Page 184 - Breeding and regulatory opportunities, Renaud

Chapter 5

22 mmol/g DW with a mean concentration of 7.1μmol/g DW, while Wang et al.

(2012) found glucoraphanin content of ive commercial hybrids and 143 parent

materials ranging from 1.57-5.95 μmol/g for the hybrids and 0.06-24.17 μmol/g

in inbred lines and Charron et al. (2005a) found ranges from 6.4-14.9 μmol/g DW.

While the means in our study are somewhat lower, they are within the range

of other studies.

A genotype efect was observed for tocopherols, but predominantly for

γ-tocopherol. The PCA biplots (Figure 5.4AB) and the correlation analysis

(Table 5.5) demonstrated the high positive correlations between δ-tocopherol,

α-tocopherol and the carotenoids (α-tocopherol and β-carotene were also highly

correlated in the Kushad et al. (1999) study. The cultivar relationship to diferent

phytochemicals was represented in the biplots as well as in the cultivar content

and stability analysis (Figure 5.1). Many cultivars with the highest concentrations

in the tocopherols and carotenoids were open pollinated cultivars, inbreds and

early maturing, older Fhybrids. Many of this same group were also relatively
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high in glucobrassicin concentrations. Kurilich et al. (1999) found that carotenoid

and tocopherol concentrations among 50 broccoli lines were highly variable and

primarily genotype dependent. Speciically, levels of β-carotene ranged from

0.4-2.4 mg/100 g FW. Ibrahim and Juvik (2009) also found broad ranges for total

carotenoid and tocopherol concentrations among 24 genotypes ranging from

55-154 mg/g DW and 35-99 mg/g DW, respectively. Farnham and Kopsell (2009)

studied the carotenoid levels of nine double haploid lines of broccoli. Similar

to our indings, lutein was the most abundant carotenoid in broccoli ranging

from 65.3-139.6 μg/g DM. The sources of variation for lutein were predominantly

genotype, followed by environment and GxE interaction, which also supports

our indings. No genotypic diferences were found for β-carotene in Farnham

and Kopsell (2009), which is in contrast to our indings. Overall, they found that

most of the carotenoids measured were positively and highly correlated to one

another as was observed in our study (Table 5.5). Kopsell et al. (2004) found lutein

levels in kale of 4.8–13.4 mg/100 g FW where the primary variance components

for both lutein and β-carotene were also genotype and season.

Our research aimed also to address the question whether the phytochemical

content of broccoli cultivars is associated with certain genotypic classes, e.g.

open pollinated vs. Fhybrids; older vs. newer cultivar releases; and between
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