Exogenous utilization of nano-biomass of Carthamus oxyacantha to improve yield and drought tolerance of wheat under rainfed conditions.

Carthamus oxyacantha is the noxious weed of Pothwar Region of Pakistan. This weed has excellent growing and surviving characteristics even under extreme stress conditions that may be due to its higher level of phenolic compounds. Similarly, utilization of nanotechnology is a novel and innovative field. Drought is threatening the productivity of wheat worldwide as a main environmental stress, especially in countries like Pakistan, where about 25% of cultivated area is rainfed. The Fourier Transform Infrared Spectroscopy spectrum of Carthamus oxyacantha nano-biomass showed the presence of seven functional groups (alcohols, phenols, alkanes, 1-amines, aromatics, aromatic amines and alkyl halides). Plant phenolic compounds can act as antioxidants, structural polymers (lignin), attractants (flavonoids and carotenoids), UV screens (flavonoids), signal compounds (salicylic acid and flavonoids) and defense response chemicals (tannins and phytoalexins). They also play a crucial role in the tolerance mechanisms against a wide range of stresses. So, it was hypothesized that the exogenous application of nano-biomass of aforesaid weed as catalytic agent may improve the drought tolerance of wheat and this technology will be proved as an environment friendly solution for drought prone areas. The nano biomass of the subject weed was prepared through top-down approach and was applied exogenously through petri dish, test tube, pot experiments and then under open field conditions at different crop growth stages of wheat. Results of petri dish, test tube and pot experiments showed positive effects of nanobiomass upto certain limits but affected negatively beyond 250 ppm. The results of field experiments showed that there were 55.55 and 68.75% increase in the crop growth rate of wheat in 2020 and 2021 by three applications of nano-biomass at 250 ppm compared to control. Similarly, 61.27 and 53.97% increase in the grain yield of wheat was recorded with nano-biomass application compared to control in 2020 and 2021 respectively. Similarly, there was 250% and 252% decrease in the proline accumulation where nano biomass was applied by three times at different growth stages of wheat as compared with control during 2020 and 2021 respectively which confirmed the presence of drought stress in control treatment but mitigation in treated plots. So, results of this study clearly exhibited that the application of this technology would be useful to mitigate drought stress under rainfed conditions and we can increase our wheat growth and production by following this technique under this changing climate. Moreover, the application of this technique is user and environment friendly. The study is also suggested to be evaluated for other crops. [ABSTRACT FROM AUTHOR]