Intraspecific variabilities in 40 accessions of African yam bean (AYB) were assessed through characterization of 48 agromorphological traits for two cropping seasons between June and December 2011 and 2012. Data were analyzed using descriptive statistics, analysis of variance (ANOVA), correlation analysis, principal component analysis, and cluster analysis (Semipartial R squared method). The accessions showed significant differences (P ≤ 0.05, P ≤ 0.01, P ≤ 0.0001) in 16 reproductive traits. Accessions TSs 66 (144.50 days), TSs 51 (144.67 days) and TSs 154 (144.67 days) were identified as early maturing accessions. The first five principal component axes explained 69.7% of the total variation with PC1 and PC2 contributing 38.9% to the total variation. Correlation coefficients were high and significant for yield traits. A highly significant correlation (r = 0.99 *** ) was observed between seed yield (kg ha -1 ) and weight of total pods per plant. Tubers were produced from 42.5% of the accessions. The accessions of AYB were meaningfully grouped into five clusters at the R-squared distance of 0.04 similarity index. Phenotypically, AYB 57 and TSs 123 were the most similar accessions with the closest distance of 0.0071. Four seed shapes were identified; oval (82.5%), globular/round (5%), oblong (10%), and rhomboid (2.5%). In order to improve the yield of AYB, the number of seeds per pod, number of pods per plant, weight of total seeds per pod, and weight of total seed per plant are important determinant factors. The genetic variabilities observed in the traits studied could be utilised for improvement of AYB.

Parkia biglobosa (Jacq.) is an important leguminous tree crop in the African Savannahs useful to the natives where it is found, for domestic use. Previous diversity studies on this tree crop had been majorly on morphological and biochemical analysis. In order to capture the maximum diversity not obtained by previous research, the study aimed at evaluating the genetic diversity of accessions of this crop in the different agroecological zones in Nigeria using RAPD markers. A total of 81 scorable bands with an average of 8.1 bands per primer were amplified among the accessions studied. Intrazonal genetic diversity analysis showed a percentage polymorphism with a range of 11.11% to 65.43% among the agroecological zones studied. Although, gene diversity was highest within Humid forest agroecological zone, a low genetic distance and high genetic similarity between the agroecological zones were observed. Cluster analysis indicated six main groups of which four groups had single accessions while the two groups clustered the remaining accessions, indicating a narrowed genetic base from the 23 accessions studied.

Variability is an important factor to consider in crop improvement programmes. This study was conducted in two years to assess genetic variability and determine relationship between seed yield, its components and tuber production characters among twelve accessions of African yam bean. Data collected were subjected to combined analysis of variance (ANOVA), Principal Component Analysis (PCA), hierarchical and K-means clustering analyses. Results obtained revealed that genotype by year (G × Y) interaction had significant effects on some of variables measured (days to first flowering, days to 50 % flowering, number of pod per plant, pod length, seed yield and tuber yield per plant) in this study.The first five principal components (PC) with Eigen values greater than 1.0 accounted for about 66.70 % of the total variation, where PC1 and PC 2 accounted for 39.48 % of variation and were associated with seed and tuber yield variables. Three heterotic groups were clearly delineated among genotypes with accessions AY03 and AY10 identified for high seed yield and tuber yield respectively. Nonsignificant relationship that existed between tuber and seed yield per plant of these accessions was recommended for further test in various agro-ecologies for their suitability, adaptability and possible exploitation of heterosis to further improve the accessions. Variabilnost je zelo pomemben dejavnik v žlahtnenjenju poljščin. Dvoletna raziskava je bila opravljena s ciljem ovrednotenja genetske variabilnosti in analize odnosov med komponentami pridelka semena ter tvorbe in značilnosti gomoljev med 12 akcesijami afriškega gomoljastega fižola. Zbrani podatki so bili obdelani z analizo variance (ANOVA), analizo glavnih komponent (PCA), hierarhično in klastersko analizo. Izsledki so pokazali, da so imele interakcije med genotipi in leti (G × Y) statistično značilen vpliv na nekatere analizirane spremenljivke kot so dnevi do prvega cvetenja, dnevi do 50 % cvetenja, število strokov na rastlino, dolžina stroka ter pridelek semen in gomoljev na rastlino. Prvih pet glavnih component (PC) z lastnimi vrednostmi več kot 1.0 je prispevalo 66.70 % celokupne variabilnosti, PC1 in PC 2 pa sta pridali še 39.48 % variabilnosti v povezavi s pridelkom semena in gomoljev. Med genotipi so se jasno oblikovale tri heterotične skupine in akcesija AY03 je bila prepoznana po velikem pridelku semen, AY10 pa po velikem pridelku gomoljev. Neznačilno povezavo med pridelkom semen in gomoljev pri teh akcesijah bi bilo priporočljivo dodatno testirati glede prilagodljivosti na različne agroekološke razmere, možnosti njihovega izboljšanja in potencialne uporabe heterotičnega učinka.

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<p class="042abstractstekst">Drought and poor soil fertility are major limitations to crop production, globally. To investigate the impacts of water deficit stress (WS) and soil nutrient amendment (SA) on growth and yield performances of maize. A two years factorial field study was carried out, using a quality protein maize (QPM) (ILE-1-OB) and a non QPM–drought tolerant check (TZPBSR-W) varieties in Ibadan. Treatments include; six fertilizer application rates; 50 and 100 (kg N ha^-1) ofNPK-20-10-10, 10.7 kg N ha^-1of Tithonia Poultry Compost (TPC), 50 N + 10.7TPC and 100 N + 10.7TPC (kg N ha^-1), three WS; the control (FW), WS at vegetative stage (STR1), and WS at reproductive stage (STR2). Leaf area (LA) and grain yield (GY) were measured using standard procedures. From the results, across WS, LA ranged from STR1 (458.90 ± 12.4) to FW (598.81 ± 13.1 cm²), GY varied from STR2 (2.94 ± 0.2 t ha^-1) to FW (6.59 ± 0.2 t ha^-1), across fertilizers, LA varied from 0 N (397.65 cm²) to 100N + 10.7TPC (622.71 cm²) and 50 N + 10.7TPC (611.03 cm²), respectively. The GY varied from 0 N (2.37 t ha^-1) to 100 N + 10.7TPC (5.82 t ha^-1) and 50N + 10.7TPC (5.26 t ha^-1).<strong> </strong>Drought stress reduced growth and GY performances of QPM, while SA with 50 kg N ha^-1 of inorganic fertilizer and 10.7 kg N ha^-1 of<em> </em>TPC enhanced growth and grain yield of maize under WS.</p>