Role of vegetable grafting in the control of abiotic stresses and effects on yield and quality

Abstract

The large-scale spread of vegetable grafting was initially promoted to increase tolerance to biotic stresses, however, grafting onto appropriate rootstocks showed up to improve scion performances under many abiotic stress conditions and often resulting in higher yield levels. Low temperature stress is one of the main issues in pepper cultivation. Genetic variability for abiotic stress tolerance is low inside the species and the number of rootstocks available for pepper is limited. Aiming to increase germplasm availability for pepper grafting and to find a rootstock that could alleviate chilling stress, grafting compatibility of Capsicum pubescens and Capsicum baccatum accessions originated from high altitudes with a widespread pepper cv was assessed and grafted transplants were used in chilling stress experiments. Two of these accessions were able to increase biomass accumulation under low temperatures compared to a commercial rootstock and showed no yield decrease or quality worsening when cultivated under optimal temperature conditions. Tomato is both a widespread crop and a model plant and it is usually grafted in specialized agricultural systems. In soilless cultivation, tomato plants can experience root hypoxia as a consequence of both misjudgments in water requirements and the progressive decrease of the air capacity of the substrate over the cultivation cycles. Commercial rootstocks with a different genetic origin were tested for their effectiveness to increase tolerance to roots hypoxia and it resulted in better physiological performances of grafted plants compared to self-grafted ones under stress conditions. The effects of grafting on yield and quality traits of tomato often depend on the specific rootstock-scion combinations. Through an experiment in which seven cherry tomato cultivars were grafted onto eight rootstocks, including both interspecific and intraspecific hybrids and compared to un-grafted plants, it was possible to identify some variables in which the role of the scion prevailed and others in which rootstock contribution was predominant. The analysis of the coefficients of variation, compared to the absolute values observed in each grafting combination, provided information regarding the ability of rootstock and scion to influence the different examined variables and on its potential benefits.