Five breeding lines and 4 cultivars were grown in replicated trials at 1 location in 1999-2000 and 2 locations in 2000-2001 cropping seasons in İzmir in order to determine the usefulness of a safety-first selection index in making selection among high yielding wheat genotypes for test weight and thousand-kernel weight. | Turk J Agric For 33 (2009) 37-45 © TÜBİTAK doi: Selection for Test Weight and Kernel Weight in High Yielding Wheat Using a Safety-First Index Emre İLKER*, Metin ALTINBAŞ, Muzaffer TOSUN Department of Field Crops, Faculty of Agriculture, Ege University, Bornova 35100, İzmir - TURKEY Received: Abstract: Five breeding lines and 4 cultivars were grown in replicated trials at 1 location in 1999-2000 and 2 locations in 2000-2001 cropping seasons in İzmir in order to determine the usefulness of a safety-first selection index in making selection among high yielding wheat genotypes for test weight and thousand-kernel weight. Genotype × environment interactions were significant for these 2 quality 2 traits. The regression coefficient (bi) of genotypes, variance (Si ) of a genotype across environments, and a safety-first index (Ii) were calculated to evaluate the stability of genotypes for test weight and thousand-kernel weights. Wheat genotypes with lower bi values and small variance (Si2) across environments (the most stable ones) tended also to have lower means for these 2 traits. However, those genotypes with the largest value of index (Ii), which is considered desirable, were found to have the highest mean values for both test – weight and thousand-kernel weight. The rank-correlation coefficient between (Ii) and (Yi) values was significant for thousand-kernel 2 weight. The ranking from Ii was significantly correlated with the rankings from the stability parameters bi and Si for test weight. 2 The rank-correlation coefficients between bi and Si for the 2 physical quality traits were highly significant and of similar magnitude (r = ). It was concluded that a safety-first selection index can be useful in plant breeding for the improvement of wheat cultivars with enhanced stability and consistency of quality characteristics when genotype × environment interaction is present. Key Words: Bread wheat, yield, safety-first index, physical .
