Page 185 - Breeding and regulatory opportunities, Renaud

Broccoli phytochemical content

commercial sources. Broccoli is typically a cross-pollinated, self-incompatible

crop species and cultivars are either open pollinated and composed of

heterogeneous genetically segregating individuals, or Fhybrids produced
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by crossing of two homozygous inbred lines, resulting in homogeneous

populations of heterozygous individuals. In the 1960’s virtually all broccoli

grown was derived from OPs. By the 1990’s almost all commercial cultivars were

hybrids (Hale and Farnham, 2007).

In our trials with 18 Fhybrids (released between 1975-2005) and 3 open
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pollinated cultivars (released from 1985-2005), we found several interesting

trends related to genotype and genotypic class performance as it related to the

three groups of phytochemicals. When analysing Fhybrid and open pollinated
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cultivars, they also demonstrated diferent performance patterns depending

upon the individual phytochemical or group of compounds analysed. When

cultivars were ranked for content and stability per phytochemical, there

were distinct trends for certain compounds such as late maturing, Fhybrids
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outperforming early maturing Fhybrids and open pollinated cultivars for
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glucoraphanin, while the inverse was found for glucobrassicin and all carotenoids

studied. This analysis was further supported by the PCA biplots that showed

a strong relationship for select cultivars to certain phytochemicals or groups

of phytochemicals such as ‘OSU OP’ to the carotenoids. When the full set of

cultivars was divided into Fhybrid and open pollinated groups and the means
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compared by phytochemical, the results further supported the individual cultivar

analysis where Fhybrids had higher mean values for glucoraphanin than the
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open pollinated cultivars (Figure 5.2A). Clear cultivar performance diferences

were identiied where early maturing versus late maturing cultivars performed

diferently depending upon the phytochemical (Figure 5.2B). We also found

that late maturing cultivars had higher concentrations for glucoraphanin than

early maturing lines (and the inverse for glucobrassicin and the carotenoids).

Picchi et al. (2012) studied the quantity of glucosinolates of an early and late

maturing cultivar of caulilower grown in one conventional and three organic

production systems, and found a signiicantly higher level of glucoraphanin

in the later maturing cultivar compared to the early maturing cultivar in the

organic production system. Another interesting trend was that cultivars with

higher concentration levels for those phytochemicals whose expression is

heavily inluenced by environmental factors were not necessarily the most

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