Germplasm Collection and Seed Diversity of Cowpea (Vigna unguiculata (L.) Walp.)

Abstract

Cowpea (Vigna unguiculata L.) is a legume crop cultivated in whole of Arabian Peninsula countries including Oman as a dual crop for both food and fodder during summer. Both consumers and farmers prefer large size seeds. This paper presents the results of collecting missions of indigenous cowpea germplasm and analysis of seed diversity of collected accessions. The collecting mission led to the accumulation of seed samples of 64 accessions with large number from the governorates of Sharqiya (North Eastern) (19), followed by Dhofar (Southern) (17), Al-Dakhiliyah (Interior) (10), South Batinah (South Coast) (9), North Batinah (North coast) (5) and Dhahira & Buraimi (4). The accessions were diverse in respect to all the seed traits studied, i.e. seed length (cm) and width (cm), 100-seed weight (g) and seed color. The accessions were grouped into 14 genetically diverse clusters based on the Principal Component Analysis, which revealed the contribution of seed length and 100-seed weight to the total variation existing in indigenous germplasm collected from all the governorates of Oman. The results of critical examination of seed color pattern of these samples indicated the presence of as many as 31 groups of which the largest group had 16 accessions followed by a group with 4 accessions, 2 groups with 3 accessions each and 9 groups with 2 accessions. There were 19 accessions numbering 193, 197, 251, 269, 276, 280, 293, 297, 301, 303, 325, 327, 328, 331, 332, 333, 339, 343 and 347 which formed groups of their own due to a unique combination of seed coat colors.