Abstract:
Cowpeas [Vigna unguiculata (L.) Walp.], Is a very important crop in the economy and food security of the populations of southern Mozambique. However, the yields of this crop are still very low and quite variable. For this reason, the identification of high-yielding and stable genotypes is crucial to ensure well-being and food security in this region. It was in this context that the present study was conducted to assess the performance and stability of 19 genotypes introduced compared to 5 genotypes already released. The tests were carried out in two experimental stations (Posto Agronómico de Ricatla, Bilene district and Posto Agronómico de Nhacoongo, Inharrime district) and on farmers' fields in the districts of Bilene and Inharrime. The tests carried out at the Ricatla and Nhacoongo experimental stations, as well as the one carried out on a farmer's machamba in Chimondzo, district of Bilene, consisted of all 24 genotypes while those of the peasant machambas consisted of groups of 6 genotypes each, totaling 4 groups . Thus, 4 peasants were needed to complete the 24 genotypes. In Bilene, each group of 6 genotypes was evaluated by 4 peasants whereas in Inharrime each group was evaluated by 6 peasants. The performance of the genotypes was evaluated using the analysis of the components of variance and the comparison of the means using the test of minimum significant difference. Stability was assessed using the GGE biplot method and measure of cultivar superiority without decomposition of the Pi statistic. The study on the performance of 19 genotypes introduced compared to 5 already released revealed that the form of management and the water deficit significantly affect the grain yield, number of pods per plant, number of seeds per pod and weight of 100 seeds. introduced genotypes that are better, equal and worse than those already released. The introduced genotypes IT00K-96, IT98K-1105-5, IT97K-284-4 and UC-CB46 are able to be proposed for release in the south of the country. The study of the yield stability of cowpea grain revealed the occurrence of qualitative interaction in the southern region of Mozambique. The genotypes IT00K-96, UC-CB46 and IT98K-1105-5 were classified as stable and suitable for cultivation in all environments studied in southern Mozambique. The two methods used to assess stability were inconsistent with each other regarding the identification of superior genotypes. However, the GGE biplot proved to be more suitable for assessing stability by providing additional information that is very relevant for the development of crop breeding programs. Combining the two studies, it can be concluded that the genotypes UC-CB46, IT00K-96 and IT98K-1105-5 present a good performance and stability in climatic conditions and management of peasants in the southern region and are therefore recommended for the release and cultivation in that region
