Evaluation of species diversity and weed community structure in sugar beet (Beta vulgaris L.) fields of Khorassan Razavi and Khorassan Shomali

Biodiversity of natural ecosystems is often studied at three levels، ecosystem، species and genetic diversity. In fact، agrobiodiversity is the outcome of species، genetic and management diversity interactions. In order to investigate the species and functional diversity and structure of weed communities in sugar beet fields of different cities in Khorassan Razavi and Khorassan Shomali، 178 farms from 12 cities were studied. Data were collected from questioners، weed population sampling and interview with farmers. The results showed that weed population in different cities composed of 56 species in 14 plant families، in which dicotyledon species were more than monocotyledons. This community، 47 species were C3 plants and others were C4 species. These 56 species also included of 36 annuals، 2 biennials and 18 prennials. Poaceae and Asteraceae families showed the most diversity amongst the monocotyledon and dicotyledon، respectively. The results also shown that Chenaran and Khauf had the most (27 species) and the least (5 species) species richness. Sorenson and Steinhaus similarity indices were showed that Chenaran and Ghouchan showed highest similarity (0. 9%) whereas، Ghouchan and Khauf showed the least similarity index (0. 2%).