A comparison of ploidy status and weed growth analysis in different habitats

ABSTRACT: Polyploidy is a situation in which an organism has a complete additional chromosome set. It has been suggested that polyploidy weeds compared to their diploid ancestors, are more capable of thriving in disturbed environments and occupying newniches because of their wide genetic variance.Experiments were done in a sample regions selected from farms and their margins in 2011 and 2012 to determine chromosome levelsand weed species’ composition of warm season crops (rice, soybean, cotton) and cold season crops (wheat, colza). The total area selected for the study covered, 38611 ha of east and west of Mazandaran and Golestanstates, respectively.1830 samples fromdestructive plants were collected from 61 fields at intervals of 20 days and from quadrats of 0.5?0.5 m. Weed species were identified and evaluations were made for chromosomesandgrowth analysis.The results showedthat there was more evidence of polyploidy inthose species with more frequency outside of fields.The factors,polyploidy and location of weeds in fieldshadno significant effect on area and weight of leaf samples, but the weight of stem was affected by location of weeds. Compared to diploids, polyploidy species had higher scores for Relative Growth Rate (RGR) and Leaf Area Ratio (LAR).It seems that morphologic and physiologic changesare affected bythe presence of weeds in hard agronomic conditions. Thisstudy recommends that for a resistance to weedcommunities, it is better to select crop species with higher scoring RGR and LAR.