Study On Investigate Of Main Virus And Cultivation Of Virus-free Fruit In Apple And Cherry

Apple and cherry trees of Jiaodong area in Shandong province were detected in National Apple Breeding Center of Yantai during 2007～2010. The damages of fruit viruses in apple and cherry orchards of this area, the effective eliminating techniques on fruit virus and the foundation of virus-free apple and cherry reproducing systems were studied. The main results were as followings:1. The damage of fruit virus of Jiaodong area in Shandong province is very serious with virus-infected ratio of apple trees reaching 55.6% and the complex virus-infected ratio was 44.4%. The main viruses on apple such as apple scar skin virus, apple mosaic virus, apple twisted limb virus, apple chlorotic leaf spot virus, apple stem pitting virus and apple stem grooving virus were identified. Virus-infected ratio of cherry trees reached 45.5% and the complex virus-infected ratio was 27.3%. The main viruses on cherry such as prunus necrotic ring spot virus, prunus dwarf virus, cherry leaf roll virus, cherry rasp leaf virus and cherry mycoplasma disease were detected.2. The main apple viruses such as apple scar skin virus, apple stem grooving virus, apple stem pitting virus, apple mosaic virus and apple chlorotic leaf spot virus could be effectively eliminated through constant high temperature (38℃) for 20 days combining with secondary stem tip culture and the eliminating ratio could reach 86.4～100%.Cherry virus-free rootstocks were obtained by changed temperature thermotherapy (37℃day 16h /32℃night 8h) for 18 days combining with the stem tip culture. After the dim lighting (10000Lx) and the changed temperature thermotherapy (37℃day 16h/32℃night 8h) for 18 days, the tender shoots of potted cherry varieties were grafted onto the virus-free rootstocks in the field. The cherry viruses such as prunus necrotic ring spot virus, prunus dwarf virus, cherry leaf roll virus and apple chlorotic leaf spot virus could also be effectively eliminated and the eliminating ratio is more than 90%.3. The best primary culture medium of apple is MS+BA0.3mg/L (the follow units are the same as this one) + IBA0.1. The best subculture medium is MS+BA0.5+IBA0.1, with the propagation coefficient reaching 4～5. The best rooting medium is 1/2MS+IAA1.5, with rooting ratio reaching 87% and the survival ratio more than 90%. The best primary culture medium of cherry rootstock is MS′+IBA0.2+BA0.5. The best subculture medium is MS′+BA0.3+TDZ0.05+IBA0.1, with propagation coefficient reaching 4.4～6.8. The best rooting medium of G5 is 1/2MS+NAA0.5+BA0.5 +Ac0.5g/L, with rooting ratio more than 87%. The best rooting medium of G6 is 1/2MS+IAA0.4+ IBA0.3+ NAA0.3, with rooting ratio reaching 74% and the survival ratio more than 93.1%.