Differences in response to phosphorus among cowpea (Vigna unguiculanta (l) walp.) cultivars

Abstract

The effect of different levels of soil phosphorus (P) on nodulation and growth of three cowpea [Vigna unguiculata (L.) Walp.] cultivars (Accra market, IT82-E32 and TVU 1977) were compared in a greenhouse study. The rates were 0, 15, 30 and 45 mg P kg-1 soil. Both nodule number and nodule dry weight were increased by P application in Accra market and TVU 1977 but did not change much in IT82-E32. Shoot dry weight of IT82-E32 was the least affected by P application. In contrast, shoot yields of Accra market and TVU 1977 with no P application, were 75 and 65 percent, respectively of the maximum obtained under P application. Pod (plus seed ) yield was highest in IT82-E32 at both the lowest and highest level of soil P. IT82-E32 also accumulated substantially higher amount of nitrogen in pods than Accra market and TVU 1977. It is possible by selection to obtain cultivars capable of good growth in soils of low P, variety IT82-E32 is a good example.

JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 1 Number 2, January (1999) pp. 10-14