Heyran, a new bread wheat cultivar under terminal drought stress conditions of cold regions of Iran

Due to limited water resources in the country, irrigated wheat cultivars in cold and temperate cold regions are faced with lack of irrigation or limited irrigation at the end of the season. In these areas, most farmers who cultivate irrigated wheat due to lack of sufficient water in the spring cannot perform enough irrigation and therefore do not get the desired result from cultivating high-yielding cultivars. Development of new cultivars with high grain yield under terminal drought stress conditions is one of the major goals of wheat breeding program for cold regions of country. Heyran new bread wheat cultivar introduced from International Research Center for Maize and Wheat (CIMMYT) to Iran through an international nursery in 2010 and was evaluated in a primary trial in four research stations (Karaj, Jolge-Rokh, Ardabil and Mashhad), and due to its favorable characteristics was selected for further evaluation in preliminary yield trials in cold regions. This line showed grain yield of 8417 kgha-1 under normal irrigation compared to the check cultivars Orum, Zareh and Mihan (with average yields of 7679, 6828 and 7772 kgha-1, respectively), and under terminal drought conditions with an average seed yield of 4653 kgha-1, compared to the check cultivars Orum, Zareh and Mihan (with average yields of 4375, 3544 and 4358 kgha-1, respectively) and was selected in both conditions. Aforementioned line showed grain yield of 8340 kgha-1 in advanced yield trial of cold regions breeding program under normal conditions compared to check cultivars Orum, Zareh and Mihan (with average yields of 7518, 7613 and 8205 kgha-1, respectively) in five locations, selected for final evaluation in adaptability test. Grain yield of this line which was presented as CD-92-6 at the adaptability test was 4470 kgha-1 against 3711 and 3743 kgha-1 of Zareh and Mihan checks cultivars under water stress conditions, respectively, during two cropping seasons 2013-14 and 2014-15. This line showed overall mean grain yield, of 5143 kgha-1 under terminal drought stress conditions in extensional farmer’s fields. For these conditions checks cultivars Hydari and Mihan showed grain yields of 4808 and 4758 kgha-1, respectively. Grain yield potential of this line was recorded as 6323 kgha-1 in Khorasan Razavi farmers' field. According to the latest evaluations the response of this line to yellow rusts was resistant to semi sensitive under severe artificial infection. Wheat line CD-92-6 has considerable cold tolerance and good bread making quality and based on its good agronomic characteristics in 2019 this line was released as Heyran, for cultivation under terminal drought stress conditions in the cold agro-climatic regions.