PNL Volume 14
Norman, D. A.
Processors and Growers Research Organisation, Thornhaugh,
Peterborough, United Kingdom
The Processors and Growers Research Organisation (PGRO) is the
center for independent evaluation of pea cultivars in the United
Kingdom. The organization has been in operation since 1944 and, in ad-
dition to a wide range of agronomic research, now annually evaluates
around 100 vining pea and 50 combining pea cultivars. Evaluation of
vinlng pea cultivars takes place in three stages. The first stage is
the screening trial. Here, new lines from plant breeders are tested for
plant type, habit, maturity, and suitability for quick-freezing or
canning; a general idea of the yield potential is also obtained. When
cultivars are to be entered for the National List Tests of an EEC member
country, they are then simultaneously entered into our preliminary
trial. At this stage more attention is paid to the yield and a more
detailed assessment is made of agronomic performance. Also, they are
screened for resistance to pea wilt (Fusarium oxvsporum race 1), downy
mildew (Peronospora viciae) and tolerance to commonly used herbicides.
The third stage of evaluation is the main trial. This consists of the
most promising varieties from the preliminary trial and once in this
trial they are evaluated for at least three consecutive years. From
here the best go on to field trials with growers and processors and, we
hope, are taken up by the industry.
In the evaluation of new cultivars for use in the UK, we are look-
ing for many qualities, some of which are outlined below.
1. Yield
A significant and consistent increase in yield over the standard
control varieties within the different maturity groups.
2. Disease resistance
Resistance to pea wilt (Fusarium oxvsporum f. pisi race 1) and
downy mildew (Peronospora viciae). Downy mildew especially is a major
problem in the UK and many new cultivars have been shown to be highly
susceptible to this disease, which has led to reduced yield.
Susceptibility to root and soilborne diseases may be genetically con-
trolled; increased root vigor and disease resistance could be very
beneficial, especially for early-maturing cultivars.
3. Maturity
Difficulties are still encountered at extreme ends of the season;
new first early cultivars are always being looked for. Late-maturing
ones are also useful for reducing the length of the drilling program and
to enable sowing to be made under less adverse conditions.
4. Plant architecture
A plant habit which is erect and open increases air circulation
within the crop canopy and helps to prevent fungal infection. A deter-
minate, erect habit allows easier operation of harvesting machinery
while also ensuring a more even maturation. Good results have recently
been obtained with reduced leaf and semi-leafless cultivars and these
types look more promising than leafless ones at present.
PNL Volume 14
5. Produce quality
For the freezing market the produce must be of a uniform bright
green color and be uniform in size, texture, and maturity. Although the
trend has been towards smaller sized peas, many processors still use the
standard medium to large sized cultivars such as 'Sprite', 'Scout', and
'Dark Skinned Perfection'. Canners are also using these cultivars, al-
though there are signs of a renewed interest in pale-seeded types.
Requests for information on PGRO and entries for the pea cultivar
trails are invited. Details can be obtaiend from:
The Processors and Growers Research Organisation
Great North Road
Thornhaugh, Peterborough PE8 6JH, England