SURVEY ON THE EXISTANCE OF ECOTYPES AMONG THE POPULATIONS OF FIELD BINDWEED

In order to identify ecotyps of field binweed (Convolvulus arvensis L.), seeds from eight proviences, including 125 populations were gathered and sent to Weed Research Department of Plant Pests & Diseases Research Institute, Tehran, Iran. These seeds planted in a uniform environment condition in Tehran. On the base of 24 morphological and physiological characteristics of seedling that derived from rhizomes, 21ecotypes recognized. Consistent variation in leaf morphology, floral characteristics and degree of leaf and flower pubescence, when ecotypes grown in an uniform conditions were found. Mature blades of the different field binweed varied in length from 2 to 4.5 cm and in width from 1.2 to 3.1 cm. Leaf shape greatly varied among the different field binweeds (Fig. 2). Leaf angle varied from 32 to 69 degree for the different ecotypes. Flower diameter varied from 1.7 to 3.3 cm for the different ecotypes. In majority of ecotypes, stigma lobes raised above the anthers. The ecotypes also differed in their flowering capacity. The earliest flowering ecotype formed flower 50 days before the latest and produced 6 times more flower per plant, which indicated further differences in seed production potential between ecotypes. The variability in growth and reproduction observed between these field binweed ecotypes may explain the survival and adaptability of a population of this weed as environmental condition and control practices change.