Working collection of crimson clover (Trifolium incarnatum L.) in the Ciscarpathia

Abstract

Aim. To identify collection accessions – sources of valuable traits for using as starting material to create varieties of perennial grasses in Western Ukraine. Results and Discussion. The vegetable protein problem is one of the main issues facing scientists whose activities are related to agriculture, ecology and other areas of biology. The Ciscarpathia is a zone of natural meadows, hayfields and pastures, where a large number of plant species belonging to different botanical families grow. Among the natural vegetation on pastures, meadows and fallows, clover species are most often found. Trifolium incarnatum L. is an annual winter-spring plant. It is widely used in agriculture as a nitrogen-fixing cover crop. The crimson clover collection comprises 24 accessions. Some promising accessions that can be used as starting material in breeding for high productivity (green mass, hay and seeds), herbage capacity, resistance to diseases and pests were selected. Reference accessions and sources of economically valuable traits, which are actively involved in breeding, were singled out. During the study (2019-2021), accessions were investigated in detail for biological and morphological features. We evaluated the crimson clover collection for germinability, winter survival, flowering time, green mass per plant, and seed yield. The results showed that the crimson clover collection could be tentatively divided into 3 groups: early-ripening (70-79 days; 37.5%), mid-ripening (83-87 days; 50.0%) and late-ripening (92-94 days; 12.5%). Nine accessions (PFZ 00625, PFZ 02148, PFZ 01264, PFZ 01266, PFZ 01295, PFZ 01273, PFZ 01270, PFZ 02266, and PFZ 02265) ripened slightly earlier. They are potential parents to develop an early-ripening population. Three accessions (PFZ 02268, PFZ 02267, and PFZ 02073) ripened significantly later than all the others. Thus, these accessions are excellent candidates to develop a late-ripening population. Depending on the region and cultivation system, farmers may be interested in both early-ripening and late-ripening crimson clover. Conclusions. Literature review allowed us to note that the studied crimson clover accessions had several advantages when used in production, namely: they are annuals, have high vegetation rates and productive potentials. Crimson clover accessions showed particularly distinct differences in autumn emergence and flowering time, indicating greater diversity and potential for breeding. In contrast, winter survival, green mass per plant showed greater intra- and inter-year variations. Autumn emergence and winter survival were found to be positively correlated, and both traits were negatively correlated with green mass per plant. Some accessions were identified as highly effective in several key traits and are of particular interest as parents in further breeding: PFZ 02118, PFZ 01270, PFZ 02267, PFZ 02073, PFZ 02072, PFZ 01290.