Impact of applied irrigation regime during specified phenological stages on cropping and its' attributes of "Le-conte" pear

الملخص EN

This study was carried out during three successive seasons 2013, 2014 and 2015 on seventeen years old Le-Conte pear trees.

The first season was considered to be on preliminary season to eliminate the residual effects of the previously used irrigation treatments.

Pear growing season was split to four phenological stages (stage I beginning of flowering to final fruit set, stage II from initial fruit set to final fruit set, stage III final fruit set to harvesting and stage IV harvesting to leaf shed).

However, control trees received 100 % of crop water requirement during all stages while the remaining trees received three water regimes (60, 80 and 120% of crop water requirement) applied at each of the phonological stages and then irrigated with the stayed stages were receiving optimal level of irrigation requirement (100 %) for the remaining stages.

The fruit set%, fruit abscission%, yield (Kg), fruit characteristic (fruit weight (gm.), fruit firmness, juice TSS % titratable acidity %), chemical analysis (Leaf content of macro nutrients (nitrogen, phosphorous, potassium content (%),magnesium, iron , zinc, manganese and copper contents (mg/l) and leaf content of photosynthetic pigments (chlorophyll (a,b) and carotenoids) parameters were assessed.

Results showed that enhancements of fruit set percentage were induced by applying 60% of the actual requirement during stage II, fruit abscission declined by increasing the applied water quantities during stage IV and producing significantly the highest yield per tree, fruit weight increase by increasing the applied water quantities during stage III, firmness and TSS increases with decreasing the actual requirement during any studied stages, the highest leaf nitrogen content was due to applying the highest regime during stage III, increasing potassium, phosphorus, magnesium, iron , copper and chlorophyll contents were attributed to the lowest regime when applied during stage II, leaf zinc and manganese content increased by applying the highest regime during stage II.