Plant breeding experiments require the use of appropriate experimental designs that will efficiently block variation due to wide heterogeneity nature of tropical soils. The primary objective of this study was to assess the effectiveness of eight different alpha-lattice designs relative to randomized complete block design for evaluating 108 genotypes of maize under rainforest agro-ecology. The maize genotypes were field-tested using three replications at two locations. Data were collected on grain yield and other agronomic traits. Data collected were subjected to analysis of variance (ANOVA) assuming randomized complete block design (RCBD) and eight alpha-lattice designs. Pearson's correlation and stepwise multiple regression analyses were used to analyze relationship among different designs and efficiency of the lattice designs over RCBD was computed. Result showed that all the alpha lattice designs except 27 × 4 were effective in evaluating the genotypes for plant height. There was significant difference (p < 0.001) among genotypes for grain yield only when data were analyzed based on 9 × 12 alpha lattice design. In addition, results showed that the proportion of variation due to blocking and R-square values of the model increased with increase in the number of blocks for grain yield. In contrast, coefficient of variation decreased with increase in the number of blocks. The result showed an increase in efficiency of the alpha lattice designs as the number of blocks increased. It could then be concluded that the more the number of blocks within replicate, the proportion of total variation due to blocking increased, the coefficient of variation (CV) reduced, coefficient of determination (R-square) increased and thus, effectiveness increased. Appropriateness of designs was trait dependent. The 9 × 12 alpha lattice design was identified to be the best in the evaluation of grain yield for the maize genotypes.

Basella alba is an underutilized vegetable with ethnobotanical importance used for culinary as well as medicinal purposes in many parts of the world. Morphological characterization and chromosome studies of the mitotic and meiotic cells of the green stemmed and the red-stemmed B. alba was carried out with a view to filling the knowledge gaps that exist in their morphological characterization and also to provide insightful information on their chromosome numbers and meiotic behaviour. The B. alba accessions studied were characterized with respect to their habit, leaves, inflorescence, fruits and seeds. Mitotic and meiotic studies were carried out on the Basella accessions using standard techniques. The morphological studies revealed significant differences between the green-stemmed and red-stemmed Basella alba with respect to the green/red colour of their stems, colour of the flower bud apex, mean plant height at flower bud initiation, mean leaf length, mean leaf width, mean petiole length, mean flower per spike, mean fruit length and mean fruit diameter. The cytological study revealed a chromosome number of 2n=4x=44 for both the green-stemmed and the red-stemmed B. alba studied. It also revealed the occurrence of chromosomal aberrations such as stickiness and precocious migration of chromosomes to the poles during meiosis, which could lead to irregular chromosome segregation that could result in chromosome instability and aberrant meiotic products within the species.

Flower thrips (Megalurothrips sjostedti Trybom) are a major pest of cowpea worldwide. Although some cowpea varieties exhibit resistance to these pests, the underlying mechanisms of this resistance remain unclear. This study aimed to explore the biochemical factors contributing to resistance against thrips and to measure the levels of specific compounds in resistant cowpea varieties. Six cowpea cultivars were tested using a randomized complete block design across three field trials. At 44 days after planting, foliage and flowers from each cowpea variety were collected for laboratory analysis. Samples from ten randomly chosen plants from each variety were combined to measure total protein, soluble amino acids, phenols, flavonoids, and total antioxidants. Data analysis revealed significant differences among the cowpea lines. Most metabolites, except flavonoids, showed considerable variation among the tested varieties. Notably, the resistant lines TVu1509, Sanzi, and TVNu1249 exhibited the highest levels of total protein. Principal component analysis indicated that the first three components explained about 83.59% of the total variation, with contributions of 36%, 28%, and 19%, respectively. In conclusion, resistance in certain cowpea lines to flower thrips is associated with higher levels of total protein, soluble amino acids, and total antioxidants.