Response of cowpea lines to low Phosphorus tolerance and response to external application of P
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Date
2012
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African Journal of Microbiology Research · July 2012
Abstract
Low availability of phosphorus (P) is a major constraint to crop production in Sahel and Sudan Savanna
of West Africa, and efforts are being made to identify cowpea genotypes with tolerance to low P and
greater P use efficiency. Arbuscular mycorrhizal fungi (AMF) enhance P uptake in low P soil. Cowpea
breeding lines (200) were examined at 3 P levels (0P, 90 kg P ha-1 as Rock Phosphate and 30 kg P ha-1
as Simple Super Phosphate (SSP) in 2002 at Minjibir, Nigeria and Toumnia, Niger. Wide apparent
variation in grain and fodder yields was found among the 200 genotypes. Grain yield response to RP
and SSP ranged from 1 to 160%. Based on the genotypes performance at low and high (SSP),
genotypes were classified. Fifteen genotypes were selected from the different P use and response
groups and further examined in the greenhouse and field studies for growth characteristics related to
tolerance to low applied P. Phosphorus application significantly (P ≤ 0.05) increased the grain and
fodder yield at both locations., shoot-root ratio but decreased AMF colonization of cowpea roots. There
were large differences in the relative P used in efficiency and the values ranged from –11 to 38 kg grain (kg P)-1
applied. AMF infection was reduced by at least 50%, while shoot-to-root ratio was significantly
increased with P application. Variation between genotypes was significant for certain paired means but
not consistent for all parameters measured, and the locations. The cowpea genotypes differ in AMF
colonization, shoot growth relative root development, and relative P use efficiency for tolerance to low
P soils and response to external application.
Description
This article is Published by African Journal of Microbiology Research · July 2012 and is also available at DOI: 10.5897/AJMR11.1599