S02 - Session P6 - Phenotypic variation assessment in cowpea - Vigna unguiculata (L.) Walp. - Portuguese landraces: exploiting new opportunities for crop improvement

Authors: Tércia Lopes *, Ana Pedrosa, Mariana Correia, Cláudia Marinho, Mafalda Resende, Mário Cristóvão, Catarina Martins, Cristophe Espírito Santo, Jorge Canhoto, Sandra Correia

Vigna unguiculata (L.) Walp (cowpea) seeds are rich in proteins. This species is climate-resilient, withstanding high temperatures and water stress, and ideal crop rotation (ability to fix nitrogen). In Portugal, more particularly in the Lardosa region (Castelo Branco), several landraces have been under cultivation and selection for many generations. These landraces are well adapted to harsh conditions but have been scarcely studied. They have a high risk of genetic erosion due to a consistent reduction in production areas. Germplasm characterization towards conservation and breeding programs is critical to reverse this alarming scenario. In the framework of the CULTIVAR project ( https://icultivar.pt ) and by working with local farmers, three regional varieties were identified as currently cultivated. These are "Arroz", "Cara-verde", and "Cara-preta and their preference was to improve the "Arroz" variety. This work aimed to assess the variation in morphological, developmental, and productivity traits to develop this crop's breeding strategies. Seeds (25) from the three landraces were sown in three replicated assays, and plant development was recorded during 110 days in greenhouse conditions. Moreover, productivity parameters were accessed for "Arroz" and "Cara-verde" varieties in field-growing conditions in two selected sites. Results showed that "Cara-verde" develops faster ( p < 0.05) than both "Arroz" and "Cara-preta" until the podfill stage. "Arroz" and "Cara-verde" showed to be more precocious varieties, attaining seed maturation earlier than "Cara-preta". No significant differences were observed regarding productivity traits in the pod and seed number and yield (seeds per pod). This phenotypic variation will be associated to the development of new omics tools (SNP markers) to select cowpea genetic resources for ongoing breeding and conservation programs.