DETERMINATION OF THE MOST SUITABLE HARVEST TIME FOR GREEN COLOR AND HIGH KERNEL QUALITY OF PISTACHIO NUT (PISTACIA VERA L.)

In this research, determination of the most suitable harvest time for the development and protection of the high quality green kernels was studied. Green kernels have great economic importance for Turkish pistachio nuts. The research was carried out on the high value market cultivars Siirt, Ohadi, Kìrmìzì and Uzun. The nuts from these cultivars were harvested at five different harvest times (26th Aug, 2rd Sept, 9th Sept, 16th sept-full maturity stage-, 23rd Sept 1991).

At the beginning stage of kernel development pistachio have green kernel color but lose their chlorophyll content near harvest. Green kernel color turns yellow-green and total chlorophyll decreases significantly with late harvests. The chlorophyll a/b ratio was between 1.30 and 0.57, and generally decreased with maturity through late harvest. In addition, effects of different handling conditions on the total chlorophyll content such as the nut shading on the trees, drying under the sun light and dark, and shell splitting were studied. These factors did not affect the total chloropyll content under these experimental conditions.

Our results demonstrate that, during kernel development before maturity, the Kìrmìzì cultivar had the highest green kernel color (as total chlorophyll 2.9 mg/100g). On all cultivars, green kernel level gave the highest correlation with weight, content of total fat and protein when nuts were harvested three weeks before full maturity.