Agriculture Reference
In-Depth Information
Flower
Compound
leaf
Petiole
Te rminal
leaflet
Stem
Leaf
stipules
Nodes
Tuber
Stolons
Fig. 5.2.
A typical potato
(
Solanum tuberosum
L.) plant
and its components during early
to mid season. (Drawing
courtesy of Jeanne Debons,
Bend, Oregon, USA.)
Roots
Seed piece
Apical (bud) end
Basal (stem) end
apically derived seed pieces usually grow more
rapidly, resulting in earlier plant emergence
than sprouts from basal end seed pieces. The de-
gree of apical dominance is affected by genotype,
tuber physiological age, environment, wounding,
and disease. Some potato cultivars exhibit stronger
apical dominance than others. The degree of
apical dominance dictates the number of stems
produced per seed piece, which in turn affects
tuber set, number of tubers per plant, and tuber
size distribution (Knowles and Knowles, 2006).
When tubers are cut for seed, an econom-
ically acceptable size range for a commercial
producer is
43-71
g (Schotzko
et al
., 1983).
Regardless of shape, the number of eyes increases
only slightly as tuber size increases. The number
of eyes depends on genotype, and thus some po-
tato cultivars produce more eyes than other s.
Seed pieces from cultivars with relatively
few eyes must often be cut larger to prevent blind
seed pieces.
5.5
Plant Morphology and Stand
Establishment
Stand establishment refers to the period of
growth from planting to the initiation of tubers.
Seed potatoes may be sprouted prior to planting,
or planted before sprouting occurs. Pre-sprout-
ing, or chitting, is a practice used to promote
early and more uniform emergence and earlier
harvest. It is more common in regions with
shorter growing seasons, especially areas in
northern Europe, and for production of early
potato crops. Pre-sprouting on a large scale re-
quires specialized equipment and facilities, such
as chitting trays or pre-sprouting bags, and is
