Variation in Broccoli Cultivar Phytochemical Content under Organic and Conventional Management Systems: Implications in Breeding for Nutrition

Abstract

Organic agriculture requires cultivars that can adapt to organic crop management systems without the use of synthetic pesticides as well as genotypes with improved nutritional value. The aim of this study encompassing 16 experiments was to compare 23 broccoli cultivars for the content of phytochemicals associated with health promotion grown under organic and conventional management in spring and fall plantings in two broccoli growing regions in the US (Oregon and Maine). The phytochemicals quantified included: glucosinolates (glucoraphanin, glucobrassicin, neoglucobrassin), tocopherols (δ-, γ-, α-tocopherol) and carotenoids (lutein, zeaxanthin, β-carotene). For glucoraphanin (17.5%) and lutein (13%), genotype was the major source of total variation; for glucobrassicin, region (36%) and the interaction of location and season (27.5%); and for neoglucobrassicin, both genotype (36.8%) and its interactions (34.4%) with season were important. For δ- and γ- tocopherols, season played the largest role in the total variation followed by location and genotype; for total carotenoids, genotype (8.41–13.03%) was the largest source of variation and its interactions with location and season. Overall, phytochemicals were not significantly influenced by management system. We observed that the cultivars with the highest concentrations of glucoraphanin had the lowest for glucobrassicin and neoglucobrassicin. The genotypes with high concentrations of glucobrassicin and neoglucobrassicin were the same cultivars and were early maturing F1 hybrids. Cultivars highest in tocopherols and carotenoids were open pollinated or early maturing F1 hybrids. We identified distinct locations and seasons where phytochemical performance was higher for each compound. Correlations among horticulture traits and phytochemicals demonstrated that glucoraphanin was negatively correlated with the carotenoids and the carotenoids were correlated with one another. Little or no association between phytochemical concentration and date of cultivar release was observed, suggesting that modern breeding has not negatively influenced the level of tested compounds. We found no significant differences among cultivars from different seed companies.

Genetic Variability of Morphological, Flowering, and Biomass Quality Traits in Hemp (Cannabis sativa L.)

“…The broad-sense heritability values (H 2 ) were calculated across the three environments, as the fraction of the genetic component (s 2 G ) to the total genotypic effect (s 2 G , s 2 GxE , and s 2 ϵ ) including the G×E interactions and the residual variance corrected by the number of blocks and environments, as in Renaud et al (2014):…”

“…These results may indicate that, despite the significant genetic component of the phenotypic variation, the small effects of the genetic component in some traits [particularly D, DW_S5(g), H, Gal%dm, GalA%dm, and Rha%dm] hampered the assessment of the G×E% interactions, and thus the ratios G×E/G are small. As a consequence, considering the definition of H 2 (Renaud et al, 2014), the ratios G×E/G below 1 can explain unexpected H 2 (Gitonga et al, 2014), ranging from 0.33 to 0.8, from traits with mostly environment component.…”

The response of broccoli (Brassica oleraceaconvar.italica) varieties on foliar application of selenium: uptake, translocation, and speciation

“…(Aspila, 2005). Whereas no differences were observed for organic compounds such as glucosinolates, tocopherols, and carotenoids in different broccoli varieties (Renaud et al, 2014), the Se contents in broccoli can be affected by the variety (Farnham et al, 2007). In our experiment, a small-scale field experiment was carried out to assess i) the potential differences in plant response on foliar Se application among different varieties of broccoli and ii) to evaluate and quantify the potential imbalance of the macro-and micronutrients in selenized broccoli plants.…”

Glucosinolates in Food

“…In an attempt to increase its intake with the diet, great efforts have been made to find the higher glucoraphanin producer among the best performing cultivars in different horticultural conditions or to stimulate its production within a specific cultivar through the application of elicitors [73][74][75]. A high glucoraphanin …”