Studies on minimizing dextran problems in sugar cane under subtropical conditions

The natural occurrence of pre-harvest dextran in fresh sugar cane grown at three geographically diversed locations in Punjab, India, was studied over a two-year period. Incidence of dextran ranged from 20 to 100% at Jalandhar whereas no dextran was detected in cane at other locations. Dextran levels associated with genotypes over all locations varied widely but differences were not significant. However, there was a trend of reduced dextran content in the test varieties with medium levels of sugar compared to levels reported in subtropical areas. In post-harvest studies, the rate of change of weight loss, sucrose decline, and dextran development were predicted by regression equations for two genotypes during 7 days of storage at 20 or 30oC. The rate of weight loss was 1.48% for CoJ 64 and 1.25% for CoJ 79 per day stored at 20oC and was 3.00 and 2.12% per day, respectively, for canes stored at 30oC. Cold storage significantly reduced the rate of sucrose loss and dextran development in both varieties. Rate of post-harvest losses was significantly lower in CoJ 79 than in CoJ 64 at both temperatures.