The Exogenous Application of Micro-Nutrient Elements and Amino Acids Improved the Yield, Nutritional Status and Quality of Mango in Arid Regions

Abstract

The mango is one of the most valuable and appealing tropical fruits due to its color, aroma, tasteful remarkable flavor, and nutritive value; however, improving the yield and quality of mango is an urgent goal in order to combat global population growth. The application of amino acids and a micronutrient mixture might improve the yield and quality features but further research is still required in arid regions. To study the combined effect of a micronutrient mixture (MM) and amino acids (AA) at different rates, twenty-seven Fagri Kalan mango trees (15 years old) were carefully selected. The foliar application effect of MM and AA on vegetative growth, total chlorophyll, leaf chemical constituents, productivity, and the fruit quality of mango trees (cv. Fagri Kalan) was investigated. The findings revealed that the investigated growth measurements and leaf chemical contents, as well as the fruiting aspects and the fruit quality improved significantly due to the application of MM and AA. A higher application rate of the micronutrient mixture (2 g L^-1) in combination with the highest amino acid concentration (2 mg L^-1) was the most effective combination that increased the yield, total soluble solids (TSS), total sugars (TS), and total carbohydrates by 28.0%, 3.0%, 5.8% and 15.0%, respectively, relative to untreated plants. The relationship between such characteristics revealed a strong positive correlation (0.80-0.95), confirming the importance of these materials in increasing the yield and quality of mangoes. Thus, using doses of MM and AA as a foliar spray four times during each growing season is recommended under similar environmental conditions and horticulture practices used in the current experiment.

Keywords: Fagri Kalan; amino acids; foliar application; fruiting aspects; mango; micronutrients; nutritional status.

Figure 1

Correlation heatmap of the studied parameters of yield, nutritional status, and quality. The parameters are shoot length (SL), shoot diameter (SD), number of leaves per shoot (N/S), number of new shoots (NNS), leaf area (LA), total chlorophyll (TC), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), manganese (Mn), total carbohydrates (Tcarb), panicle length (PL), panicle diameter (PD), fruit set (FS), fruit retention (FR), No. fruits per tree (NFT), fruit weight (FW), firmness (F), pulp weight (PW), seed weight (SW), total soluble solid (TSS), total sugar (TS), acidity (A), ascorbic acid (AC), TSS/acid ratio, peel wight (Pw), C/N ratio, yield per tree (Y kg/t), yield per feddan (Y t/fed), and yield per hectare (Y t/ha).

Figure 2

Principal Component Analysis (PCA) to show the correlation between treatments (scores) and crop parameters (vectors) for the vegetative growth and nutritional status (A), as well as the yield and quality (B). The score gradient colors from dark blue for A1M1 (without amino acids and micronutrients), light blue for A2M2 (1.0 mg L⁻¹ amino acids, and 1.0 g L⁻¹ micronutrients) and green to yellow for A3M3 (2.0 mg L⁻¹ amino acids, and 2.0 g L⁻¹ micronutrients). The loadings included shoot length (SL), shoot diameter (SD), number of leaves per shoot (N/S), number of new shoots (NNS), leaf area (LA), total chlorophyll (TC), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), manganese (Mn), total carbohydrates (Tcarb), panicle length (PL), panicle diameter (PD), fruit set (FS), fruit retention (FR), No. fruits per tree (NFT), fruit weight (FW), firmness (F), pulp weight (PW), seed weight (SW), total soluble solid (TSS), total sugar (TS), acidity (A), ascorbic acid (AC), TSS/acid ratio, peel wight (Pw), C/N ratio, yield per tree (Y kg/t), and yield per hectare (Y t/ha).

Figure 3

Daily climatic data as precipitation, wind speed, relative humidity, maximum and minimum temperatures, and solar radiation over two seasons (2019 and 2020).