| The progeny of F1 seedlings from there cross combinations (Fuji×Qinguan, Qinguan×Fuji, Qinguan×Qinguan )were used to make apple linkage maps by RAPD method , The segregation patterns and polymorphic of RAPD markers were analysised.while the infected rate and infected index of apple early defoliation disease were investigated in nature infection and artificial infection in order to know the inheritance tendency of resistance to apple earlydefoliation disease.1.In this study, the leaves growing bloom and fresh were used to isolate apple genomic DNA with improved CTAB method. Randomly amplified polymorphic DNA (RAPD) reaction factors of apple genetic DNA were compared and the optimum RAPD reaction condition for apple was obtained. The reaction mixture includes: DNA template 1.6 ng/μL, dNTPs 0.2 mM/L, 10×Buffer 2.5μL, Taq DNA polymerase 0.04 u/μL, primers 0.8 uM/L,and the total volume is 25μL.Compared with other reaction systems,it is stabilty,clarity,good repetition,and high polymorphic. This offers a good foundation to do RAPD analysis.2. The segregation patterns of RAPD markers in interspecific F1 between Qinguan and Fuji were studied. According to the segregation patterns, RAPD markers were grouped into three types: (1) 33.80% DNA makers are normal Mendelian inheritance with segregation ratio of nearly 1:1, 4.22% with segregation ratio 3:1,and 61.97% are non-segregation,:(2) deviation from Mendelian segregation ratio; (3) abnormal segregation. There exist 90.0% Mendelian segregationmarker, 7.24% RAPD marker deviating from Mendelian segregation ratio and 2.71%abnormal segregation marker.The DNA makers belong to two parents are main body with no segregation,and The DNA makers belong to only one parent is main group with segregation ratio 1:1.in this study ,fifteen DNA makers with no-segregation was found.3. The progeny of 34 F1 seedlings, resulting from across between` Fuji'x`Qinguan' were studied to construct a genetic linkage map of apple nuclear genome. For both final maps, linkage groups were determined using a LOD threshold of 3.0, Rec = 0.4. Out of the 325 RAPD primers were screened, a total of 92 were selected.Then 188 DNA markers were analysised by joinmap/exp version 3.0 software. The'Fuji'map consisted 46markers were mapped on 12 linkage groups and spanned 401.9 cM,with a marker density of 8.7 cM.The 'Qinguan'map comprised 42 markers,divided into 11 linkage groups. The average distance between two markers was 10.5 cM.two groups from parents were joined together.These make a good foundation to study the Linkage Map of apple.4. Apple spot leaf drop and Apple leaf Brown Spot were invested and compared in two varieties'Qinguan','Fuji'apple and their F1 generations . The results showed thatˋQinguanˊ had much more resistance thanˋFujiˊfrom beginning to the end .in July the infected rate and infected index of Apple leaf Brown Spot in'Qinguan'is 5.5 and 10.5 times than'Fuji'.From August to September the infected rate and infected index of Apple leaf Brown Spot in'Fuji'add up to 80.8%,59.35%.but at the same time the infected rate and infected index of Apple leaf Brown Spot in'Qinguan'was only 7.85% and 5.24%. Apple spot leaf drop had the same regulation with Apple leaf Brown Spot in'Fuji'and'Qinguan', in the end the defoliation of'Qinguan'was less than'Fuji'.5. The disease index of Apple leaf Brown Spot (Marssonina mail(P.Henn)Ito)and Apple spot leaf drop(Alternaria alternate f.sp. mali) didn't repent significantly normal distribution in three combinations.So the resistant gene was qualitative character, but it contained key resistance gene. |
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