Association-based trait mapping is an innovative methodology based on linkage disequilibrium. Studies in plants, especially in cereals, are rare. A genome-wide association study of wheat is reported, in which a large number of diversity array technology markers was used to genotype a winter wheat core collection of 96 accessions. The germplasm was structured into two sub-populations. Twenty agronomic traits were measured in field trials conducted over up to eight growing seasons. Association analysis was performed with two different approaches, the general linear model incorporating the Q-matrix only and the mixed linear model including also the kinship-matrix. In total, 385 marker-trait associations significant in both models were detected. The intrachromosomal location of many of these coincided with those of known major genes or quantitative trait loci, but others were detected in regions where no known genes have been located to date. These latter presumptive loci provide opportunities for further wheat improvement, based on a marker approach.

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In the 20 th century, grain yield of winter barley has increased due to advances in both breeding and crop management practices. Knowledge about the association of agronomic traits with genetic gains in yield potential is necessary to improve future breeding programs. Therefore, we studied the variation in grain yield, spike length, heading date, thousand grain weight, hectolitre mass and plant height of two-rowed winter barley cultivars that were released between 1977 and 2010, in a 2-year field trial. Our results showed that most of the analyzed traits were significantly affected by the cultivar, year and cultivar-by-year interaction. The present study showed that grain yield was positively correlated with the year of release. The average rate of grain yield increase in Serbia was 46 kg ha -1 per year. Further, grain yield was negatively correlated with plant height and heading date. Plant height and hectolitre mass of modern cultivars showed a significant declining trend, from the oldest to the newest cultivars. An improved understanding of the changes in agronomic traits over the last 40 years of barley breeding will help to identify targets for further breeding progress and improve the genetic potential of barley.

In this investigation, genotypes with branched, tetrastichon (two spikelets per node of the rachis), and normal spikes were used in order to induce changes in sink capacity, while high‐yielding domestic and foreign varieties served as donors of other traits. These materials were crossed by the methods of single‐, back‐, and top crossing and the desirable genotypes were selected by the pedigree method. After 10 years of breeding for the desired ideotype, whose main features had been a highly fertile spike of normal structure, short straw, curved leaves, and reduced tillering, 229 lines were tested in comparative yield trials. Among them, four lines were superior in yield and other traits to the highest yielding standards. Regarding the expected changes in sink capacity, considerable progress was made in spike length, number of grains per spike, number of grains per spikelet, and the weight of grains per spike.