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Abstract The iron has a very important role in the growth and development of the plant, iron deficiency causes chlorosis in apple trees. The main producing areas of apple in China just iron deficiency, therefore, filter out iron-efficient resources from rich apple germplasm resources, and breeding new varieties of apple rootstocks through breeding means is fundamental pathway to solve due to iron deficiency affected yield and quality of apple production. Since 1984, the project team screened iron-efficient genotypes from 40 apple stocks and found Malus xiaojinensis Cheng et Jiang, grow normally and do not exhibit symptoms of chlorosisin in conditions of very low Fe content, was considered to be an excellent germplasm with tolerance to iron deficiency. Subsequently, open pollinated hybrids groups were established on the basis of M. xiaojinensis Cheng et Jiang seedlings. In 1990, excellent grades was obtained through original selection from natural seedlings. Then after multiple selection and comparison test, bred apple clonal rootstocks Chistock #1. Chistock #1 is a tetraploid in chromosome number (2n = 4x = 68), with a capacity of apomixis, and setting rate above 85% after emasculation bagged. Then with excellent grafting compatibility, seedling dry good standing and strong solid ground, semi-dwarf, dwarf extent, effects and yield capacity were similar with simi-dwarfing apple rootstock M7. Sweet fruit flavor, palatability, and excellent quality. Resist apple early defoliation disease and branches ring rot, high resistance to apple Chlorotic leaf spot virus(CLSV), Stem pitting virus(SPV) and the Stem groove virus(SGV) and other latent virus. Chistock #1 can effectively prevent etiolation due to iron deficiency as apple rootstock in the lime parent material soil areas.
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Received: 22 April 2013
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