Effects of phosphites on ripening in kiwifruit ?Hayward?.

BAEZA, MARIA CECILIA; CASANOVAS, MABEL; GOMEZ, P.A.; YOMMI, ALEJANDRA KARINA; FASCIGLIONE, GABRIELA; ANDREU, ADRIANA; QUILLEHAUQUY, VICTORIA; BORRAJO, MARIA PAULA

Cartagena

Simposio; VIII International Postharvest Symposium.; 2016

Universidad Politécnica de Cartagena

The phosphites (Phi) are inducers of plant defenseresponse, although also other effects were reported. In kiwifruit (Actinidia deliciosa ?Hayward?), wedemonstrated that Phi-treated fruit was more tolerant to gray mold developmentcaused by Botrytis cinerea. Themechanisms are not yet well elucidated. The objective of this work was toevaluate the effect of Phi (30% P2O5, 20% K2O),0.3% (v/v) on ?Hayward? fruit maturity and quality indexes, by application atdifferent physiological stages of the fruit development: T1) one application atbloom; T2) six weekly Phi applications at the exponential phase of fruitgrowth; T3) combination of treatments, 1 and 2; T4) control (without Phi).Kiwifruits of all treatments were harvested after physiological maturity (atleast 6.2% total soluble solids content, SSC) and were analyzed at harvest interms of firmness (N), SSC (%), titratable acidity (%) and color (CIELab). Alsofruits were evaluated after 4 months of cold storage and shelf-life (7 days at20°C). Ethylene and carbon dioxide rate production were determined at 20°C inthe fruits of all treatments. The experiment was conducted during two consecutiveyears. The results show that the Phi had an effect on firmness, variationbetween years, while had no effects on other maturity indexes. Firmness ofPhi-treated fruits was higher than control ones at shelf-life, essentially whenPhi was applied at the exponential phase of fruit growth. This change in thesoftening rate was associated with the ethylene production rate that was tooaffected by some Phi treatments. Phi treatments (T2 and T3) significantlyaffected the ethylene and respiration rates, reducing significantly the valuesat the climacteric peak. This result suggests that Phi affects perception or biosynthesisof ethylene, and some of this response may be related to the induction ofsalicylic acid.