Every plant within the replicated plots was inoculated by hand with aphids, in early June, carrying either Beet yellows virus (BYV) or Beet mild yellowing virus (BMYV). From this trial yield losses of up to 42% and 20% were recorded across varieties due to the infection with either BYV or BMYV respectively. This confirms previous findings of the significance of these viruses on yield potential of sugar beet. The charts below show the relative performance of the varieties in 2018 infected with either BYV or BMYV. Although ten varieties were tested only those varieties commercially available in 2019 are presented below.
BBRO would normally wait until it had more results than just one trial in one season before releasing any information, particularly as 2018 was an atypical season due to the wet March and summer drought. However, we believe, in light of the potential virus yellows pressure forecast for 2019 (see BBRO Bulletin 2) we should release some of these provisional data as it may help growers reflect on the order in which they drill varieties and harvest them.
It is important to note this data is from a BBRO research project and is not directly linked to the Recommended List. BBRO has not been able to test all commercial varieties to date and performance of most varieties on sale has yet to be determined.
Growers should note some infected varieties that had less visible damage to the foliage during the season were low yielding, whilst on the other hand some with damaged foliage were high yielding. The conclusion (albeit from one trial in one ‘unusual’ season) is that the state of the foliage of current varieties may not necessarily be an indicator of yield under virus infection. We are still trying to understand this relationship and continue to work on this on behalf of the industry.
BBRO welcomes feedback of experiences in 2019. For the future, breeders are working to produce true tolerant/resistant varieties and are collaborating with BBRO to help develop these for the future.