A selection tool for freezing tolerance in common wheat using the fast chlorophyll a fluorescence transient

The analysis of fast chlorophyll fluorescence induction kinetics in dark-adapted leaves (JIP-test) is proposed as a rapid method for evaluating freezing tolerance in wheat. Wheat leaves were detached from the plants of 40 cultivars grown in an open-field in Smolice, during December and March of winters 2004/2005 and 2005/2006, transferred to laboratory in Krakow and frozen in -15 degrees C. Next, measurements of chlorophyll fluorescence were taken. The correlation coefficients between the JIP-test parameters with freezing tolerance data obtained in multiple field-laboratory studies, varied between 0.58 and 0.70 depending on sampling time and parameter measured. The chlorophyll fluorescence parameter, which can always be used for the screening of freezing tolerance in the method described here, is the performance index (PI), which characterizes the overall energy flow efficiency in photosystem II (PSII). The results indicate, that the technique proposed here can be useful for freezing tolerance screening in plant breeding programmes. However, this method seems to be a more reliable tool in the selection of freezing tolerant germplasm, than for discarding freezing susceptible materials.