influence of environmental factors on seed germination and seedling emergence of rye (secale cereale l.) as a volunteer plant in wheat fields

laboratory and greenhouse experiments were conducted to determine the effects of drought and salinity stress, temperature, ph and soil depth on rye germination and emergence in gorgan university of agricultural science and natural resources. optimum temperature for germination between 25 to 34.51   oc and base and ceiling temperatures were estimated as 3.3 and 40   oc, respectively. this volunteer plant withstanded against salinity stress in respect to germination. salinity stress up to 257 mm had no effect on rye seed germination, but germination decreased as salt concentration increased. the drought and salinity levels were enough for 50% inhibition of maximum germination were as -17.9 bar and 456 mm, respectively. the optimum ph for germination of ray seeds was between 4 to 6. germination at ph 4 to 6 was over 60%, and declined at alkaline ph levels (ph 7-9). maximum emergence occurred when the seeds were planted at 2 cm depth. seedling emergence was higher (70%) for seeds placed at a soil depth of 2 cm than for those placed on the soil surface (63%). germination decreased with increasing depth and no seed emerged from a depth of 8 cm. considering that rye seeds can germinate under a wide range of environmental conditions, it is not surprising that it has became a serious invasive weed in wheat fields.