Practical Implications of PGRs in Improving Fruit Juice Quality of Citrus reticulate

Abstract: Utilization of plant growth regulators significantly improves the size, quality, and yield of citrus fruits. To investigate the effect of PGRs (SA and IAA) in improving Citrus reticulata (Kinnow) fruit shape index, juice content, and other quality parameters, the experiment was carried out at two citrus orchards located in district Sahiwal (Horticultural Research Station) and district Toba Tek Singh (T.T. Sing, Mungi Bangla), Pakistan, known to produce citrus fruits with inferior quality as well as low in yield. Foliar spray of plant growth regulators, i.e., salicylic acid (SA at the rate of 100 mg/L or 725 µM), indole acetic acid (IAA at the rate of 5 mg/L or 28.6 µM), and their combination i.e., SA + IAA along with control (distilled water) were applied as foliar sprays thrice at the initiation of flowering, fruit formation, and fruit color initiation stages. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The results indicated that Kinnow fruit quality had been significantly improved by the PGRs treatment alone and in combination. The combined application of SA and IAA (SA + IAA) proved to be an excellent treatment in raising the quality of Kinnow fruits, closely followed by the treatment of plant growth regulator SA alone and IAA alone. Moreover, PCA and Pearson’s correlation indicated that CA had a negative association with all studied morpho-physiological and biochemical contents of all studied morpho-physiological and biochemical attributes of fruit juice quality. Citrus fruits grown and foliar sprayed with PGRs at the T.T. Singh site were better in taste and had higher fruit weight compared to the Sahiwal site. Current findings showed that citrus fruits and juice quality was better at the T.T. Singh site compared to the Sahiwal site because CA had a negative association with all morpho-physiological and biochemical parameters.