Comparison of Growth and Yield of some Commercial Pear Cultivars on Two Dwarf Hawthorn (Crataegus atrosanguinea) and Quince A Rootstocks

The pear orchards in Iran, are predominantly established on the seedling rootstocks, but recently, the dwarfing pear rootstocks such as Quince A, has been received more consideration for this purpose. Further to Quince A rootstock, red hawthorn (Crataegus atrosanguinea) is compatible with some pear cultivars and meanwhile causes dwarfing effects in the cultivars when using as rootstock and demonstrates high tolerance to the drought stress. In this research, the growth and bearing of five commercial pear cultivars (Shah Miveh, Dargazi, Harrow Sweet, Spadona and Bartlett) were evaluated on Quince A, red hawthorn and seedling rootstock (as control) during 2013-15. The results demonstrated the highest dwarfing for Dargazi (64.7%) and Bartlett (24.4%) on hawthorn rootstock, compared with the seedling rootstocks. Among tested cultivars, Spadona had the highest tree heights with 296.3, 220.9 and 189.9 cm on seedling, Quince A and hawthorn rootstocks, respectively. The type of rootstock had no considerable effect on fruit size, titratable acidity (TA) and total soluble solids (TSS) in different cultivars. Regarding the highest dwarfing of cultivars on hawthorn rootstock, the lowest yield per tree was observed on this rootstock. According to the index of yield per unit trunk cross-sectional area (TCA), the highest yield efficiency was obtained in Dargazi/Quince A combination and then Dargazi/hawthorn rootstock. In fire blight free regions, Spadona/hawthorn rootstock could be considered as the most appropriate combination, due to its high efficiency and low alternate bearing.