Interspecific Hybrid Rootstocks Improve Productivity of Tomato Grown under High-temperature Stress

Grafting can be a useful technology to improve productivity of vegetable crops, including tomato, particularly under the serious challenges of climate change for agricultural systems. This study aimed to evaluate the impact of some local tomato interspecific hybrid rootstocks along with Maxifort on the vegetative growth, productivity, and fruit quality of tomato under field production conditions. Heat-tolerant tomato hybrid 023 F1 was used as a scion over the two late summer seasons of 2021 and 2022. Grafting 023 F1 onto Maxifort or KFS-16 rootstocks resulted in the maximum plant growth. Similarly, Maxifort and KFS-16 rootstocks significantly increased the fruit setting percentage from 22.2% to 23.5% and 17.8% to 24.6%, total fruit yield from 33.5% to 53.7% and 29.6% to 51.6%, and marketable yields from 34.1% to 56.0% and 27.3% to 56.7%, respectively, during both seasons compared with nongrafted plants. These two rootstocks enhanced nutrient (nitrogen, phosphorus, potassium) uptake compared with nongrafted planted. However, grafting with the interspecific hybrid rootstocks (KFS-8 and KWS-9) significantly decreased the content of catalase, peroxidase, and proline, which might be associated with lower plant vigor and yield in these rootstocks. All rootstocks had an impact on fruit chemical composition; however, generally, Maxifort and KFS-16 had greater contents of vitamin C, β-carotene, and total antioxidants than nongrafted plants. KFS-16 had also greater lycopene content than nongrafted plants. These results demonstrate the potential use of Maxifort and local rootstock KFS-16 to boost the growth and yield of tomato plants under high-temperature stress in the late summer season.