Page 250 - Breeding and regulatory opportunities, Renaud

correlated with head weight and negatively correlated with carotenoids). For

traits that were strongly associated with genotype main efect (i.e. glucoraphanin

and lutein) the cultivars with the highest concentrations of these compounds

were also the most stable across trials. Season efect was greater compared to

the location (Maine versus Oregon) efect for the phytochemicals compared

to the horticulture traits (glucoraphanin being higher in fall environments;

carotenoids higher in spring environments). Unlike the horticultural traits,

phytochemical variances were not larger in organic compared to conventional

growing conditions, but repeatabilities and the ratio of correlated response to

direct response were similar, which would support the beneit of selecting in

organic systems to optimize nutrition targeted breeding programmes.

Chapter 6 assesses the main indings of Chapters 1-5 in the light of the

objectives, hypotheses and research questions of this study. Through the

combined analyses of the organic seed regulatory studies and the ield trials that

determined the horticultural and phytochemical trait performance of broccoli

cultivars grown under organic and conventional management systems, the

results are synthesised and discussed in terms of the following ive propositions:

(1) Regulatory clarity is the foundation for organic seed sector development, (2)

Organic management systems inluence horticultural and phytochemical trait

performance, (3) A crop ideotype can serve as a communication tool to arrive

at an appropriate cultivar assortment, (4) Genetic variation is a requirement to

develop optimized cultivars, and (5) Multiple seed system models contribute to

organic sector growth.Speciically, the role of an organic crop ideotype(a list of

crop varietal traits required by organic growers for optimal cultivar performance

in an organic production system) is explored. The deining an organic crop

ideotype provides a useful format for growers and breeders to communicate

the required traits. Once an ideotype has been deined, growers can match their

needs with the cultivars available, and breeders have a “blueprint” for cultivar

development. An organic crop ideotype also can be used as a communication

tool between growers and certiiers i.e. to communicate cultivardiferences that

could support derogation requests. Through this study, we sought to deine an

organic crop ideotype for broccoli through grower and breeder interviews, ield

trials and phytochemical analysis. The results of these combined studies are

translated into an outline of a broccoli crop ideotype to be used as a foundation

for developing a broccoli breeding strategy for organic agriculture. An organic

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