Investigation of genetic diversity on M2 mutant lines of Purslane (Portulaca oleracea) derived through DMS mutagenes

Purslane (Portulaca oleracea) is one of the most widely used medicinal plants in the world that has many medicinal properties.To investigate the genetic variation in the second generation (M2) of purslane lines, a nested experimental design with two replication was conducted at the research farm of Shahed University, Faculty of Agriculture during 2017-8. Experimental treatments included M2 lines treated with dimethyl sulfate (DMS) at concentrations of 0, 0.08, 0.1, 0.12 and 0.14 %. The studied traits included plant height, number of branched stem, stem diameter (SD), stem fresh weight (SFW), stem dry weight (SDW), SDW/SFW, leaf fresh weight (LFW), leaf dry weight (LDW),  LDW/LFW, plant fresh weight (PFW), plant dry weight (PDW), PDW/PFW, leaf length, leaf width, leaf shape (LS), number of capsules (NC), chlorophyll content, leaf area, hectoliters. The differences among concentrations od DMS were significant at the level of 1%. The maximum amount for traits such as SD, SFW, SDW, NC, LDW/LFW, PFW and LS was observed at the concentration of 1%. Among the 190 incomplete correlation coefficients, 28 were significant (15%) while this value was 58% in the Pearson correlation coefficient. In factor analysis, 19 variables were reduced to 6 factors, which explained 71.86% of the data variation. In path analysis with repeated data, the direct effect of SFW on PFW was higher than the indirect effect, while this trend was reversed on LFW. In path analysis with mean of replications, the maximum indirect effect on PFW was from LFW and  LDW/LFW through SFW.