Evaluation of perennial ryegrass (Lolium perenne L.) genotypes within the framework of an international pre-breeding partnership | Ganību airenes (Lolium perenne L.) genotipu izvērtējums starptautiskā pirmsselekcijas projekta ietvaros

Within the framework of the Nordic-Baltic Public-Private Partnership project “PPP for pre–breeding of perennial ryegrass (Lolium perenne L.)” various types of activities from 2015 to 2020 in LLU Research Institute of Agriculture were carried out in the investigation of ryegrass genetic material. One of them was an evaluation of perennial ryegrass varieties and gene bank accessions (hereinafter genotypes) in different agro-climatic conditions, so this type of experiment was set up in institutions involved in grass breeding of all eight participating member states, including: Norway, Sweden, Finland, Denmark, Iceland, Lithuania, Estonia and Latvia. Genotypes were selected based on the results obtained previously within this project. A total of 40 tetraploid perennial ryegrass varieties and accessions were included in the experiment in Latvia, including 21 late and 19 early types. This paper summarizes the data of late varieties. The sowing of the trial was performed in July 2018. Various agronomically and phenologically significant traits were scored, including: winter hardiness, regrowth intensity, tendency to form culms after the 1st and 2nd cut, persistence or grass cover, susceptibility to rust and other diseases, dry matter yield, forage quality etc. The results of the first two years showed that no significant differences in winter hardiness were found until now. With better persistence stood out varieties ‘Barmaxima’, ‘Aston Princess’ and ‘Spidola’ for which grass cover in the 2nd ley year was over 90%. ‘Melbolt’, ‘Barmaxima’ and ‘Aston Princess’ were more resistant to rust: rust susceptibility was assessed with 1–2.5 points while the most susceptible varieties were rated with 5–7 points on a 9-point scale. In the autumn of the 2nd ley year the varieties ‘Barmaxima’, ‘Melbolt’, ‘SW Birger’ and ‘Raminta’ stood out in green grass without visible signs of disease. The average dry matter yield in two years of use was 8.87 t haE−1–11.78 t haE−1. The most productive varieties were ‘Nashota’, ‘Raminta’ and ‘Figgjo’. All ryegrass genotypes provided high-quality fodder. Neutrally detergent fibre (NDF) indicators ranged from 38.84% to 44.55%, acid detergent fibre (ADF) from 20.5 to 23.62%. The Relative feed value (RFV) index was high for all genotypes, ranging between 147 and 175. Each variety has its own essential qualities, the study of which will allow to use the information obtained for future pre-breeding activities and breeding work.