The present research study identified garden pea varieties with pronounced
tolerance to the allelopatic action of Sorghum halepense. Nine varieties
were selected to study the effects of shoot and root weed biomass, applied
in three extract concentrations (1, 5 and 10%), on seed germination and
initial germ growth. A variance analysis of data revealed significant
influence (p <0.05) of three studied factors (variety, type and
concentration of extracts) on the investigated parameters. Statistically
insignificant was only the influence of extract type (root/aboveground
biomass) on seed germination. Based on absolute values of the allelopathic
indicator RI, which determines the degree of allelopathic inhibition in
terms of germination, germ length and weight in different varieties, the
variation was as follows: from -0.30 to -0.04, from -1.31 to -2.96 and from
-0.47 to 0.02. The total effect of allelopathic action of S. halepense on
all studied parameters, presented as a GGE-biplot analysis, defined
Pulpudeva and Puldin varieties as exhibiting higher tolerance, in contrast
to Denitsa and Vyatovo, which were sensitive. Ran I, Mira, Musala and
Vechernitsa occupied an intermediate position. Cultivation of allelopathic
tolerant varieties is a promising addition to the current weed control
strategy, especially in organic production.