Basic Information - Genetics, Genomics and Breeding of Crop Plants - page 38

1.5.7 Mutagenesis

Mutagens have the potential to generate new genetic variants, but often
cause chromosome aberrations and abnormalities in meiotic cell division.
Gundaev (1971) reports that air-dried sunflower achenes treated with 40
Gy of X-rays, and moist, swollen achenes treated with 10 Gy produced
nearly equal frequencies of chromosomal aberrations. The frequency of
abnormal anaphase and telophase divisions was about 20%. Georgieva-
Todorova (1969) also observed cytological aberrations in anaphase
following treatment of achenes with X-rays. Chromosome bridges and
fragments were the most common defect. Gamma radiation from a cobalt-60
source has been reported to affect length and stainability of sunflower
chromosomes (Kurnik et al. 1971). However, mutagenesis has been
successfully applied to generate useful traits for the improvement of
sunflower, which is especially important if the trait is not found in wild
Helianthus species or other germplasm sources.
Twenty-two cytoplasmic male sterile mutants and seven nuclear male
sterile mutants were produced by Jan and Rutger (1988) using the chemical
mutagens streptomycin and mitomycin C. These lines are H . annuus
cytoplasm which represents a new CMS source and are all stable with
degenerated anthers and fertility restored using the same restorers as CMS-
PET1. These CMS sources have the potential of being quickly utilized for
future hybrid sunflower production using the currently available restoration
lines for the CMS-PET1 cytoplasm (Jan et al. 2006c).
New variations of the tocopherol profile have been created by the use of
the chemical mutagen ethylmethane sulfonate (EMS) in the search for a
partial substitution of -tocopherol by another tocopherol derivative that

would improve the oxidative stability of sunflower oil (Velasco et al. 2004c).
From a total of 2,000 treated achenes of four Peredovik accessions, IAST-540
was selected in M 3 and IAST-1 in M 5 with -tocopherol content of 940 g/kg.

The development of sunflower oil with high oleic acid content was
report by Soldatov (1976). It was produced by treating cultivar VNIIMK
8931 with a 0.5% solution of dimethyl sulfate, a chemical mutagen. By
bulking the plants with high oleic content, the Pervenets variety was created
and released to producers in Russia by the VNIIMK Research Center
(Pukhalsky and Dvoryadkin 1978). The Pervenets variety is the parental
material for the modern-day high-oleic hybrids, as well as the NuSun ®
oilseed hybrids.
High concentrations of palmitic and stearic acid were achieved using
the mutagens sodium azide, ethylmethane sulfate, and X-rays on mature
achenes (Osorio et al. 1995). The resulting mutant lines were selected from
single M 2 and M 3 achenes. The mutant line CAS-5 had 250 g/kg palmitic