Pollen grain hormones of date palm pollinator cultivars and their relationship with hormones of different stages of ‘Piarom’ date fruit growth

Abstract

The aim of this study was to investigate the metaxenia effect of pollen grain hormones of date palm pollinators on the hormones of different stages of fruit growth. The relationships between auxin, cytokinin, gibberellin and abscisic acid hormones of ‘Shahani’, ‘Kabkab’, ‘Zahedi’, ‘Beraem’, ‘Faryab’, ‘Sheikhali’, ‘Fard’ and ‘Jarvis’ pollen grains with the amount of the same hormones in different stages of ‘Piarom’ fruit development were studied. The results showed that pollen grains of different date palm pollinators have different amounts of these hormones. Pollen grains of ‘Fard’ and ‘Sheikhali’ cultivars have higher amounts of hormones compared to other cultivars. The amount of these hormones was also very variable at different stages of fruit growth. The highest amount of hormones in different stages of ‘Piarom’ date fruit growth was observed in trees that were pollinated with pollen grains of ‘Fard’ and ‘Sheikhali’ cultivars. Also the amount of these hormones in pollen grains and different stages of fruit growth had a positive linear relationship. The positive correlation between pollen grains hormones and hormones of different stages of fruit growth confirms the metaxenia effect of pollen grains on the characteristics of ‘Piarom’ date fruit. The presence of more hormones in the fruit, which is directly related to the amount of these hormones in pollen grains, improves the quantity and quality of date palm fruits.