Showing papers on "Mutation breeding published in 2000"

Mutational studies on sugarcane using gamma irradiation

Abstract: The application of mutation breeding method was aimed at identification of mutants which possess positive agro-morphological and quality characteristics. In a series of studies between 1994 and 1998 using gamma irradiation for sugarcane, the dose sensitivity range of 4–8 kilograys (kgy) were identified for optimum germination of cane buds: The LD50 for cane buds was observed to lie between 30–50 kgy while complete lethality occurred at 70 kgy. The growth and quality traits of first generation of vegetative mutants (M1V2) tended to be reduced when gamma doses increased. This relationship which was inconsistent in M1V2 showed stabilized effects of these traits in M1V2. Artificial inoculation with smut spore were used to screen M1V3 mutants of three standard sugarcane clones of diverse origins. Eight selected mutants showing resistance to smut were identified. The significance of these clonal selections in breeding for smut resistance (which is the most important disease of sugarcane in Nigeria) have been discussed.

Optimization of Mutant Recovery from plants obtained from gamma-radiated seeds of winged bean ( Psophocarpus tetragonolobus (L) DC)

Abstract: Dry seeds of winged bean (Psophocarpus tetragonolobus (L.) DC) cvs UPS 122 and Kade 6/16 were treated with acute radiation doses of 150 Gy and 250 Gy at a dose rate of 737.32 Gy/hr from a Cobalt-60 gamma source for studies in optimisation of mutant selection in M2 and M3 populations. Mature dry pods were harvested at four different locations on each M1 plant viz. 0.5, 1.0, 1.5 and 2.0 metres from the ground. M2 seedlings we-re screened for different groups of chlorophyll deficiencies and their frequencies. Reduction in chlorophyll mutation frequency from the first formed seeds to the latest ones within the M1 pods has been observed for both cultivars studied. The high degree of chimerism recorded in the M2 seedlings present in the first-formed seeds in the M1 pods provides a clear indication that these seeds constitute a zone from which seeds for the M2 generation have to be harvested in order to give the highest probability for obtaining different types of mutants. On the other hand, significant differences in mutation frequency were not obtained in M2 seedlings from pods harvested at the various positions on the M1 plants. M1 pods can be harvested at any height on the M1 plant, but it is preferable to use the earliest mature ones to save time and labour. The zones identified on M1 plants in this investigation coupled with the use of the "spare" or "remnant" seed selection method, should provide an improved method for mutation breeding in a viny legume like the winged bean. Journal of Applied Science and Technology (JAST) , Vol. 5, Nos. 1 & 2, 2000, pp. 56 - 62

Effects of space conditions on mutation and inheritance of tomato

Abstract: Objective To study the effects of space conditions on mutation and inheritance of tomato Method Air-dried seeds of tomato were carried by a satellite for 7-15 d These seeds were planted after returning The mutagenic effects of space conditions on some of their variations of the botanical characteristics were studied Result Tomato dry seeds were carried to the outer space by satellite After returned to the earth it was found that SP1 generation was of their germination percentage lower than the control This physiological damage returned to normal in SP2 generation Seeding isoenzyme, plant growth, resistance, and output, showed variation, and profitable variation had been expressed in later generations The characters were expressed in the progenies By observation and screen, promising line of tomato TF873, was obtained Conclusion It was suggested that space conditions induce profitable mutation of crop and it a possible way for plant mutation breeding

Study on technique of mutation breeding by electron beam in chrysanthemum

Abstract: Technique of mutation breeding in chrysanthemum was studied by means of irradiating the young plant from tissue culture with electron beam The results showed that the suitable doses are 30～50Gy for the plant, which suit inducing mutation for the characters of color, petal shape and florescence In this range, the posterity is of higher mutation rate and wider mutation range, and mutation characters is stable The color mutates from pink to purplish red or orange, the petal shape from tubular to spoon or flat, the florescence is earlier 60 days than the check But the mutation rate varies greatly with different varieties, with that of pink variety higher, yellow and white varieties lower The results proved that the technique of irradiating the young plant from tissue culture is an effective method for mutation breeding in chrysanthemum