Seedling Vigour

Hi All,

An update from me prompted by Andrew and my attendance at the recent LiveSeeding kick-off meeting last week in Zagreb. Organic Arable have an important role within the project as part of the "living labs" (more on this to follow) taking advantage of our farmer network and the participatory appproach to variety testing.

I met a researcher from France who works on seedling vigour which is described as "a complex agronomic trait that includes seed longevity, germination speed, seedling growth, and early stress tolerance". Interestingly, seed vigour helps to reduce the risk of bunt, as well as making it more resilient at a vulnerable time in the crop's lifecycle. Seed vigour "determines the duration and success of the establishment period" and should lead to early vigour post establishment that will help with weed suppression and resilience against biotic and abiotic stresses. The LiveSeeding project will address this trait and perform experiments to compare seed from different sources, with organic seed, conventional re-clean only and home-saved all being tested. It is thought that the microbiome of the seed will alter depending on the source and may be part of the mechanism for promoting early vigour. The hypothesis would be that Organic seed, being produced from more biodiversity rich environments will have greater levels of beneficial microbes. It may also be that home saving provides the farm microbes that support a microbiome relevant to the environment and conditions that the seed is grown in. This may be one of the reasons behind the claim that for home-saved seed, crops "adapt" to the farm environment, which of course doesn't take place genetically when cultivating single varieties that are all genetically identical. This crop adaption to the farm environment can only be true if using mixtures or heterogenous populations that are rich in genetic diversity.

Seedling vigour is a trait that needs to be better understood and undoubtedly has a genetic basis meaning some varieties will perform better than others although environmental factors will affect it and as previously mentioned, seed source is also likely to play an important role. It may well be worth your own farm experiments to compare directly farm-saved seed with new seed to see if you can detect a difference. If saving seed, cultivating in the best possible conditions (e.g., your better fields), and a rigorous seed cleaning will all contribute to greater seedling vigour, with larger seed size also helping. Research has investigated whether the protein content of seed is an important factor but results were variable and in the end it was concluded that protein content was unlikely to have an appreciable effect in practical conditions.  Seedling vigour and early crop vigour is perhaps a trait should be included in our on-farm variety trials LiveWheat Legacy and LiveOat, with a simple ranking used for speed of emergence and for above-ground biomass following establishment, or a simple growth stage comparison as crops with the trait will reach successive early growth stages sooner for example, the 3-leaf stage (BBCH 13) or the tillering stage (BBCH 21). 

One potential finding of the LiveSeeding project may be whether buying new seed may be preferable to home-saving, as despite the farmer empowerment and cost saving, it might turn out to be a false economy if seedling vigour is reduced and disease risk increased. Beyond the Organic Principles, the project may also make the case of why the use of Organic seed is important and beneficial, especially given the number of derogations that are applied for.

Hopefully LiveSeeding will help shed some light on these important issues for Organic farming, and we will keep you updated on the progress of the project.

The same researcher was also responsible for creating a Common Bunt (Tilletia tritici) website as part of the previous project LiveSeed, to help farmers to manage the issue. The link is posted below and has plenty of useful hints and tips for reducing the risk or managing it if detected. The guide is directed to French farmers and therefore may also be more relevant for smaller scale production, but there is still a lot of good advice included.  Given the higher levels detected this year, possibly due to "favourable" conditions with some farms also being at higher risk, particularly where grain is regularly saved and resown, I thought it prudent to provide the information for managing the risk next harvest. Where grain is saved, it is imperative to get it tested for bunt given how quickly the fungi can spread and proliferate. The relative cost of disease testing is small compared to the issues that can be caused if the fungi takes hold.