Biomass yield, dry matter partitioning and physiology of commercial and Erianthus introgressed sugarcane clones under contrasting water regimes

The productivity of sugarcane is limited by several biotic and abiotic stresses, of which drought is an important environmental stress, causing substantial yield losses especially in tropical parts of the world. The present day sugarcane cultivars are derivatives of interspecific hybrids involving Saccharum officinarum and S. spontaneum and the drought tolerance is governed by S. sponaneum. Of late considerable attention has been given to utilize Erianthus Spp, the related wild genera of Saccharum, shows remarkable levels of drought tolerance under water limited condition. In this study, experiments were conducted to compare the influence of drought on biomass, yield and physiology of commercial and Erianthus introgressed clones. The results showed that the cane yield was reduced 37.98% in commercial clones compared to 24.67% in Erianthus introgressed clones under drought. The highest stress tolerance index (STI) of 1.256 was recorded in the clone CYM 08-922 which is a backcross hybrid involving Erianthus arundinaceus. Significant differences were observed for leaf area index, relative water content, lipid peroxidation and epicuticular wax content among the genotypes and between treatments. Sugar yield was most affected by drought (38.86%) followed by cane yield (33.30%), NMC (26.79%) and single cane weight (22.49%). Cane yield showed a positive and significant correlation with dry biomass under both irrigated (r = 0.303) and drought situations (r = 0.404) and among the physiological parameters, only RWC showed significant and positive correlation with cane yield (r = 0.307). The leaf dry matter was 14.55% higher under drought indicating influence of drought on translocation of dry matter from leaves to canes. Among clones CoM 0265, Co 06022, CYM 08-922, CYM 09-1369 and GU 12-31 showed greater ability to partition dry matter in to canes under drought than the other clones and had higher stress tolerant index. Cane height, number of millable stalks and RWC% showed positive and significant association with cane yield under both drought and irrigated condition and could be important parameters in screening clones under sugarcane improvement programmes.