Genetic variability of free energy in a function of drought tolerance in common bean accessions

Abstract

Characterisation of bean genotypes, particularly local landraces is important for ongoing breeding programs, especially for drought tolerance. Susceptibility to drought is emphasized when bean is grown as a stubble crop and sown at the middle of summer. The aim of this study was to compare variability of ten bean genotypes to optimal (25?C) and higher (30?C) temperatures in combination with optimal (80%) and reduced (40%) field water capacity (FWC), from the point of growth (root and shoot length and fresh matter accumulation) and thermodynamic parameters of free energy (calculated parameter after drying at 60?C, 105?C and 130?C) during the early seedlings stage. Significant and positive correlation between root length and fresh matter with free energy at symplast and chemically bound water occurred under temperature stress (i.e. 30?C). Root growth and elongation were affected by drought stress, i.e. under a combination of high temperature (30?C) and water deficit (40% FWC). Based on higher energy consumption, the ability of shoot to continue a growth in stressful conditions could be possible to achieve, as was confirm through significant and positive correlation between evaluated growth parameters in shoot and free energy of free water. It could be concluded that most of the examined dry bean accessions expressed some sensitivity to stress applied. Among genotypes tested, local landrace zecak expressed lesser susceptibility to stresses applied. Accession Maksa was more tolerant to changes at cytoplasmic level, while Medijana and Sataja 425 expressed root i.e. shoot stress tolerance. Those accessions could be considered as potentially drought tolerant genotypes.