Genotype x environment interaction and stability analyses in wheat varieties and lines grown in different ecological conditions

ABSTRACT Ph.D. Thesis GENOTYPE X ENVIRONMENT INTERACTION AND STABILITY ANALYSES IN WHEAT VARIETIES AND LINES GROWN IN DIFFERENT ECOLOGICAL CONDITIONS İlhami Özcan AYGUN Namık Kemal University in Tekirdağ Institute of Natural and Applied Sciences Department of Field Crops Supervisor: Prof. Dr. İsmet BAŞER The study was carried out on 13 advanced bread wheat lines and 10 standard bread wheat varieties to compare these varieties in 4 ecologically different locations (Tekirdağ, Kırklareli, Şanlıurfa, Konya) in 2013 and 2014. The tests were set up with 4 replications according to a randomized block test design, and the crops were planted in plots with a length of 7.5 m and a width of 1.36 m, with 500 seeds per square meter. As a result of the yield tests, the analysis of variance and significance test were performed on grain yield, yield criteria, and quality criteria data by using the JUMP 7.0 packaged software. Furthermore, the data obtained in grain yield, yield criteria, and quality criteria were subjected to the bi-plot analysis using the GEA-R packaged software. According to the bi-plot graph, the highest grain yield was obtained in the genotype G22, and the closest genotypes were G21 and G19. G13, G23, G12, G17, G15, G8, G6, G9, G10, G19, G21, and G22 were the genotypes with higher grain yields than the average whereas the other genotypes had lower grain yields than the average. G3 had low stability among the tested genotypes while G15 and G14 were the genotypes with the highest stability. In the four different locations examined, Tekirdağ and Kırklareli formed two separate mega-çevres similar to Konya and Şanlıurfa. According to the bi-plot graph, the most suitable genotypes with the highest yield are G14 and G15 for Tekirdağ location, G22 for Kırklareli location, G10 and G9 for Şanlıurfa and Konya locations. When the relation of the quality TRaits examined and the grain yields to the locations (environments) was examined by the GGE bi-plot graph, Konya was the environment where the optimum values were obtained for protein, gluten, zeleny sedimentation, gluten index and sedimentation parameters. For these parameters, Konya can be defined as a mega-çevre. According to the bi-plot graph, it can be concluded that Tekirdağ and Kırklareli, and Şanlıurfa and Konya are similar, and at the same time they show similar results in the evaluation of existing genotypes and genotypes with similar genetic TRaits, and therefore, it will be sufficient to test genotypes only in one location among similar environments. In this study, it is understood that the genotypes with the highest performance are genotype G9 for spike weight (SW) and grain weight per spike (GWS), genotype G6 for spike length (SL), genotype G11 for the number of grains per spike (NGS) and the number of spikelets (NS), and genotype G14 for grain yield (GY). When the relation of the quality TRaits and yields examined to the locations (environments) was examined by the GGE bi-plot graph, G9 was superior in terms of 1.000-grain weight and spike weight whereas G20 was superior in terms of grain yield. Cross-breeding can be performed between G9 and G20 to increase 1.000-grain weight, spike weight, and grain yield. There is no close relation between grain number per spike and spike length, and 1.000-grain weight and grain yield. Cross-breeding can be performed between G20 or G16 and G1 if genotypes with a higher grain number per spike, spike length, and grain yield are desired in the breeding studies to be conducted. At the same time, G6 crossbreeds can be created if the spike height is desired to be high, and G9 crossbreeds can be created if the 1.000-grain weight and spike weight are desired to be high. In conclusion, G20 x G11 x G6 x G9 crossbreeds can be created if the grain yield, grain number per spike, number of spikes, spike length, spike weight, and 1.000-grain weight are desired to be high. Keywords: Bread wheat, quality TRaits, grain yield, yield components, stability, bi-plot 2018, 170 pages