Effects of cultivar genotypic diversity on weeds
In overall, the total density of weeds grown in genetically diversified wheat plots was significantly (P ≤ 0.01) lower than that in the monocultures (Figure 2). Weeds grown under monocultures of Shiroodi and ERWYT 91-11 showed the highest density, 33.33 and 30.17 plant m-2 respectively. However, the lowest weed density, 18.67 plant m-2, was observed where these two genetically diversified cultivar/line grew together in a mixture (Figure 2). These were a reduction of 44 % and 38 % compared with the monocultures of Shiroodi and ERWYT 91-11 respectively. Weed density in F2 generation was less than that in other monoculture treatments, though it was not significant (Figure 2). The density of weeds in mixture of three cultivar/lines, Shiroodi: ERWYT 91-11: ERWYT …show more content…
The total weeds biomass decreased significantly (P ≤ 0.01) in genetically diversified wheat plots compared with monocultures (Figure 3). The highest weeds biomass was observed in the monocultures of ERWYT 91-11 (M2) and Shiroodi (M1), 133 and 130 g m-2 respectively. Weeds biomass was the lowest, 76 g m-2, in Shiroodi: ERWYT 91-15 mixture (I2, Figure 3). This was a reduction of ~43 % and 41 % compared to monocultures of Shiroodi and ERWYT 91-15 respectively. The biomass of weeds grow in F2 generation cropping system was 119 g m-2 which was the lowest amongst monoculture treatments, though it was still higher than that in genetically diversified wheat plots (Figure 3). Overall, there was a negative relationship between weeds density and wheat biomass (P ≤ 0.05, Figure 4-a). We also observed a negative relationship between weeds biomass and wheat biomass (P ≤ 0.05, Figure 4-b). The negative effect of wheat biomass on the density and biomass of weeds was severe where the weeds grown in genetically diverse cultivar/lines mixtures (Figures 4- a & b; I1 to