Table 1 Results from general linear mixed models testing for the effects of plant domestication (i.e., plant line), leaf area and their interaction on constitutive levels of aliphatic and indolic glucosinolates in leaves.

From: Plant domestication decreases both constitutive and induced chemical defences by direct selection against defensive traits

Variable

DF

F-value

P

Constitutive aliphatics

  Plant line

2, 6

14.60

0.005

  Leaf area

1, 120

12.36

<0.001

  Plant line × leaf area

1, 120

0.11

0.894

Constitutive indolics

  Plant line

2, 6

7.30

0.025

  Leaf area

1, 120

0.59

0.444

  Plant line × leaf area

1, 120

1.24

0.293

  1. We used three plant lines, the wild cabbage Brassica oleracea ssp. oleracea and two domesticated varieties of this species (B. oleracea var. acephala and B. oleracea var. capitata). We included leaf area (the tissue targeted for domestication) to test for a size-defence trade-off. The interaction term tests for different slopes of the relationship between constitutive glucosinolate levels and leaf area among the plant lines. F-values, degrees of freedom (numerator, denominator), and associated significance levels (P) are shown. Significant effects (P < 0.05) are in bold.
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