Endophytic Fungi Improve Growth and Yield of Wheat (Triticum aestivum L.) Under Limited Light Conditions

Shading is a major challenge to the important agronomic traits of crops, which may be caused by climate change and light obstructions in terms of various intercultural practices. The objective of this study was to investigate the yield, growth traits, photosynthetically active radiation (PAR) transmittance parameters in wheat (Triticum aestivum L.) and their interaction with endophytic fungi under various light intensities. The experiment was carried out as a split-plot with six replications in randomized complete block design. Experimental treatments consisted of four light intensities (normal light, 70, 50, and 30% of normal light) as the main factor and two fungul inoculation levels, as biofertilizer (inoculation and non-inoculation of Piriformospora indica and Trichoderma longibrachiatum) as a sub-factor. Results illustrated that low light intensity (30% of natural light) significantly reduced the growth and yield traits such as stem diameter (29%), extrusion (29%) and spike length (29%), stem (17%), flag-leaf (35%), shoot (36%), and spike dry weight (51%), spike number per m(2) (7%), grain number per spike and grain yield (44% and 52%), while increased flag leaf area (21%), plant height (25%), and peduncle length (12%). These growth and yield losses were compensated by endophytic fungi application. Besides, although normal light enhanced the weight and number of weeds, endophytic fungi application decreased these traits at every level of light treatment. Furthermore, a reverse relationship was found between photosynthetically active radiation (PAR) transmittance and leaf dry weight. Overall, this study strengthens the idea that endophytic fungi can be used as a supplement to crop production, especially in limited light conditions, to promote agronomic performance and yield of wheat plants.