Analysis of Yield Stability of Wheat Genotypes Using New Crop Properties Balance Index (CPBI) Method

The study of some important crop characteristics in a population and the consideration of the limitations and possibilities is a general way to define suitable genotypes. Data collected over six years in the cold winter experiment stations of Iran were used to determine to optimal levels of characteristics and the stability parameters of wheat varieties under rainfed conditions. The boundary lines method allowed the determination of optimal levels of days to heading, days to physiological maturity, duration of grain filling, plant height and thousand kernel weight which were 221.2 days, 259.6 days, 33.8 days, 62.5 centimeter and 28.3 grams, respectively. These data were closely equivalent to optimal levels determined using averaging method. The results showed also that the released cultivars in each location had similar maximum crop properties balance index (CPBI). The maximum CPBIs in Maragheh, Kurdestan, Zanjan, Ardabil and Uromeh regions were 155, 270, 150, 182 and 440, respectively. The analysis of adaptation of commonly grown winter wheat varieties showed that ‘Sardari’ is more suitable for regions with cold winters and cool springs along with spring precipitation; ‘Sabalan’ variety is adapted to cold winters and relatively temperate spring with abundant spring precipitation; and ‘Azar-2’ cultivar is suitable for cold falls and temperate springs along with fall-spring precipitation and minimum winter precipitation.