|BUCK, EMILY - New Zealand Institute Of Plant & Food Research|
|MCCALLUM, SUSAN - The James Hutton Institute|
Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2014
Publication Date: 8/10/2014
Publication URL: http://handle.nal.usda.gov/10113/61444
Citation: Rowland, L.J., Ogden, E.L., Bassil, N.V., Buck, E.J., Mccallum, S. 2014. Construction of a genetic linkage map of an interspecific diploid blueberry population and identification of QTL for chilling requirement and cold hardiness. Molecular Breeding. 34:2033-2048.
Interpretive Summary: Blueberry plants require exposure to low temperatures in the winter to be able to grow in the spring. The amount of low temperature exposure required is determined by the plants genes and is called the chilling requirement. Exposure to low temperature also induces the plants to become hardier in order to survive the extreme temperatures of winter. How cold hardy the plant can become is controlled by the plants genes as well. Since winters in the southern U.S. are warmer than winters in the north, the development of varieties for the southern U.S. requires varieties that require less chilling temperature in order to grow in the spring. Northern adapted varieties must be more cold hardy. Therefore, our laboratory has been working on identifying, isolating, and mapping genes that control cold hardiness and chilling requirement in blueberry. Here we describe the construction of a genetic map for identifying these genes. This map was used to locate the genes that control cold hardiness and chilling requirement. One gene with a large influence on cold hardiness and another gene with a large influence on chilling requirement were identified. Identifying genes associated with cold hardiness and chilling requirement will help scientists develop more effective strategies for developing new varieties of blueberry adapted for growth in different regions of the country.
Technical Abstract: A genetic linkage map has been constructed from an interspecific diploid blueberry population [(Vaccinium darrowii Fla4B x V. corymbosum W85-20) F1#10 x V. corymbosum W85-23] designed to segregate for cold hardiness and chilling requirement. The map is comprised of 12 linkage groups (equivalent to the haploid chromosome number of diploid blueberry) and totals 1448.7 cM. Included on the map are 280 simple sequence repeat (SSR), expressed sequence tag-polymerase chain reaction (EST-PCR), single nucleotide polymorphism (SNP), and randomly amplified polymorphic DNA (RAPD) markers. The estimated map coverage is 85.7%, and the average distance between markers is 5.6 cM. The mapping population was evaluated for two years (2009 and 2010) for mid-winter bud cold hardiness and for three years (2011-2013) for chilling requirement under controlled conditions. Broad sense heritability of both cold hardiness and chilling requirement were quite high under these conditions with values of 0.88 and 0.86, respectively. One QTL for cold hardiness and one for chilling requirement were identified that were consistent over at least two years. A second weaker QTL for chilling requirement was detected in only one of the three years.