Studies on sylleptic branching in Zizyphus species with special reference to productivity in ber (Zizyphus mauritiana Lam.) Var.Umran

Abstract

Studies on sylleptic branching of two Zizyphus species revealed that Z. mauritiana (ber) var. Umran produced lesser number of sylleptic branches than Z. oenoplia. In both species rhythm in the production of second order branches was noted. Various chemicals and growth regulators tried could not change the interval of sylleptic branching in ber, but BA, TIBA and morphactin increased the number of nodes and thereby sylleptic branches. Extent of shoot tip abscission was comparatively less in Z. oenoplia. Some of the vigorous first order branches in Z. oenoplia exhibited shoot tip reorganization. It was proposed that shoot apex at any given level of activity is self-regulatory, but its elevation from a lower to higher level of activity requires energy inputs from subtending structures. Z. oenoplia was identified to be more competitive and its use as rootstock for ber was suggested. Branch polymorphism was observed in ber. Vigorous shoots contributed 93.03% fruits on any pruned shoot; rest being from normal shoots, whereas spurs type bore no fruits. Vigorous sprouts with more basal diameter, length and nodes produced more sylleptic branches and hence more fruits. The use of branch bifurcation ratios in predicting yield was proposed based on their strong correlations with yield attributes, branch yield and ultimate tree yield. Two control points, increasing the number of vigorous sprouts and sylleptic branches, were identified to increase yield in ber. Prepruning spray of KNO3 or thiourea increased the number of vigorous and total sprouts and produced the former at a lower node. Post-pruning sprays of BA, TIBA or morphactin effectively improved the second control point. Thiourea 3% + BA 100 ppm treatment was found to be the best in the simultaneous manipulation of two control points identified. The superior treatments along with appropriate cultural practices were suggested for maximizing productivity in ber.