Evaluation of indirect selection in yield improvement of triticale genotypes under drought stress conditions

The general goal of this study is to investigate suitable triticale lines under normal conditions and drought stress using important grain yield and its components. Also, the technique of evaluating the Smith-Hazel coefficient for considering the yield components as indirect selection index, which has not been used practically in plant breeding sciences up to now, has been discussed and proposed. Accordingly, it would be possible to utilize the contribution of yield components in grain yield apply them to screen superior lines in the form of one single index. In this research two separate field experiments, normal irrigation and drought stress conditions, were conducted in three cropping years from 2016 to 2018 with 56 genotypes and two cultivars of triticale. Smith-Hazel selection index applied based on yield-related traits in such a way that the traits with a higher positive effect on grain yield were being utilized for screening aims. high heritability of yield and its component showed the possibility of using them as selection criteria to screen elite genotypes. For indirect selection the path analysis was carried out and calculated coefficient of the traits with higher impacts on yield containing number of days to flowering straw yield with negative impacts alongside flag leaf length and biomass yield with positive impacts in normal condition were used as economic coefficients. In stressful condition, spike weight and seeds and spikelet numbers per spike had a positive and significant effect on the selection index.