Investigation of sustainability of the responses, morphologicalphysiological and biochemical to recovery applications withdrought, heat stress of some stone fruit rootstocks

Climate change is increasing the frequency and severity of abiotic stress factors such as drought and high temperature, posing serious threats to agricultural productivity. Fruit cultivation, which is a significant agricultural sector worldwide, is inevitably affected by drought and high temperature stresses. One of the most crucial factors affecting productivity in fruit cultivation is the use of suitable rootstocks and cultivars for the region where cultivation will be conducted. In this study, the responses of stone fruit rootstocks GF 677, Myrobolan 29C, Marianna 2624, Rootpac 20, Rootpac 40, Rootpac R, and Garnem to single and combined applications of drought and high temperature stresses, as well as their post-stress recovery mechanisms, were investigated. Additionally, morphological, physiological, and biochemical responses were examined to determine the effects of drought and high temperature stress and recovery mechanisms on cultivar×rootstock combinations in apricot (Mikado × Myrobolan 29C, Mikado × Marianna 2624) and peach (Divadona × Rootpac 40, Divadona × Rootpac 20). In rootstock and cultivar applications, it was determined that plants showed more adverse reactions to drought and drought+high temperature stresses compared to other treatment groups. As a result of measurements and analyses conducted to determine stem diameter, plant height, leaf number, leaf area, fresh and dry weights, root length, chlorophyll content, stomatal conductance, leaf temperature, membrane permeability, leaf relative water content, NDVI values, as well as proline, MDA, H2O2, enzyme, and mineral content during stress and recovery applications; Rootpac 40 and Marianna 2624 rootstocks demonstrated superior tolerance compared to other rootstocks under stress conditions. Furthermore, Rootpac 20 and Myrobolan 29C rootstocks exhibited sensitivity particularly to combinations of drought and high temperature stress, whereas GF 677, Rootpac R, and Garnem rootstocks showed moderate stress tolerance with variable responses across different parameters. Comparison of cultivar responses to stress and recovery mechanisms revealed that the Mikado apricot cultivar grafted on Marianna 2624 rootstock was more tolerant compared to those grafted on Myrobolan 29C rootstock, while the Divadona peach cultivar grafted on Rootpac 40 rootstock demonstrated higher tolerance compared to those grafted on Rootpac 20 rootstock. These results provide valuable insights into stress response mechanisms and recovery potentials specific to rootstock and cultivar × rootstock combinations, serving as a valuable guide for drought and high temperature stress-tolerant rootstock selection and breeding programs.