Comparative Characterization Of Cultivation Performance In Virus-free ’Ruixue’ Apple Grafted On M26 And Qinganzhen 1 Dwarfing Rootstocks

Dwarfing cultivation is the ideal direction of the innovation of apple cultivation mode.Meanwhile,it is vital to develop virus-free seedlings.There are significant differences in ecological factors and rootstocks types of the main apple producing areas.Weibei is one of the high-quality apple production areas in Shaanxi province,in order to promote the high-quality and efficient production of apples in this area,the development of high-quality varieties,virus-free seedlings and suitable rootstocks are particularly important to promote dwarfing cultivation models.In this study,we selected a later-ripening yellow new apple cultivar‘Ruixue’as the material,grafting on dwarfing rootstock M26 and the semi-dwarf rootstock Qingzhen 1.This experiment focused on differences in the virus and virus-free of‘Ruixue’apple and effects of two dwarfing rootstocks on the growth performance of‘Ruixue’apple.The fruit quality and nutrient distribution were observed and analyzed,and the main results obtained are as follows:1.Virus were detected in‘Ruixue’apple using RT-PCR detection technology,and the results showed that apple stem pox virus（ASPV）and apple chlorotic leaf spot virus（ACLSV）were found in virus‘Ruixue’.However,there were no ASPV and ACLSV in virus-free.2.The growth and fruit of virus-free and virus‘Ruixue’were compared using M26 dwarf rootstock as material.The results showed that the growth of virus-free‘Ruixue’was stronger than control（virus）.The plant height,stem diameter,crown width and number of main branches of virus-free‘Ruixue’were significantly higher than virus sapling（9.1%,5.3%,23.6%,37.8%）.The content of soluble solids and the ratio of solid acid were higher than virus sapling.While,the content of Vc and total phenol in fruit were lower than virus sapling control.3.The virus-free‘Ruixue’grafted on M26 and Qingzhen 1 to compare their difference.The results showed that,compared with Ruixue/M26 combination,‘Ruixue’had stronger growth,higher germination rate and more branches grafted on Qingzhen 1,but its dwarfing and early flowering ability were poor.The germination rate and branching force of Ruixue/Qingzhen 1 combination were 1.19 times and 1.46 times higher than those of Ruixue/M26 combination,respectively,but the flowering rate was significantly decreased by80.9%compared with that of Ruixue/M26 combination.In Ruixue/Qingzhen 1 combination,the annual and biennial plant height was significantly higher than that in Ruixue/M26combination.Compared with Ruixue/M26,the stem diameter of the annual and biennial saplings in Ruixue/Qingzhen 1 was significantly increased by 33.9%and 55.9%,respectively.The crown width of Ruixue/Qingzhen 1 was always higher than that of M26 combination,and the crown was larger.In addition,the number of trunk branches of Ruixue/Qingzhen 1 was2.07 times than M26 combination.In fruit quality,the contents of soluble solids,titratable acids and total phenols in Ruixue/Qingzhen 1 were higher than those in M26 combination.The aboveground and underground biomass of Ruixue/Qingzhen 1 was more than 1.23 times than M26 combination.Compared with M26 combination,the number of roots of Qingzhen 1increased by more than 72.8%.In terms of ¹³C and ¹⁵N absorption and transport capacity,the absorption of ¹³C in roots and stems of Qingzhen 1 combination was 2.6 times and 1.96 times than M26 combination,respectively.The allocation rate of ¹³C in roots and stems increased by 7.4%and 8.3%,but decreased by 11.8%in fruit.Compared with M26,the ¹⁵N content in roots was increased by 47.97%and the distribution rate was increased by 20.1%.Compared with Ruixue/M26,the ¹⁵N content in stems and leaves was decreased by 40.5%and 35.0%,and the distribution rate was also decreased by 9.5%and 9.2%,all of which were significant differences.In conclusion,compared with M26 rootstock,Qinganzhen 1 is more beneficial to the growth and shaping of‘Ruixue’saplings.