Grg. Clover et al., The use of radiation interception and transpiration to predict the yield of healthy, droughted and virus-infected sugar beet, J AGR SCI, 136, 2001, pp. 169-178
dThis paper reports an analysis of the yield of sugar beet crops grown unde
r experimental conditions between 1993 and 1995 in the UK. Crops were eithe
r healthy (unstressed) or subjected to drought, infection with Beet yellows
virus (BW) or a combination of both. The study investigated whether the la
rge differences in yield between the crops grown in different seasons and s
ubjected to different stresses could be accounted for by simple relationshi
ps between total biomass and radiation interception (epsilon (s)), transpir
ation (epsilon (w)) or epsilon (s) and epsilon (w) adjusted for mean satura
tion deficit (Omega (s) and Omega (w) respectively). Mean values of epsilon
(s), epsilon (w), Omega (s) and Omega (w) in healthy crops were 1.42 g/MJ,
0.89 g/kg, 6.76 g/kPa/MJ and 4.29 g/kPa/kg respectively. Variations in the
dry matter yield between seasons were best accounted for by Omega (w) and
less well by epsilon (w) or epsilon (s).Omega (s) accounted for least varia
tion in yield between seasons. None of these relationships remained constan
t in stressed plants; both drought and BW-infection decreased epsilon (s) (
and Omega (s)) but Omega (w) was increased by drought and decreased by BYV-
infection. However, in common with healthy crops, seasonal variation in yie
lds was best accounted for by Omega (w). Mean values of epsilon (s), Omega
(s), epsilon (w) and Omega (w) for all healthy, infected and droughted crop
s accounted for 61, 50, 88 and 97% of the Variation in dry matter yield bet
ween experiments respectively. Accurate prediction of the yield of stressed
plants requires a knowledge of their infection and drought status. If this
information is unavailable then the mean value of Omega (w) for healthy, i
nfected and droughted crops will provide a reasonable prediction of the yie
ld of such crops.