The Effect of Spraying with Some Growth Regulators and Amino Compounds on Fruit Drops, Yield, and Fruit Quality and Rutability In ‘Hayany’ Date Palm

Abstract

This research was conducted to study the effect of spraying with 0.5 mM Naphthalene acetic acid (NAA), 2.5 mM salicylic acid (SA), 1 mM aspartic acid (ASP) and 1 mM putrescine (PUT) alone or in combinations on productivity and fruit quality of 'Hayany' date palm. Eight treatments were applied twice: at 30 days after complete hand pollination (ACHP) and at start of Khalal (Bisr) stage (16 weeks, ACHP). The result showed that 1 mM PUT treatment reduced fruit drops, especially in the kimri stage, and gave the highest fruit retention and palm yield. Oppositely, 1 mM ASP caused a significant increase fruit drops in both kimri and bisr stages and a significant reduction in palm yield compared the control and the other treatments. Moreover, spraying with 0.5 mM NAA or the combination between ASP and SA induced an improvement in yield of palm compared to the control. Spraying with 1 mM PUT improved the weight of fruit, flesh, and seed as well as increase fruit size. The combined treatment with 0.5 mM NAA + 1 mM ASP caused a significant increase in the soluble sugars content. Furthermore, all treatments produced a significant increase in the ascorbic acid content as compared to the control. In addition, spraying date palm with 0.5 mM NAA alone or in combination with 2.5 mM SA or 1 mM ASP decreasing fruit contents of anthocyanins, titratable acidity, total soluble solids, and a lack of rutability index. So, these NAAtreatments led to maintaining fruit quality of 'Hayany' dates.