T. Farquhar et H. Meyer-phillips, Relative safety factors against global buckling, anchorage rotation, and tissue rupture in wheat, J THEOR BIO, 211(1), 2001, pp. 55-65
The objective of this study was to quantify the effect of specific physical
and biological factors on the relative likelihood of biomechanical failure
in wheat. Wind-related crop damage is a major obstacle to wheat production
that costs several billion dollars per year. The four factors varied in th
is study were breeding line, dwarfing gene dose, soil type, and fertilizati
on. A theoretical model describing the dynamic structural response of livin
g plants was used to define margins of safety against global buckling, anch
orage rotation, and tissue rupture. These relative safety factors were defi
ned for each treatment in comparison with a tall wheat variety selected fro
m a breeding line called Seri and grown in sandy soil with low fertilizatio
n. Compared to this reference, the relative safety factor against global bu
ckling was increased (+39%, p < 0.01), and the relative safety factor again
st anchorage rotation was decreased (-11%, p < 0.025), by one allele of the
dwarfing gene. The relative safety factor against tissue rupture was unaff
ected by the dwarfing gene but was consistently lower (-26%, p < 0.01) in a
second breeding line called Kauz. Soil type and fertility did not affect t
he relative safety factors and this negative finding was significant at p <
0.05. The key finding was that the strength of wheat was affected more by
genetic rather than by environmental factors, which suggests that some vari
eties are intrinsically more robust than others. Also, the relative safety
factor against anchorage rotation was inversely proportional to the relativ
e safety factor against buckling, which suggests that there are competing c
onstraints on the dynamic structural behavior of wheat. (C) 2001 Academic P
ress.