Gene expression differences under freezing and ice encasement stress in between temporal populations

The experiment was aimed at studying gene expression differences between three temporal populations of two timothy cultivars; Engmo (Early=1988, Mid=2003 & Current=2020) and Noreng (Early=1998, Mid=2010 & Current=2020), under freezing stress and Ice encasement stress. The idea is when the temporally separated populations; the ancestor and its descendant populations, were subjected to similar stress conditions the gene expression differences between populations could be due to plasticity or adaptation and the non-random changes in gene expression could be indicative of adaptative responses. The cold acclimated samples were used as controls in both freezing and ice encasement comparisons