Evaluation of Bulgarian winter common wheat varieties of yield stability in South Bulgaria.

The study was conducted during the period 2009–2011 at three locations of South Bulgaria with different agro-climatic conditions – Instute of Plant Genetic Resources Sadovo, the Experimental Stations in Sredets and Ivaylo. Were tested 21 prospective winter common wheat varieties breeded in IPGR Sadovo and DZI General Toshevo, using block dising with four replication and 10 m2 plot size. The aim of the study was to determine the productivity, yield stability and genetic distance of the main Bulgarian varieties of common winter wheat in relation with their use while breeding and growing them in South Bulgaria . The resulting values for the parameters σi2 and Si2 identified the varieties Slaveya, Karina , Yunak and Boryana as the most stable ones, showing the least interaction with the environment . The indicator for the yield and stability Ysi defined as the most valuable the varieties Geya1, Yunak, Boryana, Boliarka , Kristi, Iveta , Albena and Diamant regarding their selection. At the same time the most stable regarding all tested parameters are both varieties Yunak and Boryana.