EFFECTS OF ENVIRONMENTAL-FACTORS ON DORMANCY AND GERMINATION OF CRENATE BROOMRAPE (OROBANCHE CRENATA)

The effects of acid scarification, prechilling, summer irrigation, and root extract stimulant from faba bean plants grown during different s easons on crenate broomrape seed dormancy and germination were determi ned, Immersion of 6- to 12-mo old seed in 0.5 to 5 N H2SO4 solution fr om 1 to 20 min increased germination by 20%, Similarly, seed pretreatm ent at temperatures between -4 and 6 C increased germination, regardle ss of the pretreatment duration, Results suggest that the hard seed co at is an important dormancy mechanism in newly formed crenate broomrap e seeds, Summer irrigation did not substantially change the germinatio n capacity of crenate broomrape seeds, The germination stimulant activ ity of the root extract from faba bean plants grown during different s easons varied considerably, decreasing in this order: autumn > winter > spring > summer, This suggests an ecological adaptation of crenate b roomrape to its main host crop.