Evaluation of grain yield and its stability of common wheat varieties in various environmental conditions

N. Tsenov1*, T. Gubatov1, I. Yanchev2

1Department of Wheat Breeding and Technology, Agronom Breeding Company, 9300 Dobrich, Bulgaria
2Department of Plant Science, Faculty of Agronomy, Agricultural University, 4000 Plovdiv, Bulgaria

(Manuscript received 8 May 2022; accepted for publication 20 February 2023)

Abstract. The aim of the study was to assess the size and stability of grain yield of a group of varieties grown in different conditions of the country. The study included a total of forty samples of winter common wheat, developed by Agronom breeding company. The field experiment was conducted in three typical grain production locations of the country: Dobrich, Trastenik and Straldja, in the period 2017-2019. All aspects of the interaction of varieties with environmental conditions were analyzed using two statistical programs PBSTAT and GEA-R. Through their application, 16 different parameters were calculated, through the ranks of which stability was assessed. The data obtained from the individual parameters were subjected to direct comparison with the modules of the programs GenStat 15, JMP 14 and GGE Biplot 6.3, which have a visual representation of the results for the level of yield and stability of each cultivar. The stability of only the varieties with higher yield than the check cultivar was monitored. Their stability was monitored and measured through all software products before a conclusion was made about its level. The share of genotype and its interaction with environment was only about 20% of the total variation. The conditions in the individual locations have a significant impact on the yield performance, which causes a strong change in the yield in the individual varieties. It causes a drastic change in the rank of the yield by locations. Against the background of strong G x E interaction, only six varieties have been identified: ABC Aldo, ABC Grosso, ABC Lombardya, ABC Klausius, ABC Zigmund and ABC Navo, whose average yields were proven to be higher than those of the check variety LG Avenue. Their high productive potential was realized to a degree that guarantees high stability in changing conditions of the used regions. Current statistical models were effective in quickly and efficiently determining all possible levels of combination between genotype yield and stability. The newly created varieties showed higher stability than the already established ones, as their productivity was at a much higher level. Breeding, accompanied by ecological tests of many advanced lines, shows that it was possible to combine high yields with relatively high stability with enough varieties for successful zoning throughout the country.