Beitrag in Konferenzband

Yield and anthocyanin content in purple carrots with reduced nitrogen supply


Details zur Publikation

AutorenlisteSchmidt L., Zinkernagel J.

Jahr der Veröffentlichung2014

Buchtitel49. Gartenbauwissenschaftliche Jahrestagung : Kurzfassung der Vorträge und Poster

SerientitelBGHL-Schriftenreihe

Serienzählung30

Erste Seite46

URLhttp://www.dgg-online.org/tagung_dresden_2014/infos/Abstractband_Inhalt_2014.pdf#68

SprachenEnglisch


Abstract
Purple carrots yield high contents of anthocyanins. However, it is not known how the anthocyanin yield can be further increased by agricultural practices such as fertilization. Thus, this study elucidated the impact of decreased nitrogen (N) supply on the yield and the anthocyanin content in two varieties of purple carrots. The varieties ’Deep Purple’ and ’Purple Sun’ (Bejo, Warmenhuizen, NL) were grown in the field in 2012. The experiment was conducted as two-factorial (factors: variety and N) block design with four replications. The amount of N fertilizer was reduced by 50% in half of the plots as compared to recommended levels ("Nred"). At harvest in autumn 2012, the carrots were washed and classified into marketable and non-marketable fractions. A subset of plants were randomly chosen for further measurements (length and weight of leaves and root, diameter of the root) and for rating of the degree of inner colouration. Spectroscopic measurements were taken on the roots with the Multiplex device (Force-A, Orsay Cedex, France). Parameters expressing the anthocyanin content and the N status were recorded. The parts previously used for measurements were sampled for chemical analyses. Total anthocyanins were extracted in 80% methanol and their concentration was determined photometrically according to the pH shift method. The total yield (marketable and non-marketable), the leaf mass and the root length were significantly higher in ’Deep Purple’ but there were no effects of reduced N supply. The root weight and the root diameter did not differ significantly between varieties and N supply treatments. The degree of inner colouration and the concentration of total anthocyanins were stronger in ’Deep Purple’ but reduced N supply had no effect. In ’Purple Sun’, the anthocyanin content was significantly increased by the "Nred" treatment. The spectroscopic parameters determined indicated significant differences due to variety but not due to N supply. Taken  together,  the  anthocyanin  yield  is  higher  in  ’Deep  Purple’.  Consequently,  this  variety should be preferred if growing purple carrots for dye production. However, in ’Purple Sun’, the anthocyanin content can be increased by reducing the N supply without negative effects on the yield.