Citrus production in Texas is a 200 million dollar industry located in the Lower Rio Grande Valley.This area in South Texas is subjected to different abiotic stresses, being freezes the most important environmental threat to citrus production.Some abiotic stresses such as flooding caused by hurricanes, prolonged droughts or low/highnutrient content can interact with the freeze tolerance of citrus. Thus understanding and evaluating the abiotic stresses affecting citrus production and their interaction with freezesis a first step to help growers improve the freeze tolerance of their citrus.Also, a novel method for improving freeze tolerance of citrus is studied in this thesis. The foliar or ground application of a plant hormone (abscisicacid, ABA) involved in the process of cold acclimation of trees may provide a new approach to combat freezes.To date, ABA has not been commercially used to increase freeze tolerance in fruit trees, although ABA is available in the market as a plant growth regulator to control dormancy and induce cold tolerance in seeds of herbaceous crops for early planting. Thus, if this technique is improved and doses are optimized, it will be a tremendous help for winter protection for citrus in regions were late freezes occur.
July 20, 2015
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