Chickling pea (Lathyrus cicera L.) resistance to rust and powdery mildew under QTLs scrutiny

Abstract

Chickling pea (Lathyrus cicera) is a feed and fodder crop, with great adaptability to inauspicious environments (drought, flood and salinity), high protein content and resistance to serious diseases, being an alternative to marginal soils and cropping systems diversification. Partial resistance to rust and powdery mildew has been described in this species, but its genetic control is still not elucidated, hampering its use on resistance breeding. In order to unveil this genetic control, a QTL analysis was performed using a RILs population, segregating for rust and powdery mildew resistance. 108 F5 RILs (BGE008277xBGE023542) were evaluated for rust (Uromyces pisi) and powdery mildew (Erysiphe pisi) disease severity under controlled conditions, in three independent experiments. Significant differences for rust and powdery mildew resistance were detected be tween genotypes, experiments and also for GxE interaction. QTL mapping was therefore performed separately per experiment. Broad-sense hereditability/ experiment had a maximum value of 78% and 84% for rust and powdery mildew resistance respectively. Using the developed RIL linkage map with a total of 258 markers (SNP, SSR, ITAP), covering 757.11cM in 8 major and 3 minor linkages groups, one common QTL for rust and powdery mildew resistance was detected. This QTL region explained respectively, 15.5 and 16.7 % of the genetic variance observed. In addition, a second non-overlapping QTL was detected for powdery mildew, explaining 23.6 % of the observed genetic variance. These QTLs represent valuable candidate regions for further characterization and development of markers linked to disease resistance in L. cicera.