production and primary evaluation of apple (mallus domestica borkh.) hybrid rootstocks

apple is the most important fruits in the world and development of vegetative rootstocks is the priority of our country. to obtain apple rootstocks compatible with soil conditions in iran, many crosses were carried out among native-dwarf genotype (azayesh and morabaee) as female parents and commercial rootstocks (b9, m9, m27) as male parents from 2005 to 2007. primary evaluation of progenies was done for selecting of easy rooted and mealy aphid (eriosoma lanigerum) resistance. 218 genotypes were selected among 3032 hybrids based on high resistance to mealy aphid and high rooting ability. rooting ability of hard wood cuttings, in hot bed conditions evaluated in the second phase and 13 genotypes with high length and number of roots as well as callus amount were selected. results showed that progeny of azayesh × (m27, m9 and b9) had high rooting ability while progeny of morabaee×(m27, m9 and b9) had low rooting ability. ratios of main root number to hairy root number on open pollinated progeny of iranian genotypes were more than imported rootstocks. these characteristics are important for establishment of rootstocks in soil and for their drought tolerance. they also indicate better acclimation ability to soil conditions of our country.