Selection of rootstocks for better morphological characters and resistance to low-temperature stress in the sweet pepper cultivar ‘Hongxing No. 2’

To promote the stress resilience of sweet pepper crops (Capsicum annuum L.) and phase out the use of pesticides and other environmentally harmful materials, grafting has been used to integrate biotic or abiotic stress-resistance characteristics with sustainable crop production. This study aimed to determine the changes in the morphological characteristics, physiological features and low-temperature resistance of the sweet pepper cultivar ‘Hongxing No. 2’ grafted onto five rootstocks (‘No. 14’, ‘No. 15’, ‘No. 16’, ‘Jiaozhen108’, and ‘J4-908’) and itself. The morphological features of the aerial organs and roots of the different graft combinations were monitored, as were the activities of active oxygen-scavenging enzymes. Most morphological and physiological characteristics were significantly improved in the graft combination No. 2/Jiaozhen108, which indicated that Jiaozhen108 had a higher graft affinity with Hongxing No. 2 than the other rootstocks. No. 2/Jiaozhen108 also had a higher resistance to low temperatures. Therefore, the Jiaozhen108 rootstock is considered a quality candidate for grafting with the sweet pepper cultivar Hongxing No. 2, providing a theoretical basis for the screening and greenhouse production of low-temperature resistant stocks.