Assessment of two Sarpo Clones, 2013
Before submitting a potato clone to the costly UK National
Listing process, breeders gather a huge amount of information to ensure the
clone they are submitting has the highest chance of being accepted. This information covers yield, disease
resistance, eating and cooking assessments, appearance and every other aspect
of the clone’s performance. The National List committee judge each clone by its
Value for Cultivation and Use (VCU). It also needs to be Distinct, Uniform and
Stable (DUS).
Two Sarpo clones, #12 (Crow “A”) and #32 (Crow “B”), were
trialled by 33 growers around the UK. Sites
were widely distributed and covered the north of Scotland to Guernsey and
Belfast. A wide range of sites ensured that the two clones were exposed to
different soil types, growing techniques, weather and also different strains of
the UK blight population (Phytophthora
infestans). Growers were asked for
their observations on blight resistance, vigour, maturity, yield, cooking and
eating qualities and any other comments.
These findings are summarised below.
Resistance to Late-Blight disease
A much drier summer than in recent years resulted in blight
occurring later in many areas. Comments
on blight resistance frequently mentioned that infection occurred at the time
of senescence (plants stop growing and foliage turns yellow) for Crow A, which
is known to be of earlier maturity than Crow B.
In general, Crow B was more blight resistant than Crow A. This supports
previous results from SRT field trials.
No tuber blight was recorded in either clone. All growers said that the foliage of non-Sarpo
varieties was more susceptible to blight.
Crow A grown in Belfast showing
multiple blight lesions. Picture
courtesy of Dr Louise Cooke
Yield and Appearance of Tubers
The average yield from two plants was 2.23kg for Crow A
compared with 1.66kg for Crow B, based on responses from 11 growers. Crow A was also the most uniform in shape and
size and had the better skin finish according to the majority of respondents. In
areas where soils condition were very dry, Crow B was often described as having
rough, cracked or netted skin. Crow A
was less affected.
Yield from two plants of Crow A
(left) and Crow B (right). Picture
courtesy of Alys Fowler.
Other Observations in the Garden
Common scab was a frequent problem with Crow B, an
observation consistent with those in SRT field trials. Crow A was less affected. Scab is aggravated
by dry soil at the time of tuber initiation. Both clones had some reported
mis-shapes and green tubers which could be corrected in commercial fields by
de-stoning and deeper planting. Slug
damage was reported at low levels in both clones. There were no reports of soft or dry rots in
the harvested tubers.
Crow B showing extremely high levels
of common scab and some greening. Picture courtesy of Dr Louise Cooke
Cooking and
Taste
Both clones were judged very favourably for cooking
characteristics and taste. Examples of
comments on the two clones are as follows:
Crow A:
“Nice and nutty”; “as good as Kifli”; “smooth and firm and
excellent as a salad potato”; “floury and good tasting”
Crow B:
“Earthy, floury and good”; “fluffy and perfect for
roasting”; “good shape for chipping”, “a bit dry but good flavour”
The only wholly negative comment from one grower was that Crow
B was “horrid, bitter and soapy” when boiled.
Conclusions
Based on the results provided by our Crowd of growers, I
would recommend Crow A as the better clone to take on to the National
List. However, I would advise that the
trial was repeated, as 2013 was not an ideal year to assess blight resistance
in many areas. I would also advise
adding another clone, #25, to the assessment in 2014.
We already have large amount of data for Crow A and Crow B
from SRT field trials. This has been
greatly enhanced by feedback from Crowdfunders in 2013. However, before we can proceed with
confidence to National List submission more information is needed for both
clones. To this end it is suggested that
a standardised “score sheet” is prepared so that better observations on
maturity, crop vigour and cooking qualities can be made.
Simon White, Trials and Seed Manager,
SRT
Henfaes Research Centre, February,
2014
