Physiological studies on irrigation of "LE-CONTE" pear trees / Mohmed Ahmed Abdelwahab Eliwa ; Supervised Ramzy George Stino , Mohamed Essam Shawky , Mohamed Abdelaziz Abdelmohsen

Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Pomology

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 as a preliminary season to eliminate the residual effects of the previously used irrigation treatments. Pear growing season was split into four phenological stages (stage I beginning of flowering to final fruit set, stage II from initial fruit set to final fruit set, stage III from final fruit set to harvesting and stage IV from harvesting to leaf shed). However, control trees received 100 % of crop water requirement during all stages while the remaining trees received one of the following 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 with the optimal level of irrigation requirement (100 %) for the remaining stages. The fruit set%, fruit abscission%, yield (Kg), fruit characteristic, vegetative growth parameters, chemical analysis including leaf macro and micro nutrients content and leaf photosynthetic pigments content, enzymatic activities activity, total proteins, carbohydrates, phenols and proline (in leaves), phytohormons (in bud) 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 this producing significantly the highest yield per tree, fruit weight increased by increasing the applied water quantities during stage III, while firmness and TSS increased with decreasing the actual requirement during any studied stages

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