Characterization of Italian populations ofLoliumspp. resistant and susceptible to diclofop by inter simple sequence repeat

Abstract

Three ItalianLoliumweed populations, one susceptible and two resistant to diclofop, were characterized by the technique of inter simple sequence repeats (ISSR). The goal of this study was to taxonomically identify theseLoliumpopulations as well as to evaluate evidence for introgression of ISSR fragments fromFestucaand the potential role of this introgression in the diclofop response. ISSR analysis confirmed the genomic background of the weed populations to be consistent with that ofLolium. However, the great range of variation in ISSR banding patterns highlighted that the three ryegrass accessions are mixed populations made up of individuals resulting presumably from intrageneric and intergeneric hybridization in theLolium–Festucacomplex. TwoFestucagenus-discriminating and 20Festucaspecies-discriminating ISSR markers were screened among all the three ryegrass populations. The resistant Tuscania population carried the highest percentage ofFestucagenome (16.8%) followed by the resistant Roma (13.6%) and susceptible Vetralla (7.6%) populations. On the basis of these data some influence ofFestucagenome in diclofop resistance levels of studied ryegrass populations could be hypothesized.