Genotypic variation in the germination of common bean in response to cold temperature stress

Abstract

Beans (Phaseolus vulgaris) are regarded as a susceptible crop to suboptimal temperatures. In temperate regions, low temperatures reduce establishment of beans when planted early in the growing season. Seeds of 14 cultivars/lines or beans were germinated in petri dishes at a constant 8, 10, 12, or 18°C or at 12 h alternating temperatures of 10/8, 12/8 or 18/8°C. Differences in germination percentages and rates between cultivars/lines were significant, especially at low temperatures. Cultivars/lines that germinated best and quickly at constant 8°C were ‘Volare’, ‘Great Northern (G.N.) Tara’, ‘G.N. Belneb # 1’, ‘G.N. Spinel’, and ‘San Cristobal’. Germination percent and rate of ‘Pinto-UI-111’ and ‘Canadian Wonder’ increased significantly when temperatures were increased by 2 to 4°C for 12 h per 24 h, compared with a constant 8°C. Whereas, germination of ‘G.N. Belneb # 1’ was reduced. Polyacrylamide gel electrophoresis was used to study the effect of cold treatment on polypeptide patterns of seven cultivars/lines. Seeds were germinated at 18°C constant for 96 h or at 18°C for 48 h followed by 48 h at 2 or 8°C. During cold treatment the synthesis of some polypeptides increased. ‘Volare’, ‘G.N. Tara’ ‘Pinto-UI-111’ and ‘Canadian Wonder’ showed changes in polypeptide patterns, while Alubia-33-1, ‘Michigan 84100’ and BAT-1225 showed no changes in polypeptide patterns if compared to the control (96 h at 18°C in the dark). This suggests a likely essential role of these proteins in the development of chilling tolerance.