Effect of Mycorrhiza, vermicompost and Nano silicon on agronomic and physiological traits of triticale under different intensities drought stress

Drought is the most severe abiotic stress factor limiting plant growth and crop production. Drought stress decreases the yield of many crops by inhibits plant photosynthesis and photosystem II efficiency. Mycorrhiza application is a strategy that can improve plant performance under stress environments and, consequently enhance plant growth through different mechanisms. The mechanisms used by mycorrhiza to enhance the water relations of host plants are not amply clear, however, this may occur by increasing water absorption by external hyphae, regulation of stomatal apparatus, increase in activity of antioxidant enzymes and absorption of nutrients particularly phosphorus. Also, vermicompost can directly increase plant production through increasing available plant nutrients and indirectly promote soil quality by improving soil structure and stimulating microbial activities, relative to conventional chemical fertilization. Silicon is an essential micronutrient for biological systems and plays a crucial physiological role in photosynthetic rate and chlorophyll content. Therefore, the aim of this study was to evaluate the effects of mycorrhiza, vermicompost and silicon on some physiological and agronomic traits of triticale under different intensities drought stress.

an experiment as factorial was conducted based on randomized complete block design with three replications in a research greenhouse of faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabil during 2020. The experimental factors were included irrigation in three levels (normal irrigation as control; moderate water limitation or irrigation withholding at 50% of heading stage; severe water limitation or irrigation withholding at 50% of poddind stage), application of organic and bio fertilizers (no application of bio fertilizers as control, application of vermicompost, Mycorrhiza application, both application vermicompost and Mycorrhiza), foliar application of Nano Silicon (foliar application with water as control and foliar application of 2 g.L-1).

The results showed that 81 days after planting, both application of vermicompost with Mycorrhiza and nano silicon foliar application under normal irrigation conditions, increased maximum fluorescence (43.93%), variable fluorescence (97.41%), quantum yield (37.05%), chlorophyll index (60.62%), nitrogen index (42.75%) and relative water content of flag leaf (84.27%) in comparison with no application of organic and bio fertilizers and nano silicon under irrigation withholding in podding stage. no application of organic and bio fertilizers and nano silicon under full irrigation increased electrical conductivity and minimum fluorescence of flag leaf. Also, both application of vermicompost with Mycorrhiza and nano silicon foliar application under normal irrigation conditions, increased grain yield (59.52%) in comparison with no application of organic and bio fertilizers and nano silicon under irrigation withholding in podding stage.

It seems that the application of organic and bio fertilizers and nano silicon can increase the grain yield of triticale under water limitation due to improve chlorophyll fluorescence and some physiological traits.