Grafting in Capsicum peppers as a strategy to mitigate the effects of climate change on yield and quality factors

Abstract

Climate change in the Mediterranean areas is increasing problems on droughts, water availability and salinization of irrigation water. These are probably some of the most limiting factors on farming, especially in vegetables production. Capsicum peppers, one the most valuable vegetables in Spain, are quite sensitive to water deficit and particularly to salinity. The use of rootstocks tolerant to these abiotic stresses could be explored as a short/mid-term solution. In this work, we evaluated the ability as rootstocks of several accessions, together commercial F1 ‘Robusto’ and ‘Oscos’, with the cultivar ‘Herminio’ as scion, under control, drought (30% decrease irrigation) and salinity (5.8 dS m-1) in Campo de Cartagena area (Murcia, Spain). Yield and fruit weight, and water content, ascorbic acid content (AAC) and total phenolics (TP) at the unripe and fully ripe commercial stages were evaluated. Under control conditions, our rootstocks did not provide extra vigour and yield as none showed higher performance than the non-grafted ‘Herminio’ in yield (10 kg m-2) and fruit weight (215 g). However, drought and salinity conditions revealed that some accessions might be useful as rootstocks, providing higher yields and/or fruit size than ‘Herminio’, particularly yield under drought, i.e. 5-7 kg m-2 while ‘Herminio’ only achieved 4 kg m-2, and fruit weight in both stress conditions (i.e. 190-223 g vs 173 g under drought, 187-209 g vs 158 g under salinity). On average, drought increased the levels of antioxidants at both ripening stages, while salinity decreased them, specially AAC. Also, remarkable rootstock × treatment interactions, particularly in phenolics, enabled identifying several rootstocks providing high levels of antioxidants at both ripening stages and under both abiotic stresses, improving those from non-grafted ‘Herminio’.