abstract abیtract


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 2011-2012. The experiment was carried out with four replications in a completely random blockdesign to study the effects of two concentrations of EM (0 and 1%), three irrigation levels (normal irrigation 100%-control-and irrigation after depletion of 33 and 66% of available water), and four almond rootstocks including GF677 and selected natural hybrid of peach × almond (H1and H2), and almond vegetative rootstock (local control).In this study,EMtreatments for 60 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 33% and 66% 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 0.01 level of probability. Comparison of means showed that the highest fresh and dry weight and leaf are awere observed forGF677and H1.Rootstockannualgrowth rate was also different. Most of the growth was related to the H1 Rootstocks. Thes urvival ratewas significantly different from the Rootstocks ofGF677,andH1showedthe highestpercentage of survival. The degree of adaptation to drought in varieties of almonds is different. The results showed that changes ingrowthparametersinGF677and H1were observed less often than other rootstocks. Because of strong roots,GF677and H1continue to attract more minerals under stress conditions.
Analysis of variance showed that the between irrigation levels for all treatments were significantly different at 0.01 level of probability. Comparison of means showed that among the study traits, the highest amount was obtained from complete irrigation, while irrigationat66 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<0.01). Comparison of means revealed that the application of EM increasedthese traits compared to control. Effective Microorganisms, can increase plant growth, leaf area, fresh and dry weight of shoots and roots, and plant biomass. This phenomenon could bedue to better growth of roots. It is due to the biological activity of micro organisms in composition of EM.
Considering the results of this study, among examined traits, length, dry weightand root volume were suitable markers for evaluating water stress tolerance in almonds and the H1 rootstock (natural hybrid of peach × almond) was identified as the resistant rootstock to water stress. Impact of EM on the growth factors and survival of seedlings was dependent on the type of rootstock and the impact of EM on the water stress tolerance was different from the genetic characteristics of the rootstock.
The relationship of linear regression was used to identify markers related to water stress. Between the markers tested, length, root volume and root dry weight have higher correlation with survival of rootstock. Accordingly, them entioned markers are appropriate to measure the amount of water stress tolerance of almond rootstocks.
Conclusion: The results of this study, Natural hybrid H1, are resistant rootstocks in dry conditions. Effect of Effective Microorganism (EM) on the growth and drought resistance characteristics, depends on the type of rootstock. Accordingly, this substance cannot berecommended for all root stocks and cultivars. Further investigation of the effects of the combination on the desired plant exists. In addition, the influence of these substances for full irrigation was higher, because more suitable growing conditions exist. On this basis, effect of this combination is dependent on environmental conditions.

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abیtract abstract. (2016). abstract. علوم باغبانی, 29(3). https://doi.org/10.22067/jhorts4.v0i0.53287
نوع مقاله
علمی - پژوهشی