Chloroplast DNA Similarity of Smooth Bromegrass with Other Pooid Cereals: Implications for Plant Breeding

Abstract

Restriction site (RS) variation in the chloroplast genome has been useful in discerning evolutionary relationships. This information enables plant breeders to determine the primary, secondary, and tertiary gene pools of crop plants. In this study, chloroplast DNA (cpDNA) RS maps of smooth bromegrass (Bromus inermis Leyss.) were compared with those of wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.), and oat (Arena sativa L.). The number of common RS for the enzymes KpnI, PstI, PvuII, SalI and XhoI was scored, providing data to calculate the genetic distance (p) among the taxa. Clustering analysis showed that smooth bromegrass (tribe Bromeae) is very closely related to wheat, rye and barley of the tribe Triticeae and more distantly related to oat (tribe Aveneae). It was of interest to find that smooth bromegrass was more closely related than barley to wheat and rye. The cpDNA relationships suggest that bromegrasses are a potentially important component of the gene pool in the breeding of pooid cereals. Bromegrasses are a useful source of genes for disease resistance, agronomic properties, and nutritional value that could be introgressed into their close relatives.