Maximum bending stress (MPa) against proportion of wood to axial second moment of area of the stem.

<p>(A) Shrub phenotypes of the wild taxon show higher values of maximum stress compared with shrub phenotypes of the domesticate. (B) Climber phenotypes of wild and domesticated taxa show little difference in maximum bending stress.</p

Types of failure as measured in 3-point bending tests in stems of wild taxa in French Guiana and in Rondônia, Brazil and domesticated manioc (<i>Manihot esculenta</i> subsp. <i>esculenta</i>) from French Guiana and Brazil (results of chi² tests with <i>P</i>-values comparing wild and domesticated taxa).

<p>See text for data on shrubs and climbers from the limited data set from Brazil.</p

Stiffness (MPa) against proportion of wood cylinder to second moment of area of the stem.

<p>(A) Shrub phenotypes of the wild taxon show significantly higher stem stiffness for a given contribution of wood cylinder to second moment of area compared with shrubs of the domesticate. (B) A similar, but less marked difference is seen between climber phenotypes of the wild and domesticated taxa.</p

Box plots of maximum stress for shrub and climber phenotypes of wild and domesticated manioc.

<p>(A) Wild shrubs from French Guiana show consistently higher values of maximum stress compared with wild climbers. (B) There is no difference in maximum stress between shrubs and climbers in the domesticated species from French Guiana. (Graph and statistics parameters as for Fig. 3; Mann-Whitney test not performed on size class 10.1–15.0 mm because of limited sample size).</p

Vessel size and density traits (means ± s. d.) with <i>P</i>-values of Mann–Whitney tests comparing medians between shrub phenotypes of the wild and domesticated manioc and between climber phenotypes of these two taxa.

<p>Vessel size and density traits (means ± s. d.) with <i>P</i>-values of Mann–Whitney tests comparing medians between shrub phenotypes of the wild and domesticated manioc and between climber phenotypes of these two taxa.</p

Transverse sections of wood cylinders showing different starch grain densities from French Guiana.

<p>(A) Wild shrub (B) domesticated shrub Sections were made at a thickness of 60 µm and stained with 1% iodine solution in 90% ethanol for 5 minutes; scale bar  =  250 µm).</p

Wild and domesticated manioc from French Guiana: Spearman rank correlation coefficients (R_s) of wood cylinder geometry (% contribution of wood cylinder to axial second moment of area of stem) with (i) Young’s modulus (bending) and (ii) maximum bending stress.

<p>Wild and domesticated manioc from French Guiana: Spearman rank correlation coefficients (R_s) of wood cylinder geometry (% contribution of wood cylinder to axial second moment of area of stem) with (i) Young’s modulus (bending) and (ii) maximum bending stress.</p

Microfibril angle for shrub and climber phenotypes of wild and domesticated manioc in French Guiana.

<p>(A) MFA at relative distances within wood cylinder from pith to bark for wild and domesticated shrubs. (B) MFA at relative distance within wood cylinder from pith to bark for shrubs and climbers of the domesticate. (C) Young’s modulus against MFA at periphery of wood cylinder for shrub phenotypes of the wild and the domesticated taxon. Each symbol represents a segment of stem in the range of 0.3 to 2.5 m above ground level. (D) Young’s modulus against MFA at periphery of wood cylinder for shrubs and climbers of the domesticate. Each symbol represents a segment of stem in the range of 0.3 to 4.0 m above ground level.</p

Xylem tissue traits as measured in transverse sections (means ± s. d.) with <i>P</i>-values of Mann–Whitney tests comparing medians between shrub phenotypes of wild and domesticated manioc and between climber phenotypes of these two taxa in French Guiana.

<p>Xylem tissue traits as measured in transverse sections (means ± s. d.) with <i>P</i>-values of Mann–Whitney tests comparing medians between shrub phenotypes of wild and domesticated manioc and between climber phenotypes of these two taxa in French Guiana.</p

Stiffness (MPa) against xylem cell wall cross-sectional contribution to xylem tissue.

<p>(A) Shrub phenotypes of the wild and domesticated taxa. (B) Climber phenotypes of the wild and domesticated taxa.</p