Pericarp-Imposed Dormancy in Sunflower: Physiological Basis, Impact on Crop Emergence, and Removal at an Industrial Scale

BATLLA D.; GERBALDO M.; RODRÍGUEZ M.V.; BENECH ARNOLD R.L.; DOMÍNGUEZ C.; WINDAUER L.B.

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2016 vol. 56 p. 1 - 11

0011-183X

Sunflower (Helianthus annuus L.) achenes often display pericarp-imposed22 dormancy, which is long-lasting and causes serious problems to crop production23 and the seed industry. For this study we assessed an extensively used sunflower24 inbred line that has this type of dormancy. Our goals were i) to determine the effect25 of pericarp on germination and to evaluate its impact on crop field emergence, ii) to26 provide insight into the physiological basis of pericarp-imposed dormancy by27 determining the effects of ABA accumulation in the embryo and the embryo28 sensitivity to ABA during incubation at different temperatures, iii) to assess the29 effect of oxidant agents and other compounds on dormancy termination, and iv) to30 evaluate the feasibility of using oxidants to remove dormancy at an industrial scale.31 Incubation at high temperatures (i.e., 25-30ºC) allowed the expression of32 dormancy, which was imposed by the pericarp and was accompanied by an33 increase in embryo sensitivity to ABA, but not in ABA concentration. Treated34 achenes with sodium hypochlorite, or their incubation in presence of an ethylene35 precursor or gibberellins overcame dormancy. ABA concentration decreased36 during incubation when treated with sodium hypochlorite. Application of sodium37 hypochlorite on a commercial seed lot (i.e., washing with 3 and 7%, after additional38 chemicals used by the industry were applied) resulted in higher germination39 compared with dormant non-treated controls. Field trials showed that pericarp-40 imposed dormancy reduced crop emergence in the inbred line tested herein.41 However, treating achenes with sodium hypochlorite using described industrial42 procedures improved field emergence.