Effect of Different Concentrations of Paclobutrazol on Increasing Tolerance of Sugarcane (CP48-103 variety) to Winter Conditions in the Southern Region of Ahvaz (South West of Iran)

The application of paclobutrazol as a growth stimulant not only increases the cold tolerance of sugarcane but also enhances its yield.
To investigate the effect of different concentrations of paclobutrazol in enhancing winter tolerance of sugarcane variety CP48-103 this study was carried out.
Current research was done during the 2013 cropping season according randomized complete block design (RCBD) with three replications. The studied treatments were as control group (untreated(, burning of cold-damaged shoots, harvesting cold-damaged shoots without hormone consumption, harvesting cold-damaged shoots and spraying with a solution of 100 mg.lit-1 paclobutrazol, harvesting cold-damaged shoots and spraying with a solution of 150 mg.lit-1 paclobutrazol, spraying solution on cold-damaged shoots with a concentration of 100 mg.lit-1 paclobutrazol, spraying solution on cold-damaged shoots with a concentration of 150 mg.lit-1 paclobutrazol.
The highest chlorophyll content, measured at 40 (Spad), was observed in harvesting cold-damaged shoots and spraying with a solution of 150 mg.lit-1 paclobutrazol. Among the treatments, the highest amount of syrup (with an average of 31%) was observed in the treatment of burning of cold-damaged shoots, while the lowest amount (with an average of 28%) was found in the treatment of harvesting cold-damaged shoots without hormone consumption. The sucrose percentage displayed a significant increase from October 15 to October 30 in different treatments. This indicates that the sucrose content in the sugarcane increased during this period across all treatments. The burning treatment resulted in the lowest percentage of sucrose, with an average of 11%. The percentage of extractable sugar reached its peak on December 6 and across different treatments, the highest amount of extractable sugar (with an average of 8.5%) was obtained from treatment involving the harvesting cold-damaged shoots and spraying with a solution of 150 mg.lit-1 paclobutrazol. In terms of stem yield, the highest and lowest values (with an average of 59800 and 51280 kg.ha-1, respectively) were recorded in treatment of harvesting cold-damaged shoots and spraying with a solution of 150 mg.lit-1 paclobutrazol and control treatment, respectively.
The treatment involving the application of paclobutrazol significantly increased the stem yield of sugarcane compared to the control treatment.