Identification of Drought-Tolerant Co-canes Based on Physiological Traits, Yield Attributes and Drought Tolerance Indices

A field experiment was conducted to investigate the effect of water stress on early and mid-late categories of Co-canes, i.e., [Co 98014, Co 0118, Co 0238, Co 07023, Co 15023 (early) and Co 0124, Co 05011, Co 11027, Co 15027, Co 12029 (mid-late)]. The experiment consists of stress treatments in main plot, i.e. (control and water stress) and ten Co-canes in subplot were laid out in factorial randomized block design with three replications. The water stress was imposed by withholding irrigation during formative phase. The observations recorded on morphological, physiological and yield attributes have suggested possible key characteristics of water stress tolerance. Leaf area and cane length exhibited 37.3% and 26.53% reduction under drought condition in comparison to the control. Co 05011 (78.77%) and Co 0238 (76.88%) showed/maintained better RWC under stress condition with mean reduction of 16.70% over Co-canes RWC. Water stress also caused reduction in gas exchange traits and the associated pigments by 56.57% in stomatal conductance (gS), 56.55% in photosynthetic rate (pN), 38.21% in transpiration rate (E), 28.01% in internal CO₂ (Ci) and 16.86% in the chlorophyll content. Maximum water use efficiency (pN/E) under drought stress was recorded in Co 0238 (4.12) and Co 98014 (3.93). Total number of tillers, number of millable canes, single cane weight and cane yield were also reduced under water stress but Co 98014, Co 05011, Co 0238, Co 12029 and Co 15023 showed lesser reduction in these traits. Further, the cane yield data were subjected to different drought tolerance indices viz. stress susceptibility index, stress tolerance index and yield index. Results obtained from physiological and yield attributes as well as tolerance indices indicated that Co 98014, Co 05011, Co 0238 and Co 12029 had the potential to grow well under water stress conditions for sustaining sugarcane production and hence could be used as tolerant germplasm in crop improvement programs.