Evaluation of qualitative characteristics and grain yield of soybean (Glycine max L.) in response to pretreatment and foliar application of marjoram (Origanum majorana L.) extract

An experiment was conducted in the research field of Shahroud University as a factorial based on completely randomized blocks in three replications to study the effects of marjoram extract on some qualitative characteristics and grain yield of soybean. The first factor was foliar application of extract in three levels (distilled water spraying, extract spraying of 40 and 60%) and the second factor was marjoram extract in five levels (no pretreatment, pretreatment with extract of 40 and 60% each for 6 and 9 hours). Foliar applications of 40% and 60% marjoram extract increased leaf anthocyanin by 11.2 and 6.5%, respectively, when compared to the control. The highest grain number per pod and grain yield were observed after a 6-hour pre-treatment with concentrations of 40 and 60% extract, followed by a foliar application of 40% extract. Pre-treatment with concentrations of 40% and 60% for 9 hours increased relative water content by 34% when compared to the control. Foliar application of 40 and 60% marjoram extract increased leaf flavonoid content by 1.56 and 1.71%, respectively, when compared to the control. According to the findings, a pre-treatment with a 40% concentration for 6 hours followed by a foliar application of a 40% extract is the best treatment combination for improving the quality characteristics and grain yield of soybean.