Mutations induced by irradiation are widely used for developing
new varieties of plants. This study was conducted during the four winter
seasons from 2015 / 2 0 1 6 through 2018 / 2 0 1 9 at the experimental
station of Plant Research Department, Nuclear Research Center, Atomic
Energy Authority, Inshas, Egypt. The aim of this study was to estimate
the magnitude of genetic variability in yield and its attributes, practice
visual selection for yield and its components in irradiated bread wheat
(line10) with 300Gy and 350Gy of gamma rays in the M2 and M3
generation and evaluation of bread wheat mutations for yield and its
components in the M4 generation. The results showed that gamma
irradiation dose of 300Gy was more effective in creating genetic
variation in quantitative traits in the M2 population of bread wheat (Line
10) as compared to irradiation treatment of 350Gy. High values of
genotypic coefficient of variability, heritability and expected genetic
advance were found for number of spikes / plant and medium values for
100 - grain weight and no. of grains /spike. Positive and significant
correlation coefficient (r=776*) was found between yield and No. of
spikes / plant, positive but not significant correlation coefficients
between grain yield and No. of grains /spike and 100- grain weight.
Results indicated that yield components could be considered useful
selection criteria for improving grain yield in wheat. In the M3 progeny
test, data indicated that some of the selected plants (high yielding)
expressed the traits of their M2 selections. Therefore, they were
considered breed true. In M4 generation, family 1 was characterized by a
reduced plant height (79.3cm), Family 2 by high number of spikes /
plant, long spike, heavy 100- grain weight (6.0g), high number of
grains /spike and high grain yield/ plant, Family 3 by high number of
spikes / plant, heavy 100- grain weight (6.25g) and high grain
yield/ plant, Family 4 by high number of spikes/ plant, heavy 100 - grain
weight (6.03g), high number of grains/spike and high grain
yield/ plant,but heading was late. Family 5 was characterized by a heavy
100 - grain weight (6.27g). These new families well be tested in further
experiments.