Bel Hadj Chedli Rim*, Abid Ghassen, Sassi Khaled
The effects of the artificial inoculation by two biofertilizer based on Arbuscular Mycorrhizal Fungi (AMF) in the presence and absence of compost were studied on some morphological, physiological and agronomical traits of cultivated durum wheat (Triticum turgidum L. var. durum Desf.) in Northern Tunisia according to organic cropping system. Their effects were also investigated on the expression profiles genes involved in nitrogen assimilation: (GS) and (NR) encoding for Glutamine Synthetase and Nitrate Reductase respectively. Results indicated that the best grain yield, 1000 grain weight, grain number per spike, spike number per square meter and spike length, are obtained in plants that received the combined treatment (compost before planting and inoculations with AMF). This treatment significantly increased biological yield (9.1 quintals/ha against 7.2 quintals/ha in the control), chlorophyll (29.18 mg/g FM against 13.24 mg/g FM in the control), dry weight (7.1 T/ha against 5.1 t / ha in the control), plant height (76.61 cm against 66.6 cm in the control) and the leaf area (18.93 cm2 against 12.4 cm2 in the control). On the other hand, results indicated that an over-expression of (GS) was observed after the application of AMF and also in the combined treatment (AMF-compost) especially during grain filling stage. Higher expression of NR was also recorded in mycorrhizal-composted wheat plant after and before grain filling stages. Thus, this approach helped to reveal the importance of the application of mycorrhizae-compost in terms of improving plant growth and wheat production.