Dormancy imposed by pericarp in sunflower (Helianthus annuus) achenes could be removed with sodium hypochlorite at industrial scale

CONSTANZA DOMINGUEZ; DIEGO BATLLA; ROBERTO LUIS BENECH-ARNOLD

Congreso; 11th Conference of the International Society for Seed Science; 2014

Dormancy is an undesirable trait for agriculture. For example, in sunflower achenes the usual presence of dormancy causes serious problems to crop production and to the seed industry. The objectives of this work were i) to determinate the expression of dormancy at different incubation temperatures in achenes, seeds (i.e. achenes without pericarp) and embryos (i.e. grains without pericarp neither seed coat) of one sunflower line in which dormancy is apparently imposed by the pericarp, ii) to assess the effect of an oxidant source (sodium hypochlorite) on the germination of sunflower achenes with pericarp-imposed dormancy, and iii) to evaluate the extent to which an eventual effect of the oxidant source on dormancy removal could be used at an industrial scale (i.e. seed industry). To achieve the first objective, achenes, seeds and embryos were incubated at temperatures at which dormancy is differentially expressed. Results showed that, in this sunflower line, achene dormancy was imposed only by the pericarp and that it was expressed at high temperature. Achenes (control) and achenes washed during two minutes with sodium hypochlorite at 0,5% (treated achenes) were incubated at different temperatures. Treated achenes showed a significant higher germination percentage than control achenes. Finally, achenes were exposed to different treatments: 1-sprinkling achenes with sodium hypochlorite at different concentrations, 2-washing achenes during two minutes with sodium hypochlorite at different concentrations and 3-no treated achenes (control). All treatments were done at an industrial scale level. After treated achenes were sown in the field and emergence was evaluated. Treatments with application of sodium hypochlorite showed a significantly higher emergence than non treated achenes. Obtained results suggest that the use of sodium hypochlorite appears as a promising technology to be applied on an industrial scale to remove pericarp imposed dormancy in sunflower achenes.