Characterization of Hordeum vulgare - Hordeum bulbosum chromosome substitution lines by restriction fragment length polymorphism analysis.

Plants obtained from crosses between Hordeum vulgare and H. bulbosum were previously analyzed cytologically and for isozyme composition. They were identified as possessing substitutions of one or more H. vulgare chromosomes by their H. bulbosum homoeologues. To confirm their constitution and assess the merits of molecular techniques, chromosome-specific probes developed for the Triticeae were hybridized to Southern blots of DNA extracted from these plants and their parents. The hybridization patterns in the substitution plants confirmed that particular chromosomes of H. vulgare were replaced by their H. bulbosum homoeologues. For most probes, heterozygosity between pairs of H. bulbosum chromosomes was recorded. A possible duplication involving H. bulbosum homoeologues of barley chromosomes 4 and 7 was observed. Although molecular and cytological methods for analyzing chromosomally engineered plants are complementary, molecular probes may uncover differences not discernible using light microscopy or isozyme analysis.