Biostimulant Application Improves Yield Parameters and Accentuates Fruit Color of Annurca Apples

Abstract

The Annurca apple is a typical fruit from Southern Italy that is notable for its high firmness and characteristic flavor, and presents positive effects on human health. The aim of the present study was to improve the agronomic characteristics of Annurca trees and the quality of their fruits by the use of plant biostimulants. We performed the study with three biostimulants (protein hydrolysates, seaweed extracts, and microalgae) to determine their effects on trees and fruits at harvest and during fridge conservation. The measurements in the field concerned the production per plant, the number of fruits, the diameter and fruit weight, the diameter of trunk, the weight of pruning, the first harvest %, and yield efficiency (plant prod./TCSA) for both growing seasons 2018–2019. The analyzed fruit parameters at harvest and during the fridge conservation were: flesh firmness, epicarp color, total soluble solids, pH, and titratable acidity. The results showed positive effects of the biostimulants on the production and the color parameters, especially with microalgae enhancing fruit redness (5-fold) and color index (8.5-fold). In particular, protein hydrolysates and microalgae increased the production (10.4%), diameter of the fruits (7.0%), the first harvest percentage (37.8%), and yield efficiency (6.9%). The tested plant biostimulants showed no significant effect on the measured qualitative parameters. This study represents the first detailed research on the use of different types of biostimulants on Annurca trees and their impact on the quality of its fruits from harvest to storage, and may present a sustainable alternative for the “melaio” processes.

Foliar application of biostimulants and silicon enhances yield and fruit quality of ‘Page’ mandarin via altering physiochemical properties

“…According to this study, nutrient solutions, particularly seaweed extract, increased the rind color indices of mandarin fruits (Table 8). Similarly to our study, increases in fruit color index with the use of biostimulants have been reported in apples (43,44) and grapes [45], which may be due to the ability of biostimulants to modulate the activity of endogenous hormones, resulting in the induction of color biosynthesis pathways in the skin of the fruit (46, 47). Conversely, the results of the current study are contrary to those obtained by Tarantino et al [48,49] on apricots and Tarantino et al [50] on pomegranates, which showed no effect of biostimulants on the fruit color index.…”