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White Pearl


Denomination: 'White Pearl'
Botanical Name: Solanum tuberosum
Applicant/Holder: Wisconsin Alumni Research Foundation
P.O. Box 7365
Madison, Wisconsin
United States of America
Breeder: Jiming Jiang, Madison, United States of America
Horia I. Groza, Carmichael, United States of America
Bryan D. Bowen, Rhinelander, United States of America
Agent in Canada: Torys LLP
Suite 3000, 79 Wellington Street West
Box 270, TD Centre
Toronto, Ontario
M5K 1N2
Tel: 416-865-0040
Application Date: 2006-06-12
Application Number: 06-5504
Grant of Rights Date: 2008-06-26
Certificate Number: 3236
Grant of Rights Termination Date: 2026-06-26

Variety Description

Varieties used for comparison: 'Snowden' and 'Bintje'

Summary: 'White Pearl' has a more upright growth habit than the reference varieties. 'White Pearl' has a shorter plant height than 'Bintje'. 'White Pearl' has a larger corolla size than the reference varieties. 'White Pearl' has white tuber flesh while 'Snowden' has cream coloured flesh and 'Bintje' has light yellow flesh. 'White Pearl' has a larger light sprout than the reference varieties. 'White Pearl' has a conical shaped light sprout while 'Snowden' has a spherical light sprout and 'Bintje' has an ovoid light sprout. 'White Pearl' has very strong anthocyanin colouration with a high proportion of blue in the base of the light sprout while 'Snowden' has absent to weak anthocyanin with an absent or low proportion of blue. 'White Pearl' has strong anthocyanin and dense pubescence on the tip of the light sprout while 'Snowden' has absent or very weak anthocyanin and sparse pubescence on the tip.


PLANT: upright growth habit, intermediate type foliage structure
STEM: medium anthocyanin colouration evenly distributed along the stem, thin, nodes with absent or very low swelling

LEAVES: light green, intermediate silhouette, weak anthocyanin colouration on upper side of rachis, medium anthocyanin on petiole, shallow to medium depth of veins, absent or very weak waviness of margin, weak glossiness on upper side, no pubescence on leaves at apical rosette, medium presence of secondary leaflets
TERMINAL LEAFLET: broad ovate, cuspidate to acuminate tip, cordate base, absent or very low frequency of coalescence with lateral leaflets
LATERAL LEAFLETS: medium size, narrow ovate shape, acute tip, cordate base

INFLORESCENCE: medium flowering profusion, medium size, flower buds persistent, absent or very weak anthocyanin colouration in flower bud.
COROLLA: white, large, weakly prominent star, weak anthocyanin colouration on peduncle

TUBER: round
TUBER SKIN: light beige, yellow at base of eye, rough texture
TUBER EYES: medium in depth, evenly distributed, eyebrows slightly prominent
TUBER FLESH: white, no secondary colour

LIGHT SPROUT: large, conical shape, low number of root tips, short lateral shoots
BASE: very strong anthocyanin colouration, high proportion of blue in anthocyanin, medium pubescence
TIP: smaller than base in size, closed habit, strong anthocyanin colouration, dense pubescence.

Origin & Breeding History: 'White Pearl' originated from a cross between 'Snowden' and S 440, made at Rhinelander Agricultural Research Station, Madison, Wisconsin, USA in 1991. A conventional breeding scheme based on individual clonal selection in generation F1 was used. The main selection criteria used in selection of this variety were round tuber shape, white flesh, good chip colour, specific gravity and higher cold sweetening resistance than 'Snowden'.

Tests & Trials: Trials for 'White Pearl' were conducted in Drummond, New Brunswick in 2006. All entries were planted in single-row plots. Plots consisted of rows 22 metres long with 30 cm in row spacing and between row spacing of 91 cm. Measured characteristics were based on 10 measurements. Colour determinations were made using the 1986 RHS colour chart.

Comparison table for 'White Pearl' with reference varieties 'Snowden' and 'Bintje'

Plant height (cm)

  'White Pearl' 'Snowden' 'Bintje'
mean 60.9 62.2 81.4
std. deviation 2.9 5.1 1.7

Click on image for larger view
White Pearl
Potato: 'White Pearl' (centre) with reference varieties 'Snowden' (left) and 'Bintje' (right)

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