Page 174 - Breeding and regulatory opportunities, Renaud

Chapter 5

in concentration and most stable and are indicated in the highlighted ‘red

circle’ per phytochemical (Figure 5.1A-I). For glucoraphanin, the same group

of cultivars had both the highest concentrations and were the most stable

across production systems (Figure 5.1A; Supplemental Table 5.4). While for

glucobrassicin, a diferent set of cultivars had the highest concentrations across

production systems (Figure 5.1B; Supplemental Table 5.5). Overall stability of all

cultivars across production system was less related to cultivar mean

concentrations for glucobrassicin than for glucoraphanin. None of the cultivars

with the highest concentration for neoglucobrassicin were in the top quartile

for stability across trials; all cultivars with the highest neoglucobrassicin content

were in the bottom half for stability (Figure 5.1C; Supplemental Table 5.6).

Linear regression revealed a statistically signiicant association between higher

concentrations of glucoraphanin and greater stability (Figure 5.3), but no such

pattern was seen for any other glucosinolates. Some but not all cultivars that

had the highest concentrations of α-tocopherol were among the top group

for δ- and/or γ-tocopherol. There was no relationship between δ-tocopherol

concentrations and stability, but both γ- and α- tocopherols had higher

concentrations associated with greater stability (Figure 5.1D-F; Supplemental

Tables 4.7-4.9). Open pollinated and early maturing cultivars had the highest

and most stable concentrations for all carotenoids (Figure 5.1G-I; Supplemental

Tables 4.10-4.12).

5.3.5 Comparison of phytochemical concentration by genotype

classiication

The open pollinated and Fhybrid cultivars were compared across trials for each
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phytochemical analysed (Figure 5.2A). The levels of glucoraphanin in Fhybrids
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tended to be higher than the open pollinated cultivars. But the inverse trend was

observed for glucobrassicin, which was supported by the ranking and stability

analysis where the Fhybrids showed higher levels and more stability across
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trials than the open pollinated cultivars for glucoraphanin. The reverse was

observed for glucobrassicin. For the carotenoids, the open pollinated cultivars

had a signiicantly higher mean value of lutein and zeaxanthin and tended to

be higher for β-carotene compared to the Fhybrids.
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