Evaluation of genetic variation in pigweed (Amaranthus spp) based on morphological and physiological traits by using of nitroxin

In consideration of nutrition deficiency in grasslands, utilizing of biological fertilizer and cultivation of resistant plants such as pigweed may help to amend grasslands. Thus, in order to evaluation nitroxin effects on pigweed, a factorial experiments was performed based on a completely randomized design at Damavand during 2010. The first factor consisted of three levels of nitroxin (0, 1, 2 Kilogram per hectares) and the second factor consisted of eight species of Amaranthus from different regions of Iran. Evaluated traits consisted of fresh and dry weights, stem height, dry matter percent, leaf number and area, chlorophyll a, b and total chlorophyll contents, chlorophyll a to b ratio, carotenoids contents, carotenoids to total chlorophyll ratio, anthocyanin and flavonoid contents. Analysis of variance and mean comparison showed that the first and second factors and their interaction were significant on most of the studied traits. A. retroflexus from Zarand Kerman was the best based on the most of the traits. The best answer were achieved in 1 kg/ha nitroxin for the most of traits. The best results for stem fresh and dry matters were achieved in 1 and 2 kg/ha nitroxin for A. retroflexus from Zarand Kerman. The best results for plant pigments were achieved in 2 kg/ha nitroxin in A. retroflexus from Tehran. Based on principal components analysis, the first three components could explain 88% of the total variance.