Effect of nitrogen and cane density on cane architecture, fruit and fruit yield components in primocane bearing red Raspberries
Abstract
Nitrogen fertilization and cane density management are
the most critical factors in the commercial production of red
raspberries. In general, little is known about these factors
in relation to primocane bearing red raspberries and their
effect on fruit yield. In two separate experiments, four
levels of nitrogen and four levels of cane density were
investigated on 2 primocane bearing red raspberries, Rubus
strigosus, selections '8008' and '8114', respectively. The
experiments were conducted at three sites in Manitoba: a clay
soil at st. Adolphe, a clay-loam soil at Morden, and a sandy
soil at Souris. In the second year of the study (1991), only
the latter two sites were used. A nitrogen response experiment
was repeated in a soilless medium in a green house in 1991.
Parameters investigated included number of flowers per
lateral and per cane, fruit set, fruit yield (per cane and per
plot), number of fruits per lateral, fruit size, fruit dry
weight, cane height, cane diameter, number of nodes per cane,
internode lengths, number of laterals per cane, length of
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laterals and lateral branch angle. High nitrogen and low cane
density had similar effects on fruit yield components: canes
were larger in diameter, and the canes had more laterals which
were progressively longer towards the bottom of the cane. At
high cane density the relationship of lateral length from the
tip to the bottom of the cane was curvilinear. The lateral
branch angle increased with cane density. Similarly, both high
nitrogen and low cane density increased the number of laterals
and the proportion of cane that fruited. High nitrogen
increased cane height while low cane density decreased cane
height. Nitrogen and low cane density increased the number of
fruits per lateral and per cane, fruit size and fruit yield
per cane.- Nitrogen increased the overall fruit yield by as
much as 3 times on the sandy soils but had less effect on
clay-loam soils. In the cane density study, although overall
fruit yield increased with increasing cane density, the
increases were not significant due to the greater productivity
of individual canes at low cane density. The increase in
overall fruit yield stabilised at high cane density and there
was a tendency for it to decrease after an optimum number of
canes per meter row was reached. The application of nitrogen
increased fruit yields significantly.
It can be concluded that nitrogen fertilization and cane
density management could improve yield component performance
and the yield potential of primocane bearing red raspberries.
Citation
Master of SciencePublisher
Department of Plant Science University of Manitoba