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Changes in the dry matter, sugar, plant fibre and lignin contents of swede, rape and kale roots in response to turnip root fly ( Delia floralis ) larval damage
Author(s) -
Hopkins Richard J,
Birch A Nicholas E,
Griffiths D Wynne,
Morrison Ian M,
McKinlay Roderick G
Publication year - 1995
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740690308
Subject(s) - sugar , dry matter , lignin , larva , biology , botany , agronomy , horticulture , food science
Plants from two genotypes of swede ( Brassica napus var napobrassica ), kale ( B oleracea var. acephala ) and rape ( B napus var napus ) were each inoculated at the three to four true leaf stage with 10 eggs of the turnip root fly, Delia floralis . After 8 weeks the damage caused by the resultant larvae significantly reduced the weight of leaves, stems and roots compared with uninoculated plants, with the greatest reduction (26–46%) being found in the roots. Dry matter content, which did not differ between either crop type or cultivar, was unaffected by larval damage. Ethanol‐soluble sugar content was reduced in all cases by larval damage, but only significantly in one rape and one swede cultivar. The effect of D floralis damage on the concentrations of individual sugars (glucose, fructose and sucrose) was crop type and cultivar dependent. The neutral detergent fibre and lignin contents of the undamaged swede roots were significantly lower than in either the undamaged kale or rape cultivars studied. In all crop types the neutral detergent fibre and lignin content significantly increased following D floralis damage. The six Brassica genotypes studied fell into two groups on the basis of host status for D floralis . The two kale cultivars and the forage rape Hobson were considered poor hosts for D floralis , with low percent age pupation (38–41%) and low pupae weight (12.5–14.4 mg). The two swedes and the oilseed rape Ariana were considered good host for D floralis , with both higher percentage pupation (51–59%) and pupae weights (19.8–20.0 mg). The possible relationships between the root composition of undamaged and attacked roots, and D floralis resistance are discussed.