3. Drought tolerance of Bulgarian common bean genotypes, characterized by some physiological and biochemical parameters

Author: Zlatko Zlatev, Malgorzata Berova, Vladimir Krastev, Diana Svetleva, Petya Parvanova, Daniela Miteva, Zhana Mitrovska, Stephka Chankova


This study aims to characterize sensitivity to the drought of some Bulgarian common bean genotypes, studying physiological (leaf water potential and leaf gas exchange) and biochemical (proline content) parameters to introduce them in farther breeding programs for creation of new cultivars with better drought tolerance. Fourteen common bean genotypes – five mutant lines and nine cultivars (8 Bulgarian and a Mexican one – BAT 477), were tested in three years investigations conducted in the field of the department Genetic and Plant Breeding at Agricultural University, Plovdiv. Mutant lines (M19-generation) were previously obtained by treatment of seeds from the cultivar Dobroudjanka 2 with ethylmethan sulphonate (EMS) and N-nithroso-N-ethyl urea (NEU). BAT 477 was used as a control variant. The obtained results in that study highlight the fact that water deficit influenced leaf water relations in young common bean plants. Changes in water potential (Ψw) were the highest in mutant lines D2-6.2-3 М ЕМS (№ 3), D2-3.1-3 М NEU (№ 5) and cultivars – Plovdiv 15 M (№ 12) and Dobrudjanka 2 (№ 13). Leaf gas exchange parameters, comparing to the control variant (BAT 477), were higher in Bulgarian common bean genotypes – D2-3.1-3 М NEU (№ 5) and Dobrudjanka 2 (№ 13). During rainfed conditions the following Bulgarian genotypes have a bigger amount of proline: mutant lines D2-6.2-3 М ЕМS (№ 3), D2-3.1-3 М NEU (№ 5) and cultivars Doubrudjanski ran (№ 10) and Dobrudjanka 2 (№ 13) in comparison to the other studied genotypes. Based on water relations and leaf gas exchange parameters, mutant line D2-3.1-3 М NEU (№ 5) and cultivar Dobrudjanka 2 (№ 13), studied for stress tolerance, can be included as donors for drought tolerance in further breeding programs. All data presented in the tables and the figure are averaged on the basis of the results obtained from the three-years investigations.

Keywords: Leaf gas exchange, leaf water potential, Phaseolus vulgaris L., proline.