Obtaining resistant rootstocks to alkaline soils in apple by somaclonal variation.

In the present research we made a search for finding apple genotypes tolerant to alkaline soils in the country. Two wild genotypes were found, the first growing in calcareous soils, pH 7.2, of Abar kouh (Shahroud) as a very old wild spur type and the second one a local genotype in Azerbayjan Gahrbi called Khan Almasi. The major part of experiment was focused on Abar kouh genotype resulting very healthy without any foliar chlorosis, dark green leafs, short internodes and very tolerant to diseases. Root suckers and trunk suckers were chosen as adapt explants. Three interdependent articulated researches parts were designed, the first part as a micropropagation plan for true to type micropropagation of selected tree using buds and microcuttings. The second part consisting in regeneration studies with use of the relative in vitro leafs obtained during micropropagation. The third part of research the preparation of stressing alkaline mediums with gradual increase of pH degree where the obtained regenerants were cultured. During the preliminary selection tolerant regenerants were individuated and were cloned. The results confirmed achievement a complete protocol of micropropagation in all stages: sterilization, establishment and proliferation with use of (BAP, Kinetin æ TDZ), elongation (GA3); and in rooting phase using dark together with (NAA æ IBA ). Successful acclimation was attained for Abar kouh genotype completing micropropagation process. The latter genotype had many advantages as a potential rootstock but it was found not an easy rooting genotype even the protocol of rooting was achieved. The micropropagated shoots served both as control and relative in vitro leafs as the main source of regeneration investigations to produce new regenerants. So, in vitro leafs were used in callogenesis and regeneration studies with use of TDZ, BA, 2-4D and Gluthatione in independent successive experiments. Evident morphological differences were observed within regenerants like roset forms, fast growing stem and others compared with the true to type micropropagated shoots. New regenerants, probable mutants, were encoded and cloned separately, then transferred in specific high alkaline levels as pH stressing substrates, ranging from 5.6 to 8.5, to individuate tolerant ones. At the end of selective stage, in Paper Bridge conditions embedded with specific liquid mediums, growth traits were measured and viability period of each regenerant were registered. 19 morphotypes were selected and cloned while susceptible regenerants were omitted. The preliminary in vitro rooting experiments, in broad sense, showed not easy rooting behavior of the cloned morphotypes. In the next project it should be deeply examined.