Last week’s Teagasc Tillage Conference was a tight online affair that delivered sharp messages from recent and ongoing research.
We heard about some of the research on oats, rye, BYDV monitoring and beans, and we were also told about how the VICCI project was delivering real benefits for plant breeders and, hopefully, ultimately for farmers.
This was part one of a split conference and the second session will take place on 17 February.
A research project being conducted across Ireland, Wales and England is testing the justification of having optimum nitrogen rates for individual oat varieties. This might seem unusual in terms of other cereals, but the study has already found significant differences in the optimum N rate for individual varieties sown in spring, but not in winter.
The reason this would be a factor in oats is that increasing N rate, even up to the optimum level for grain yield, tends to be negative for grain quality characteristics such as specific weight and screenings. With more of the crop destined for quality markets with a price premium, it is increasingly important that growers do not penalise themselves by applying excess nitrogen.
This is just one year’s work and it is planned to have Husky sown at the Carlow sites for the 2021 trial year
The research, which used all UK-recommended winter (true winter types) and spring varieties, thus far, found that high N rates could push some varieties below the 52KPH cut-off required as a minimum spec. The research tested nitrogen levels up to 300kg N/ha and found that increasing N rate decreased specific weight and increased screenings in most varieties.
This is just one year’s work and it is planned to have Husky sown at the Carlow sites for the 2021 trial year. It is possible that an autumn-sown spring variety would show somewhat different responses.
Late last year, Teagasc carried out a survey of bean growers and Sheila Alves, Teagasc Oak Park, reported some of the findings. The 81 grower respondents reported bean yields ranging from 1.2 to 7.6t/ha. That yield range obviously had huge implications for margin, from very negative to pleasantly positive. It is also likely to affect the grower’s attitude to the crop in future years.
The top 25% of yields ranged from 5.4 to 7.6t/ha
Roughly a quarter of the growers (23) had yields between 1.2 and 4.2t/ha and the average performance of this group was 3.2t/ha, which left a negative margin of €63/ha, including the protein aid. The top 25% of yields ranged from 5.4 to 7.6t/ha – a very credible performance given the potential impact of the drought last year. The average yield in this grouping was 6.1t/ha and this resulted in a comparable margin of €545/ha.
While all the reasons for this yield variability may not be known, Sheila said that getting the plant density between 25 and 35 plants per square metre, getting the crop planted between mid-February and mid-March and getting fungicide timing right, starting at the early to mid-flowering stage and following up at the pod setting/pod filling stage, were all critical factors in crop performance.
While it was not mentioned, soil fertility is also of paramount importance to this crop.
Teagasc is currently putting in place a new monitoring system for aphid migration and BYDV risk assessment. This involves the erection of three tall suction towers, which collect aphids to be assessed for both species and virus.
Max Schughart said he has begun working on aphid and virus monitoring using suction towers that pull insects from the air, moving at 12m height. The spread of BYDV is primarily driven by two aphid species, the bird cherry-oat aphid and the grain aphid, so these are of greatest interest. As well as counting the numbers in flight, the captured aphids are also tested for the presence of virus, because if they are not carrying BYDV, they cannot transmit it. Up to now, all control advice was based solely on aphid numbers.
Last year was the first year of testing, so there is limited information available so far. However, spikes of aphid flight were detected in different weeks and Max indicated that numbers of winged aphids are always much higher when the mean temperature is at 15°C or higher. This could be seen clearly in the results he presented. However, he also observed that the numbers of flying aphids captured were noticeably lower in periods of high wind and rain.
In all instances, the predictions being evaluated will be cross-referenced by infield sampling for aphids and virus
While there were differences in the flight patterns for the two species, Max said that aphid flight largely finished around the end of October in 2020, but there were very small numbers after that time.
During question time, Ewen Mullins of Teagasc said the monitoring towers were only part of a more comprehensive evaluation process, where there will also be a number of mobile 6m towers used to test the accuracy of the taller fixed towers. In all instances, the predictions being evaluated will be cross-referenced by infield sampling for aphids and virus.
One other element of the new aphid monitoring system involves the use of digital droplet PCR testing. This can be used to detect very low levels of the virus, to test individual aphids for the presence of BYDV and to test for the presence of the virus in symptomless leaves.
Asked if the influence of high wind speed on aphid flight was because they preferred not to fly or if the trap could not pull them from the high air speed, Max said the belief is that they prefer not to fly in high wind.
Dan Milbourne of Teagasc explained how new breeding techniques and technologies are being used at Teagasc to enhance the genetic base of possible future varieties. He told us that the potato breeding programme at Oak Park has produced a new variety that is resistant to both types of potato cyst nematode, with the help of new breeding technologies and genetic markers (see ifj.ie/potato).
Having tested over 1,000 lines acquired from the UK, they found that some had very good natural resistance
Dan said they have taken a number of field bean varieties and produced a variant that has yielded well in trials, and it appears to be more resistant to diseases. This information can now be shared with plant breeders to help them breed varieties better suited to the Irish climate.
He also explained how they used genetic tools to identify new sources of resistance to septoria. Having tested over 1,000 lines acquired from the UK, they found that some had very good natural resistance. After crossing some of the good ones together to produce new lines, they found that some of these had even better resistance to septoria than either of their parents.
This finding helped unravel the basis of genetic resistance to septoria and opened up discussions and collaboration with plant breeders.
Again, it is hoped that this collaboration will help in the production of new varieties that are better suited to withstand the vagaries of the Irish climate.