Propagation of some apricot clonal rootstocks and their influence on growth of nursery trees

The rooting ability of rootstocks ‘Myrobalan 29C’ (M29C), ‘Pumiselect’ and ‘Ishtara’ propagated by hardwood cuttings and the vigor they induced to the scions of four apricot cultivars (‘Hargrand’, ‘Bergeron’, ‘Goldrich’ and ‘Pinkcot’) in the second year nursery field were studied in the period 2012-2014. Hardwood cuttings of all tested rootstocks showed a very high percentage of rooting, over 99%. Between 93.9 and 95.2% of the rooted cuttings reached a thickness of the annual shoot allowing performance of T-budding in August. All three rootstocks provided good development of the scions. At the end of the second year, the trees on ‘Pumiselect’ rootstock had the lowest thickness. Greater thicknesses of both rootstock and scion were recorded in trees budded on rootstocks ‘M29C’ and ‘Ishtara’, but no consistent differences between these rootstocks were found. The trees of the four tested apricot cultivars budded on rootstocks ‘M29C’ and ‘Ishtara’ have greater height and total scion growth than trees of these tested cultivars on ‘Pumiselect’ rootstock. During the study period in the second year nursery field no consistent differences were noted between rootstocks ‘M29C’ and ‘Ishtara’ regarding the growth characteristics they induce to the tested apricot cultivars.