Study on the correlation between the expression of PpDAM5 and PpDAM6 and chilling requirements in peach

Peach production is easily managed, but to achieve stable production, the trees must also blossom neatly. However, this is a challenge in subtropical regions, as the chilling requirement (CR) of many varieties cannot be satisfied. To introduce and breed low CR varieties, their CR must first be determined, but the traditional measurement method (branch hydroponics) takes time and is inefficient. This study systematically determined whether the correlation between the expression of PpDAM5 and PpDAM6 genes and CR remained stable. The results showed that when the cold temperature induction reaches the peak in winter, the expression of both PpDAM5 and PpDAM6 genes in the bud and the leaf was positively correlated with the CR of the variety; moreover, this found to be stable in all of the test varieties. Thus, under the premise that cultivars can be induced entry into dormancy by cold temperature, a fluorescence quantitative PCR determination method to measure the CR of varieties was established. The method is practical for quickly determining the CR of newly introduced varieties and also provides an efficient method of rapidly screening varieties for use in future breeding programs.