New Sources of Fusarium Root Rot Resistance in Phaseolus vulgaris L.1

Abstract

A procedure using nutrient culture media was developed to screen bean seedlings on an individual plant basis for reaction to Fusarium solani (Mart.) Appel & Wr. f. sp. phaseoli (Burk.) Snyd. & Hans. From over 800 accessions, 18 plant introductions and several cultivars of Phaseolus vulgaris were found to be either resistant or tolerant. Susceptible plants, grown with ammonium nitrate as the nitrogen source (210 ppm N) showed reduced symptoms compared to plants grown on nitrate-N only. Ammonium as the sole nitrogen source was toxic to bean seedlings at identical nitrogen concentrations. Results based on the nutrient culture technique were generally consistent with field reactions.