Response to Chilling of Zea mays, Tripsacum dactyloides and their Hybrid

Abstract

Maize (Zea mays ssp. mays) and eastern gamagrass (Tripsacum dactyloides) are known for their susceptibility to chilling injuries. Their hybrid (Z. mays × T. dactyloides) showed higher tolerance to low temperatures (−2 °C) in the field than its parents. Exposure to 5 °C for 2 or 3 d reduced the variable to maximal chlorophyll fluorescence ratio (FV/FM), an indicator of the maximum photochemical efficiency of the photosystem 2, and the variable to minimal fluorescence ratio (FV/F0) more in maize and eastern gamagrass than in hybrid plants. Chlorophyll contents for rewarming plants (25 °C for 3 d) were lower than before chilling in both parents while values for hybrid plants were similar. Electrolyte leakage was higher in chilled than control plants but it did not show significant differences among genotypes. Our data suggest that hybrid plants have higher capacity to recover from chilling injury in controlled conditions than their parents.