Services

Background to the Characteristics

Yields
Yields of all varieties are expressed as percentages of the control in the tables. For all crops, the control is calculated as the mean, or average, fungicide treated yield of the control varieties that are selected on a UK basis. The untreated yields are expressed as a percentage of the fungicide treated control. Both fungicide treated and untreated yields represent the mean performance of the varieties in trials during the five-year period 2002 to 2006.
Treated yields
Fungicide programmes were applied to these trials in order to keep disease incidences below 5% infection of the leaf area. These treated yields indicate the potential yield of the varieties in the absence of disease. Treated trials of winter wheat, winter barley and winter oats may also have received applications of plant growth regulators where the risk of lodging has been high.
Untreated yields
In these trials where no fungicide treatment is applied, natural infections by a number of diseases may occur at various stages during the growing season. Varieties have differing levels of infection because they carry different types and levels of resistance to each of the diseases. Infection by disease leads to a reduction in the capacity of varieties to produce grain yield. Differences in yield between varieties in untreated trials are normally greater than in treated trials. Comments on untreated yields in variety descriptions refer to their performance relative to other varieties when untreated.
Use of information on yields from treated and untreated trials
Growers have different approaches to the use of fungicides. Some will prefer a programme that protects completely against all disease infection. Yields in the treated trials indicate which varieties are likely to give the best performances with this approach. Others will prefer to use chemicals as and when disease occurs. Yields in the untreated trials indicate which varieties are likely to need fewer applications of fungicide in order to produce high yields and, conversely, where risks are greater if less-than-complete control of disease is achieved.
Grain quality
Information presented in the tables on specific weight and 1000 grain weight of spring barley, winter barley, winter wheat, spring oat and winter oat varieties and on kernel content of spring and winter oat varieties, is from the fungicide treated trials in Northern Ireland. Specific weight, measured in kilograms per hectolitre (kg/hl), is important when selling grain. For winter and spring oats, specific weight has been determined on grain which was cleaned prior to measurement. Although individual crops will vary, the information on specific weight, grain weight and kernel content, presented in this booklet, shows accurate relative values for the varieties.

Oat screenings can be important when selling grain to the quality market. Oat varieties are screened over a 2 mm sieve for 15 seconds and the proportion passing through recorded as a percentage. It must be noted that these fluctuate greatly from season to season.

Free kernels and empty husks, i.e. grains that fail to develop kernels, may be present in harvested oats and are undesirable for milling. All current spring oat varieties produce few empty husks but vary in their tendency to produce free kernels. Several of the winter oat varieties are particularly prone to producing free kernels and some also produce empty husks. Details are provided in the variety descriptions as significant, some or little tendency to produce free kernels and/or empty husks.
Straw characteristics
Straw length, using data from untreated trials grown in Northern Ireland (except for winter oats where data from the fungicide-treated but without plant growth regulator trials are used), is expressed in centimetres, compared with Doyen for spring barley, Emotion for spring oats, Cannock for winter barley, Richmond for winter wheat and SW Dalguise for winter oats. Straw yield was determined from winter and spring barley trials at Hillsborough and Crossnacreevy, respectively, and is reported in the descriptions of varieties of these crops as low, intermediate or high. Spring barley straw yields are from the fungicide treated plots where high yields were 2.5 t/ha or greater, intermediate yields were 2.1 – 2.5 t/ha and low yields less than 2.1 t/ha. Winter barley straw yields are from the fungicide treated plots that also received a plant growth regulator with yields greater than 4.7 t/ha being described as high, those of less than 3.7 t/ha as low and between 3.7 and 4.7 t/ha as intermediate.

Straw strength is described as standing power and is calculated using both lodging and leaning data. It is expressed in the tables on a 1 to 9 scale, where a high figure indicates a high degree of straw strength. Straw characteristics, such as brackling, necking (in barley only) and ear loss, are referred to as required in the variety descriptions. Brackling and necking affect the ripening straw, brackling occurring in the lower part of the stem and necking below the ear. Brackling need not be damaging unless the ears lie on the soil surface; necking is more serious, though only if a clean break occurs, leading to ear loss in bad weather. Straw characteristics are determined from untreated trial data.
Disease
Resistance of the varieties to mildew, leaf blotch (Rhynchosporium) and Septoria, depending on crop, is expressed on a 1 to 9 scale in the tables, where a high figure indicates that the variety shows a high degree of resistance. The resistance of varieties to other diseases is referred to in individual variety descriptions where necessary. Information used to derive these resistances on mildew, leaf blotch and Septoria is drawn from naturally occurring field infections in trial plots in Northern Ireland in which there was no chemical control of diseases. If insufficient disease is present in the trials in Northern Ireland to allow resistance ratings to be assigned, the scores presented in the HGCA Recommended List 2007 have been used. Mildew scores in spring barley, net blotch scores in winter barley and mildew, yellow rust and glume blotch scores in winter wheat are taken from the HGCA Recommended List 2007.

Disease incidences on cereal crops in Northern Ireland are much more variable from year to year and crop-to-crop than in Great Britain. In 2006, the levels of disease recorded in untreated trials were generally higher than in 2005. In some cases, this appears to have contributed to a decline in the over-years untreated yields. The following brief comments (based on data from the untreated trials) provide information on disease incidences in Northern Ireland in 2006.

Winter barley - Leaf blotch infections appeared earlier and at higher levels this year. At Limavady, most varieties were affected and by the end of June levels had increased markedly with the worst affected varieties having >40% infection. At Crossnacreevy, leaf blotch appeared in early May and increased throughout the growing season to peak at 75% in some varieties. At Downpatrick, similar maximum levels of infection were also recorded by mid – June, but levels were low prior to this. The incidences of leaf blotch were much lower at Hillsborough. Even by mid/late-June most varieties had very little, with 8% recorded as the maximum. Little or no mildew was found at three of the four winter barley trial sites. Significant infections were recorded only at Crossnacreevy where a couple of varieties had 5% by mid-May, increasing to more widespread infections of up to 10% by mid-June. As with mildew, net blotch was only recorded above trace amounts at Crossnacreevy with four varieties having 1% infection. Physiological spotting was not observed at Downpatrick, but was found at significant levels at the other three trial sites. At Limavady, infections increased to a maximum of 28% at the end of June. At Hillsborough, some varieties had up to 10% by mid-June. At Crossnacreevy, trace levels in early May increased to significant levels (10 – 25 %) in some varieties by mid –June.

Winter wheat – Septoria was found at much higher levels of infection this year compared to 2005. The Crossnacreevy trial was worst affected, the disease appearing in early-May and increasing to >30% in all varieties by mid-July. The highest recorded infection was 60% with several varieties having >50%. A similar pattern was recorded at Downpatrick. Septoria infections at Limavady were much lower with less than 10% infection in several varieties in mid-July, although the worst affected variety had 42%. Mildew infections were low again in 2006, none being recorded at Crossnacreevy and Limavady. At Downpatrick, slight infections (<1%) were found in a few varieties. Little physiological spotting was found at Limavady (maximum of 5%) and Downpatrick (<1%). In mid-July at Limavady, slight infections of Fusarium were observed on the ears of most varieties (maximum of 5%).

Winter oats – Mildew did not appear in the winter oat trial at Crossnacreevy until mid-June and ranged from 0 – 10% infection. By the second week of July, this had increased in all varieties, ranging from 2 – 50%. There was very little Septoria avenae in the oat trial all season. It was first recorded at the beginning of July and the maximum level of infection was <4%. Crown rust was also first recorded at the beginning of July, much earlier than usual, several varieties having <2% infection with a maximum of 37%. By mid-July, the infection had increased significantly, ranging from 7 – 57%.

Spring barley – Leaf blotch infections were on the whole low in 2006. At Newtownards no leaf blotch was recorded. At the other three trial sites, significant Rhynchosporium infections did not appear until well into July. At Crossnacreevy, most varieties had low levels of infection of <5% with only two varieties having infections >5%. Similarly at Strabane, maximum levels of 7% were recorded by late-July. At Coleraine, trace amounts of leaf blotch were recorded towards the end of June and by late-July all varieties were affected, ranging from <5 – 35%. Mildew was not observed at Strabane, with trace amounts in a handful of varieties at Crossnacreevy, Coleraine and Newtownards. Net blotch was more widespread and at higher levels in 2006 than in previous years. At Coleraine, it started to appear in late-June and all varieties were infected by late-July, ranging from 5 – 17%. Similarly at Crossnacreevy, all varieties were infected by net blotch but the level of infection was lower than that at Coleraine, ranging from 1 – 6%. Only a few varieties had trace amounts at Newtownards and no net blotch was seen at Strabane. Physiological spotting only appeared in trace amounts at Strabane and was not observed at the other three spring barley trial sites.

Spring oats – Very little mildew was recorded at the two spring oat trials until the end of July in 2006. By this time, the percentage infection ranged from 0.1 – 45% and 0 – 50% at Crossnacreevy and Loughgall, respectively. Crown rust was not found at either spring oat trial site. Very little Septoria avenae was observed in 2006. By the end of July maximum infections of 4 and 0.1% were recorded at Crossnacreevy and Loughgall, respectively.
Maturity
Spring barley varieties differ in maturity by approximately two weeks from earliest to very latest. There are only minor differences in maturity amongst spring oat, winter barley, winter wheat and winter oat varieties. Maturity of varieties is included in the tables for all crops as early (E), intermediate (I) or late (L) to ripen.
Sprouting
Germination of grain in the standing crop is extremely detrimental to the quality of the harvested grain and, whilst it can occur in all crops, it is most commonly a problem of wheat. Some varieties showed greater tendencies to sprouting than others. Growers in the wetter areas of Northern Ireland have always taken account of this problem when selecting varieties. The tendency to sprout is indicated in individual variety descriptions if it constitutes a particular strength or weakness of that variety.