Genetic Mapping and QTL Analysis in Interspecific Chestnut Population

Genetic linkage map were constructed in interspecific population between Japanese chestnut (Castanea crenata Sieb et Zucc.) and Seguin chestnut (C. seguinii Dode).  These maps were constructed based on Amplified Fragment Length Polymorphism markers (AFLPs) and Simple Sequence Repeat markers (SSRs).  A map of Japanese chestnut as female parent consisted of 139 loci including 132 AFLPs and 7 SSRs on 13 linkage groups of 629 cM in a total length.  A map of Seguin chestnut as paternal parent consisted of 133 loci including 123 AFLPs and 10 SSRs on 13 linkage groups of 764 cM in a total length.  On a map of Japanese chestnut, a major QTL was detected for nut weight.  On the other hand, 8 major QTLs were detected for plant height, leaf size, number of leaf vein, nut weight, pollen fertility and the time of bud break on a map of Seguin chestnut.  Interestingly, 5 out of 8 QTLs for plant height in 2009, plant height in 2010, leaf size, number of leaf vein and the time of bud break were located at the almost same position on a map of Seguin chestnut.  The highest LOD score, 37.69, were observed for the plant height in 2010.  The results suggested that the plant height was controlled by a major gene.