Quantitative Trait Loci Controlling Fusarium Head Blight Resistance and Low Deoxynivalenol Content in Hexaploid Wheat Population from ‘Arina’ and NK93604

Breeding for Fusarium head blight (FHB) resistant wheat adapted to the Norwegian climatic conditions is one of the top priorities in the country. This study was conducted to characterize QTLs for FHB resistance and low deoxynivalenol (DON) content in a population of 93 double haploid lines from a cross between ‘Arina’ and NK93604. Both parents have moderate levels of resistance to FHB. The population was assessed for FHB resistance under field conditions for 3 yr (2001 to 2003), and DON content was analyzed from seed samples in the 2002 experiment. The two traits showed significant genetic variation and were significantly correlated with each other. Composite interval mapping (CIM) identified four QTLs using the 3 yr mean for FHB resistance on chromosomes 1AL, 1BL, 6BS, and 7AL. The QTLs on 1AL, 1BL, and 7AL were consistently detected in all 3 yr, and explained 27.9, 19.6, and 14.8% of the phenotypic variation, respectively. The QTLs on chromosomes 1BL and 6BS originated from Arina, whereas those on 1AL and 7AL were from NK93604. None of the QTLs for FHB resistance detected in this study were coincident with those previously reported in the Arina/‘Forno’ population. Two major QTLs, both derived from NK93604, on chromosomes 1AL and 2AS were identified for DON content that explained 27.9 and 26.7% of the variation, respectively. Amajor QTL for FHB resistance on 1AL coincided with a QTL for DON content. As far as we are aware, the QTL on chromosome 1AL is novel and not reported elsewhere. Data from the present study provides breeders with additional information on chromosomal regions associated with FHB resistance and DON content in European wheats and will help guide the development of FHB-resistant wheat. FUSARIUM HEAD BLIGHT or scab is one the most destructive diseases of wheat worldwide, due to grain yield losses and the production of mycotoxins when natural inoculum is abundant during warm and humid weather at flowering. FHB causes premature plant death or blighting of the spikes, and often substantially reduces grain yield and quality (Bai and Shaner, 1994). Infected kernels are contaminated with mycotoxins, which have been shown to be harmful to animals (Desjardins and Hohn, 1997) and also are a safety concern in food. The most common toxin associated with FHB is deoxynivalenol (DON). It is generally agreed that breeding for new varieties with high levels of resistance is considered to be the most efficient, long-term control for FHB, as it is assumed to provide durable protection (Mesterhazy, 1995). Therefore, the major focus in international research is to identify, characterize, and exploit genes that confer resistance. FHB resistance is quantitatively inherited and controlled by either major or minor quantitative trait loci (QTLs). QTLs for FHB resistance have been reported in all hexaploid wheat chromosomes except 1A (Anderson et al., 2001; Kolb et al., 2001; Yang et al., 2005). Kolb et al. (2001) proposed several reasons for differences among reports on the location of FHB resistance genes including, among others, the type and sources of resistance studied by different research groups, and the variation in techniques employed for phenotypic evaluation (point inoculation versus spray inoculation). Spray inoculation tends to detect both resistances to initial infection (Type I) and to spread within the tissues (Type II), whereas point inoculation tends to demonstrate Type II resistance only. In FHB resistance breeding efforts both in Europe and North America, the main emphasis has long been on exploiting resistance, mainly from Chinese, Japanese, and Brazilian spring wheat germplasm. However, many backcrosses are needed to incorporate these exotic sources into adapted varieties, making this a long-term strategy. An alternative short-term approach has been to exploit moderate resistance already present in adapted material, as documented by Saur (1991) and Mielke (1980). Mapping studies based on spray inoculation in field conditions in ‘Renan’ 3 ‘Recital’ population, for example, revealed three stable QTLs from Renan on chromosomes 2B and 5A (Gervais et al., 2003), whereas Paillard et al. (2004) reported two major QTLs from Arina from an Arina 3 Forno population on chromosomes 4A and 6D. However, the Arina 3 Forno map for chromosome 4A and 6D (Paillard et al., 2003) had two limitations: (i) the maps consisted of very few markers; and (ii) the flanking markers on either side of both chromosomes are RFLPs, which are not breeder-friendly for high-throughput molecular breeding strategies. We recently published a linkage map in a double haploid (DH) population derived from a cross between Arina (a Swiss winter wheat; accession number 01C0104276) and NK93604 (a Norwegian spring wheat breeding line) using diversity arrays technology (DArT), amplified fragment length polymorphism (AFLP), and simple sequence repeat (SSR) markers (Semagn et al., 2006). The objectives of this study were Kassa Semagn, Africa Rice Center (WARDA), 01 BP 2031, Cotonou, Benin; Helge Skinnes, Åsmund Bjørnstad, Anne Guri Marøy, and Yalew Tarkegne, Dep. of Plant and Environmental Sciences, Norwegian Univ. of Life Sciences, P.O. Box 5003, N-1432, Ås, Norway. Received 16 Feb. 2006. *Corresponding author (helge.skinnes@ umb.no). Published in Crop Sci. 47:294–303 (2007). Genomics, Molecular Genetics & Biotechnology doi:10.2135/cropsci2006.02.0095 a Crop Science Society of America 677 S. Segoe Rd., Madison, WI 53711 USA Abbreviations: AFLP, amplified fragment length polymorphism; ArNK, Arina 3 NK93604; CIM, composite interval mapping; cM, centimorgan; d.a.i., days after inoculation; DArT, diversity arrays technology; d.f., degrees of freedom; d8, sum degree Celsius 3 day; DH, double haploid; DON, deoxynivalenol; FHB, Fusarium head blight; LOD, log of odds; QTL, quantitative trait loci; R, proportion of variance explained by QTL; RFLP, restriction fragment length polymorphism; SSR, simple sequence repeat; CV, cross validation. R e p ro d u c e d fr o m C ro p S c ie n c e . P u b lis h e d b y C ro p S c ie n c e S o c ie ty o f A m e ri c a . A ll c o p y ri g h ts re s e rv e d . 294 Published online February 6, 2007