The aim of this study was to investigate genetic control of the traits number of days to flowering (NDF) and number of days to maturity (NDM) in a cowpea cross. Genetic parameters were estimated in segregating and nonsegregating generations of a cross between two contrasting cowpea genotypes (MNC05-828C-1-9-1 × MNC04-792F-146). No evidence for maternal effect was found for either trait. Broad and narrow sense heritability estimates were above 50%, allowing genetic gains from selection of plants in the F 2 generation. High significance of additive gene effects and low contribution of dominance and epistatic effects were detected for both traits. The estimated number of genes controlling the traits was around 4 for NDF and 5 for NDM. The results suggest that early-maturing cowpea self-fertilized cultivars can be developed through standard breeding approaches, meeting the demands of modern agricultural systems for more crop seasons per year and mechanized harvesting.

Cowpea is a great socioeconomically important leguminous plant worldwide. The crop is an excellent source of proteins and minerals, mainly for the poorest populations. It is cultivated in some states of Brazil. The Piauí semi-arid is the most yielding zone in the state. Thus, the selection of superior cowpea genotypes for multi-traits and adaptabilities to this growing area is very important for the small-scale and medium-scale farmers in Piauí. The objective of this study was to select the superior cowpea lines for their multi-traits and adaptabilities to the Piauí semi-arid zone based on the genotype by the yield*trait (GYT) Biplot approach. Seventeen elite lines and three cultivars were evaluated in a randomized complete block design with four replications under the rainfed growing condition at three different locations away from the Piauí semi-arid zone. The following traits were evaluated: the number of days to flowering, pod length, the number of grains per pod, weight of one hundred grains, grain index, grain yield, Fe and Zn contents, and also the cooking quality. The analysis of variance (ANOVA), the grouping of means, and simultaneous selection by the GYT Biplot were implemented. Through the GYT Biplot approach, the two lines, MNC11-1013E-35 and MNC11-1013E-15, were found superior because they combined the traits, grain-yield with the yield components and nutritional traits simultaneously during the cultivation in the Piauí semi-arid zone. However, the MNC11-1052E-3 line was better in the combination of yield and cooking quality than the other lines.

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The objective of this work was to select cowpea lines with compound inflorescences that show a high potential to generate the first commercial cultivar with this characteristic in Brazil. Thirty-seven lines were evaluated in a randomized complete block design, with two replicates, in 2021, in the municipality of Teresina, in the state of Piauí. The following traits were evaluated: number of days to the onset of flowering, plant size, commercial grain quality, number of grains per pod, weight of 100 grains, and grain yield. Deviance analyzes were performed by the restricted maximum likelihood/ best unbiased linear predictor methodology, and the values and genetic parameters necessary to carry out simultaneous selection were estimated based on the rank sum index. A statistical difference was detected between the lines evaluated by the likelihood ratio test (LRT). In general, genetic variance was the largest component of phenotypic variance for the evaluated traits. The ten most promising cowpea lines with compound inflorescences are: MNC15-33E-123, MNC15-33E-178, MNC15-33E-222, MNC15-33E-171, MNC15-33E-232, MNC15-33E-223, MNC15-33E-219, MNC15-33E-183, MNC15-33E-91, and MNC15-33E-165. These lines were selected for the next selection stages and show a high potential to generate the first commercial cowpea cultivar with compound inflorescences in Brazil.

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