ABSTRACT
This study was conducted to assess the impact of breeding on yield, vegetative period, plant height, 1000-grain weight, and resistance to lodging of spring barley cultivars and to identify the related changes in plant characteristics. A set of 106 spring barley accessions of Slovak origin and former Czechoslovakia origin, developed from 1900 to 2003, was studied in 2004-2005. Significant breeding progress was observed for plant height, 1000-grain weight, and yield. An analysis of variance revealed strong influences of year and genotype on traits of study. Cluster analysis grouped germplasm accessions into two large distinct clusters, the first one of which, with several exceptions, comprising old, and the second one, new genotypes. Principal components 1 and 2 accounted for about 72.8% of variability in germplasm accessions; mainly plant height, lodging, and grain yield accounted for this portion of variability. During the years 1900-2003, increases in grain yield of spring barley were generally associated with reduced plant height and improved lodging resistance. An increase in 1000-grain weight across 100 years was rather small. The genotypes developed between 1972 and 1985, the so-called "Diamant's set" period, and the genotypes developed later [1985-2003], were characterized by improved lodging tolerance, increased yield, and disease resistance. No trend across time was observed for length of vegetative period.
