ABSTRACT
Cotton (Gossypium hirsutum) is a global cash crop which has gained importance in earning foreign exchange for each country. Bacterial blight caused by Xanthomonascitri subsp. malvacearum (Xcm) has been a seriousdisease in Pakistan's cotton belt on multiple occasions. Bacterium was isolated and identified through various biochemical and diagnostic tests wherehypersensitivity reaction, Gram staining, KOH (potassium hydroxide), catalase, starch hydrolysis, lecithinase and Tween 80 hydrolysis tests confirmed bacterium as Gram-negative and plant pathogenic. Xcm perpetuation assays wereevaluated on various cotton varieties under glasshouse conditions in completely randomized design by three different methods, wherein the scratch method proved to be the best upon CIM-496 and showed 83.33% disease incidence as compared with the other two methods, where Bt-3701 responded with 53.33% incidence via the spray gun method, and 50% with the water splash method on CIM-616, as compared with the control. Similarly, for disease severity percentage, Bt-3701 was pragmatic with 47.21% through scratch method, whereas, in the spray gun method, 45.51% disease severity was noted upon Bt-802, and 31.27% was calculated on Cyto-179 through the water splash method. Owing to the unique antibacterial properties of aqueous plant extracts, the poison food technique showed Aloe vera, Mentha piperita, Syzygiumcumini and Azadirachta indica with 17.77, 29.33, 18.33 and 20.22 bacterial colonies counted on nutrient agarmedium petri plate, respectively, as compared with the control. Measurement of the inhibition zone by disk diffusion technique showed Mentha piperita, Syzygiumcumini, Citrus limon, Moringa oleifera and Syzygium aromaticum to present the most promising results by calculating the maximum diameter of the inhibition zone, viz., 8.58, 8.55, 8.52, 8.49 and 8.41 (mm), respectively, at the highest tested concentration (75 ppm, parts per million) compared with the control. It is probable that the decoction's interaction with the pathogen population on the host plant will need to be considered in future experiments. However, at this moment, more research into the effective management of cotton bacterial blight by plant extracts in terms of concentration determination and development of biopesticides will provide future avenues to avoid environmental pollution.
ABSTRACT
Mismanagement in foliar fertilizer application at different crop stages decreases the productivity of the crop. Likewise, higher application of phosphorus (P) beyond recommended application rates not only decrease zinc (Zn) uptake in rice but also increase fertilizer use cost. Inoculation of arbuscular mycorrhizae (AMF) may optimize the uptake of P and improve crops production via organic secretions. That's why the current study was conducted to examine the individual and coordinated effects of 0.5% Zn (0.5Zn) foliar spray (tillering (T) and/or panicle (P) initiation stage) and AMF application. Application of foliar 0.5Zn at tillering+panicle stage remained significantly better for significant enhancement in plant height, spike length, gas exchange attributes and total chlorophyll contents than control. A significant decrease in electrolyte leakage Also validated the effectiveness of treatment 0.5ZnT+P compared to control. Compared to control, the maximum increase in N (14.5 and 25.7%), P (42.1 and 33.3%), K (22.2 and 30.0%) and Zn (19.3 and 27.8%) accumulation was also found in 0.5ZnT+P, with and without AMF, respectively. In conclusion, 0.5ZnT+P with AMF is a better approach than sole application of Zn at tillering or panicle initiation stages. Nevertheless, more investigations are suggested at field level under variable climatic zones to confirm the effectiveness of 0.5ZnT+P with AMF for improvement in rice growth and production.
