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Denomination: 'Defender'
Previously Proposed Denomination: 'A90586-11'
Botanical Name: Solanum tuberosum
Applicant/Holder: University of Idaho
Office of Technology Transfer
875 Perimeter Drive, MS3003
Moscow, Idaho
United States of America
Breeder: Jeffrey C. Stark, University of Idaho, Idaho Falls, 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: 2003-12-29(priority claimed)
Application Number: 03-3929
Protective direction granted: 2003-12-29
Grant of Rights Date: 2006-04-20
Certificate Number: 2427
Grant of Rights Termination Date: 2024-04-20

Variety Description

Variety used for comparison: 'Shepody'

Summary: 'Defender' has a taller plant height than 'Shepody'. 'Defender' has a lower flowering profusion and smaller inflorescence size than 'Shepody'. The flower buds drop more readily for 'Defender' than for 'Shepody'. 'Defender' has white flowers while 'Shepody' has red-violet flowers. 'Defender' has a netted skin texture while 'Shepody' has a smooth skin texture. 'Defender' has a larger light sprout which is broad cylindrical in shape while 'Shepody' has a smaller, conical light sprout. 'Defender' has sparser pubescence on the light sprout base than 'Shepody'. 'Defender' has a more open light sprout tip habit than 'Shepody'.


'Defender' has a semi-upright growth habit and produces a leaf type plant. The stems are medium in thickness and have absent to weak anthocyanin colouration which is located in the leaf axils. The nodes have low to medium swelling.

'Defender' has medium green leaves and an intermediate leaf silhouette. The leaf rachis and petiole have no anthocyanin colouration. The terminal leaflet is medium ovate in shape with an acute to acuminate shaped tip and cordate shaped base. The terminal and lateral leaflets have an absent to very low frequency of coalescence. The lateral leaflets are medium in size and are narrowly ovate in shape with an acute to acuminate shaped tip and cordate shaped base. The leaf veins are shallow in depth. The terminal and lateral leaflets have weak to medium waviness of the margin and have medium glossiness of the upper surface. The leaf blades have moderate pubescence at the apical rosette. The presence of secondary leaflets is medium to strong.

'Defender' has a very low to low flowering profusion and a very small inflorescence size. The flower buds are very weakly persistent and have no anthocyanin colouration. The corolla is white in colour, small to medium in size and has a moderately prominent star. The peduncle has no anthocyanin colouration.

The tubers have light beige skin with yellow colour at the base of the eye. The skin develops medium anthocyanin colouration when exposed to light. The skin texture is netted and the tubers are oblong to oval in shape. The tuber eyes are intermediate in depth and are evenly distributed. The tuber eyebrows are moderately prominent. The tuber flesh is cream in colour with no secondary colour present.

'Defender' has a large light sprout which is broad cylindrical in shape. The light sprout base has medium anthocyanin with an absent to low proportion of blue. The base has sparse pubescence. The tip of the light sprout is smaller in size in relation to the base. The tip has an intermediate habit and has no anthocyanin colouration. The tip has medium pubescence. There are a medium number of root tips and the lateral roots are short in length.

Origin & Breeding History: 'Defender' originated from a cross between 'KSA195-90', a breeding clone from Poland, and 'Ranger Russet'. The cross was made at the University of Idaho's Aberdeen Research and Extension Center in 1990. It was first selected in the field in 1992 and evaluated for 11 years. 'Defender' was tested under the experimental designation A90586-11 in the Western Regional Trials in 2000 to 2002. Selection criteria included resistance to late blight and tuber quality.

Tests & Trials: Trials for 'Defender' were conducted in North Tilley, New Brunswick in 2004. A randomized 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 meters long and between row spacing of 91 cm. Measured characteristics were based on 10 measurements. Colour determinations were made using the RHS colour chart.

Comparison tables for 'Defender' with reference variety 'Shepody'

Plant height (cm)

  'Defender' 'Shepody'
mean 64.6 57.5
std. deviation 3.4 4.2

Colour of corolla (RHS)

  'Defender' 'Shepody'
inner surface 157D 85A
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