A method for screeningPhaseolusgenotypes for tolerance to low temperatures

Abstract

Results are presented which show the importance of temperature and seed size in determining seedling weight in Phaseolus. On the basis of these results a test is described for revealing differences between genotypes in their tolerance to low temperatures. Weighed seeds are sown in pots and put in a controlled environment set to give a constant temperature of 12.5 °C and a light intensity of 61 W/m² from fluorescent and 28 W/m² from tungsten lamps. Plants are harvested after 40 days and log plant weight is plotted against log seed weight. Regressions are calculated, and varieties having high positive residuals are considered to be cold tolerant. Of 305 genotypes tested, 46 good and 11 poor genotypes have been selected for further studies.