The effects of high temperature on dormancy and hypocotyl-root growth of wild common bean (Phaseolus vulgaris L.)

The aim of this study was to investigate the effects of scarification and high temperature on dormancy and initial hypocotyl-root growth of two wild common bean (Phaseolus vulgaris L.) samples differing in geographic origin and in the domesticated common bean. The wild common bean samples exhibited large differences in the proportion of dormant seeds (ranging from 20 to 70%25), depending on their size and origin, with noticeable differences in their rates of imbibiton. In addition, mechanical scarification broke the wild seed dormancy. High temperatures (30-45°C) also broke dormancy in some wild subsamples but killed some seeds in others, particularly those of small size. High temperatures also induced a small but significant increase in water uptake during imbibition. Initial hypocotyl-root growth from small wild seeds was not affected with the increase of temperature, except at 45°C when the growth fell sharply. In contrast, initial hypocotyl-root growth from large wild seeds increased at exposure of 30 to 40°C, but at 45°C the growth was also diminished. Although high temperatures did not affected water uptake in domesticated common bean, especially at 35-45°C, germination and initial hypocotyl-root growth were severely affected. Therefore, the data suggest that high temperature during germination has a positive relationship with the breaking of dormancy of wild common bean, but deteriorated the seed of domesticated common bean.

VIVO