Planting density impact on the processes of fruit-bearing wood formation and leafi ness of pear tree crowns in intensive orchards of Crimea

Abstract

In order to increase the productivity of modern intensive orchards, it is important to select scion-rootstock combinations of early-fruiting and high-yielding cultivars with a compact crown that provide a small crown size and enable dense tree planting. This increases the yield of plantations per unit area and reduces labor costs for tree maintenance and harvesting. The research aims to study the eff ect of dense planting patterns on tree growth processes and fruit-bearing wood formation in the crown as well as to determine the productivity index of the leaf surface of pears grafted onto the BA 29 quince rootstock. The research object was the cultivar Maria. The crown shape is a slender spindle; the planting density in the orchard ranges from 1428 to 2500 trees/ha. Based on the obtained results, an optimal planting pattern of 4x1 m (2500 trees/ha) in the form of a slender spindle is identifi ed and recommended for use in commercial horticulture in Crimea. With this planting pattern, the leaf area, fruit formation density per meter of fruit-bearing wood, specifi c density of crown leafi ness per 1 m2 of projection and 1 m3 of crown volume were established to be 1.5–1.6 times higher compared to other planting schemes. It has also been determined that pear trees grown with the above planting pattern are of more compact sizes. They are 6.3 and 7.4 % smaller in trunk growth vigor, 10.0 and 15.0 % smaller in crown projection, 9.6 and 7.2 % smaller in crown volume. In addition, with an increase in row spacing between trees to 4x1.75 m, these parameters increase by 10.5 %, 11.5 %, and 7.1 % compared to trees planted according to the 4x1.5 m pattern (control). However, plantation productivity and lifecycle are signifi cantly reduced by the harmful activity of phytophages (plant feeders) and pathogens, which requires their constant monitoring