In this regard, sunflower has not yet arrived into the GMO era. The reason is that sunflower is recalcitrant to transformation by means of Agrobacterium
infection and is a plant very difficult to regenerate from cell cultures. Few advances have been made on transformation (either
by floral dip or embryo infiltration) so there are no transgenic sunflower lines for commercial exploitation at the present time.
However, these facts have not limited the improvement of sunflower lines using other techniques. Thus, sunflower is a plant easy
to mutagenize by both physical and chemical methods. So, excellent results have been reported by using ethylmethane sulfonate
or sodium azide to produce mutagenized populations of sunflower
seeds [9,10]. These chemical mutagens promote point mutations
during DNA duplication. Furthermore, sunflower can also be
mutagenized using ionizing radiation (X- or gamma-rays), which
is responsible for the breakdown of large fragments of DNA, and
thus cause deletions and mutations during the process of DNA
repair. The population of mutagenized seeds can be later screened
by TILLING [11] or, in the case of fatty acid compositional mutants,
they can be found by direct GC analysis using half seeds (a nondestructive screening method in which the distal part of the seed
is submitted to analysis and the apical part is used for propagation). Moreover, breeding of sunflower is eased by the simple dip-
loid genetics of this plant. Another positive aspect of sunflower
breeding is the relatively high genetic variability and the existence
of several wild species of the genus Helianthus that could be a
source of traits of interest to be transferred to commercial sunflower hybrids [12,13]. The breeding of sunflower, combined with
the techniques of mutagenesis, have produced lines of sunflower
with higher oil content, increased resistant to pests, dryness or
salinity, as well as of mutants with altered fatty acid composition
in their seeds. These improve agricultural, nutritional and technological characteristics of sunflower (and its oil). Moreover, since
the crop is not a GMO it should, therefore, be more acceptable to
a sceptical public (see above).
In this regard, sunflower has not yet arrived into the GMO era. The reason is that sunflower is recalcitrant to transformation by means of Agrobacteriuminfection and is a plant very difficult to regenerate from cell cultures. Few advances have been made on transformation (eitherby floral dip or embryo infiltration) so there are no transgenic sunflower lines for commercial exploitation at the present time.However, these facts have not limited the improvement of sunflower lines using other techniques. Thus, sunflower is a plant easyto mutagenize by both physical and chemical methods. So, excellent results have been reported by using ethylmethane sulfonateor sodium azide to produce mutagenized populations of sunflowerseeds [9,10]. These chemical mutagens promote point mutationsduring DNA duplication. Furthermore, sunflower can also bemutagenized using ionizing radiation (X- or gamma-rays), whichis responsible for the breakdown of large fragments of DNA, andthus cause deletions and mutations during the process of DNArepair. The population of mutagenized seeds can be later screenedby TILLING [11] or, in the case of fatty acid compositional mutants,they can be found by direct GC analysis using half seeds (a nondestructive screening method in which the distal part of the seedis submitted to analysis and the apical part is used for propagation). Moreover, breeding of sunflower is eased by the simple dip-loid genetics of this plant. Another positive aspect of sunflowerbreeding is the relatively high genetic variability and the existenceof several wild species of the genus Helianthus that could be asource of traits of interest to be transferred to commercial sunflower hybrids [12,13]. The breeding of sunflower, combined withthe techniques of mutagenesis, have produced lines of sunflowerwith higher oil content, increased resistant to pests, dryness orsalinity, as well as of mutants with altered fatty acid compositionin their seeds. These improve agricultural, nutritional and technological characteristics of sunflower (and its oil). Moreover, sincethe crop is not a GMO it should, therefore, be more acceptable toa sceptical public (see above).
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