Analyzing Phytohormone Levels in Fruits of Date Palm Phoenix dactylifera L. Derived from Tissue Culture under Different Pollination Treatments

Abstract

This study evaluated three male date palm varieties, namely, Red-Ganami, Red-Ganami + Khakri Al-Adi and Red-Ganami + Al-Canary, in three age of spathes (early, late and middle) in a private orchard at Al-Seebah district, Basrah province. The plants were subjected to two pollination dates immediately after opening of female flowers and three days after opening of female flowers. The contents of auxin-like substances, gibberellin and abscisic acid in the flowers were determined. The second pollination date resulted in the highest contents of auxins, gibberellins and abscisic acid, with values of 24.305, 138.660 and 12.355 µg.gm-1, respectively. The mixture of Red-Ganami + canary cultivars had the highest concentrations of auxin 24.512 µg.gm -1 and gibberellins 136.842 µg.gm-1, whereas Red-Ganami had the highest concentration of abscisic acid 3.554 μg.gm-1. Early age of spathes showed significant differences in the concentrations of auxin and abscisic acid, with average values of 26.015 and 14.031 µg.gm-1, respectively. Late postmenopausal age recorded the highest concentration of gibberellins at 136.842 μg.gm-1. For the two- and three-way interactions, a statistically significant superiority was observed in most of the study coefficients. In conclusion, the contents of auxins, gibberellins and abscisic acid significantly differed with the pollination date and the pollin cultivar combinations showed the highest concentrations of these substances. The different ages of male puberty also affected pollination and fertilization