Plant & Animal Genome IX Conference

Workshop: Fruit/Nut Tree
W27_03.html

GENETIC AND PHYSICAL MAPPING OF THE EVERGREEN GENE

¹ Horticulture Department, Clemson University, Clemson, SC 29634

² U.S. Department of Agriculture/ARS, Appalachian Fruit Research Station, Box 45, Wiltshire Rd, Kearneysville, WV 25430

³ Biology Department, Clemson University, Clemson, SC 29634

The 'Evergreen' phenotype of peach [Prunus persica (L.) Batsch] was identified as an unique material for studying the process of winter dormancy and cold-hardiness in trees. One single recessive gene (evergreen or evg) controls the evergreen trait. A local genetic linkage map was constructed for the evg gene using the cross 'Empress' (bractitic dwarf) x 'Evergreen' (PI 442380) and amplified fragment length polymorphyism (AFLP) and bulked segregant analysis (BSA) techniques. This map consisted of 14 loci, covering a total genetic distance of 163.8 cM. Four dominant AFLP markers, EAT/MCAC, ETT/MCCA2, EAT/MCTA and ETT/MACC, were found to be tightly linked to the evg locus and were converted into STS (sequence tagged site) markers. The goal is to use these markers for marker-assisted selection for breeding peach cultivars. A peach BAC library was constructed for physical mapping and cloning this evg gene. BAC clones containing these STS markers were identified and are being used to initiate chromosomal walking to the evg locus. Microsatellite markers in these peach BAC clones have been characterized. With four microsatellite markers, we anchored the local genetic linkage group to the complete peach genetic map developed by Lu et al. Five BAC clones were placed in this evg gene region using microsatellite mapping analysis. Chromosomal walking was started from the 18F12 BAC clone, 1 cM from evg locus. Cloning and utilization of the evg gene will be discussed.