A cultivar Giza2 of Vicia faba was treated with gamma rays doses of 30 and
60 Gy and ethyl methane sulfonate (EMS) at conc. of 0.15 and 0.30% and the effects
were assessed in M5 and M6 generations. The effect of mutagens was studied using
a number of parameters, such as morphological growth characters, some
physiological parameters, flowering and yield attributes, and nutritive values of seeds.
All faba bean mutants induced by gamma irradiation and EMS tended to
increase in most growth characters, and the maximum increase in this respect was
achieved by the mutants No.7, 4 and 10. On the other hand, mutant No.1 was nearly
similar to the untreated plants in most growth characters.
Concentration of chlorophyll a, b and total chlorophyll as well as carotenoids
tended to arise in all mutants (except mutant No.2) over the untreated plants, mutants
No.7, 8, 9 and 1 had the highest pigments conc. in both M5 and M6 generations. The
ratios of chl.a/b as well as total chl.lcarotenoids in most mutants of both generations
did not show clearly changes comparable with the control.
Leaves in all mutants had higher total water content (TWC) and relative
water content (RWC) but lower water deficit (LWD) except mutants No.4 for TWC and
8 for both RWC and LWD that showed a reverse trend. The best mutant for the
highest' RWC and the lowest LWD was mutant NO.1. Transpiration rate was
significantly reduced in most mutants except some mutants in M5 generation, and the
lowest one was recorded by mutant No.7. Use of water by mutants for producing dry
seeds and dry matter (WUE) was more efficient than that the untreated plants.
mutants No.1 and 4 showed the best WUE.
Mutants showed different trends in the number of flowers, the greatest one
was achieved by mutants No.1, 2, 3, 4 and 7. Mutants exceeded over the untreated
plants in pod set (%), sharply reduced in flower and pod shedding percentage, mutant
No.1 (M5) and NO.7 (M6) were the best in this respect. Pod, seed and straw yield
tended to increase in most mutants, mutants NO.1 and 4 had the highest pod and
seed' yield while the highest straw yield was achieved by mutants NO.8 (M5) and 1
(M6). Mutants No.4, 5, 2 and 8 (M5) and No.1, 4 and 8 (M6), recorded the highest
seed index. Shelling percentage was higher in all mutants except mutants NO.3 and
10.
The chemical composition of faba bean mutants seeds in both M5 and M6
generations indicate that most mutants had higher nutritive value with some
exceptions. It is worthy that mutants No.5, 4 and 7 recorded the highest protein conc.
while mutants NO.6 and 9 contained the highest carbohydrate cone. comparable with
the other mutants.