The Effect of Different Levels of Water Stress on Some Physiological, Quantitative and Qualitative Characteristics of Rainfed Fig (Ficus carica L. cv. Sabz)

Fig trees are the most common type of rainfed orchards in Fars province. In droughts, due to rainfall decline, the trees water requirement is not met and supplementary irrigation is necessary. Thereby, to reduce the damage caused by drought stress on fig (Sabz cultivar) under rainfed conditions, the present study was carried out to evaluate the effect of different levels of water stress on quantitative and qualitative characteristics. Experiment was conducted in a randomized complete block design with four replications (one tree per each replication) in Estahban fig research station. The treatments comprised of different water stress index (WSI), 0.0 (no water stress), 0.2, 0.4, 0.6, 0.8 and without supplementary irrigation. WSI was determined by recording leaf temperature, environmental humidity and air temperature and its effect on figs characteristics was measured. Results showed that the 0.4 WSI had the lowest leafy chlorosis disorder (1.4%) with one-time supplementary irrigation annually (1.5 m3 water per tree for each supplementary irrigation), but the difference was not significant with the 0.0 WSI (6 times supplementary irrigation equal to 9 m3 water per tree annually). The value of leaf relative water content in the 0.4 WSI was 53.4%. The 0.4 WSI showed the highest content of chlorophyll, carotenoid, syconium number per shoot and high quality (open ostiole) of dried fruit with the values of 0.05, 3.25 mg. g-1, 3.2 and 3.6%, respectively however the differences were not significant with the 0.0 WSI. In general, the 0.4 WSI was recommended for Sabz cultivar fig to maintain tree health, production of acceptable quality fruits, save groundwater, and sustainable agriculture.