Effect of growth regulators and seaweed extract on vegetative phenology in mango (Mangifera indica)

A field experiment was conducted to find out the effect of seaweed extract, Paclobutrazol, potassium nitrate, 6-benzyl amino purine and pruning on the pattern of vegetative flushing episodes and growth pattern in May-June, July-August and September-October flush in order to regulate the growth, which enhances blooming flushes in 16-year old mango trees cv. Kesar during 2010–12 at Junagadh, Gujarat. The selected shoots of mango cv. Kesar were pruned back by 10 cm and sprayed with 2% urea during last week of May, i.e. after harvesting. Different doses of Paclobutrazol (5g and 7.5g a.i) were applied as drench and 6-BA (100 and 200 ppm), seaweed extract (3 and 5%), KNO₃ (4 and 6%) and CaNO₃ (4 and 6%) were applied as foliar spray to evaluate the morphological characteristics of growth cycles (flushing episodes). 6-BA (100 ppm) exhibited maximum summer flush (May-June). However, lower flushing (September-October) was achieved with PP₃₃₃ (7.5g a.i), followed by 6-BA (200 ppm) and seaweed extract (5 and 3%). CaNO₃ (6%) exhibited maximum mean length of flush while seaweed extract (3%) exhibited minimum number of days for flush emergence and complete extension of vegetative growth with maximum number of flushes/shoot and maximum number of leaves/shoot with 6-BA (100 ppm). The P₃₃₃, 6-BA and seaweed extract showed promising effect in reducing September-October vegetative flush which modified flowering time.