Physiological Responses of Interspecific and Intergeneric Hybrids of Sugarcane under Early Drought Stress Conditions

Nithaya Leanasawat, Watanachai Lontom, Patcahrin Songsri and Manit Kosittrakun

Background and Objective: Drought is one of the important problems that drastically affect sugarcane production in several countries. The objective of this experiment was to investigate certain physiological characteristics of drought-stressed sugarcane plants under plastic house conditions. Materials and Methods: The experiment was arranged in a completely randomized design with four replications. Five sugarcane genotypes were grown. These included three commercial cultivars [Khon Kaen 3 (drought tolerant), KpK98-40 (drought susceptible) and KK07-037] and two clones derived from Saccharum spontaneum and Erianthus sp. (KK08-214 and E08-4-019, respectively). The five sugarcane genotypes were subjected to water stress when they were 110 days old. The plants were divided into two groups: the controlled group regularly receiving water at the field capacity and the experimental group (under water stress) receiving 1/3 available water. After they were irrigated for 73 days, chlorophyll fluorescence (Fv/Fm), leaf greenness (SPAD value), water potential, electrolyte leakage and shoot fresh and dry weight were determined. Results: The results revealed that drought stress caused Fv/Fm and leaf water potential to decrease significantly (p<0.05) but electrolyte leakage in the leaves of all sugarcane genotypes to increase significantly (p<0.05). The leaf greenness of E08-4-019 was significantly (p<0.05) higher than that of the other genotypes with low electrolyte leakage during drought stress. Conclusion: E08-4-019 tolerated drought stress. Physiological traits can be used in selecting cultivars for increased efficiency in sugarcane breeding for drought tolerance.

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