Submitted to: Sugar Cane International
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/6/2004
Publication Date: 10/20/2004
Citation: Tai, P.Y.P., Miller, J.D., Morris, D.R., Glynn, N.C., Edme, S.J. Electrolyte leakage test for evaluating sugarcane freezing tolerance. Sugar Cane International. 22:3-7. 2004. Interpretive Summary: Sugarcane crops are frequently subjected to freeze injury in subtropical regions. Breeding for tolerance to frost injury is an important objective of sugarcane cultivar improvement for those regions. A reproducible procedure has been developed to assess freeze injury of sugarcane leaves based on electrolyte leakage test of leaf segments. The plants were grown in pots for about three months before being exposed to the cold treatments including 25 C and higher in greenhouse (control), a constant 4 C in a growth chamber for 2 to 6 days and below 10 C for various lengths of time over several consecutive nights under field conditions. Leaf samples were then collected and subjected to a range of subfreezing temperature treatments (minus 2 to minus 4 C or minus 2 to minus 11 C) for the measurement of electrolyte leakage. Clones originating from tropical islands tended to produce higher percentage leakage than did clones from the sub-temperate regions after being exposed to subfreezing temperature treatments. Results showed a wide range of ability to cold harden among those sugarcane clones based on the percentage leaching of the leaf segments. The experiments can be conducted in a growth chamber under controlled environments with a flexible testing schedule. The electrolyte leakage procedure can be more effective and objective for measuring freezing tolerance in breeding and genetic studies in sugarcane.
Technical Abstract: Seventeen sugarcane plants including Saccharum spontaneum, S. officinarum, commercial cultivars, and F1 hybrids were exposed to cold treatments in growth chamber and field studies to assess freezing injury of foliage based on measurement of electrolyte leakage. The plants were grown in pots for about three months before being exposed to subfreezing temperatures (minus 2 to minus 11 C) for the measurement of electrolyte leakage. Plants growing in the greenhouse served as a control. Plants were also subjected to natural freezes in the field. The percentage leaching of three leaf segments of the first complete leaves (top, middle and base) on each plant showed the top segment had the highest mean percentage leaching and was used for all other experiments. The effect of low temperature treatment on percentage leaching varied among sugarcane clones with a rapid increase in electrolyte leakage among S. officinarum clones whereas S. spontaneun and F1 clones had a relatively slow increase in leakage as the subfreezing temperature was gradually lowered. Results showed a wide range of the ability to cold harden among those sugarcane clones after being exposed to cold treatment. Electrolyte leakage of clones grown in growth chamber was negatively correlated with percentage green leaf tissue of the same clones grown in the field. The electrolyte leakage method is simple, rapid and reproducible, and has potential for distinguishing cold tolerance among sugarcane genotypes.