Genetic mapping of common bunt resistance and plant height QTL in wheat

Abstract

Common bunt, also known as stinking smut, is caused by seed borne fungi Tilletia tritici (Bjerk.) Wint. [syn. Tilletia caries (DC.) Tul.] and Tilletia laevis Kühn [syn. Tilletia foetida (Wallr.) Liro.]. Common bunt is known to cause grain yield and quality losses in wheat due to bunt ball formation and infestation of the grain. The objectives of this research were to identify and map quantitative trait loci (QTL) for common bunt resistance, to study the epistatic interactions between the identified QTL, and investigate the co-localization of bunt resistance with plant height. A population of 261 doubled haploid lines from the cross Carberry/AC Cadillac and checks were genotyped with polymorphic genome wide microsatellite and DArT(®) markers. The lines were grown in 2011, 2012, and 2013 in separate nurseries for common bunt incidence and height evaluation. AC Cadillac contributed a QTL (QCbt.spa-6D) for common bunt resistance on chromosome 6D at markers XwPt-1695, XwPt-672044, and XwPt-5114. Carberry contributed QTL for bunt resistance on chromosomes 1B (QCbt.spa-1B at XwPt743523) 4B (QCbt.spa-4B at XwPt-744434-Xwmc617), 4D (QCbt.spa-4D at XwPt-9747), 5B (QCbt.spa-5B at XtPt-3719) and 7D (QCbt.spa-7D at Xwmc273). Significant epistatic interactions were identified for percent bunt incidence between QCbt.spa-1B × QCbt.spa-4B and QCbt.spa-1B × QCbt.spa-6D, and QTL by environment interaction between QCbt.spa-1B × QCbt.spa-6D. Plant height QTL were found on chromosomes 4B (QPh.spa-4B) and 6D (QPh.spa-6D) that co-located with bunt resistance QTL. The identification of previously unreported common bunt resistance QTL (on chromosomes 4B, 4D and 7D), and new understanding of QTL × QTL interactions will facilitate marker-assisted breeding for common bunt resistance.

A novel QTL associated with dwarf bunt resistance in Idaho 444 winter wheat

“…The two studies also used different inoculum sources: the Blizzard study used the common bunt races T-19 or T-19 and L-16, while this study used the composite dwarf bunt races. Additional common bunt HPR QTL have been reported from other resistance sources, including: 7A (Fofana et al 2008; Dumalasová et al 2012), 7B (Dumalasová et al 2012; Knox et al 2013), 5B (Dumalasová et al 2012; Singh et al 2016), 4D (Singh et al 2016), and 6D (Menzies, et al 2006; Singh et al 2016), while none of these HPR QTL were detected in the present study. Singh et al (2016) found that the common bunt HPR QTL co-localized with other beneficial traits including height and rust resistance.…”

“…Additional common bunt HPR QTL have been reported from other resistance sources, including: 7A (Fofana et al 2008; Dumalasová et al 2012), 7B (Dumalasová et al 2012; Knox et al 2013), 5B (Dumalasová et al 2012; Singh et al 2016), 4D (Singh et al 2016), and 6D (Menzies, et al 2006; Singh et al 2016), while none of these HPR QTL were detected in the present study. Singh et al (2016) found that the common bunt HPR QTL co-localized with other beneficial traits including height and rust resistance. The three IDO444-derived QTL have no pleiotropic effect on other traits, such as coleoptile and root length (Li et al 2011), stripe rust (Chen et al 2012), grain yield, heading data, or height (Zhang et al 2014) previously mapped in this population.…”

“…Singh et al (2016) reported a minor QTL on 7D for common bunt HPR derived from the resistance source, ‘Carberry’. Phenotypically, the Carberry QTL is substantially different than Q.DB.ui - 7DS as the Carberry 7D HPR was negligible.…”

“…One QTL on 1BS for common bunt was reported in two spring wheats, AC Domain (Fofana et al 2008) and Carberry (Singh et al 2016), a US winter wheat Blizzard (Wang et al 2009), and a European winter wheat Trintella (Dumalasová et al 2012). Additional QTL were reported on 7A (Fofana et al 2008; Dumalasová et al 2012), 7B (Dumalasová et al 2012; Knox et al 2013), 5B (Dumalasová et al 2012; Singh et al 2016), 4D (Singh et al 2016), 6D (Menzies, et al 2006; Singh et al 2016), and 7D (Singh et al 2016). Markers for Bt10 on 6D have also been developed (Laroche et al 2000; Menzies et al 2006).…”

QTL mapping of wheat plant architectural characteristics and their genetic relationship with seven QTLs conferring resistance to sheath blight

“…Previous studies have shown that one resistance gene against Ug99 races of stem rust was identified in this region, as well as one resistance QTL to common bunt disease (caused by Tilletia tritici Wint and T . laevis Kühn), which was also co-located with a QTL for plant height [36,37]. It is unknown whether the gene for the Ug99 resistance and the QTL for common bunt resistance have any relationship with the plant canopy traits in this region.…”