Abstract

In the present investigation studies were made on the Phyto-toxicity of Heavy Metal Mercury (Hg) in four Wheat (Triticum aestivumL) varieties taking into consideration Germination Percentage (GP) and Speed of Germination Index (SGI) to bring out varietal tolerance behavior. It was observed that the germination decreased in the four wheat varieties viz., V1 Lok-1, V2 UP-2338, V3 PBW-154 and V4 PBW-502 with increasing concentration of Hg. A comparison with controls in the four varieties recorded in the controls: at 24 hours GP was lowest in the variety V1 (23.66%) and highest in V4 (26.66%); at 48 hours lowest in V1 (51.0%) and highest in V4 (54.66%); at 72 hours lowest in V1 (61.33%) and highest in V3 (66.66%); at 96 hours lowest in V2 (82.0%) and highest in V3 and V4 (84.33%) and at 120 hours lowest in V2 (86.0%) and highest in V3 (94.0%) respectively. On the other hand, in 100, 200 and 300ppm of mercury concentration treatments there was no germination found at all at 24 hours in all the four varieties while in 100ppm at 48 hours lowest GP was in V2 (16.0%) and highest in V3 and V4 (21.33%); at 72 hours lowest in V4 (31.33%) and highest in V2 (36.0%); at 96 hours lowest in V1 (44.0%) and highest in V2 (49.0%) and at 120 hours lowest in V4 (51.0%) and highest in V2 (53.66%) respectively. In 200ppm Hg concentration at 48 hours lowest GP was found in V4 (9.66%) and highest in V3 (13.66%) respectively; at 72 hours lowest in V4 (25.66%) and highest in V1 (37.0%); 96 hours lowest in V4 (37.33%) and highest in V1 (43.0%) and at 120 hours lowest in V3 (42.0%) and highest in V4 (48.33%) respectively. Lastly, in 300ppm at 48 hours lowest GP was in V4 (3.0%) and highest in V1 (5.0%); at 72 hours lowest in V2 (8.0%) and highest in V1 (12.0%); 96 hours lowest in V4 (17.0%) and highest in V1 (21.66%) and at 120 hours lowest in V2 (26.0%) and highest in V1 (32.33%) respectively. A comparison with controls in the four varieties recorded maximum average GP (65.13%) in control sets of var. V3 whereas minimum (11.2%) was recorded in the 300ppm Hg treatment sets in the var. V2. On the other hand, data on the basis of percent over control showed maximum GP (48.98%) in the var. V2 in 100ppm Hg treatment and the minimum (18.0%) was also recorded in the var. V2 in 300ppm Hg treatment. Showing a clear cut maximum decrease of (-81.99%) in the var. V2 in 300ppm Hg treatment and also minimum decrease of (-51.02%) in the var. V2 in 100ppm Hg treatment. With this SGI showed the trend as highest (811.66) in controls of V3 while lowest of (102.0) in V2 in 300ppm Hg treatment while data on percent over control basis showed highest (43.08) in 100ppm Hg treatment in the var. V1 while lowest (13.03) in 300ppm Hg treatment in the var. V2. Showing maximum decrease of (-86.96) in the var. V2 in 300ppm Hg treatment and minimum decrease of (-56.91) in the var. V1 in 100ppm Hg treatment.

Keywords: Wheat varieties; Germination percentage (GP); Speed of germination index (SGI); Mercury toleranc