Grafting Pepper onto Tolerant Rootstocks: An Environmental-Friendly Technique Overcome Water and Salt Stress

Abstract  -  Scientia Horticulturae  2017

Salinity and water shortages are two of the biggest environmental constraints that crops have to face in the climate change scenario. A fast and efficient way to overcome these stresses under the prism of a sustainable crop management is the use of grafting, combining the desired cultivar with the rootstock providing tolerances to abiotic stresses. Our aim was to validate three accessions previously selected for their tolerances to salt and water stresses (A25, B14 and C12) as rootstocks, in real field conditions. The physiological and productive behavior of the commercial pepper ‘Adige’ (A) grafted onto these accessions was compared along the growing cycle with this cultivar grafted onto the commercial rootstock ‘Antinema’ (ANT) and with the ungrafted pepper plant (A).

Under water and salt stress, grafted plants onto the selected accessions, gave higher marketable yields than ungrafted plants or that plants grafted onto ANT, particularly the A25 accession. This rootstock was able to maintain high photosynthesis levels under stressing conditions through different adjustments made in the physiological processes, such as proline accumulation. The ANT rootstock showed comparable yields to A25 in control conditions. Under salt stress, Na⁺ and Cl⁻ were equally accumulated in A/A25 plants and the ungrafted ones, but A/ANT, A/B14 and A/C12 were more restrictive in their absorption along the growing season. These results reinforce the idea that the use of tolerant pepper rootstocks is a good adaptation strategy for abiotic stressing conditions. The results also suggest that the abiotic stress was alleviated by the lack of negative effects mainly on photosynthesis, which maintained plant growth and the marketable yield.