Suchergebnisse

Abstract
The aim of this work was to develop a red clover variety adapted to agro-climatic conditions of Latvia, suitable for different requirements of forage producers, resistant to most widespread diseases and producing high seed yield annually. Medium late ripening diploid red clover variety 'Jancis' was created at the LLU Research Institute of Agriculture in long-term work carried out since 1985. After free pollination of best samples of red clover collections from the VIR (St. Petersburg), individual and family selection among hybrids were carried out for approximately 20 years. Finally, best breeding line Nr. 43047 was registered as a variety 'Jancis'. The variety is characterised by good winter hardiness, high dry matter yield (10-12 t·ha-1) and good persistence in the sward - up to 3-4 years. The variety is characterised by a long stem (90-110 cm) with 8-9 internodes, dark green leaves with a distinctive brighter picture, medium length and width of medial leaflet, and bright pink flower heads. 'Jancis' has stable annual seed yield in the conditions of Latvia; under favourable conditions reaching 500- 600 kg·ha-1 seeds. Since 2010, the variety 'Jancis' has been included in the common Latvian and EU Plant Variety Catalogue.

Accessions with no germinating seeds are a common problem in plant gene banks and research institutions. Our goal was to elaborate and apply an in vitro method of germination and multiplication of old aged seeds of red and alsike clover and alfalfa. Eighteen clover and five alfalfa accessions were used for germination in vitro. Most of the accessions had produced seeds more than 20 years ago and the seeds did not germinate in soil. Seed pre-treatment with different concentrations of potassium permanganate, as well as addition of phytohormones, AgNO3 and activated carbon to germinating media were tested. Plantlets for all germinated accessions were obtained, even in the case when seeds were 44-year-old (alfalfa). Germination rate in vitro not always correlated with seed age and ranged from 2 to 72%. Pre-treatment with potassium permanganate was effective both for seeds sterilisation and germination stimulation. Most germinated seeds formed phenotypically normal seedlings with all organs. In vitro multiplication of obtained clover plants was performed. Best results were achieved by micropropagation of stem segments approximately 2 mm in length. Number of finally obtained plants depended not only on seed germination ability, but also on micropropagation ability in relation to genotype, and on acclimatization success in soil after in vitro cultivation