Sustainable improvement in the yield of aromatic plants for essential oil production is the need of time. For this many technologies are employed today by the farmers. However use of rhizosphere fungi seems to be highly economical, user friendly and sustainable, hence this approach is considered in the present investigation. For present study lemon grass seedlings were raised in plastic pots containing soil inoculated with rhizosphere fungi. The effect of rhizosphere fungi on essential oil content revealed that there was enhancement in the range of 0.1 to 0.8 per cent. The variation was differing from species to species but highest was in Trichoderma viride and lowest in Aspergillus terreus. The treatment of different fertilizers showed significant effect on quantitative expression of essential oil composition of Cymbopogon citratus. The results showed maximum contents of citral a, citral b and Linalool in the treatment of T. viride. Maximum geraniol and geranyl acetate content was recorded in A. niger treated plant. The present study confirmed that T. viride is more efficient than the other rhizosphere fungi in enhancing oil, citral a, citral b and linalool content in C. citratus which may be exploited on commercial level.

The study of rhizospheric microbial flora for the enhancement of aroma compounds is well recognized. The rhizosphere microbes also play very important role in improving medicinal values of plants. Rhizospheric microbes affect the plant physiology by imparting several useful effects such as nitrogen fixation, nutrient uptake, and production of secondary metabolites in the medicinal and aromatic plants. Recent days there are increasing the interests in the research of the relation between rhizosphere microbes associated with medicinal plant for the improvement of quality of medicinal plants. A large variety of fungi and bacteria is recognized in the rhizosphere soil of medicinal plants that showed significant effect in secondary metabolite alteration and uptake of plant nutrient. There are reports that rhizosphere fungi not only enhanced the growth parameters in plants but also considerably modulated essential oil’s quality. This study highlighted the researches performed on active role of rhizosphere fungi on explored medicinal and aromatic plants. As the use of organic material is one of the constituents of good agricultural practices (GAPs). Therefore, this review also investigates the environmental concerns reducing the use harmful chemicals as well as recommendation for utilization of biological and organics in agriculture. Therefore, a proper understanding of role of rhizosphere mycoflora associated with the medicinal plants is essential.

Crop production is directly associated with the improvement of germplasm, which is mainly reliant on genetic diversity. Diversity among various genotypes has been investigated employing a variety of statistical approaches. The most widely utilized of these methods for determining the genetic overlap of genotypes is multivariate. In the present investigation, a total of 27 onion genotypes/advanced lines/varieties comprising high and low total soluble solids (TSS) white onion lines along with red varieties were evaluated at the ICAR-Directorate of Onion and Garlic Research station. Data were recorded on seven biochemical parameters. In multivariate analysis, genotypes were clustered into three major groups: the first group comprised thirteen genotypes with high TSS; however, the second group (eight) comprised low TSS white onion genotypes, and in the third group (six), mostly red varieties were clubbed together. The analysis primarily focused on the trait TSS; it was significantly associated with the antioxidant assay 2, 2-diphenyl-1-picrylhydrazyl(DPPH) AE, while total sugar content was positively associated with the antioxidant assay 2, 2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid)ABTS. In principal component analysis (PCA), the first three principal components (PCs) with >1 Eigen value contributed 71.36% of the variability among genotypes. Characters with a maximum value at PC1 were total soluble solids (0.48), antioxidant capacity AE DPPH (0.46), and total sugar content (0.49). PC2 comprises total phenolic content (0.62) and total flavonoid content (0.62); for PC3, the major contributors were thiosulfinate content (0.82) and antioxidant capacity ABTS (0.32). From the findings of the present study, the best-performing high TSS lines can be used for advancement through strongly correlated traits using breeding strategies. These sorted high TSS lines (W-103, W-107, and W-123) (>22 °Brix.), high-sugar-content genotypes (W-108, W-111, and W-308), and W-361, which recorded high thiosulfinate content, can be advanced or used as parental material for the development of processing-suitable onion varieties.

Essential oil (EO) of Ocimum species has several industrial applications and is used in drug, perfumery, food and flavour, aromatherapy, cosmeceutical and pesticidal industry. Ocimum species are rich in EO with major constituent eugenol, linalool, methyl eugenol, citral and camphor. EO compositions of O. basilicum, O. gratissimum, O. kilimandscharicum and O. tenuiflorum were analysed by using GC-MS. Considerable differences in chemical composition and oil content were observed in studied species. The therapeutically active compound eugenol is observed as a major compound in O. basilicum (26.76 %) and O. gratissimum (89.75 %) and methyl eugenol majorly found in O. tenuiflorum (84.99 %). Major compounds camphor (23.37 %) and β-copaene (34.82 %) are characterised and identified in O. kilimandscharicum. Two compounds viz. 2,6-Octadienal, 3,7-dimethyl-, (Z)-(20.01 %) and citral (20.11 %) were observed as major constituent in O. basilicum. Total 24 compounds characterised and identified in O. basilicum, 14 compounds in O. gratissimum, 17 in O. kilimandscharicum and 16 compounds in O. tenuiflorum.

In the present investigation, the chemical composition of essential oil of Madhuca longifolia var. latifolia (Roxb.) A.Chev. flowers was studied for its aroma compounds. The essential oil was isolated using hydrodistillation method. The chemical composition of isolated essential oil was investigated by using gas chromatography equipped with flame ionization detector (GC) and gas chromatography coupled with mass spectrometry (GC/MS) which identified total 25 compounds. The major constituents found in the essential oil of M. longifolia var. latifolia flowers are (E,E)-Farnesol (29.56%), (Z,E)-α-Farnesene (12.84%), Dendrolasin (8.95%), 2,3-Dihydrofarnesol (8.69%), (E,E)-α-Farnesene (7.37%), Nonanal (5.69%), and β-Farnesene (4.38%). The results indicated that the M. longifolia var. latifolia essential oil was a rich source of sesquiterpenes.