Influence of genotype and environments on quality of winter wheat varieties in Northern Bulgaria

The investigation included 16 varieties from first and second quality group according to the Bulgarian state standard. The aim of the investigation was to find out the level of influence of different environmental factors on wheat quality indices; to follow the response of the varieties to various combinations of growing conditions; to investigate the ability of the varieties to realize their potential for quality under specific environments. The investigation was carried out at Dobrudzha Agricultural Institute – General Toshevo - DAI and at Institute of Agriculture and Seed Science, Obraztsov Chiflik, Rouse - OCH during 2004 – 2007 by the Latin square method in 5 replications. The expression of 6 grain quality indices which give information about various quality aspects was analyzed: test weight, sedimentation value of flour, wet gluten content in grain, valorimeric value - valorimeter, conditional units, and loaf volume, determined according to the methods adopted at the DAI laboratory. It was found out that the independent influence of the genotype had the lowest effect on the variation of the quality indices of the investigated wheat varieties. The influence of the location was the highest on wet gluten content and valorimetric value. The year conditions had the highest effect on the expression of the characters test weight and loaf volume. The varieties from the quality group, compared to the varieties from the second group as a whole, realized their quality potential under more favorable combinations of conditions. Compared to the quality standard Pobeda, the varieties from the first group, which had lower mean values, were more stable to the changeable growing conditions. The varieties with higher indices differed in their response according to the standard. Most susceptible to changeable environments were varieties Demetra and Zlatina, and most stable were varieties Aglika, Albena and Preslav.