Mapping quantitative trait loci for resistance to Pratylenchus thornei from synthetic hexaploid wheat in the International Triticeae Mapping Initiative (ITMI) population

Abstract

Abstract. Root-lesion nematode (Pratylenchus thornei) is a serious pathogen of wheat in many countries. The International Triticeae Mapping Initiative (ITMI) population of recombinant inbred lines (RILs) was assessed for resistance to P. thornei to determine the chromosome locations of the resistance genes. The ITMI population is derived from a cross between the resistant synthetic hexaploid wheat W-7984 and a susceptible bread wheat cultivar Opata 85. Two years of phenotypic data for resistance to P. thornei were obtained in replicated glasshouse trials. Quantitative trait locus (QTL) analysis was performed using available segregation and map data for 114 RILs. A QTL on chromosome 6DS showed consistent effects for reduced nematode numbers (partial resistance) across years and accounted for 11% and 23% of the phenotypic variation. A second QTL for P. thornei resistance on chromosome 2BS accounted for an additional 19% and 5%. Restriction fragment length polymorphism (RFLP) and simple sequence repeat (SSR) markers associated with the QTLs are physically located in regions rich in major genes at the distal ends of the short chromosome arms of 6D and 2B. SSR markers with potential for marker-assisted selection of P. thornei resistance effective in different genetic backgrounds have been identified.

A genetic analysis of weed competitive ability in spring wheat

“…(Song et al 2005). The population is genetically diverse for many agronomic traits and has been used to investigate wheat quality traits (Nelson et al 2006), tillering, growth habit, spike morphology, gross morphology (Li et al 2002), heading, maturity, plant height, leaf colour (Kulwal et al 2003), as well as many diseases and pests (Friesen and Faris 2004;Sardesai et al 2005;Zwart et al 2006). Several of these traits are thought to contribute to competitive ability (Lemerle et al 2001a).…”

Quantitative Trait Loci and Crop Performance under Abiotic Stress: Where Do We Stand?: Table I.

“…However, MAS has contributed very little to the release of improved cultivars with greater tolerance to abiotic stresses, and this is perhaps partly because, with only a few exceptions (LeDeaux et al, 2006;MacMillan et al, 2006;Welcker et al, 2007), interactions between multiple stresses are seldom considered. Therefore, promising strategies to improve performance under water-limiting conditions involve MAS of genes and QTLs for tolerance to abiotic and biotic factors that impair root growth and function, such as nematodes in soybean (Glycine max; Ha et al, 2007) and bread wheat (Langridge, 2005;Zwart et al, 2006), high B in barley (Hordeum vulgare) and bread wheat (Langridge, 2005;Schnurbusch et al, 2007;Sutton et al, 2007), and Al toxicity in rice (Nguyen et al, 2003) and sorghum (Sorghum bicolor; Magalhaes et al, 2007). A common feature of cereal responses to drought, heat, and cold stresses near flowering and during early stages of seed growth is a reduction of reproductive fertility.…”

A Review of Root Lesion Nematode: Identification and Plant Resistance

“…Studies of descents of W-7984 (resistant) × Opata85 (susceptible), CPI133872 (resistant) × Janz (susceptible), AUS13124 (resistant) × Janz (susceptible), AUS4926 (resistant) × Janz showed many quantitative traits loci (QTL) with resistance to P. neglectus and/or P. thornei. QTLs with resistance to P. thornei inheriting from W-7984 were located on chromosome 2BS, 6DS and 6DL [36]. A major QTL was identified on Chromosome 6DS and was associated with resistance to both P. thornei and P. neglectus.…”