Association analysis of morpho-phenological traits in oriental tobacco (Nicotiana tabacum L.) with SSR markers under presence and absence of orobanche conditions

Identification of genetic loci controlling quantitative trait is an important subject in genetics and breeding programs, particularly under stress conditions. Broomrape is a holophrastic weed in tobacco (Nicotiana tabacum L.) fields with devastating effects on its dry leaf yield production. In the present study, the reaction of 89 tobacco genotypes was evaluated against broomrape (Orobanche aegyptiaca) in randomized complete block design with three replications during two successive years in pot conditions. In each year, the genotypes were planted separately in non-inoculated and inoculated conditions. In broomrape conditions the soil was mixed with 0.06 g of broomrape seed. In the molecular experiment, 26 SSR primers pairs was used for preparing the molecular profile of genotypes. Studying population structure as a prerequisite for association analysis with bayesian method revealed that there are two possible subgroups (K=2) in the studied population. Based on D′ statistics, 4.31% of possible SSR locus pairs showed significant level of linkage disequilibrium (P