Page 161 - Breeding and regulatory opportunities, Renaud

Broccoli phytochemical content

negatively inluenced the level of tested compounds. We found no signiicant

diferences among cultivars from diferent seed companies.

Keywords

Genotype × environment interaction, organic agriculture, Brassica oleracea,

glucosinolates, tocopherols, carotenoids, breeding, health promotion

5.1 Introduction:

Organic food consumption is in part driven by consumer perception that

organic foods are more nutritious and simultaneously less potentially harmful

to human health (Saba and Messina, 2003; Stolz et al., 2011). Studies, such

as Smith-Sprangler et al., (2012), have concluded that there is little evidence

for diferences in health beneits between organic and conventional products,

but other studies have indicated that organic vegetables and fruits contain

higher concentrations of certain plant phytochemicals associated with health

promotion than those produced conventionally (Asami et al., 2003; Chassy et

al., 2004; Brandt et al., 2011; Hunter et al., 2011; Koh et al., 2012). A number

of these compounds are produced by plants in response to environmental

stress or pathogen infection, providing a potential explanation of why

concentrations of these compounds might be higher in plants grown in

organic systems without application of pesticides (e.g. Crozier et al., 2006). In

addition, higher phytochemical levels may be due to the efects that diferent

fertilization practices have on plant metabolism. Synthetic fertilizers used in

conventional agriculture are more readily available to plants than organic

fertilizers (Bourn and Prescott, 2002). Nutrients derived from organic fertilizers

need to be mineralized, and the availability of these nutrients depends on soil

moisture, temperature and level of activity of soil organisms (Mäder et al., 2002).

Conventional systems seek to maximize yields, resulting in a relative decrease

of plant phytochemicals and secondary metabolites (Martinez-Ballaesta et al.,

2008; Meyer and Adam, 2008; Mozafar, 1993; Zhao et al., 2006). Correspondingly,

compounds such as phenolics, lavonoids, and indolyl glucosinolates may be

induced by biotic or abiotic stress (Dixon and Paiva, 1995; Kim and Juvik, 2011).

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