Functional characteristics of local wild-growing germplasm from tedera (Bituminaria bituminosa (L.) Stirt.)

Abstract

Tedera or arabian pea (Bituminaria bituminosa (L.) Stirt.) is a perennial pasture legume of Mediterranean origin, which is also naturally distributed in our country. Its increased participation in post-fire successions or in degraded xerothermic grassland communities suggests the importance of this species for the functioning of meadow ecosystems in Northern Bulgaria under conditions of adverse anthropogenic and climatic impacts. The article presents results on the biological, morphological, bioproductive and reproductive manifestations of tedera populations in relation to the conditions of habitats typical of the hilly regions of the Danube Plain and the Central Fore-Balkans. The experimental work was carried out in the period 2022-2024. It was found that differences in the soil conditions of the habitats, as well as differences in climatic factors over the years, do not cause significant reactions in the phenological development of the species. A significant effect of habitat was observed in terms of productivity of fresh and dry biomass, as well as in terms of all observed reproductive characteristics. The highest values for yield of fresh and dry vegetative mass were recorded for population 144, developing on leached chernozem soils, at the lowest altitude. Population 420, which develops on heavily eroded gray forest soils on sloping terrain and the highest altitude, is significantly less productive and poorly leafed, but stands out with the most abundant flowering, significantly higher specific seed mass and the highest seed yield per unit area. Among the observed seed yield components, the number and yield of seeds per inflorescence are most affected by environmental conditions. Significant phenotypic variability was observed, associated with specific habitat conditions and in terms of plant height, specific leaf area and specific leaf mass. In both experimental years, population 375, which develops under conditions of partial shading on eroded cinnamon-podzolic soils, has the highest relative growth rate, estimated by the values of the indicated growth indicators.