Responses of pepper to deficit irrigation for paprika production

Pepper (Capsicum annuum L.) production is normally carried out under irrigation as the crop is very susceptible to water shortage. Deficit irrigation strategies in pepper for paprika could increase production and facilitate mechanical harvest and, at the same time, save water. We conducted a field experiment that imposed water deficits, either during ripening (T1) or throughout the season (T2), and compared them to a fully irrigated control (T3). Stem water potential varied from −0.6 MPa in T3, early in the season to −1.5 MPa in T2 prior to harvest. Applied irrigation water for T1, T2, and T3 was 456, 346 and 480 mm, respectively. Water deficits depress leaf area and biomass production but did not affect the proportion of flowers that set fruit. Dry fruit weight in T2 at harvest was 66% of T3, but did not differ significantly between T1 and T3. However, commercial yield (based on colour production) was significantly higher in T3 than in the other two treatments, as the late water deficits imposed in T1 delayed harvest. We concluded that water deficits, either sustained or applied at fruit ripening, required for mechanical harvest do not hasten ripening and are detrimental to commercial yields and that pepper plants should be well supplied with water until harvest for maximum paprika production.