PAG-II Plant Genome II Conference

Town & Country Conference Center, San Diego, CA, January, 1994.


PG-II: MOLECULAR AND MORPHOLOGICAL MARKERS FOR A DWARFING GENE FROM THE CITRUS ROOTSTOCK PONCIRUS TRIFOLIATA 'FLYING DRAGON'

MOLECULAR AND MORPHOLOGICAL MARKERS FOR A DWARFING GENE FROM THE CITRUS ROOTSTOCK PONCIRUS TRIFOLIATA 'FLYING DRAGON'.

Frank Suozhan Cheng 1 and Mikeal L. Roose 2. l Department of Horticullural Sciences, Cornell University, Geneva, NY 14456; 2 Department of Botany and Plant Sciences, University of California, Riverside, CA 92521.


The 'Flying Dragon' cultivar of Poncirus trifoliata is a dwarfing rootstock for citrus. It is also resistant to several important diseases and pests. A population of self-pollinated seedlings of 'Flying Dragon' was used to find markers for dwarfing. Each progeny seedling was budded with 'Cutter Valencia' orange and planted in the field to evaluate the dwarfing effect of the seedling rootstock. Dwarfing effect was determined by measuring trunk circumference at 5 years after planting. The distribution of trunk circumferences was bimodal with 31 dwarfing trees and 10 non-dwarf. This suggests that the dwarfing effect of this rootstock is controlled by a single dominant gene for which 'Flying Dragon' is heterozygous. Bulked segregant analysis was used to identify 4 markers linked to the dwarfing gene. Two morphological characteristics of 'Flying Dragon', curved thorns and twisted trunk growth were closely linked to, or pleiotropic effects of the dwarfing gene.


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