Control measures of root rot fungal pathogens by producing resistance against twelve wheat cultivars under greenhouse in Nebraska State of USA

摘要

Susceptibility or resistance against three strains of root rot pathogens of twelve wheat cultivars were analyzed in Nebraska State of USA. It was mainly focused on the screening of twelve wheat varieties against Fusarium graminearum strain W433 and two strains (G256 and W1624) of Rhizoctonia solani . These pathogens contributed to significant yield reduction. Agar plug inoculation and biological control agents culture suspension techniques were used for experimental trials. The disease severity was measured against three fungal strains by agar plug inoculation method (APIM). It was observed that wheat cultivars (WC) Freeman (2.00) and NW07505 (2.50) were moderately resistant while Overland (3.25), Overland FHB10 (3.00), Panhandle (3.75), Ruth (3.50), Mattern (3.75), RedHawk (3.00) and SY-Wolf (3.25) rated as susceptible against Fusarium graminearum strain W433. Overland FHB10 (1.75), Panhandle (2.00), NW07505 (3.00) showed moderate resistance and Freeman (4.00), Ruth (3.75), Mattern (4.25), McGill (4.00) rated as susceptible against Rhizoctonia solani strain G256. Similarly, Rhizoctonia solani strain W1624 showed less disease severity against Freeman (2.00), NW07505 (2.00), SY-Wolf (2.00) while more severity appeared against Overland (3.50), Robidoux (3.50), Ruth (4.00), Mattern (4.00). According to statistical evaluation, all artificially inoculated wheat cultivars (WC) with W433 strain showed almost similar shoot length (L) while fresh weight (FW) of shoot was slightly variable between treated and non-treated varieties. Similarly, root length, root FW and dry weight (DW) of wheat lines appeared significantly similar. It was estimated that all artificially inoculated WC indicated slightly reduced biomass in comparison to control after six week harvesting periods. Shoot length of five artificially inoculated WC with strain G256 as V 1 (Freeman), V 6 (Ruth), V 7 (Settlers), and V 9 (Mattern) showed less weight when compared with control. Wheat lines V 6 (Ruth), V 7 (Settlers), V 9 (Mattern) and V 11 (RedHawk) also reduced shoot FW weight after pathogen inoculation. Dry weight of shoot was also reduced in seven varieties after inoculation of W1624 strain. It was noted that Rhizoctonia strain W1624 was more virulent to cause root rot disease and reduced more biomass of yield components in comparison to Rhizoctonia strain G256.