Nonparametric stability methods for interpreting genotype by environment interaction of bread wheat genotypes (Triticum aestivum L. )

ABSTRACT

Evaluation of performance stability and high yield is essential for yield trials conducted in different environments. We determined the stability of 10 bread wheat (Triticum aestivum L.) genotypes (5 cultivars and 5 advanced lines) using nonparametric stability measures and compared nonparametric stability statistics across 19 environments in the Central Anatolian Region of Turkey. Experiments were setup in a randomized complete block design with four replications. Nonparametric stability measures revealed that AL-2, Karahan-99 and Altay-2000 were the most stable and well adapted genotypes across the 19 environments. In addition, it was concluded that graphs of mean grain yield (t ha-1) vs. nonparametric measures (Si(1), Si(2), S(3), Si(6) and sigma-gy) values and kr vs. sigma-r values could enhance visual efficiency of genotype selection based on genotype by environment interaction. Furthermore, high TOP values, Si(3) and Si(6) were associated with high grain yield, but the other nonparametric stability measures were not positively correlated with grain yield and instead characterized a static concept of stability. Choice of genotype for increased grain yield in bread wheat would, therefore, be expected to change yield stability by increasing the values of the Si(3), Si(6) and TOP nonparametric stability statistics.