Identification of quantitative trait loci associated with resistance to ascochyta blight disease in [P665xMessire] and [Wt10245xWt11238] pea (Pisum sativum L.) mapping populations

Trabajo presentado en el IV International Ascochyta Workshop (Ascochyta 2016), celebrado en Tróia (Portugal) el 10 y 11 de octubre de 2016.
Ascochyta blight disease is one of the main constraints for pea cultivation. QTL analysis were performed in [P665×Messire] and [Wt10245×Wt11238] pea mapping populations to identify the genomic regions controlling resistance to ascochyta blight. Disease assess ments were performed under field conditions during 5 years at Radzików, Poland, using the scale reported by Xue et al. (1996) (0 –resistant, 9 –susceptible). Average ascochyta disease (AAD) scoring was 2.09 for [P665×Messire] RIL population, 2.5 for Mes sire and 1.5 for P665 in 2008. In 2009 (AAD) scoring for this population was 4.14, 5 for Messire and 3.5 for P665. In 2013 (AAD) scoring was 4.18, 5.5 for Messire and 2.7 for P665. In 2014 (AAD) scoring was 4.05 and 5.0 for Messire. In 2015 (AAD) rating was 3.98 and 4.8 for Messire. Therefore P665 was more resistant to ascochyta blight than Messire under our field conditions as reported previously by Fondevilla et al. (2008). Average ascochyta disease scoring value was higher for [P665×Messire] than for [Wt10245×Wt11238] population [(AAD) for population 3.6, 3 for Wt10245 line and 4 for Wt11238 line in 2011, 4.36 for the RIL population, 3.3 for Wt10245 line and 4.9 for Wt11238 line in 2014]. Three QTLs associated with resistance to ascochyta blight were identified on [P665×Messire] linkage map. QTLs were not conserved across the years what may be due to the strong influence of environmental conditions on the measured traits. Seven QTLs associated with resistance in 2011 and four associated with resistance in 2014 were detected in the [Wt10245×Wt11238] population. Two QTLs were found in the same genomic region in both populations (in LGIIIB, near AA170 and in LGVB, near Pis_GEN_27_2_1 and AD280 marker). QTLs in similar intervals were detected by Carrillo et al. (2014) in Spanish conditions, suggesting the existence of genetic factors controlling resistance effective in different genetic backgrounds and environments: one in LGIII (near AA170 marker) and two in LGV (near AD280 marker0. According to these authors some genes co-localizing with QTLs may have an interesting role in defense and therefore, they could be candidate genes involved in resistance to D. pinodes in P665.
The study is supported by National Multi-Year Program “Improvement of domestic sources of plant protein, their production, economy and feeding technologies”.