Determination of Best Varieties and Planting Date for Wheat Varieties(Triticom aestivum L.) in Gonbad Kavous Using GGE Biplot Method

In order to study the effect of planting date on five cultivars of wheat (Khazar1, Falat, Zagros, Kohdasht, Karim) an experiment was conducted as a split-plot randomized complete block in Research Farm of Gonbad Kavous University, Gonbad Kavous, in northern Iran at 2013-2014. Main plots contained nine planting dates (November 4th, November 19th, December 3rd, December 18th, January 2nd, January 18th, February 8th, February 23rd and March 9th) and sub plots were the cultivars. According to the Biplot, cultivar Kohdasht had the highest seed yield and medium stability and Khazar1 had the highest stability and medium grain yield. Falat produced the lowest seed yield and Karim produced the most. Planting dates of November 4th and 19th had the highest seed yield and stability, respectively. Kuhdasht and Khazar were the nearest to an ideal genotype and planting date of November 19th was nearest to an ideal planting date. The cultivar Falat and planting date of December 18th were identified as the unsuitable cultivar and planting date. All results taken together, lead us to the conclusion that seeding cultivar Kohdasht at either November 4th or 19th may lead to the highest and most stable seed yield, though further studies in upcoming years are recommended.