Study On The Technique System Of Micropropagation In Vitro Of Pear Dwarfing Rootstocks

In this study the shoot tips isolated from P. pyrifolia ' Shehbuzhi', 'S2', 'S5' and 'PDR54' were used as explants. By means of the orthogonal experiment design, analysis of variance and multiple comparisons, the factors including genotupes, basical medial, plant growth regulators were analysed. The results were as follow.-(1) Considering the comprehensive index shoot qulity numbers and length, the best sub-culture medium for in vitro perliferation of four varieties was respectively as follows:For 'Shenbuzhi' , the sutiable prescription for proliferation was MS + 1.0mg/LBA.For ' S2', the best medium of proliferation was MS+3mg/LBA+0.2mg/LIBA +2mg/LGA3.For 'S5', the sutiable prescription for proliferation was MS+2.0mg/LBA+ lmg/LIBA+lmg/LGA3.For 'PDR54', the best medium of proliferation was QL + 3.0mg/LBA+ 0.1mg/LIB A+4mg/L GA3.( 2 ) According to rooting rate, mean root number, mean root length, root fresh weight per shoot and root dry weight per shot tested, the optimal rooting condition for four viarieties was respctively as follows:For ' Shenbuzhi', microcuttings were incubated the root iniation medium 1/4MS supplemented with IB A at 5.0mg/LIBA and sucrose at 30.0g/L in darkness for 10 days, followed by 1/4MS containing sucrose at 30.0g/L and 1.0g/LAC.For ' S2', shoots were placed in the medium of 1/2QL supplemented with IBA at 5.0mg/LIBA and sucrose at 5.0g/L in darkness for 10 days, followed by 1/2QL containing sucrose at 5.0g/L and 0.5g/LAC.For ' S5', microcutting were inoculated in 1/2MS containing IBA at 5.0mg/L and sucrose at 15.0g/L in darkness for 10 days, and then transferred into root formation medium 1/2MS supplemented with IBA at 5.0mg/L , sucrose at 15.0g/L and 0.5g/LAC.For 'PDR54', shoots were first inoculated in 1/4MS containing IBA at 2.5mg/LIBA and sucrose at 15.0g/L in darkness for 10 days, and 1/4MS supplemented with IBA at 2.5mg/L, sucrose at 15.0g/L and 1.0g/LAC for the rest.