“…Environmental stresses imposed on the parent plants can induce genetic changes in the offspring of flax (Durrant, 1958(Durrant, , 1962(Durrant, , 1971(Durrant, , 1974(Durrant, , 1981, peas (Highkin, 1958a(Highkin, , b, 1961Ketellapper, 1963) and Nicotiana rustica (Hill, 1965;Perkins et al, 1971;Moore & Eglington, 1973;Towey & Jinks, 1976). However, no heritable change could be found in watercress, peas, carrots and lettuce associated with differences in parent plant nutrition (Austin & Longden, 1965;Maxon Smith, 1976).…”