Mango Fruit Yield and Critical Quality Parameters Respond to Foliar and Soil Applications of Zinc and Boron

Abstract

Mango (Mangifera indica L.), the sixth most important fruit crop worldwide, is likely at risk under a climate change scenario of accelerated soil organic matter mineralization and constrained plant nutrient supplies such as zinc (Zn) and boron (B). We identified the optimum nutrient formulation and application method to possibly rectify nutrient deficits in mango plants grown in one of the warmest and driest regions-Multan, Pakistan. We evaluated the yield and physiological (quality) responses of 20-year-old mango trees to seven treatments of foliar and soil applications of Zn and B. Combined soil application of B and Zn resulted in optimum increases in leaf mineral B and Zn and fruit-set, retention, yield, pulp recovery and total soluble solids at ripening (p = 0.021), while reducing titratable acidity and early fruit shedding (p = 0.034). Additionally, this treatment improved fruit quality (taste, flavour, texture, aroma, acceptability; p ≤ 0.05). Yield was found to be correlated with retention percentage (P ≤ 0.001; R² = 0.91), which was in turn related to fruit-set number panicle^-1 (P = 0.039; R² = 0.61). Therefore, we suggest that combined soil application of B and Zn mitigates leaf mineral deficiencies and improves the yield and quality of mango more efficiently than other individual or combined foliar or soil treatments used in this study.

Keywords: Mangifera indica L.; aroma; flavour; fruit quality; fruit retention; fruit set; fruit yield; nutrient; orchard; organoleptic; taste; texture.

Figure 1

Effect of foliar and soil B and Zn treatments on: (A) mango fruit retention percentage and (B) fruit yield (kg plant⁻¹). Between-year significant differences (p < 0.05) within a treatment are shown using lower case letters. Only 3-y means are being used to compare between-treatment significant differences (p < 0.05) shown using capital letters. Each error bar indicates ± SD of the mean (n = 4). Bars sharing the same letters are not different at p = 0.05.

Figure 2

(A) Relationship between fruit-set number per panicle and fruit retention (%), and fruit yield (kg plant⁻¹). Each point shows mean (n = 7) values. (B) Relationship between fruit retention percentage and fruit yield per plant. Each point shows means (n = 7) of fruit retention percentage, and fruit yield per plant. Every correlation showed significant at p < 0.05.

Figure 3

Spearman ranking correlation of five sensory evaluation fruit quality traits (n = 10): taste, flavour, texture, aroma and overall acceptability as affected by treatments. Within each treatment, all variables were correlated (P < 0.05). Each error bar indicates ± SD of the mean (n = 10). Bars sharing the same letters are not different at p = 0.05. Letters should be compared for each variable across treatments.

Figure 4

Graphical scheme showing the arrangement of seven treatments repeated four times in a randomized complete block design (RCBD) in the experimental mango orchard at Mango Research Station, Multan, Pakistan.