A RAD-based linkage map of kiwifruit (Actinidia chinensis Pl.) as a tool to improve the genome assembly and to scan the genomic region of the gender determinant for the marker-assisted breeding
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Kiwifruit breeding still largely relies on phenotypic observation of cross progeny grown in the field to fruiting maturity, without any selection prior to the juvenility being overcome. Developing markers for the selection of traits of interest would greatly help breeders to rapidly screen breeding populations. With the aim of mapping several traits of interest in kiwifruit, a F1 population of diploid (2n = 58) Actinidia chinensis was produced by combining parents with contrasting phenotypic traits. Ninety-four individuals were preliminarily analyzed to obtain a saturated genetic map based on 167 SSRs from the literature and 12,586 segregating restriction-site-associated DNA (RAD) loci obtained through an approach known as genotyping-by-sequencing (GBS) based on haplotype calling of SNP markers identified by a modified double digest restriction-associated DNA sequencing (ddRADseq) protocol as proposed by Peterson et al. (2012). To improve the accuracy of genotype calling, restriction-site-associated reads were aligned to the scaffolds of the recently published kiwifruit genome (Huang et al. 2013). This strategy provided genetic anchoring to 557 Mbp (90 %) of the assembly, helping also to anchor some 120 unmapped Mbp and to identify some mis-joined scaffolds. The analysis of the region controlling the dioecy in kiwifruit, spanning 16 scaffolds in the pseudomolecule 25 of the genome assembly (approximately 4.9 Mbp), with RAD markers that co-segregated with the gender determinant, allowed to sort out markers suitable for marker-assisted selection for the gender in the mapping population with successful extension to further controlled crosses having parents at different ploidy level and belonging to the A. chinensis/Actinidia deliciosa complex.
KeywordsGenotyping-by-sequencing Next-generation sequencing Single-nucleotide polymorphism Genetic map Marker-assisted selection
This research was developed within the program Chile-Italia D09I1136 “Mejoramiento Genético del Kiwi apoyado en la Selección Asistida por Marcadores” supported by the Chilean Government- FONDEF. Authors are grateful to Dr. Ross Ferguson for the manuscript revision.
- Cipriani G, Morgante M (1993) Evidence of chloroplast variation DNA variation in the genus Actinidia revealed by restriction analysis of PCR - amplified fragments. J Genet Breeding 47:319–326Google Scholar
- Fraser LG, Tsang GK, Datson PM, De Silva HN, Harvey CF, Gill GP, Crowhurst RN, McNeilage MA (2009) A gene-rich linkage map in the dioecious species Actinidia chinensis (kiwifruit) reveals putative X/Y sex-determining chromosomes. BMC Genomics 10:102. doi: 10.1186/1471-2164-10-102 PubMedCentralCrossRefPubMedGoogle Scholar
- McNeilage MA, Fraser LG, Tsang GK, Datson PM, De Silva HN, Crowhurst RN, Ferguson AR (2012) Molecular genetics and genomics and kiwifruit breeding. Acta Horticulturae 913:63–70Google Scholar
- Rozen S, Skaletsky H (2000) Primer3 on the WWW for general users and for biologist programmers. In: Krawetz S, Misener S (eds) Methods Mol Biol, vol 132. Humana Press, Totowa, pp 365–386Google Scholar
- Testolin R (2012) Breeding the future: what fruit breeders can learn from breeders of cows and chickens. Chronica Horticulturae 52(2):6–8Google Scholar
- Testolin R (2013) Kiwifruit breeding: from the phenotypic analysis of parents to the genomic estimation of their breeding value (GEBV). Acta Horticulturae 913:123–130Google Scholar
- Van Ooijen JW (2006) JoinMap® 4, Software for the mapping of quantitative trait loci in experimental populations. Kyazma B.V, WageningenGoogle Scholar