Improving the quality of mother seeds of corn (Zea mays L.) cultivars grown in saline soil using combination of biochar, mycorrhizal fungus and silicon foliar application

IntroductionThe seed is the most important input of the agricultural section, which provides the reproduction, survival and extension of the plant. Therefore, identifying the factors affecting seed production and its quality at the production and harvesting stages is very important. Previous reports show that the use of soil modifier compounds such as biochar, arbuscular mycorrhizal fungus (AMF), and silicon foliar application can improve the germination indices of produced seeds under environmental stressess conditions, especially salinity stress. So far, the experiments conducted to investigate the effect of biochar, mycorrhizal fungus and silicon foliar application on plant growth and salinity stress tolerance have mostly been about the individual applications of each of these soil modifiers, and there is little evidence of their synergistic effects, especially for plants grown under saline soil conditions. The objective of this experiment was to investigate the synergistic effects of biochar, arbuscular mycorrhizal fungus and silicon foliar application on improving the quality of mother class seeds of maize variety under saline soil conditions. Materials and methodsThis study was conducted as a factorial experiment in a randomized complete block design with three replications in a research field with an electrical conductivity of 6.01 dS.m-1, in Fasa city, Fars province, in 2020. The first factor was three varieties of maize, including early- maturity variety 370, mid-maturity variety 604, and late-maturity variety 704, and the second factor was soil modifier compounds in eight levels, including no-application of modifier compounds as control, biochar, AMF, silicon foliar application, biochar + AMF, biochar + silicon, AMF + silicon and biochar + AMF + silicon. The measured traits included the concentration of sodium and potassium, activity of alpha and beta amylase enzymes, and seed germination and seedling growth indices. Statistical analyzes including analysis of variance and comparison of means were performed with Duncan's multiple range test at the 5% probability level using SAS software ver. 9.1. Research findingsThe results of this experiment showed that sodium concentration of seedling in cultivar 704 was reduced by 31% in the combined treatment of biochar + mycorrhizal fungus + silicon foliar application compared to the control treatment. The use of soil modifier treatments alone and in combination caused a decrease in the ratio of sodium to potassium, electrical conductivity of seeds as well as an increase in potassium concentration. An increase of 57% and 25% of alpha and beta amylase enzymes was observed in the combined treatment of biochar + mycorrhizal fungus + silicon foliar application compared to the control treatment. Also, application of soil modifier resources alone at a lower level could cause a significant increase in germination percentage. Seedling dry weight in the combined treatment of biochar + mycorrhizal fungus + silicon foliar application showed an increase of 15% and 10% in varieties 604 and 370, respectively. On the other hand, the highest seed germination and 1000-grain weight in the studied corn varieties were also observed in the combined treatments of biochar + mycorrhizal fungus + silicon foliar application. ConclusionIn total, the results of this experiment showed the positive effect of soil modifier sources in improving of germination characteristics and seedling growth indices of corn varieties. Based on these results, the combined application of biochar + mycorrhizal fungus + silicon foliar application is recommended to improve the quality of seed production in corn varieties under salt stress conditions.