Characterization by RFLP analysis and genomic in situ hybridization of a recombinant and a monosomic substitution plant derived from Hordeum vulgare L. x Hordeum bulbosum L. crosses.

Interspecific crosses in Hordeum have been made with the aim of transferring desirable traits, such as disease resistance, from a wild species, Hordeum bulbosum, into cultivated barley (Hordeum vulgare). Interspecific recombinants have previously been identified using several methods, but there are limitations with all the techniques. We improved our ability to characterize progeny from H. vulgare x H. bulbosum crosses by using genomic in situ hybridization (GISH). The plant material comprised a recombinant and a monosomic alien substitution plant derived from H. vulgare x H. bulbosum crosses. The recombinant possesses a pubescent leaf sheath conferred by a gene transferred from H. bulbosum into barley cultivar Golden Promise. The use of GISH on a plant homozygous for the pubescence gene confirmed the presence of H. bulbosum DNA located distally on two barley chromosomes and we mapped the introgression to barley chromosome 4HL using RFLP analysis. Furthermore, by means of an allelism test we found that the transferred gene for pubescence is allelic or closely linked to a gene for pubescence (Hs) located on barley chromosome 4HL. The presence of a single H. bulbosum chromosome in the monosomic substitution plant was confirmed by GISH. A distal introgression of H. bulbosum DNA was also observed on one barley chromosome, which was located on chromosome 3HL by RFLP analysis.