Determination of direct and indirect effects between gran yield and other agronomical traits in bread wheat (Triticum aestivum L.) F2 populations

This study was carried out to investigate the adaptation and agricultural characteristics of F2 generation populations which are obtained from F1 crosses at Tekirdağ Namık Kemal University in Aegean Region. 23 hybrid populations and 15 parent lines used as a parent were tested in the randomized complete blocks design with three replications at Ege University Menemen Research and Application Center during 2017-2018 growing period. Agricultural traits were mesured such as plant height, number of days to heading, number of day to maturity, upper node length, flag leaf area, spike length, spike number in spike, grain number in spike, thousand grain weight, grain yield per plant. The main purpose of this research is; to determine the parameters that directly and indirectly affect the yield of bread wheat crosses and genotypes and to provide selection criterion for future breeding studies. According to the research results, when the mean values of the crosses and parents were measured, plant height was varied between 73,60-123,47 cm, flowering 128,33-156 days, maturity 151,33-180,67 days, upper node length 4,77 - 14,97 cm, flag leaf area 31,92-15,88 cm2, spike length 7,7-11,5 cm, spikelets quantity of spike 15,82-23,85, for grain number in a spike 33,60-62,17 and per thousand grain weights 25,60-40,71 grams, mean grain yield per plant 4-8,67 grams. As a result, it was found that crosses and parental lines showed different advantages for each agronomical traits. It was found that NZFE-62 line had the highest grain yield per plant and It was determined that this genotype had earliness in terms of number of the days to heading but showed the latest maturity. It was found that 4162-28 x Tekirdağ crosses population showed better results then others about flag leaf area, flowering days and thousand grain weight. Also NZFE-62 x Tekirdağ crosses population have the highest upper node lenght and NZFMT-14 perantal lines had the most quantity about sparklets quantity of spike. 4162-28 perantal line showed best result on spike length and grain number in a spike. When correlation coefficients were examined, it was found that there was a positive correlation between grain yield and other traits except flag leaf area. It was evaluated that grain yield have statistically significant correlation between upper node lenght and thousand grain weights at level of 95 % probabity and also grain number on a spike at level of 99 % probabity. According to path analysis results the direct effect of grain number on a spike and thousand grain weight traits were found important on grain yield significantly. Also it was found that upper node lenght and plant height traits have important correlation but it was concluded that their indirect effects on grain yield must be observed because their direct effects on grain yield remain low level. As a result our study is showed that grain number on a spike and thousand grain weight traits can be used as a selection criteria for next bread wheat breeding studies.