FACTORS AFFECTING
THE GERMINATION AND ESTABLISHMENT OF MONOGERM SUGAR BEET
1. INTRODUCTION
The final yield of sugar obtained
from the sugar beet crop (Beta vulgaris L.) is
determined by many factors, including: the length of the growing
season, the incidence of diseases and pests, and the prevailing weather
conditions (Biscoe, Draycott & Jaggard 1980). These factors
have a direct or indirect effect on photosynthesis and consequently the
amount of assimilate translocated to the roots. It is therefore the
duration of the leaves which can produce assimilate (i.e. excluding
excessively shaded and diseased leaves) that determines the maximum
potential yield.
The actual yield obtained is
determined by the amount of solar radiation intercepted and utilised by
the leaf canopy over the - whole growing season. Scott, English, Wood
& Unsworth (1973) have shown that a good linear relationship
between sugar yield and both total incident and intercepted radiation
exists.
The grower cannot of course control
the amount of incident radiation but his objective must be to ensure as
much of it is intercepted as possible. However under the ambient Spring
soil temperatures of the U.K., sugar beet is very slow in emerging and
establishing, and complete leaf coverage does not occur until July.
It was estimated by Scott &
Jaggard (1978) that just over 50% of the total radiation is intercepted
by crops in the ground between April and October. The rest strikes bare
ground and is wasted.
There is clearly considerable scope
for improving the efficiency of interception by achieving full leaf
coverage sooner It is in fact the slow rate of growth over the early
part of the season that results in late leaf coverage and poor
radiation interception. Growers would welcome any feasible method of
improving the early growth of the crop.
The objective of this thesis is to
discuss the early stages of sugar beet growth and the various problems
affecting establishment that exist with sugar beet seed, both in its
production and performance in the field.
