Denomination: 'Snowhite475'
Previously Proposed Denomination: 'HY475'
Botanical Name: Triticum aestivum
Applicant/Holder: Agriculture & Agri-Food Canada, Swift Current Research and Development Centre
1 Airport Road
P.O. Box 1030
Swift Current, Saskatchewan
S9H 3X2
Breeder: Ron De Pauw, Agriculture & Agri-Food Canada, Swift Current, Saskatchewan
Agent in Canada: FarmPure Seeds Inc.
426 McDonald Street
Regina, Saskatchewan
S4N 6E1
Tel: 306-791-0500 ext 223
Application Date: 2004-04-26
Application Number: 04-4178
Grant of Rights Date: 2007-08-13
Certificate Number: 2824
Date rights surrendered: 2008-08-14

Variety Description

Varieties used for comparison: 'AC Karma' and 'AC Vista'

Summary: 'Snowhite475' has medium anthocyanin on the coleoptile while 'AC Vista' has no anthocyanin. 'Snowhite475' has a longer flag leaf than 'AC Karma' and a wider flag leaf than the reference varieties. 'Snowhite475' has medium to strong anthocyanin on the flag leaf auricles while 'AC Karma' has weak anthocyanin. 'Snowhite475' matures earlier and has a shorter plant height than 'AC Karma'. 'Snowhite475' has stronger glaucosity on the culm neck than 'AC Vista'. 'Snowhite475' has a more spreading awn attitude than 'AC Karma'. 'Snowhite475' has a longer spike than 'AC Vista'. 'Snowhite475' has an ovate kernel shape while the reference varieties have an elliptical to broad elliptical kernel shape. 'Snowhite475' has an ovate shaped germ while the reference varieties have an elliptical shaped germ.


PLANT: spring type, growth habit intermediate between erect and prostrate (at booting)

SEEDLING (at four leaf stage): medium anthocyanin on the coleoptile, sparse pubescence on lower leaf sheath and blade

FLAG LEAF: medium to high frequency of plants with recurved flag leaves, very sparse pubescence on blade and sheath, medium to strong anthocyanin colouration on auricles, medium glaucosity on sheath

CULM: neck with medium to strong glaucosity and very slight curvature

STRAW: pith thin in cross section, very weak anthocyanin at maturity

SPIKE: parallel sided to tapering in shape, medium density, incline to erect at maturity, medium glaucosity, white in colour

AWNS: present, medium in length, spreading attitude, white colour

GLUME: lower glume glabrous, shoulder elevated to straight with some strongly elevated, shoulder width ranging from very narrow to medium, beak slightly curved to straight, beak length short to medium

KERNEL: hard white, medium to large in size, long to midlong in length, midwide in width, ovate in shape, cheek rounded, brush hairs midlong, germ midsize to small in size and ovate in shape, crease midwide and middeep

DISEASE REACTION: susceptible to Fusarium head blight (Fusarium graminearum, Fusarium species), resistant to Common bunt (Tilletia caries, Tilletia foetida), resistant to races T2, T10, T39 and susceptible to race T9 of Loose smut (Ustilago tritici), moderately susceptible to Leaf rust (Puccinia triticina) and moderately resistant to Stem rust (Puccinia graminia f.sp.tritici).

Origin & Breeding History: 'Snowhite475' originated from the cross HY398/Karma//HY413, made in 1995 at the Semiarid Prairie Agricultural Research Centre of Agriculture & Agri-Food Canada, Swift Current, Saskatchewan. The F1 seed was planted as individual plants in an out of season nursery near Brawley, California. The F2 seedlings were inoculated with leaf and stem rust and plants exhibiting a resistant reaction were grown out as individual plants in a greenhouse near Swift Current. The F3 seed was inoculated with common bunt, grown as individual plants in a leaf and stem rust epiphytotic nursery and selected on the basis of resistance to diseases and agronomic traits. The F4 generation was grown as head rows in a out of season nursery near Christchurch, New Zealand. In the F5, screening for quantitative and qualitative traits was completed in Saskatchewan and Alberta. The F5 heads were selected on the basis of maturity, threshed and the F6 seed grown in New Zealand. The F7 generation was grown out as a replicated trial in Saskatchewan and Alberta. Reaction to leaf and stem rust was measured in an epiphytotic nursery near Glenlea, Manitoba. Remnant seed from the yield trials was used to assess grain quality and kernel characteristics. An experimental line designated, 9525-FM15 was evaluated in the High Yielding Wheat 'A' test in 2000. It was later designated as HY475 and evaluated in the High Yielding Wheat Cooperative test from 2001 to 2003.

Tests & Trials: 'Snowhite475' was tested for morphological characteristics at the Semiarid Prairie Agricultural Research Centre of Agriculture & Agri-Food Canada, Swift Current, Saskatchewan in 2003 and 2004. The trials consisted of four replications containing four rows, three metres in length. Spacing between rows was 23 cm and the seeding rate was 220 seeds per metre squared. A completely Randomized Block experimental design was used. Measured characteristics were based on 40 measurements.

Comparison tables for 'Snowhite475' with reference varieties 'AC Karma' and 'AC Vista'

Flag leaf length (cm)

  'Snowhite475' 'AC Karma' 'AC Vista'
mean 22.4 17.6 21.4
std. deviation 2.4 1.9 3.6

Flag leaf width (mm)

  'Snowhite475' 'AC Karma' 'AC Vista'
mean 16.5 14.8 15.1
std. deviation 1.3 1.1 1.0

Number of days to heading

  'Snowhite475' 'AC Karma' 'AC Vista'
days 56 61 57

Plant height (cm)

  'Snowhite475' 'AC Karma' 'AC Vista'
mean 80 86 82
std. deviation 6.1 5.9 7.6

Spike length (cm)

  'Snowhite475' 'AC Karma' 'AC Vista'
mean 10.2 10.2 9.3
std. deviation 0.8 0.6 0.6

Click on image for larger view
Wheat: 'Snowhite475' (left) with reference varieties 'AC Karma' (centre) and 'AC Vista' (right)

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