Influence of neutron irradiation and phosphorus on the performance of groundnut [Arachis hypogaea (L.)] genotypes grown on a P-deficient alfisols at Samaru, Nigeria

Abstract

There is a dearth of information on the effective irradiation dose for inducing variability in groundnut genotypes. A screen house experiment was conducted at the Department of Soil Science, Ahmadu Bello University, Zaria (ABU). It was to investigate the effect of induced genetic variability (by neutron irradiation) and four phosphorus rates (0, 20, 40 and 60 kg P₂O₅ ha^-1) on the performance of some groundnut [(Arachis hypogaea (L.)] genotypes grown on a P-deficient Alfisols at Samaru, Zaria. A fraction of each of the two genotypes (SAMNUT 24 and SAMNUT 26) was irradiated, in a 5-Curie Americium-Beryllium (Am-Be) isotope neutron source, having a thermal neutron flux of 2.7387 x 10⁴ n cm^-2 sec^-1 for six days, at the Centre for Energy Research and Training, ABU. The irradiated (G_1A and G_2A) and nonradiated (G_1B and G_2B) seeds; and the P rates were laid out in a randomised complete block design (RCBD), in a screen house, and replicated thrice. Data collected during the study included; plant height, numbers of branches, flowers, nodules, leaves and chlorophyll content (CC). Both G_1A and G_2A significantly (P<0.0001) produced the highest CC, highest numbers of branches, leaves, flowers, nodules and effective nodules; and the tallest plants. Treatment with 60 kg P₂O₅ ha^-1 significantly (P<0.0001) increased the number of leaves, flowers, branches and plant height. The irradiated genotypes were generally observed to significantly perform better than their non-radiated counterparts under the application of both 60 kg P₂O₅ ha^-1 and 20 kg P₂O₅ ha-1. Thus, application of 20 kg P₂O₅ ha^-1 is recommended for optimum plant height, flowers and CC in groundnut production; while 60 kg P₂O₅ ha^-1 is recommended for optimum numbers of branches and leaves, especially when the irradiated SAMNUT 24 and SAMNUT 26 are to be used for production of both seeds and biomass.

Keywords: Alfisols, Chlorophyll content, Neutron irradiation, SAMNUT