Deficit irrigation and ascorbic acid in guava cultivation at different development stages

Irrigação deficitária e ácido ascórbico no cultivo de goiabeira em diferentes estádios de desenvolvimento

In the semi-arid region of Northeast Brazil, irregular rainfall throughout the year has become a challenge for agricultural production. Given the above, this study evaluated the effects of foliar application of ascorbic acid on the morphophysiology, production components and fruit quality of guava cv. Paluma under irrigation strategies with water deficit. Treatments consisted of a combination of seven irrigation strategies with water deficit - IMS (SE - plants under full irrigation throughout the cycle - 100% crop evapotranspiration - ETc; VE - plants irrigated with water deficit (50% ETc) in the vegetative stage; FL - flowering stage; FR - fruiting stage; MAT - in the fruit maturation stage; VE/FL - in the vegetative and flowering stages; VE/FR - vegetative and fruiting stages) and four concentrations of ascorbic acid - AsA (0, 200, 400 and 600 mg L^-1), distributed in a randomized block design, in a split-plot scheme with three replicates, with each plot consisting of 3 usable plants. Water deficit in the vegetative/fruiting stage negatively affected growth in stem diameter, crown volume, crown diameter and vegetative vigor index, average fruit weight, and polar and equatorial diameter of guava fruits at 390 days after transplanting. Foliar application of ascorbic acid at a concentration of 600 mg L^-1 promoted positive effects on total fruit weight and yield of guava at 390 days after transplanting. Water deficit in the maturation stage stimulated the synthesis of vitamin C and soluble solids in guava plants at 390 days after transplanting.

Key words:
Psidium guajava L.; non-enzymatic compound; water deficit.