PROSPECTS OF AGRONOMIC IMPROVEMENT IN SPRING BARLEY-BASED ON A COMPARISON OF OLD AND NEW GERMPLASM

The aim of this study was to determine the direction and magnitude of change in morphological and agronomical characters of spring barley (H ordeum vulgare L.) in Germany over a period of 80 years and to assess the value of various strategies for further crop improvement. Old and new two-rowed cultivars, eight in each case, were tested together with their F-2 intra-group diallel crosses in a field trial at Braunschwei g-Volkenrode in 1994. New parents and their crosses showed a higher dr y matter grain and total biomass yield, a lower plant height, and a hi gher harvest index as compared to the respective old germplasm. The an nual genetic gain in grain yield was estimated at 0.15%. The superior grain yield of the new germplasm was attributable to the higher number of ears per plant and the larger kernel weight. The F-2 mid-parent he terosis in grain yield was 7.6 and 7.2% for the old and new crosses, r espectively. The differences between the two types of crosses were non significant except for the higher heterosis for plant height in the ne w crosses. General combining ability effects were significant for all characters in both types of crosses, whereas specific combining abilit y effects were significant in a few cases only. In the new crosses, a significant positive correlation was found between grain yield and str aw yield (r = 0.52), whereas no such association was observed between grain yield and harvest index. For further gain in grain yield, improv ement of the straw yield is more promising than increasing harvest ind ex.