EXOTIC BARLEY GERMPLASM - VARIATION AND EFFECTS ON AGRONOMIC TRAITS IN COMPLEX CROSSES

Utilization of exotic germplasm offers an approach to broaden genetic variability in breeding populations. This study was conducted in order to 1) compare germplasm of exotic origin with adapted Swedish barleys with respect to genetic differences and 2) to evaluate how exotic mat erial affected agronomic performance in complex crosses. Allozyme stud ies showed the following Nei's gene diversities among parents: 0.13 (a dapted parents), 0.16 (landraces) and 0.25 (H. spontaneum). Cluster an alysis indicated that parental groups were genetically divergent. Earl iness, straw length, number of ears per plant and thousand kernel weig ht (TKW) were studied. Variation in agronomic traits showed the follow ing pattern: landraces > H. spontaneum > adapted lines. The best sourc es for earliness were adapted parents and landraces. Mean straw length was greatest in H. spontaneum lines. Number of ears per plant was qui te similar in all groups. The highest TKW was among landraces and adap ted parents. Hybrids from the complex crossing programme exceeded pare nts in earliness and TKW. An index composed from the four traits showe d the most favorable frequency distributions for adapted parents and h ybrids. Both genetic and agronomic studies indicate that new valuable variation from exotic germplasm may be introduced into barley breeding material.