HEAT STABILITY OF THE MEMBRANE AND HEAT TOLERANCE IN VARIETIES OF Saccharum spp.

Abstract

The heat tolerance of four varieties of sugar cane (Mex 68-1345, Mex 68-P-23, CP 72-2086 and Mex 79-431) was evaluated in the plant cycle under rainfed conditions, through the heat stability test of the cell membrane. The relative percentage of the damage to the cell membrane (DCM %) was used as indicator of heat tolerance. The varieties showed differential responses, with Mex 68-1345 and CP 72-2086 being more tolerant to heat, in function of the relative percentage of the damage to the cell membrane being lower, in addition to a high water potential during the hours of heat, primarily of Mex 68-1345, and good capacity for recovery based on the leaf temperature during the afternoon, reaching the lowest
temperature of all the varieties.