Disease Impact on Wheat Yield Potential and Prospects of Genetic Control

Abstract

Wheat is grown worldwide in diverse geographical regions, environments, and production systems. Although many diseases and pests are known to reduce grain yield potential and quality, the three rusts and powdery mildew fungi have historically caused major crop losses and continue to remain economically important despite the widespread use of host resistance and fungicides. The evolution and fast spread of virulent and more aggressive race lineages of rust fungi have only worsened the situation. Fusarium head blight, leaf spotting diseases, and, more recently, wheat blast (in South America and Bangladesh) have become diseases of major importance in recent years largely because of intensive production systems, the expansion of conservation agriculture, undesirable crop rotations, or increased dependency on fungicides. High genetic diversity for race-specific and quantitative resistance is known for most diseases; their selection through phenotyping reinforced with molecular strategies offers great promise in achieving more durable resistance and enhancing global wheat productivity.

Durum wheat and septoria tritici blotch: genes and prospects for breeding

“…However, we clearly demonstrated that stacking QTLs contributed to wide spectrum resistance observed in "Agili39", showing that gene pyramiding is an effective strategy for widening efficacy as evidenced in many other studies (McDonald and Mundt 2016;Singh et al 2017;Singh et al 2014;Singh et al 2011;Singh et al 2015;Singh et al 2005;Singh et al 2016). Albeit that two-way and three-way interactions (chapter 4) not always effectively reduce disease severity -as further demonstrated in our analyses of resistance in contemporary durum cultivars (Chapter 5) -we showed that accumulating the markers for the putative Stb9 allele and 1A-QTL considerably reduced disease in the seedling stage with a dominant effect of the Stb9 over the 1A-QTL.…”

Yellow Rust Epidemics Worldwide Were Caused by Pathogen Races from Divergent Genetic Lineages

“…Crops like wheat, which are cultivated worldwide across diverse agro-ecological zones, provide a vast niche for their pathogens at local, regional, and continental scales (von Broembsen, 1989; Brasier and Buck, 2001). Wheat pathogens have been controlled to a large extent via ongoing and large-scale breeding efforts to improve disease resistance, which is economical, environment friendly and sometimes the only available option (Singh et al, 2016). Successful deployment of resistant crop varieties at larger scales and in different regions would, however, require better understanding of pathogen diversity for virulence across regions (Brown and Hovmøller, 2002).…”

“…tritici (Leonard and Szabo, 2005; Singh et al, 2008; Berlin et al, 2013). All the three rusts have been shown to cause huge losses in different areas, years and environments favoring disease epidemics (Dean et al, 2012; Pardey et al, 2013; Beddow et al, 2015; Singh et al, 2016). Nonetheless yellow rust in particular has been reported as an increasing problem (Hovmøller et al, 2010) with repeated cases of worldwide invasions (Wellings, 2007; Ali et al, 2014a; Hovmøller et al, 2016; Walter et al, 2016) possibly due to a combination of long distance migration capacity (Zadoks, 1961; Brown and Hovmøller, 2002), high rates of mutation from avirulence to virulence (Hovmøller and Justesen, 2007b), adaptation to different climatic conditions (Markell and Milus, 2008; Milus et al, 2009), existence of recombinant and highly diverse populations (Ali et al, 2014a; Thach et al, 2016a) and the potential creation of new variants through a sexual cycle (Jin et al, 2010; Rodriguez-Algaba et al, 2014).…”

Divergent and convergent modes of interaction between wheat and Puccinia graminis f. sp. tritici isolates revealed by the comparative gene co-expression network and genome analyses

“…tritici ( Pgt ) is the causal agent of wheat stem rust that poses a major threat to wheat production around the world [1–3]. Like other biotrophic plant pathogens, Pgt infects susceptible host plants by engaging in a complex interaction that involves multiple proteins from both the fungus and plant.…”