RFLP markers associated with major genes controlling heading date evaluated in a barley germ plasm pool

Adjustment of crop phenology to resources and constraints of the production environment is crucial for barley adaptation to dry-land environments. The aims of this study were to characterize (under field and under controlled conditions) the diverse heading responses of barley cultivars grown in Spai n, and to identify phenotypic trait-molecular marker associations with rest riction fragment length polymorphism (RFLP) probes which are linked to majo r loci controlling vernalization (Sh and Sh(2)) and photoperiod (Ppd-H1 and Ppd-H2) sensitivities in barley. Thirty-two cultivars were sown in held tr ials for 3 years in four locations in northern Spain (10 autumn and nine wi nter sowings), and for 1 year in southern Spain (autumn sowing), and 2 year s in Scotland (spring sowings); they were also studied under four glasshous e treatments, combining presence/absence of vernalization and short/long ph otoperiod. These cultivars were examined for the presence of RFLP polymorph isms with four probes and three restriction enzymes. Analyses of variance d etected a number of associations which were quite consistent with expectati ons, suggesting that marker-loci associations found in mapping populations are, to some extent, maintained in a germ plasm pool, and may be useful for germ plasm characterization and marker-assisted selection in breeding prog rammes. Two possible epistatic interactions among the probes were detected, one of them possibly related to a short-day vernalization response.