Effect of Salicylic Acid and Chelated Magnesium Sulfate on Fruit Quality Improvement (Physical Characteristics) in Pear (cv. Louise Bonne)

Abstract

Introduction: Fruit quality is described based on the crop functions (for industry or table) and/or difference of the consumer tastes in different societies. The conformity of the quality with consumer demands has an effective role in improvement of the marketing process. For example, elongated pears are preferred for the processing industries and conserving productions. The lack of attention to retaining of quality and/or improvement of apparent situation of gardening product in proportion to consumer demands decreases especial consumer acceptance. The necessity of having desired quality characteristics in pear fruits from the characters viewpoint of fruit specific gravity (major rating criterion of pears) and proportion of length to diameter (minor rating), because of their role in market acceptance and pricing, is evident. Fruit quality, while harvesting, as one of the components of plants fertility influenced under different parameters like nourishment and could be managed during growth season. In other words, the gain of qualities proportionated to consumers demands and/or processing industries is possible by the use of acquired method such as the kind of mother plant nutrition, and control of pests and diseases, etc. In the current research, the effect of salicylic acid and chelated magnesium sulfate was studied on physical indexes of fruits quality of pear fruit. Materials and Methods: In order to study the effect of treatment agents, an experiment was conducted in the ecological conditions of Qazvinon Pear trees belonging to Louise Bonne cultivar in the Randomized Complete Block Design. The treatments includecontrol group (with andwithout water),chelated magnesium sulfate with concentration of 0.5 gram in a liter, chelated magnesium sulfate with concentration of 0.7gram in a liter, salicylic acid with concentration of0.1 gram in a liter,the compound treatment of salicylic acid with concentration of 0.1 andchelated magnesium sulfate with concentration of 0.5 gram in a liter, the compound treatment of salicylic acid with concentration of 0.1andchelated magnesium sulfate with concentration of 0.7gram in a liter, salicylic acid with concentration of 0.5gram in a liter,the compound treatment of salicylic acid with concentration of 0.5andchelatedmagnesium sulfate with concentration of 0.5 gram in a liter, and the compound treatment of salicylic acid withconcentration of 0.5andchelated magnesium sulfate with concentration of 0.7gram in a liter. Measuring the attributes of fruit weight, fruitvolume, fruit specific gravity(W/V), fruit length, fruit diameter and fruit shape index (L/D) were made in two successive years (2012, 2013).Diameter andlength of fruit earned by nondestructive method and by using digital caliper (Mitutoyo) in the place of maximum length and width diameters andlength: diameter ratio by division of these two parameters. Fruit weight estimated by digital scale (0.01 g) and its volume by the difference of the water level of scaled column and fruit density was calculated by using formula d=M/V. The statistic calculations of measured characteristics were made using MSTATC and SPSS soft wares and the comparison of means using Duncan's test. Results and discussion: The results indicated that the plants nourishment using organic and mineral combinations had an influence on quality characteristics and there was a significant difference among combinations in most cases (p< 0.01). In the way that the extent of changes among different treatments was changeable in the case of fruit length between 64.67 to 76.82 mm, fruit diameter between 45.01 to 57.81 mm, proportion oflength to diameter between 1.28 to 1.59 mm, fruitvolume between 54.67 to 128.7cm3, fruit weight between 67.39 to 121.7 g and fruit specific gravity between 0.72 to 0.97 g to cm3. Maximum weight, volume and specific gravity in fruits were allocated to the treatment of salicylic acid with concentration of 0.1gram in a liter, the compound treatment of salicylic acid with concentration of 0.1 and chelated magnesium sulfate with concentration of 0.5gram in a liter, and the compound treatment of salicylic acid with concentration of 0.5and chelated magnesium sulfate with concentration of 0.7 gram in a liter, respectively and the least amount in each of the three cases was related to the treatment of salicylic acid with concentration of 0.5 gram in a liter, too. The most and the least amount oflength: diameter ratio were allocated to the treatment of salicylic acid with concentration of 0.5 gram in a liter and the compound treatment of salicylic acid with concentration of 0.1 and chelated magnesium sulfate with concentration of 0.5gram in a liter, respectively. The increase of crop quality by salicylic acid in plants under tension conforms to the other study results. Salicylic acid has an important role in regulating various physiological processes such as growth, plant development, ion absorption and photosynthesis. Therefore, the application of salicylic acid as a plant growth regulator besides the mineral compound of chelated magnesium sulfate is effective on physical indexes of fruit quality in Pear. Conclusions: The results indicated that the fruits treated with salicylicacid with concentration of 0.5 gram in a liter had more proportion of length to diameter and less specific gravityrelated to others and the aforesaid treatment can be paid attention as proposed nutrition to produce lighter and more extended pear fruits, depending on the purpose.Furthermore, the compound treatment of salicylic acid with concentration of 0.5 and chelated magnesium sulfate with concentration of 0.7 gram in a litercan be paid attention as proposed nutrition to produce heavier pear fruits, too and that is because of its allocation of the most amount of fruit specific gravity.

Keywords

• Fruit Shape Index
• Fruit Specific Gravity
• Length to Diameter Ratio
• Nutrition