Herbe-book, new calculation method now online
The new version of the Herbe-book website, which lists forage plant varieties and enables their agronomic value to be compared, went online on 27 September.
It is based on the calculation method developed as part of the Herbe-book Recherche project, run by GEVES since 2022.
The values displayed on the website come from the VSCU forage trials supervised by GEVES as part of the variety registration process. In order to be able to compare them with varieties tested in different years, their values have been re-estimated using a new statistical method. The aim of this change in calculation method is to make better use of the intrinsic value of varieties, while taking better account of the effect of the environment and the year in which the varieties were tested.
In this way, the genetic progress made in forage plants can be better exploited, and farmers and stockbreeders can choose better varieties.
The calculation method used until now was based on the average values of varieties and controls obtained throughout the evaluation network. However, this method had its limitations, particularly when comparing varieties that had not been tested together, as it took incomplete account of environmental effects.
The new statistical approach, known as the “mixed model method”, makes it possible to obtain an adjusted average of the characteristics studied for each variety. This method takes better account of other sources of variability, such as effects linked to the years or locations of the VSCU trials, which are likely to influence the value of these characteristics.
The Herbe-book Recherche project involved GEVES, INRAE, UFS, SEMAE and Arvalis, enabling the data from more than 5,000 trials carried out by GEVES teams over the last 20 years to be upgraded.
The new calculation method was presented to industry professionals during a webinar, the replay of which is available on the SEMAE website.
Numerous articles describing, among other things, the origin of the data and statistical processing are available on the brand new version of the Herbe-book website.
