DRY BEAN GENOTYPES SUSCEPTIBILITY AND ADAPTATION MECHANISMS TO IRON CHLOROSIS

Abstract

Two experiments were carried out under greenhouse conditions. In the first one the susceptibility to iron chlorosis was evaluated in 23 cultivars of dry beans (Phaseolus vulgaris L.) using the Hoagland?s nutrient solution at 0.1 ppm level of Fe-EDTA. It was found out that Bayo Zacatecas was the most tolerant genotype (Fe-efficient), while Garbancillo Supremo was the most susceptible (Fe-inefficient). In the second experiment, both Bayo Zacatecas and Garbancillo Supremo genotypes were grown with 0 and 2 ppm levels of Fe-EDTA in a Steinberg?s nutrient solution. Bayo Zacatecas showed higher and sooner acidification response; such response can be related with its Fe-efficiency. Likewise, Bayo Zacatecas showed the highest values of chlorophyll concentration and nitrate reductase activity in comparison with Garbancillo Supremo. Both chlorophyll concentration and nitrate reductase activity were related with the genotypes Fe-efficiency. About the mineral concentration, the highest values were found in the Fe-inefficient genotype without Fe-EDTA addition.