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Denomination: 'A91556-1W'
Botanical Name: Solanum tuberosum
Applicant/Holder: The Regents of the University of California
Innovation Alliances and Services - Office of the President
1111 Franklin Street
Oakland, California
United States of America
Breeder: John Shih, The Regents of the University of California, Oakland, United States of America
Agent in Canada: Global Agri Services Inc.
376 New Maryland Highway
New Maryland, New Brunswick
E3C 1E5
Tel: 506-462-9493
Application Date: 2003-02-24
Application Number: 04-4059
Grant of Rights Date: 2007-10-02
Certificate Number: 2946
Date rights surrendered: 2008-09-29

Variety Description

Variety used for comparison: 'Calwhite'

Summary: 'A91556-1W' has a shorter plant height and narrower leaves than 'Calwhite'. 'A91556-1W' has weak to medium anthocyanin on the petiole while 'Calwhite' has no anthocyanin. The skin colour of the tubers of 'A91556-1W' is yellow whereas it is light beige in the reference variety. The base of the eyes of 'A91556-1W' is yellow whereas it is white for 'Calwhite'. 'A91556-1W' has an ovoid shaped light sprout while 'Calwhite' has a broad cylindrical light sprout. The pubescence on the light sprouts of 'A91556-1W' is sparse at the base and moderate at the tip, whereas it is dense at the base and sparse at the tip for 'Calwhite'.


PLANT: upright growth habit, leaf type foliage structure

STEM: medium anthocyanin in lower half, main stem medium to moderately thick, swelling of nodes absent or very low

LEAF: medium to dark green, open silhouette, weak anthocyanin in rachis, weak to moderate anthocyanin in petiole
TERMINAL LEAFLET: narrowly ovate, acute to acuminate tip, obtuse base, low frequency of coalescence of terminal and lateral leaflets
LATERAL LEAFLETS: small, narrowly ovate, acute to acuminate tip, obtuse to cordate base, moderately deep veins, moderate to strong waviness of margins, medium glossiness, no pubescence on blade (at apical rosette), moderate presence of secondary leaflets

INFLORESCENCE: medium in size, medium to high flowering profusion, buds persistent, strong to very strong anthocyanin in buds
COROLLA: medium in size, white, moderately prominent star
PEDUNCLE: weak anthocyanin

TUBER: oblong, eyes flat to shallow and evenly distributed, eyebrows not prominent, white coloured flesh with no secondary colour
SKIN: yellow, yellow at base of eye, medium anthocyanin when exposed to light, smooth to rough texture

LIGHT SPROUT: large, ovoid, few root tips, short lateral roots
BASE: very strong anthocyanin, high proportion of blue, sparse pubescence
TIP: smaller than base, intermediate habit, weak anthocyanin, medium pubescence.

Origin & Breeding History: 'A91556-1W' was developed by University of California breeders Ronald E. Voss and Hebert A. Philips. The variety originated from a cross between varieties 'BC0038-1' and 'A8519-4' made in Aberdeen, Idaho, in 1991. The clone was grown as a seedling and harvested in 1992. The resulting tubers were planted in 1993 and selected from single hill and first year seedlings in the same year. Tubers were selected from a 12 hill trial in 1994. The variety was entered in a preliminary yield trial in 1995 and grown in an intermediate yield trial in 1996. It was grown at 2 different locations in 1996, in a 12 and 27 hill observational trial, with selection occurring at both locations. The variety was again grown in two different locations in 1997, one location being a 27 hill observational trial and the other a 2x27 hill observational trial. It was grown in a replicated yield trial in 1998. A91556-1W was selected out of an F1 population using the following selection criteria: healthy strong vine type and good vigour, early maturity, tuber shape, tuber colour, tuber quality, good yield and lack of defects such as growth cracks, rotten tubers and pointed ends.

Tests & Trials: Trials for 'A91556-1W' were conducted in Drummond, New Brunswick in 2005. A block design was used with four replicates per variety. All entries were planted in single-row plots and each entry had one replicate per block. Plots consisted of rows 5.5 metres long 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 tables for 'A91556-1W' with reference variety 'Calwhite'

Plant height (cm)

  'A91556-1W' 'Calwhite'
mean 52.0 64.3
std. deviation 2.2 4.1

Leaf length (cm)

  'A91556-1W' 'Calwhite'
mean 28.6 31.6
std. deviation 2.3 2.2

Leaf width (cm)

  'A91556-1W' 'Calwhite'
mean 14.8 21.7
std. deviation 1.1 1.9

Colour of corolla (RHS)

  'A91556-1W' 'Calwhite'
inner surface 157D 155A

Click on image for larger view
Potato: 'A91556-1W' (left) with reference variety 'Calwhite' (right)

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