Abstract
A comparative assessment of temperature sensitivity, based on stability of chromosomal mechanisms and fertility, of some polyploid wheat species and their diploid progenitors was made by subjecting plants to a temperature of 40±1°C (R.H. 70) for durations ranging from 12 to 72 hours. All the diploids were observed to be considerably more sensitive than the polyploids. The differential response of varieties within a ploidy group was very marked; winter types being strikingly more resistant than the spring forms. These observatiens have been discussed with regard to the contributions of polyploidy in relation to adaptability of the bread wheats.
