Ethephon (2-chloroethylphosphonic acid) combined with short prechilling improves germination in stored beechnuts
2003
Muller, C. | Laroppe, E.
Beechnuts are deeply dormant and require long cold prechilling before they germinate (one to three months). The methodology of pretreatment without medium at controlled moisture content applied before or after storage is the best method to take into account the dormancy and the heterogeneity within a seedlot (consequence of the genetic variability). It allows a very fast and grouped seedling emergence in the nursery. However, this long prechilling often damages older, less vigorous seedlots. The effect of chemical treatments on dormancy breaking, in particular growth regulators, as a means of shortening the treatment, has been studied. In previous experiments ethephon was shown to strongly stimulate percentage and germination rate of freshly collected beechnuts and to reduce the duration of the cold requirement by half in comparison with the classical pretreatment which needs 4 to 20 weeks. In the present study ethephon + short prechilling (3 weeks) strongly stimulates germination and seedling emergence of beechnuts stored for 3 years at either 7 or 9% moisture content. It avoids the viability loss of less-vigorous beech seeds during longer prechilling (5 weeks) and allows restoring the initial potential of the seedlots. No significant effect of storage moisture content is observed on seedling emergence when seeds are short-prechilled with ethephon. Thus, ethephon used in association with short cold treatment opens new prospects for dormancy breaking particularly in nurseries where short prechilling are preferred.
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