara breeding.

INTERAKSI JENIS GALUR DAN MULSA TERHADAP PERTUMBUHAN TANAMAN KACANG BAMBARA (Vigna subterranea (L). Verdcourt)

Kacang bambara adalah salah satu tanaman jenis kacang-kacangan yangdikembangkan di Indonesia karena memiliki gizi yang kompetitif. Upaya meningkatkanhasil tanaman kacang bambara di lakukan melalui penanaman berbagai jenis galur kacangbambara dan jenis mulsa. Penelitian ini bertujuan mengetahui interaksi jenis galur dan mulsapada tanaman kacang bambara (Vigna subterranea (L). Penelitian ini dilaksanakan di jlnPesantren Rt 01 Rw 02 Desa Pengulu, Kecamatan Sidayu, Kabupaten Gresik Jawa Timur,pada ketinggian 7 m dpl pada bulan Juni - Agustus 2020. Penelitian menggunakan duafaktor, Faktor pertama yaitu jenis galur (G) yang terdiri atas 2 (dua) taraf perlakuan galurJawa Barat (G1), galur Gresik (G2). Faktor kedua yaitu jenis mulsa (M) terdiri atas 3 (tiga)yaitu, mulsa plastik (M1), mulsa brangkasan kacang bambara 6 ton/ha (M2), mulsa jeramipadi 6 ton/ha (M3). Analisis data menggunakan analisis sidik ragam lebih lanjut apabilaterdapat perbedaan nyata pada uji F 5%, dilanjutkan dengan Uji Duncan’s multiple rangetest pada taraf 5%. Untuk mengetahui keeratan hubungan dua variabel atau lebih digunakanuji korelasi. Hasil penelitian menunjukkan terdapat interaksi nyata perlakuan jenis galur danmulsa pada variabel tinggi tanaman pada umur pengamatan 2 mst, 4 mst, dan 6 mst. Tinggitanaman terbaik ditunjukkan oleh kombinasi perlakuan mulsa brangkasan kacang bambaradan galur Gresik (M2G2)