Todor Gubatov1 and Vanya Delibaltova2
1 Wheat Breeding and Seed production Department, Agronom 1 Holding, 9300 Dobrich, Bulgaria
2 Agricultural University, Department of Plant Growing, 4000 Plovdiv, Bulgaria
Gubatov, T. & Delibaltova, V. (2020). Evaluation of wheat varieties by the stability of grain yield in multi environmental trails. Bulg. J. Agric. Sci., 26(2), 384–394
Changing grain yields as a result of growing conditions is the basis for assessing the stability of each variety. It determines the value of the genotype against the background of the other varieties in the group. The purpose of this study is to analyze and establish the effectiveness of various grain yield stability indexes in conditions where we have a strong interaction of a variety by environments.
A group of 40 winter wheat varieties have been tested with respect to grain yield at three locations of the country for two consecutive seasons. Against the background of the established genotype by environment interaction, eighteen statistical indices were determined and analyzed to determine the stability of genotypes. The correlation relationships between the ranks of all indices, including the grain yield, are analyzed. These are those which, together with grain yield, could independently characterize the value of each variety in relation to known check varieties, both in specific and in a wide range of environments.
The values of the calculated indices included in the study show significant differences between the stability of the varieties. This stability can be determined by several of the surveyed indices, such as NP⁽³⁾, NP⁽⁴⁾ and S⁽⁶⁾, as well as the experimentally determined result index AR6. Several of the latest varieties such as (9) ARO Sankti, (17) ABC Veto, (31) Riana, (36) ABC Klausius, 38 ABC Zigmund and 40 ABC Navo have the rare ability to realize high and stable yields in the main wheat-growing regions of the country.
The measurement of variation in grain yield of the variety grown under different conditions is mandatory in determining its breeding value. The correlations between the ranks of the indices differ from grain yield, which indicates the need for careful analysis when interpreting them. The grain yield level after correction by its stability is the right approach for grouping varieties to target them in specific environmental conditions. The spatial location of the varieties studied through yield ranges and stability is an effective way of objectively comparing them with the standards. The grain yield stability of each variety can be assessed quickly, accurately and correctly by using modern statistical packages created for that purpose.