Effects of Deficient Irrigation on Some of the Morpho-physiological Characteristics of Four Fig Cultivars

The amount of water available to plants includes one of the most important factors that affect the growth of plants. The objective of the present study was to investigate and compare the tolerance of different fig types (Ficus carica L.) to different low irrigation treatments.
A factorial trial based on a completely randomized design with 3 replications was carried out in Ferdowsi University of Mashhad. The treatments of this experiment were four levels of irrigation including; supplying enough water to pots (100% field capacity), mild stress (75% field capacity), average stress (50% field capacity) and severe stress (25% field capacity) on Green, Black, Shah Fig and Matthew cultivars. Some of morphological and physiological traits like stem growth, leaf umber, leaf area, root length, root area, fresh and dry weight of shoot and root, root to shoot ratio, relative water content, electrolyte leakage, total chlorophyll and proline were measured.
According to the results, significant differences were observed between different irrigation treatments for all measured parameters. The highest level of stem growth, leaf umber and leaf area were detected in control treatment (100% field capacity), while the lowest contents were observed in severe stress (25% field capacity). The results showed that the fresh and dry weight of shoot and root decreased with increasing drought stress, so that the lowest amounts were observed in severe stress treatment (25% field capacity). The levels of relative water content was significantly affected by different irrigation treatments, since treated plants with severe stress treatment (25% field capacity) had the lowest relative water values, while the highest levels was observed in control treatment (100% field capacity). The highest and lowest of total chlorophyll content was observed in control treatments (100% field capacity) and severe stress (25% field capacity), respectively. Among the study treatments, severe stress treatment (25% field capacity) had the highest amount of root length, root area, root to shoot ratio and control treatment had the lowest root length, root area, root to shoot ratio. The obtained results detected that electrolyte leakage increased with increasing drought stress. The severe stress treatment (25% field capacity), had the highest proline content, followed by the average stress treatment (50% field capacity), while the lowest value was observed in control (100% field capacity). A variation in terms of all measured parameters also was observed among the cultivars and the differences were statistically significant. Among the presently tested cultivars, Black has the best resistant ability to drought stress than in other cultivar.
This research showed all measured parameters were significantly affected by irrigation treatments and cultivars. These data demonstrated that cultivar was the main parameter which influences the morpho-physiological properties in figs.