A Comprehensive Approach Toward Conserving Malus Germplasm

Authors: Volk, Gayle; Richards, Christopher; Forsline, Philip

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/29/2009
Publication Date: 7/29/2009
Citation: Volk, G.M., Richards, C.M., Forsline, P.L. 2009. A comprehensive approach toward conserving Malus germplasm. Molecular Markers in Horticulture Symposium. July 29-August 1, 2009 Corvallis, OR. pp. 7. Meeting Abstract.

Interpretive Summary: The USDA-National Plant Germplasm System apple (Malus) collection has traditionally been conserved by maintaining orchards in Geneva, NY and cryopreserving dormant buds of clones. The orchard Malus collection includes hundreds of M. sieversii and M. orientalis individuals. The variation in these wild relative species is valued primarily for their diverse alleles, rather than for their specific genotypes. We have developed core collections based on both phenotypic and genotypic (microsatellite) characters to identify a limited number of individuals that represent the diversity of the wild collections. In addition to maintaining selected individuals in orchard core collections, we propose that wild species should be conserved as seeds from strategically selected crosses. This would ensure that many diverse individuals are available for future selection and physiology programs, rather than a limited number of specific genotypes. Crosses have been performed among core collection individuals for two of the three complementary core collections proposed for the M. sieversii collection to produce seeds that can be stored for long-term storage. This conservation approach that promotes preservation of selected clones as well as diverse sets of seeds for vegetatively propagated collections has several advantages. It ensures that valuable alleles in wild collections are conserved, reduces the labor involved in cryopreserving vegetative propagules, and also maintains diverse individuals in field settings that are available for pollen and dormant budwood distribution.

Technical Abstract: The USDA-National Plant Germplasm System apple (Malus) collection has traditionally been conserved by maintaining orchards in Geneva, NY and cryopreserving dormant buds of clones. The orchard Malus collection includes hundreds of M. sieversii and M. orientalis individuals. The variation in these wild relative species is valued primarily for their diverse alleles, rather than for their specific genotypes. We have developed core collections based on both phenotypic and genotypic (microsatellite) characters to identify a limited number of individuals that represent the diversity of the wild collections. In addition to maintaining selected individuals in orchard core collections, we propose that wild species should be conserved as seeds from strategically selected crosses. This would ensure that many diverse individuals are available for future selection and physiology programs, rather than a limited number of specific genotypes. Crosses have been performed among core collection individuals for two of the three complementary core collections proposed for the M. sieversii collection to produce seeds that can be stored for long-term storage. This conservation approach that promotes preservation of selected clones as well as diverse sets of seeds for vegetatively propagated collections has several advantages. It ensures that valuable alleles in wild collections are conserved, reduces the labor involved in cryopreserving vegetative propagules, and also maintains diverse individuals in field settings that are available for pollen and dormant budwood distribution.