Study on the seed production and germination dynamic of common milkweed (Asclepias syriaca L.)

The common milkweed causes considerable damages on the agricultural and nature conservation areas. The area occupied by this weed is continuously bigger. The common milkweed is spread over North-America between the 35th and 50th degree of western Latitude and 60th 103rd degree of longitude. Millions of hectares are polluted by this weed in the United States. Important is its spread also in Asia (Iraq), in Europe (Carpathian Basin, Poland, Bulgaria, Switzerland, France, Austria, Germany), as well as in the area of the former Soviet Union (Belorussia, The Baltic Countries, Caucasus, and the Ukraine). Though the basic biological characters of this plant are well known, still its control is a significant problem, the damages increase on the areas occupied by this weed. We collect seed samples from several Hungarian areas in 2007. After the sampling we determined the average sprout length and the number of follicle as well as the average seed numbers in the follicle. We determined also the weight of thousand seeds of the resultant seed samples. At natural circumstances the seedlings appear at a soil temperature of 15 degrees C during the end of April and first week of May. Under Laboratory circumstances the dormancy of the seeds ceases continuously from November on, germinate at a temperature of 20-30 degrees C, the maximum germination can be achieved in the first part of April. At January we started germination examinations with the seeds in Petri dish, among laboratory condition.