Production of slender cocksfoot (Dactylis polygama H.) tetraploid populations and their assessment for agromorphological characteristics

Some attempts have been made recently to expand the range of perennial grasses tailored to the requirements of modem farming. Attention has been drawn to the forage plant species that have not been widely used so far. Apart from the common cocksfoot (Dactylis glomerata L.), which is traditionally used as a forage, another cocksfoot species slender cocksfoot (Dactylis polygama H.) can be found in natural habitats in Lithuania. The plants of this species are characterised by some attractive traits: late maturity, better and more stable indicators of feeding value, and lesser aggressiveness (do not form tussocks). The genus Dactylis includes diploid (2n = 2x = 14) and tetraploid (2n = 4x = 28) species. The tetraploid D. glomerata varieties exhibit better agromorphological and quality characteristics. The current work was aimed to develop more productive tetraploid populations of slender cocksfoot and to assess them for agromorphological traits and compare them with diploid populations. The most effective method of tetraploid populations' development was proved to be colchicine treatment of meristems of young inflorescences by maintaining them on a nutrient medium supplemented with 0.2% colchicine for 96 h. Depending on the genotype, the tetraiploid yield ranged from 16.7% to 100%. A comparison of averaged biomass qualitative and quantitative indicators of diploid and tetraploid populations showed the tetraploid populations of D. polygama to be more, albeit negligibly, productive and of better quality.