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:
“Nice and nutty”; “as good as Kifli”; “smooth and firm and excellent as a salad potato”; “floury and good tasting”
“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.
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