The article presents the results of a study on the effect of multiple reproductions on the morphological and biological characteristics of an ultra-ripe red clover (Trifolium pratense L.) variety Rannii 2 using varietal seed production technology. The study used the original seeds of the Rannii 2 variety, which were stored for long-term preservation in 1987, and the Rannii 2 seeds from the seed conservation nursery, obtained in 2024 after multiple rounds of reproduction in primary seed production nurseries. The research was conducted in the conditions of a selection and greenhouse complex, using 80 genotypes in each batch of seeds. The characteristics of the seed material indicated that the seeds from the 1987 harvest had a weight of 1000 seeds of 2.1 g and a germination rate of 48 %, while the seeds from 2024 had a weight of 2.0 g and a germination rate of 86 %, respectively. Analysis and mathematical processing of phenological observation data throughout the growing season and morphological characteristics of the studied populations showed that for all studied indicators, the differences between the samples are not significant with a probability of 95 %. It has been established that the use of varietal seed production technology in the primary seed production chain, including strict spatial isolation, desiccation and harvesting of seed grass when no more than 75 % of the heads are ripe, obtaining seeds from the second cutting with an interval of 3–4 reproductions, using seed grass in the second year of use with an interval of 4–5 reproductions, ensures long-term maintenance of varietal characteristics in the population.
Novoselov et al. (Thu,) studied this question.