Page 29 - Breeding and regulatory opportunities, Renaud

General introduction

cereals (Murphy et al., 2007; Löschenberger et al., 2008; Wolfe et al., 2008) and

for onion (Osman et al., 2008) but not for the Brassica vegetables.

Another issue of concern to breeders who aim to service the organic market

is whether breeding under low-input and variable growing conditions might

be less eicient, because of the expected lower heritability of quantitative

traits. Similar discussions had been going on for selecting in and for low-

inputs conditions in Southern countries (e.g. Ceccarelli, 1996). Heterogeneous

environments make it diicult to apply consistent selection pressure because it

is often diicult to identify a single or a few superior genotypes across all sets of

conditions. However, when the target system is characterized by heterogeneity

of environmental conditions, varieties selected under high-yielding conditions

may fail to satisfy farmers’ needs under low-input conditions (e.g. Murphy et

al., 2007). Because heterogeneous environmental conditions are a feature of

organic systems, some researchers have emphasized the value of alternative

breeding models such as decentralized or participatory selection (e.g. Myers

and Kean, 2007; Chable et al., 2008; Desclaux et al., 2008). The formal breeding

industry has become more interested in breeding for the organic market over

the course of the study presented in this thesis, providing opportunities to

contribute evidence to inform these discussions.

1.3.5 Breeding techniques

Breeding methods have evolved rapidly in recent years to service an expanding

seed market. The organic sector has argued that several techniques used in

conventional breeding programmes would not comply with the principles of

organic agriculture (Lammerts van Bueren et al., 2007). Organic agriculture has

philosophically and legally rejected the technology of genetic modiication

(GM), where GM organisms are deined as ‘organisms in which the genetic

material has been altered in a way that does not occur naturally by mating

and/or natural recombination’ (IFOAM, 2012). Under this deinition of genetic

modiication protoplast fusion is also included, and is therefore not compatible

with organic principles (Haring et al., 2009; Chable et al., 2012; Myers et al.,

2012). Protoplast fusion was used to introduce cytoplasmic male sterility

(CMS) for use in Brassica hybrid breeding programs. CMS has not been found

to naturally occur in Brassica species such as broccoli. In some cases, CMS

replaced the older technique based on self-incompatibility for hybrid seed

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