Exogenous application of nutrient elements effectively reduces grape cracking and improves fruit quality

Abstract

Cracking results in a decline in the economic benefits of grape production and fruit quality. Spraying nutrient elements is the most effective economical method to reduce fruit cracking. However, studies examining the effects of nutrient elements on fruit cracking and quality are limited. This study studied the effects of different elements on grape cracking and fruit quality. The results revealed that, except for 0.3% NH4NO3 treatment (NT), all other treatments caused a decrease in the fruit cracking of “Muscat Hamburg” and “Jumeigui”. The 0.20% CaCl2 + 0.20% MgSO4 + 0.20% FeSO4 + 0.10% H3BO3 (MT) treatment resulted in the most significant reduction in the cracking rate among all treatments, and the decrease rate reached 59.27% of “Muscat Hamburg” and 70.49% of “Jumeigui”. We found that fruit quality improved under all treatments, and the comprehensive membership function showed that the 0.30% NH4NO3 + 0.30% Na2HPO4 + 0.10% K2O + 0.20% CaCl2 + 0.20% MgSO4 + 0.20% FeSO4 + 0.10% H3BO3 (CT) and 0.30% NH4NO3 + 0.30% Na2HPO4 + 0.10% K2O (NPKT) treatments were the most effective. Analysis of fruit texture showed that pericarp strength and fruit hardness significantly improved under the CT treatment. Correlation analysis showed that phosphorus, potassium, calcium, magnesium, and boron application were negatively correlated with fruit cracking. Additionally, principal components analysis was used to comprehensively evaluate 21 single indicators of the two varieties at the maturity stage, the treatment with the highest score of reducing fruit cracking rate and improving fruit quality were MT and CT; this finding can be used to prevent fruit cracking and improve the fruit quality in grape production.