abstract

Introduction: One of the microbiological preparations used for this study was Effective Microorganisms (EM), being a commercial mixture of photosynthesizing bacteria, Actinomycetes, lactic acid bacteria, yeasts and fermenting fungi. The microbiological composition of the EM concentrateincludesStreptomyces albus, Propioni bacterium freudenreichil, Streptococcus lactis, Aspergillus oryzae, Mucor hiemalis, Saccharomycescerevisiae and Candida utilis. Moreover, EM also contains an unspecified amount of Lactobacillus sp. Rhodo pseudomonas sp. and Streptomyces griseus. Effective Microorganisms have a positive effect on the decomposition of organic matter, limiting putrefaction, increasing nitrogen content in the root medium of plants, phosphorus, improving soil fertility and as a result contributing to the growth and development of the root systems of plants. Selection of almond vegetative rootstocks for water stress tolerance is important for almond crop production in arid and semi-arid regions. The study of the eco-morphological characteristics that determine the success of a rootstock in a particular environment is a powerful tool for both agricultural management and breeding purposes. The aim of this work was to select the new rootstocks for water shortage tolerance, impact of water stress as well as Effective Microorganism (EM) on morphological characteristics of almond rootstocks. Materials and Methods: In order to select the new rootstocks for water shortage tolerance, impact of water stress as well as EMonmorphologicalcharacteristics of almondrootstocks were studiedin thedepartment ofHorticulture, Ferdowsi University of Mashhad, in ۲۰۱۱-۲۰۱۲. The experiment was carried out with four replications in a completely random blockdesign to study the effects of two concentrations of EM (۰ and ۱%), three irrigation levels (normal irrigation ۱۰۰%-control-and irrigation after depletion of ۳۳ and ۶۶% of available water), and four almond rootstocks including GF۶۷۷ and selected natural hybrid of peach × almond (H۱and H۲), and almond vegetative rootstock (local control).In this study,EMtreatments for ۶۰ days before stress treatments were applied so that in each irrigation, EM solution to a concentration of one percent was given to half of the experiment pots. Other pots were irrigated equally with normal water. Stress levels were applied from July as follow: full irrigation, watering after unloading ۳۳% and ۶۶% soil moisture availability. In order to evaluate the performance, seedling survival, plant growth, number of leaves, leaf area, root fresh and dry weight and leaves and root length were measured. Results and Discussion: Analysis of variance showed that between rootstock levels across all treatments were significantly differences at ۰.۰۱ level of probability. Comparison of means showed that the highest fresh and dry weight and leaf are awere observed forGF۶۷۷and H۱.Rootstockannualgrowth rate was also different. Most of the growth was related to the H۱ Rootstocks. Thes urvival ratewas significantly different from the Rootstocks ofGF۶۷۷,andH۱showedthe highestpercentage of survival. The degree of adaptation to drought in varieties of almonds is different. The results showed that changes ingrowthparametersinGF۶۷۷and H۱were observed less often than other rootstocks. Because of strong roots,GF۶۷۷and H۱continue to attract more minerals under stress conditions. Analysis of variance showed that the between irrigation levels for all treatments were significantly different at ۰.۰۱ level of probability. Comparison of means showed that among the study traits, the highest amount was obtained from complete irrigation, while irrigationat۶۶ percenthad the least amount. Water stress may directly affect photosyn thesis, through leaf photochemicalprocessorindirectly,byclosing stomata, reducingleaf area and growth. The results showed that the levels of(EM) on the leaf surface, leaf number, annual growth, root dry weight and volume were significantly different (p

کلیدواژه ها:

Effective Microorganisms ، Dehydration ، Natural hybrid ، Survival of rootstock