Expression of CMe-ACS1 and Ethylene Receptor Genes in Melon F1 Progenies under Cold Storage Condition

Introducing new melon types able to endure cold storage and cold transportation is among the major goals of breeders. Therefore, providing a better understanding of the fruit physiological traits and postharvest associated genes expression can help to select the superior type for cold storage condition. This experiment was carried out to investigate the postharvest behavior of various melon lines and their F1 breeds based on fruit characteristics and their relation to the expression of CMe-ACS1, CM-ETR1 and CM-ETR2 genes during cold storage. For this purpose, six melon inbred lines were cross-pollinated to form a full diallel F1 population. Thus, the studied population constituted 6 parental lines, 15 direct hybrids, and 15 reciprocal F1 hybrids. After fruits harvest and during one month of storage, fruits firmness loss, color changes, and weight loss were evaluated. A significant positive correlation coefficient was found between CMe-ACS1 gene expression and ACC content with two distinct clusters based on this relation. Gene expression profiles referred to the presence of gradual and continuous senescence behaviors in the studied types, which was reflected in their physiological postharvest performance. G1 cluster types expressed the studied receptor genes at lower rates compared to the other groups. The G1 corresponded with P3 and P4 groups that were characterized by low physiological changes and thus better postharvest performance during cold storage. This result highlights the importance of Persian inodorus melons, generally, and the line ‘Khatouni’, specifically, in melon breeding programs for postharvest purposes.