Productivity of potato seed-tubers from different latitudes
Date
1993-08
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Type
Degree Level
Doctoral
Abstract
Potato (Solanum tuberosum L.) seed-tubers from northern
latitudes are usually more vigorous and higher yielding than
seed from more southern latitudes. It is not clear whether
the superiority of northern seed is due to physiological
and/or disease related causes. This study was conducted to
examine the relative growth and yield potential of Norland
and Russet Burbank seed from different latitudes with the
objective of relating seed-tuber vigour to physiological or
pathological factors associated with seed production
environment. In a five year study, comparisons were made
for seed sources from Saskatchewan, Colorado, Minnesota,
Nebraska and Wisconsisn that provided a range of
environmental conditions.
Norland and Russet Burbank seed from Saskatchewan
usually outyielded seed from Minnesota or Nebraska but was
rarely better than Colorado seed. Tuber yields for the
various Saskatchewan seed sources were similar. Lower
yields for Russet Burbank from the southern sources was
associated with reduced seed piece vigour and greater hill-to-
hill variability. However, with Norland, yield increases for northern seed was mainly due to increased seed piece
vigour.
Northern seed lots produced more vigorous and
persistent haulms than southern seed. Premature senescence
of plants from southern seed was caused by reduced
allocation of dry matter to shoots in favour of tubers.
This differential allocation was, in turn, triggered by high
levels of tuberizing stimulus present in the southern seed.
Differences in shoot vigour, mainstem number, tuber
initiation, tuber yield, and tuber dry matter concentration
did not indicate that seed-tubers from cooler (northern)
sites were physiologically younger than seed from relatively
warmer (southern) sites. Rather, seed-tuber vigour
appeared to be more closely related to the extent of diurnal
temperature fluctuations at each seed production site.
Seed potatoes from Saskatchewan retained their
productive vigour over Minnesota source for at least two
generations. Cycling low yielding Minnesota seed through
Saskatoon increased its productive capacity. However,
cycling superior Saskatchewan seed through Minnesota reduced
its yield potential but it was still superior to seed grown
continuously in Minnesota. This is further evidence that
the site related variability of seed stocks is due to
physiological factors rather than disease conditions.
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Degree
Doctor of Philosophy (Ph.D.)
Department
Horticulture
Program
Horticulture