Screening of Superior Lines of Salt-Tolerant Dwarfing Rootstock for Apple and Establishment of in vitro Rapid Propagation System
Duan Siyue
Qu Yanjie
Wang Xinlian
Yan Kejia
Xue Dongwei
Jiang Shenghui
Zhang Yugang
Hou Hongmin
Abstract：Saline-alkali soil has a wide distribution in China's main apple-producing areas.Apples are mainly propagated by grafting,and their stress resistance largely depend on the rootstock.In this experiment,seeds from the open-pollinated progeny of Russian5(R5)were used as the material,and seven salt-tolerant superior rootstock lines were screened out by simulating salt stress with 200 mmol/L of NaCl.And then,using SSR(simple sequence repeats)technology,the rootstock progeny were identified with the Dw1 and Dw2 dwarfing gene markers by comparison with Russian2(R2),R5,M9/T337,M26,Qingzhen 1 and Pingyitian-cha.The results showed that R5-1,R5-2,R5-3,R5-6,R5-8,R2-1,R2-9 and R2-11 contained at lest one Dw1 dwarfing gene marker,and all contained Dw2 dwarfing gene markers.Finally,the salt-tolerant superior lines of R5-3,R5-4 and R5-5 were selected to establish in vitro rapid-propagation systems.The results showed that the optimal proliferation culture medium for R5-3,R5-4 and R5-5 was MS+0.5 mg·L-1 6-BA+0.1 mg·L-1 NAA+3%sucrose+0.7%agar with an average proliferation coefficient of 4.22,4.44 and 4.89,respectively.Taking the number of roots,rooting rate and root growth status into account,it was concluded that the optimal rooting culture medium for R5-3 and R5-5 was 1/2MS+0.5 mg·L-1 IBA+3%sucrose+0.7%agar,while that was 1/2MS+1.5 mg·L-1 IBA+3%sucrose+0.7%agar for R5-4 and 1/2MS+1.0 mg·L-1 IBA+3%sucrose+0.7%agar for R5-6.In addition,salt stress treatment and osmotic potential measurement showed that the salt tolerance of all superior rootstock lines were stronger than that of the parent R5,among which,R5-3,R5-4 and R5-5 had the least salt damage and showed stronger salt tolerance,R5-1 and R5-6 had yellow leaves and salt stains,showing lower salt tolerance than R5-3,R5-4 and R5-5 lines.The findings of this study could pro-vide theoretical foundations and resource reserves for the cultivation of superior salt-tolerant self-rooted apple rootstocks,which has certain significance for promoting the sustained and healthy development of China's ap-ple industry.
Keywords：Apple dwarfing rootstockSalt toleranceMolecular markerRapid propagation system
Publication Date：2026-02-28
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：9( 41-49 )