Improvement of Grain Yield and Yield Associated Traits in Bread Wheat (Triticum aestivum L.) Genotypes Through Mutation Breeding Using Gamma Irradiation.

The present research was conducted to evaluate the M1, M2, M3 and M4 bread wheat (Triticum aestivum L.) mutant populations for yield and yield related traits during 2010-11, 2011-12, 2012-13 and 2013-14 at Tekirdağ ecological conditions. Three wheat genotypes were treated with different levels of gamma rays (100 Gy, 200 Gy, 300 Gy, 400 Gy, 500 Gy and Control). The mutated plants were evaluated along with parental lines (control) for grain yield (GY) and its contributing traits such as plant height (PH), spike length (SL), the number of spikelets per spike (NSPS), the number of grains per spike (NGPS), grain weight per spike (GWPS), harvest index (HI) and thousand grain weight (TGW) under field conditions. The results obtained from the present study showed that the genotypes significantly and variably differed in their response for various traits at different gamma rays doses. The traits such as PH, TGW and grain yield (GY) showed generally reduction with higher gamma irradiation doses as compared to low doses, while mutagenic treatments shifted the mean values mostly towards the negative direction in the other yield components. But, the negative or positive shifts were not unidirectional or equally effective for all the traits. These findings suggested that the variability could be induced through the use of gamma irradiations in bread wheat. Some of the traits showed improvement due to the induced mutations could be used in future wheat breeding programs. The differences in mean values and the nature of variability observed in M2 indicated a possible preference of selection in M3 generation. [ABSTRACT FROM AUTHOR]