| Field surveys of apple seedling quality were carried out in Shandong and ShaanxiProvince, which was the basis of apple breeding and revision of China national standard forapple seedlings.1279seedlings in Shandong and1494seedlings in Shaanxi were randomlyselected as experimental materials. According to China national standard of apple seedlings,the number of lateral root, length of rootstock, length of interstock, height, plant diameter andgradient were measured and analyzed. Compared with this standard, the quality of appleseedlings in Shaanxi and Shandong Province is poor (the proportions of grade1seedling werelower than14%and7%in general nursery,21.5%and59.5%in domenstration nursery ofShandong Province and Shaanxi Province, respectively). In production,2-year-old dwarfseedlings accounted for a considerable proportion, but the quality was hardly meet the gradeof national standard requirements。We found that the height and interstock length of appleseedlings could meet the requirement of grade1of China national standard(≥120cm）; Inaddition to the2-year-old dwarf seedlings, the average plant diameter of other types appleseedlings are all higher than the requirement of grade （3≥0.8cm~<1.0cm）; about the numberof lateral root, China national standard requires it should be more than3, but in the production,the percentage of unqualified apple seedlings are approximate15%in general nursery andapproximate8%in demonstrarion nursery. We also found that over85%of vigorous stockcould not meet the requirement of rootstock length in national standard（≤5cm）and72%of3-year-old dwarf seedlings’s rootstock length were less than5cm in demonstration nursery.We made a comprehensive analysis and found that the overall quality of apple nursery shouldbe improved and China national standard of apple seedling should be further revised.Nowadays the dwarf intensity cultivation is the most important planting pattern of apple.The dwarf interstook is used for dwarfing cultivation in China. In this research, materialswere six rootstock-scion combinations,’Fukuhima Spur’ and ’Changfu2’ were used for scions,Malus robusta Rehd., M26and M9for interstocks and Malus robusta Rehd for rootstock. Some indexes of growth and physiological indicators of leaves were measured in the growthprocess. The contents of Endogenous hormones, carbohydrates and nitrogen, phosphorus andpotassium were determined in different periods. The primary conclusions were as follows:1、The rootstock-scion combinations of apple seedling had a significant influence on theplant height,’Fukuhima Spur’ significantly promoted the leaf quality. The internode numberof ’Changfu2’ was greater than ’Fukuhima Spur’. M9has made a significant increase in thenumber of cluster twigs, and a significant decrease in the number of short shoots and longshoots.2、In the fast-growing period, the dwarf trees had a lower content of GA3. ABA/IAAmight be a indicator of the growth potential, because the higher trees have more ABA/IAA.Dwarfing treatment of apple saplings made a significant reduction of (IAA+GA3+ZT+ZR)/ABA and the changement of (IAA+GA3+ZT+ZR)/ABA in ’Changfu2’ was greater than’Fukuhima Spur’.3、The rootstock-scion combinations had made a major impact on the carbohydrateaccumulation in growing cycle. Saplings with M9had the higher contents of starch andnon-structural carbohydrate. There is no significant difference in content of carbonhydratebetween scions.4、There is no significant difference in the content of K between different rootstock-scioncombinations of young apple trees; the content of N in leaves were significantly differbetween interstocks, M9(17.23mg/g)> Malus robusta Rehd.(15.73mg/g)> M26(12.58mg/g);the content of P in leaves of ’Fukuhima Spur’ was significantly higher than ’Changfu2’. |
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