Changes in sugar quality, tannin and mineral contents during fruit development in date palm (Phoenix dactylifera L.) fruits

The reducing, non-reducing sugar, tannin and three nutrients were determined in fruits of eight cultivars grown at Bikaner during three stages of fruit development. Results showed that most of the studied characters (physical and chemical) at three stages of fruit maturity differed from one cultivar to another cultivar. Higher values of fruit and seed weight as well as length and width were found at full doka stage and minimum in the initiation of doka stage. Sugar contents accumulated gradually during fruit development in all cultivars were also varying among eight cultivars. Calcium content increased at full doka then it decreased gradually. Also in micronutrients (Zn and Fe) similar trend was found.