engleski

Validation of quantitative trait loci for resistance to Mycosphaerella pinodes in Pisum sativum subsp. syriacum under filed conditions

Ascochyta blight, caused by Mycosphaerella pinodes (Berk & Blox) Versterg. is one of the most important pea pathogens. The highest levels of resistance to the disease have been identified in wild species of Pisum (1, 2, and 3). Increasing our knowledge about the genetic control of the resistance in these wild accessions would facilitate their use in breeding programs. In previous studies a linkage map was developed using a population of 111 recombinant inbred lines (RILs), derived from the cross between the Pisum sativum L. subsp. syriacum Berg line P-665, partially resistant to M. pinodes, and the susceptible cultivar Pisum sativum L. cv. Messire. QTL analysis revealed four genomic regions associated with resistance to M. pinodes under controlled chamber conditions in this population. The objective of this study was to validate the stability of these QTLs under field conditions. The RIL population and parental lines were screened for resistance to M. pinodes during 2004-2005 and 2005-2006 seasons in an experimental plot located at Cordoba, Spain. In addition, the traits as flowering date and growth habit were scored. A significant correlation between disease scores under growth chamber conditions and resistance under field conditions was observed and two QTLs (mp2 and mp4) were commons to both environments. Flowering date and growth habit had a strong influence in the level of resistance to M. pinodes in the field conditions but they were not associated with resistance under controlled chamber conditions. The major QTL detected in field conditions (mp5) explained from 31 to 46% of the phenotypic variation depending on the trait scored and was co-localized with the major QTL for flowering date (df1) and the RAPD marker more tightly associated with growth habit (AI14_1353).

Ascochyta blight; Mycosphaerella pinodes; Pisum sativum subsp. syriacum; pea; quantitative trait loci

nije evidentirano