Sucrose accumulation in different sugarcane varieties subjected to thermal stress at formative stage

Development and improvement of renewable energy sources is a vital task to cope with fossil fuel associated consequences on nature. Recently, green energy has been emerged as an alternative for the said challenge. Sugarcane (Saccharum officinarum) is the principal source of sucrose and bioethanol worldwide. However, unfavorable climatic condition particularly episodes of heat waves cause significant reduction in sugarcane biomass and sucrose accumulation. Selection of appropriate variety at formative stage is one of the vital approaches to cope with global warming and may reduce economic loss in cultivation of this annual crop. So, the study was formulated to a) elucidate the varietal differences for sucrose accumulation under thermal stress and b) understand the physiological and biochemical response towards high temperature. Therefore, two sugarcane cultivars viz S-2003-US-633 (high sucrose accumulation) and SPF-238 (low sucrose accumulation) were subjected to heat stress at formative stage. Cell membrane thermostability (CMT), lipid per-oxidation (LPO) and level of oxidative stress, were monitored as stress damage indicators while variation in proline accumulation showed osmoregulatory potentials. Non-reducing and reducing sugars proportion in the total sugar assessed and correlated with soluble protein concentration to mimic the activities of sugar metabolizing enzymes. Results revealed positive relationship of proline and protein content with total sugars in S-2003-US-633 as compared to SPF-238. The later crop had low sucrose may be due to low CMT, higher MDA, and H/sub 2/O/sub 2/. It is evident that cultivar S-2003-US-633 tolerated heat stress based on its physio-chemical managements and ensures high sucrose recovery. The study suggests potential application of the indices in field evaluation and selection of climate resilient sugarcane plant at formative stage to cope with yield and economic loss of this annual cash crop in times of climate change. (author)