Diallel analysis of cowpea [ Vigna unguiculata (L.) Walp.] for seed size, and resistance to Alectra vogelii Benth.

Cowpea production is hampered by several abiotic and biotic constraints. Parasitic weed Alectra vogelii is a formidable biotic constraint in cowpea production. This study was implemented to determine gene actions involved in cowpea seed size and its resistance to Alectra in order to determine the appropriate breeding approach to develop resistant cowpea varieties to Alectra vogelii . For this purpose, a half diallel of 9 parents was developed at Kamboinse in 2016. The F1 and their parents were screened in screen house with Alectra vogelii seed collected from Alectra infested field in Koupela in centre east Burkina Faso. Data were collected on dates to cowpea flowering, cowpea hundred seeds weight and the severity of Alectra 70 days after planting and analysed with Diall 98 software. Both additive and non-additive gene actions were operative for the investigated characters. Additive gene effects were more important, resulting in high narrow sense heritability, inferring that breeding progress can be achieved through backcross or single seed descent method. Keywords : additive, Burkina Faso, dominance, general combining ability, gene action, heritability.