Study On Graft Compatibility Between 'Bramley's Seedling' Apple And Different Rootstocks

‘Bramley's seedling' apple grafted on Mulus robusta,M.prunifolia,M.prunifolia var.Ringo,M.micromalus,M.sieboldii and M.zumi was studied to learn their graft compatibility between the scion bud and the rootstocks and then to provide theoretical reference for selecting more suitable rootstock that enhance the cultural adaptability of ‘Bramley's seedling' apple.The indexes such as graft survival rate,shoots and leaves growth,photosynthetic and physiological characteristics and anatomical structure of the graft unions were determined and analyzed in the experiment.The results showed that there were very significant differences in the respect of the survival rates between the scion buds grafted on the six different rootstocks from M.spp.,with the highest survival rate for the scion buds grafted on M.robusta and the lowest one for that grafted on M.zumi.The grafting buds on M.zumi and M.sieboldii sprouted earlier and grew slower than those grafted on the other four rotstocks did,with the longest shoot growing for the graft union of ‘Bramley's seedling' on M.robusta and the thickest shoot growing for that of ‘Bramley's seedling' on M.micromalus.The leaves of M.robusta and ‘Bramley's seedling' graft union had the highest net photosynthetic rate,the largest leaf area and the largest ratio of palisade to spongy tissues while the leaves of M.zumi and ‘Bramley's seedling' graft union had the lowest net photosynthetic rate,the smallest leaf area and the smallest ratio of palisade to spongy tissues in all the tested materials.According to comprehensive analysis the photosynthetic strength of six Malus species used as the rootstocks of ‘Bramley's seedling' could be ordered as M.robusta > M.prunifolia var.Ringo > M.prunifolia >M.sieboldii >M.micromalus >M.zumi.PPO and SOD activities were relatively lower while MDA and soluble protein contents were relatively higher when M.prunifolia,M.robusta and M.prunifolia var.Ringo were used as the rootstocks.The highest activities of PPO and SOD,the highest contents of MDA and low soluble protein were found when M.zumi was used as the rootstock.The soluble sugar and starch extracted separately from the scion and the rootstock cortex expressed relative higher content ratios of the scion to the rootstock in the graft union of M.zumi and M.sieboldii.The IAA contents in the leaves of the shoots on M.prunifolia and M.robusta were the highest in all and had no significant differences between the scion and the rootstock.The IAA contents in the leaves were the lowest of all the tested materials and had relative bigger differences between the scion and the rootstock when M.sieboldii and M.zumi were used as the rootstocks.There were no significant differences in branch-cortex ratio and small differences in the structure of shoot cross section between ‘Bramley's Seedling' and the rootstocks of M.prunifolia and M.robusta.But M.zumi and M.sieboldii had significant difference with ‘Bramley's seedling' in branch-cortex ratio and relative big difference with the scion in the structure of shoot cross section.When M.prunifolia and M.robusta were used as rootstocks the graft unions had small difference in the tissue structures between scions and rootstocks and healed normally.When M.zumi and M.sieboldii were used as rootstocks the graft unions had relative big difference in the tissue structure between scions and rootstocks and healed abnormally.It's more likely for the scion grafted on M.zumi and M.sieboldii to split from the rootstocks.Conclusions can be drown from the indexes quoted above and membership function analysis and the scion growth morphology that the graft compatibility of six tested species with ‘Bramley's seedling apple can be ranked as M.robusta > M.prunifolia > M.prunifolia var.ringo>M.micromalus> M.sieboldii > M.zumi.It is suggested that M.robusta,M.prunifolia and M.prunifolia var.ringo could be used as appropriate rootstocks of ‘Bramley's seedling' apple.