Effect of organic fertilization on productivity of some newly introduced basil varieties under Siwa Oasis conditions

A split-plot design field trial was carried out on Ocimum basilicum L. plants at Siwa Oasis, Egypt, during the 2018 and 2019 seasons to study the effect of organic fertilization, cultivation of some foreign varieties, and their combination on yield. The main plots included applying two compost manure levels before planting (24 and 48 m3/hectare). Subplots included cultivating five basil varieties (local and four foreign varieties: lime basil, smuglyanka basil, purple basil, and purple ruffles basil). The results revealed that applying compost manure at the highest level significantly increased herb and oil yield attributes over the lowest level. The evaluation of varieties showed that the purple ruffles and purple varieties were the most tolerant to abiotic stresses and recorded the significantly maximum herbage and oil yield. The essential oil chemical composition was affected by the interaction within treatments and harvest time. Applying 48 m3 compost/hectare and cultivation of foreign purple variety should be recommended in this region to produce the best yield quantity and quality characteristics (oil of high linalool of 50.95%–75.01% and minimum estragole of 0.00%–0.02%, as well as attractive flavor and color) which could promote exports.