STUDIES TO IMPROVE GROWTH AND PRODUCTIVITY OF PLUM TREES UNDER DESERT CONDITIONS

Abstract

The present study was conducted on 6 years ‘Sapphire’ plum trees budded on Nemagurd rootstock through two successive seasons 2015 and 2016. This investigation aimed to 1) study the self and cross-compatability of 'Sapphire' cultivar, 2) determine chilling requirements and buds endodormancy stage, 3) identify the best hydrogen cyanamide application time to increase fruit set and yield, 4) determine fruit growth curve stages, to identify the pit hardening stage to be used at various horticultural practices, 5) effect of some boron treatments to improve fruit set and fruit quality, 6) evaluate some NAA treatments to increase fruiting and 7) study of nitrogen foliar spray application to increase fruit retention. Florescence microscope examination and hand pollination treatments showed that, 'Sapphire' cultivar is self-incompatible cultivar 'Pioneer' cultivar pollen grains are cross-compatible with 'Sapphire'. 'Sapphire' plum cultivar entered into endodormancy period in November 12th till February 16th in first season and in November 10th till January 19th in second season of the study. Dormex (commercial product containing 49% hydrogen cyanamide) application with 2% concentration at 60 and 50 days before expected bloom of 'sapphire' cultivar lead to bloom overlapping with 'Pioneer' cultivar and significantly increased fruit set and yield compared with control trees.