Transforming fruit production by plant growth regulators

Abstract

Naturally occurring phytohormones, their chemical analogs, hormone-releasing agents, hormone sensitivity altering agents and hormone synthesis inhibitors collectively form plant growth regulators (Hajam et al, 2017). In order to increase the yield of monoecious crops, the increase female flowers are prerequisite for the same, Ethrel (250-1000 ppm) and CPPU (20-80 ppm) sprays work to induce female and intersexual flowers in male plants of papaya (Kumar, 1998). Fruit quality fulfillment comes to be a paramount concern of the researchers and fruit grower’s important goal, particularly regarding optimising size, increasing firmness, TSS and protection against russeting, sunburn and other physiological disorders. Foliar sprays of PGRs (GA3 at 20-40 ppm or NAA at 25-50 ppm) enhanced apple yield and fruit quality traits (Osama et al., 2015). GA3 increase fruit size, improves fruit firmness, increases vitamin-C, TSS, total sugars, sweetness index and overall sensory ratings of ‘Red Delicious’ apples (Hajam, 2017). Gibberellic acid and salicylic acid are also reported to increase yield, fruit acidity, reducing sugars, TSS, TSS/ acid ratio, fruit firmness and fruit chlorophyll a and b content peach trees (El-Shazly, 2013). Ethylene serves as a key ripening hormone of climacteric fruits and can influence ripening in many non-climacteric fruits (Giovannoni et al., 2010). Treatment with high concentrations of ethylene stimulates respiration and increases the levels of fatty acids (FA) and volatiles and at the same time decreases firmness (Banday, 2006; Harb et al., 2008). The combined spray of NAA 10 ppm and ethephon 150 ppm at full bloom can reduce fruit set up to 34 % in apple (Banday, 2006).