Studies On Ornamental Peach Systematics Using Molecular Markers

Based on 12 years studies on ornamental peach (Prunus persica (L.) Batsch.), especially these three years collecting and studying ornamental peach cultivars from Japan and USA, AFLP and ISSR markers had been successfully constructed among 51 ornamental peach taxa. An updated ornamental peach systematics and DNA fingerprinting library had been established with both morphological and molecular evidence.All 51 ornamental peach taxa were from Beijing Botanical Garden (China), National Institute of Fruit Tree Science, Tsukuba (Japan), and JC Raulston Arboretum at the North Carolina State University, Raleigh, North Carolina (USA) and collected by author herself.This dissertation is completed in collaboration with Beijing Forestry University, University of Maine and Harvard University. The experiments and datum analyses were completed in both Harvard University and University of Maine. Dissertation (both English and Chinese versions) was written at the University of Maine and revised in Beijing Forestry University.Both AFLP and ISSR could generate large amount detailed fragments with high polymorphisms and have higher reproducibility compared with other molecular markers. Therefore, these two molecular techniques were applied for this ornamental peach study. No literature on application of AFLP and ISSR for ornamental peach has been found and this innovational work brought their applications further to systematics, genetic relationship, cultivar identification, guided breeding, and nomenclature.Ornamental peach originates from China. There is 3000 years cultivation history in China. No appointed institution is serving as the International Registration Authority (IRA) for ornamental peach so far in the world. The systematics and DNA fingerprinting library established through this study have provided the supporting justification for China to apply IRA for ornamental peach.The major results were as follows:AFLP markers had successfully constructed genetic relationship among 51 ornamental peach taxa. The results showed that AFLP is a powerful technique for detecting the origination and development of ornamental peach taxa.ISSR markers had successfully constructed genetic relationships among 16 ornamental peach taxa. The results demonstrated that ISSR fingerprinting is an efficient technique to reveal group genetic relationships of ornamental peach. The protocol and ISSR-PCR conditions for ornamental peach had been established.DNA fingerprinting library of 51 ornamental peach taxa had been established by using 6 AFLP primer combinations. This DNA library is a great example to apply molecular data for the aid of guided breeding and nomenclature for cultivated plants. Molecular data are powerful addition for nomenclature and cultivar registration and should be included in the International Code of Nomenclature for Cultivated Plants (ICNCP). Recommendation provisions based on ornamental peach AFLP analysis were proposed for amending the revision of future ICNCP.Combined AFLP and ISSR markers provided better genetic information and relationships of 16 ornamental peach taxa. The results suggested that both AFLP and ISSR analysis should have great potential to estimate phylogeny and elucidate the hierarchy among ornamental peach cultivars.An updated ornamental peach systematics had been established with both morphological and molecular evidence. The nomenclatural status of all known ornamental peach in the world had been reinstated or corrected. A worldwide ornamental peach checklist was presented to apply International Registration Authority for ornamental peach by Beijing Botanical Garden in Beijing, China.