Construction Of A Moleculer Genetic Linkage Map And QTL Analysis For Some Traits In Pear Fruit

With rich Pyrus. germplasm resources in China, the molecular genetic linkage map construction andagronomic traits or gene lacation have an important significance on the molecular marker assisted breedingof pea. In this study, the ‘Shinseiki’originated from western Japan was used as female parent, the‘Chonghuadali’ originated from Sichuan province in China was used as the male parent, and210strains ofF1hybrid of them were used as mapping group. JoinMap4.0was ued to construct a pear genetic linkagemap based on ISSR、SRAP and SSR molecular markers. And13fruit traits of pear were statisted andcorrelation analysised. The main research results were as follows:1. This study establishedt the suitable PCR reaction system of pear through orthogonal experimentaldesign.96polymorphic primers were screened from288primers, and received154polymorphic hands.2. A high density genetic linkage map based on8ISSR markers、79SRAP markers and9SSRmarkers was constructed by using the JoinMap4.0.96markers were located on14genetic linkage groups.The total distance of the pear covering genome was1530cM with the average15.9cM distance betweenevery2markers and6.9marker locis in each linkage group.3. Correlation analysis of the13fruit traits of pear was carried by using SPSS19.0and Excel2013.The results showed that fruit transverse diameter were significantly positive correlated with fruit verticaldiameter (R=0.975**). Fruit stem length has the smallest significantly positive correlated with fruit dot size(R=0.200**). The seed number has a significant negative correlation with fruit skin color (R=-0.155**)andtotal soluble solids concentration (R=-1.140*).4. The Quantitative Trait Loc（iQTL）linked to13agronomic traits of fruit was analyzed using intervalmapping methhod in MapQTL4.0software. A total40QTL locis were located:1QTL locis was for fruitdeveloping period trait,5QTL locis were for fruit weight trait (3locis were separation or tight chainphenomenon),6QTL locis were for fruit stem length,2QTL locis were for fruit core size,5QTL lociswere for total soluble concentration,8QTL locis were for seed number,4QTL locis were for fruit dot size,7QTL locis were for fruit skin color and4QTL locis were for flesh flavour. No efficient QTL locis abouttransverse diameter, vertical diameter, fruit quality and fruit shaps were not detected. The40QTLs aboutfruit traits distributed on7linkage groups. It had8QTLs with LOD≥2.5, and could be considered as aeffective QTL. The QTLs with LOD≥3.5were as more as32, and it could be considered that it has maineffective QTL. The distance13kinds of fruit character chain of QTL loci and their recent molecular markerloci was all from0to5.0cM. The nearest location was2QTL locis of FDS-2and FDS-3associated withGuoDian size. The least distance of FDS-2and FDS-3from their nearest maker (UBC840-700) andF2R1-500were all1.5cM.