Ubonratchathani Black Grain Cowpea

Abstract

The aim of this research project was to improve the yield of the black grain cowpea by in 1997-2002. The selection of pure line was 26 black grain cowpea lines at Ubon Ratchathani Field Crops Research Center during 1997-2002. After 4 experimental studies of selection, twelve lines of black grain cowpea were selected and the yield trials were conducted in the field both upland and lowland. The grain yield of the selected lines grown in upland at the Field Crops Research Centre during the rainy season was determined in comparison to a local variety of black grain cowpea obtained from Loei province. For the lowland, the study was carried out at five farms in Ubon Ratchathani province during the dry season after the major rice harvest grain and the yield two these selected lines was compared to that of a local veriety the mottled grain cowpea obtained from Ubon Ratchathani province. The results showed that the line CP 4-2-3-1 produced the highest yield of 75 kg/rai and 183 kg/rai for growing in upland and lowland that was 3 and 9% higher than local varieties respectively. Line CP 4-2-3-1 was moderately resistant to bacterial leaf blight, compared with susceptibility to the disease of local variety black grain cowpea from Loei. Furthermore, line CP 4-2-3-1 producted a high biomass of 1,274 ka/rai of the first at dry pod growth stage (60-65 days after emergence) which was 19.8% higher than the variety black grain cowpea from Loei. In addition, line CP 4-2-3-1 had high nutrients contents of nitrogen, phosphorus and potassium was 31.2, 21.4 and 24.0 kg/rai, respectively. Accordingly, line CP 4-2-3-1 can be used as organic fertilizer after harvesting at the first dry pod stage. Therefore, ling CP 4-2-3-1 was approved as a new recommended cowpea variety to farmers. If was realized and named “Ubonratchathani” black grain cowpea by the Department of Agriculture on 31 March 2003.