Fine mapping of Co, a gene controlling columnar growth habit located on apple (Malus×domestica Borkh.) linkage group 10

Abstract

Tree architecture and shoot morphology are important factors in apple production systems. Because a columnar growth habit facilitates highdensity planting and labour-saving fruit production methods, columnar apple breeding programmes are spreading worldwide. Columnar growth habit is controlled by a single dominant gene, Co, on linkage group 10. Fine mapping of Co was conducted using 1000 F 1 progeny plants from 31 populations. Novel simple sequence-repeat (SSR) markers were developed based on the genome sequence of apple ÔGolden DeliciousÕ and analysed for linkage to Co. Graphical genotyping of 22 progeny with recombination event in the vicinity of Co identified three SSR markers (Mdo.chr10.12, Mdo.chr10.13 and Mdo.chr10.14) that co-segregated with Co. Mdo.chr10.12 and Mdo.chr10.14 are well suited for marker-assisted selection because the sizes of the alleles linked to Co are different from those found in common ancestors of current apple breeding germplasm. The Co region was delimited to a 196-kb region of the apple genome, between markers Mdo.chr10.11 and Mdo.chr10.15.

Tracing a key player in the regulation of plant architecture: the columnar growth habit of apple trees (Malus × domestica)

“…They delimited the Co gene region to 196 kb, a similar size as in Bai et al (2012). However, the markers developed by Moriya et al (2012) Moriya et al (2012), but does not span the chromosomal location predicted for Co by Bai et al (2012). Furthermore, marker C18470-25831, which Bai et al (2012) found to be linked to Co, showed three recombinants in the mapping population of Baldi et al (2012).…”

“…The newly delimited region contains 20 annotated genes and 7 predicted genes, 3 of which code for homologs of Lateral Organ Boundaries Domain transcription factors in Arabidopsis (Majer and Hochholdinger 2011) and were thus considered the most likely candidates for Co (Bai et al 2012). Moriya et al (2012) also developed SSR markers based on the Golden Delicious genome sequence and used 1,000 F 1 individuals from 31 populations for linkage analysis. They delimited the Co gene region to 196 kb, a similar size as in Bai et al (2012).…”

Practical DNA markers to Estimate Apple (Malus x domestica Borkh.) Skin Color, Ethylene Production and Pathogen Resistance

“…DS4 adaptor was ligated to digest genomic DNA to perform genome walking [21,27]. Then attachment of DS5 adaptor was tried and successfully amplified apple S-RNase fragment [5]. Attachment of the DS5 adaptor to the forward primer slightly reduced PCR amplification of the target sequence, together with amplification of non-specific smear DNA band.…”

“…For example, the SSR (simple sequence repeat) -type DNA marker NZmsEB119405 for Cg locus estimates crown gall resistance of apple rootstock cultivars [4]. Another SSR-type DNA markers such as Mdo.chr10.14 for the Co locus is genetically linked to the columnar tree shape of apple scion cultivar 'Wijcik' [5]. We have also recently developed a sequencingbased DNA marker APPLid for determination of apple S alleles [6].…”

A and MdMYB1 allele-specific markers controlling apple (Malus x domestica Borkh.) skin color and suitability for marker-assisted selection

“…The application of MAS to apple-breeding programs has mainly focused on certain well-known traits of interest, including resistance to scab, flavor, firmness, columnar growth habit, and skin color (Takos et al, 2006;Bus et al, 2007;Zhu and Barritt, 2008;Moriya et al, 2012). For the skin color trait, it has been shown that a RAPD DNA marker derived from the red skin gene, Rf, is able to discriminate between most red and non-red apple cultivars, and has been used in advanced breeding selections (Cheng et al, 1996).…”