Characterization of mycosphaerella blight resistance, lodging resistance, and micronutrient concentration in a field pea recombinant inbred line population

Field pea (Pisum sativum L.) production in western Canada is often negatively affected by mycosphaerella blight and lodging. Micronutrient (selenium, zinc and iron) concentration is one of the important quality traits determining the market value of field pea. Therefore, improving mycosphaerella blight resistance, lodging resistance, and micronutrient concentration are important pea breeding objectives. Moderate genetic variation for these traits have been observed in field pea germplasm. In order to map the quantitative trait loci (QTLs) associated with these traits, a population of 142 F7:9 and F7:10 recombinant inbred lines (RILs) derived from a cross between Carrera (susceptible to mycosphaerella blight and lodging) and CDC Striker (moderately resistant to mycosphaerella blight and lodging) were evaluated at Saskatoon and Rosthern, SK, Canada in 2010 and 2011. Over 2010 and 2011, mean area under the disease progress curve (AUDPC) of mycosphaerella blight ranged from 131 to 205 and 144 to 235 for Saskatoon and Rosthern, respectively. At physiological maturity, mean lodging ratings of the RILs ranged from 3.8 to 8.3 at Saskatoon and 4.5 to 8.5 at Rosthern. Mean selenium concentration ranged from 1.16 to 4.35 ppm at Saskatoon and 0.18 to 0.81 ppm at Rosthern. Mean zinc concentration ranged from 25.45 to 37.71 ppm at Saskatoon and from 25.08 to 38.15 ppm at Rosthern. Mean iron concentration varied from 41.85 to 58.80 ppm at Saskatoon and from 39.13 to 58.80 ppm at Rosthern. A genetic linkage map consisting of 56 simple sequence repeat (SSR) markers was generated. The total coverage of the map was 288.3 cM and the average distance between markers was 5.1 cM. A region between markers AA491 and AA278 on linkage group III was identified as harboring QTLs associated with mycosphaerella blight, lodging, zinc and iron concentration. All QTLs were derived from CDC Striker, except one associated with higher Zn concentration which was derived from Carrera. The total phenotypic variation of each trait explained by the QTL was 18.5%, 10.1%, 11.4% and 13.1%, respectively