The Effect Of Different Dwarf Intermediate Rootstocks On The Growth Results And Mineral Element Absorption Of ’Changfu 2’

Intensive cultivation of dwarf rootstocks is a development trend of the apple industry.Gansu Longdong is located in the apple-dominant production area of Loess Plateau,with the change of apple cultivation mode,dwarf anvil intensive cultivation mode is gradually promoted,the change from traditional arboriculture mode to dwarf cultivation mode is the general trend,and the selection of suitable dwarf rootstock is the technical key in the change of dwarf anvil intensive cultivation mode.This study relied on the Qingcheng Apple Experiment Station in Gansu Province and took ’Changfu 2’ as the research object,four SH rootstocks(SH1,SH6,SH38,SC1),four M rootstocks(M26,M9,T337,M7)and JM7 rootstocks were used to select a total of nine dwarf intermediate rootstocks,the growth characteristics,yield,fruit quality and mineral uptake of ’Changfu 2’ grafted on nine dwarf intermediate rootstocks were measured and analyzed in 2021 and 2022,screening of suitable dwarf intermediate rootstocks in terms of mineral elements and fruit yield quality,with the aim of providing a reference basis for the promotion and cultivation of apples with corresponding dwarf intermediate rootstocks in the local area,The main results are as follows:1.Investigation of tree growth characteristics,single plant yield and commercial rate of nine dwarf intermediate rootstocks of ’Changfu 2’,the results indicate that in terms of phenology,the defoliation period of the SH series intermediate rootstock ’Changfu 2’ were10 to 30 days earlier than other rootstocks;the defoliation period of ’Changfu 2’ with SH6 as the intermediate stock was the earliest,starting in late October,there is no significant difference in other 5 dwarf intermediate stock plants.In terms of tree growth,the T337 and JM7 intermediate rootstocks ’Changfu 2’ were tall and strong;the SH1,SC1,M7,M9 and M26 intermediate rootstocks ’Changfu 2’ were moderate;the SH6 and SH38 intermediate rootstocks ’Changfu 2’ were short and weak.In terms of single plant yield and commodity rate,M series and JM7 intermediate rootstock ’Changfu 2’ had higher yields,maintaining over 30 kg/plant for two years,with a commodity rate of over 80%,SH6 intermediate rootstock ’Changfu 2’ had the worst single plant yield and commodity rate,with a two-year yield of 6.16 kg/plant and 12.30 kg/plant respectively,it is less than a quarter of the highest yield of M26 and T337 intermediate rootstock ’Changfu 2’,and the commodity rate was only about 50%.2.The fruit quality of 9 dwarfing intermediate rootstocks ’Changfu 2’ were compared,the results showed that the average single fruit weight of M series and JM7 intermediate rootstocks ’Changfu 2’ were higher,both reaching over 300 g,while the fruit size of SH6 and SH38 intermediate rootstocks ’Changfu 2’ was smaller,with an average single fruit weight of only about 250 g;SH series intermediate rootstocks ’Changfu 2’ had relatively high fruit hardness,fruit brightness,soluble solids content and titratable acid content.3.A comparison was made on the absorption of mineral elements in the leaves and fruits of 9 dwarfed intermediate rootstocks ’Changfu 2’.The results showed that the mineral element content of each rootstock panicle combination at different stages were slightly different,but the trends of changes were relatively similar.For the leaves,the trends of N,Cu and Zn were increasing-decreasing-increasing-decreasing,the trends of Ca,Mg and Mn were increasing-decreasing,the trends of P and K were decreasing-increasing-decreasing,the trend of Fe was continuously increasing.The leaves of the M series intermediate rootstocks ’Changfu 2’ absorbed nine mineral elements better than those of the SH series intermediate rootstocks ’Changfu 2’.For fruits,the trends of N,Fe and Cu were decreasing-increasing,the trends of K and Zn were decreasing-increasing-decreasing,the trends of P,Ca,Mg and Mn elements were continuously decreasing.The fruit of M series and JM7 intermediate rootstocks ’Changfu 2’ had better absorption and utilization of N,K,Mg,Mn and Cu elements,the fruit of SH series intermediate rootstocks ’Changfu 2’ had better absorption and utilization of P,Ca,Fe and Zn elements.4.Correlation analysis was conducted on the correlation between individual plant yield,commodity rate,fruit quality indicators and the mineral element content of leaves and fruits in each period.The results showed that fruit yield and fruit weight were significantly and positively correlated with leaf N and Mn content at all periods;the commercial rate was significantly and positively correlated with leaf N content in May,June and July;fruit hardness was significantly and negatively correlated with leaf Mn content in all periods and significantly and positively correlated with fruit Ca content;soluble solids content was negatively and significantly correlated with N,K and Mn in leaf and fruit;titratable acid content was negatively and significantly correlated with P in expanding fruit,Mg in ripening fruit and Fe in leaves at harvest;fruit brightness was significantly and negatively correlated with leaf Mn content in all periods,fruit N and fruit K content;the solid acid ratio was significantly and negatively correlated with leaf K content during fruit expansion.5.The comprehensive comparison of principal component analysis and affiliation function analysis showed that when the base rootstock was Xinjiang wild apple,the intermediate rootstocks M9 and M7 of ’Changfu 2’ were suitable for planting and promotion in Gansu Longdong region.In contrast,SH38 and SH6 intermediate rootstocks performed the worst and were not suitable for planting ’Changfu 2’ in this region.