Selecting vegetative/generative/dwarfing rootstocks for improving fruit yield and quality in water stressed sweet peppers

Rootstock breeding for vegetable crops includes desirable traits such as compatibility with the scion, increased productivity and quality under stressful environments and improved use of soil, water and fertilizer resources. The effects of three commercial rootstocks (Atlante, Creonte and Terrano) on the agronomical and physiological responses of a commercial sweet pepper variety (cv Herminio) to deficit irrigation (50% of optimal) have been studied. Although the three rootstocks increased total and marketable yield under control and deficit irrigation, Creonte produced the most productive and water use efficient plants, with until 25% more marketable yield than the ungrafted cv Herminio, and about 10% more than the other rootstocks, although in detriment of some chemical fruit quality traits. Moreover, the plants grafted onto Creonte registered the highest photosynthetic activity and leaf water content and more stable leaf area and biomass under water stress, while those parameters were more reduced in the other graft combinations. These Creonte-mediated effects were not related to root biomass (since it was more affected by the stress in this rootstock) but rather to the capacity of maintaining a high reproductive/vegetative ratio, while Atlante is a vigorous vegetative rootstock and Terrano is rather a dwarfing-reproductive rootstock that produces efficient compact plants without negative effects on fruit quality.