Denomination: 'PS6545701'
Botanical Name: Lactuca sativa
Applicant/Holder: Seminis Vegetable Seeds, Inc.
800 North Lindbergh Blvd.
St. Louis, Missouri
United States of America
Breeder: Alexandria Quesada, Seminis Vegetable Seeds, Inc., St. Louis, United States of America
Agent in Canada: Seminis Vegetable Seeds, Inc.
613 Tomahawk Cresent
Ancaster, Ontario
L9G 3T4
Tel: 905-304-1795
Application Date: 2004-05-26
Application Number: 04-4314
Grant of Rights Date: 2010-02-25
Certificate Number: 3805
Date rights revoked: 2012-07-09

Variety Description

Variety used for comparison: 'Green Towers'

Summary: The leaf of 'PS6545701' is obovate in shape whereas it is elliptic in 'Green Towers'. The upper side of the leaves of 'PS6545701' have weak to medium glossiness whereas it is very weak on 'Green Towers'. The margins of 'PS6545701' have strong undulation whereas it is very weak on 'Green Towers'. The depth and density of incisions on the apical parts of the margins of 'PS6545701' are medium whereas they are shallow and sparse on 'Green Towers'. Seed colour of 'PS6545701' is black whereas it is white in 'Green Towers'.


SEEDLING: absent or very weak anthocyanin colouration
COTYLEDONS: small to medium size, elliptic shape

PLANT: romaine type
OUTER LEAVES: greyish-green to bluish green, medium to dark intensity of colour
LEAF: thick, obovate shape, no anthocyanin colouration, weak to medium glossiness, concave to flat surface profile, entire
ATTITUDE: semi-erect at 10-12 leaf stage, erect to semi-erect at harvest maturity
BLISTERING: very weak, small blisters
LEAF BLADE: entire, strong undulation of margins, flabellate (fan-shaped) venation
MARGINS INCISIONS AT APEX: medium depth, medium density

SEED: black

Origin & Breeding History: 'PS6545701' was derived from crossing 'PI206964' with 'Salinas 88' in 1993 at the Seminis Vegetable Seed Research Station in Arroyo Grande, California, USA. Pedigree selection breeding method was used, using both single plant selection and mass selection practices. Selection criteria for 'PS6545701' included choosing a variety that appeared like romaine lettuce yet exhibited internal characteristics of an iceberg variety such as colour, texture, taste and density as well as contrasting inner and outer leaf colour.

Tests & Trials: The tests and trials for 'PS6545701' were conducted at Bank Gardens, Lynden, Ontario and Princeton, Ontario during the summers of 2007 and 2008. The trials consisted of a minimum of 105 plants, across a minimum of 3 replicates. Plants were spaced at 15 and 25 centimetre spacings, with a row spacing of 75 centimetres. Measured characteristics were based on 10 measurements.

Comparison tables for 'PS6545701' with reference variety 'Green Towers'

Plant diameter (cm)

  'PS6545701' 'Green Towers'
mean 29.5 30.8
std. deviation 2.9 3.9

Days to beginning of bolting under long day conditions

  'PS6545701' 'Green Towers'
number of days 53 54

Days to harvest maturity

  'PS6545701' 'Green Towers'
number of days 45 45

Click on image for larger view
Lettuce: 'PS654701' (left) with reference variety 'Green Towers' (right)

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