Towards a Saturated Molecular Genetic Linkage Map for Cultivated Sunflower

Abstract

The density and utility of the molecular genetic linkage map of the widespread use of RFLP markers and maps in suncultivated sunflower (Helianthus annuus L.) has been greatly inflower has been restricted by a lack of public RFLP creased by the development and mapping of several hundred simple sequence repeat (SSR) markers. Of 1089 public SSR markers de-probes, consequent lack of a dense public RFLP map, scribed thus far, 408 have been mapped in a recombinant inbred line and low-throughput nature of RFLP markers. The diffi-(RIL) mapping population (RHA280 ϫ RHA801). The goal of the culties posed by the historic lack of public, single-copy present research was to increase the density of the sunflower map by DNA markers were only weakly offset by the emerconstructing a new RIL map (PHA ϫ PHB) based on SSRs, adding gence of facile, universal DNA markers, e.g., RAPDs loci for newly developed SSR markers to the RHA280 ϫ RHA801 RIL (Williams et al., 1990, 1993) and AFLPs (Vos et al., map, and integrating the restriction fragment length polymorphism 1995). RAPDs have primarily been used for tagging (RFLP) and SSR maps of sunflower. The latter was accomplished by phenotypic loci in sunflower, e.g., rust (Puccinia helianadding 120 SSR marker loci to a backbone of 80 RFLP marker loci thi Schw.) and Orobanche cumana Wallr. resistance on the HA370 ϫ HA372 F 2 map. The map spanned 1275.4 centimorgans (cM) and had a mean density of 6.3 cM per locus. The genes (Lawson et al., 1998; Lu et al., 2000). While RAPD PHA ϫ PHB SSR map was constructed from 264 SSR marker loci, and AFLP markers have a multitude of uses, both are spanned 1199.4 cM, and had a mean density of 4.5 cM per locus. The dominant, multicopy, and often nonspecific in nature RHA280 ϫ RHA801 map was constructed by adding 118 new SSR and, as a whole, unsatisfactory for establishing a geand insertion-deletion (INDEL) marker loci to 459 previously nome-wide framework of DNA markers for anchoring mapped SSR marker loci. The 577-locus map spanned 1423.0 cM and cross referencing genetic linkage maps. Single-copy, and had a mean density of 2.5 cM per locus. The three maps were codominant DNA markers, e.g., SSRs, are preferred for constructed from 1044 DNA marker loci (701 unique SSR and 89 such purposes and, until recently, have been lacking unique RFLP or INDEL marker loci) and supply a dense genomein sunflower. wide framework of sequence-based DNA markers for molecular breeding and genomics research in sunflower.

Quantitative Trait Locus Analysis of the Early Domestication of Sunflower

“…Genotyping for the genetic map was then carried out for 111 variable codominant loci, including 108 simple-sequence repeats All values are expressed as mean 6 standard error (SSRs) that were previously mapped in sunflower Yu et al 2003;Lai et al 2005). The SSRs were fluorescently labeled with 6FAM, TET, HEX, or VIC either by direct labeling of the 59 end of the forward primer or using a modification of the three-primer PCR methodology presented by Schuelke (2000), previously adapted for sunflower by Wills et al (2005).…”

Proteomic Analysis of Near-Isogenic Sunflower Varieties Differing in Seed Oil Traits

“…12,13,15 RHA280 and RHA801 are the parents of a recombinant inbred line (RIL) mapping population segregating for apical branching (B), 16 pericarp hypodermis pigment (Hyp), 17 and pericarp phytomelanin pigment (P) loci, in addition to quantitative trait loci (QTL) for several genetically correlated seed traits, for example, seed oil concentration, 100-seed weight, and kernel-to-pericarp weight ratio. 15,18,19 Tang et al 15 reported seed oil concentrations of 254 g/kg for RHA280 and 481 g/kg for RHA801 from seed samples harvested from plants grown at Corvallis, OR, in 2000 and 2001.…”

Identification and mapping of SNPs from ESTs in sunflower

“…The RILs were developed by single-seed descent from the same two cultivars (RHA280 and RHA801) employed for the majority of EST sequencing. A dense map of anonymous markers already exists for this population Yu et al 2003); consequently, it has become the primary reference population for molecular breeding and comparative genomics research in sunflower (e.g., Burke et al 2004;Lai et al 2005). Ninety-four RILs from this cross were employed for population screening and map construction.…”

“…EST-based markers found to be polymorphic by DHPLC were added to the RHA280 × RHA801 reference map for H. annuus Yu et al 2003) using the program MAPMAKER/EXP 3.0b (Lander et al 1987) under the "RI Self" model. Because the RHA280 × RHA801 map contains 459 SSRs , a subset of 196 evenly spaced markers was chosen to establish a framework for each linkage group (LG), then tested for a unique best order via the "ripple" command (parameters five marker windows and reporting alternative orders with LOD <3).…”

“…However, shortly thereafter several restriction fragment length polymorphism maps were published for the domesticated sunflower (Berry et al 1995;Gentzbittel et al 1995Gentzbittel et al , 1999Jan et al 1998), establishing a standard nomenclature for sunflower linkage groups and providing framework markers for comparisons among maps (Gedil et al 2001). More recently, high-resolution linkage maps based on more than 1,000 simple sequence repeat (SSR) and other sequence-tagged-site markers have been developed for the cultivated sunflower Yu et al 2003) and several wild species Burke et al 2004;Lai et al 2005).…”