Kamla Singh

Chemical weed control in Bulgarian coriander (Coriandrum sativum L.)

Abstract Field investigations carried out in two winter seasons of 1984–85 and 1985–86 on clay‐loam soil at the Central Institute of Medicinal and Aromatic Plants, Regional Centre, Pantnagar, Naintial, India revealed that unrestricted weed growth reduced the seed and oil yields of Bulgarian coriander (Coriandrum sativum L. cv. S 33) by 40.3 and 37.0%, respectively. Applications of pendimethalin and fluchloralin at 0.75 and 1.00 kg a.i./ha, respectively causing 76.5 and 71.9% weed control, were most promising treatments, and gave seed and oil yields comparable to weed‐free check. Applications of oxadiazon at 0.25–0.75 kg a.i./ha and propanil at 1–2 kg a.i./ ha, although proved selective but failed to produce desired results. None of the treatments impaired the quality of coriander seed oil, measured in terms of d‐linalool content.

Production techniques for the cultivation of safed musli (Chlorophytum borivilianum)

Summary Chlorophytum borivilianum (family Liliaceae) is a high-value medicinal plant becoming rare because it is harvested fromthe wild. To encourage its adoption as a crop plant, propagation and cultural methods were investigated under semi-arid tropic conditions of Hyderabad, India. Single tubers will sprout if attached to a portion of crown, and yields of fresh tuber and musli (the peeled and dried end-product) were improved by increasing the planting weight of tubers to 12.5.g per unit. Further, at this unit weight of planting material, the tuber multiplication ratio (ratio between fresh tuber yield andweight of planting material, 4.63) and musli-fresh tuber ratio (0.17) were highest. Yields were also increased by farmyardmanure (FYM) at 40.t ha-1 because of significant improvements in number, length and thickness of tuber and musli-fresh tuber ratio. Plant size and yields of fresh tuber and musli were greater in a potexperiment with up to 25.mg N kg-l of soil. Pinching of inflorescences increased leaf (18%) and tuber lengths (32%) and the yields of fresh tubers (22%) and musli (30%).

Volatile Constituents of Essential Oils Isolated from Different Parts of Alpinia calcarata Rosc.

Abstract The essential oils isolated from different parts of Alpinia calcarata Rosc., (family: Zingiberaceae) growing in Hyderabad, south India, were analyzed by capillary GC and GC/MS. The oil yields were: flower 0.06%, leaf sheath 0.03%, stem 0.05% and root 0.18%. Sixty-two compounds accounting for 92.3–98.3% of the oils were identified. The flower oil contained β-pinene (12.5%), 1,8-cineole (12.8%) and (E)-methyl cinnamate (12.3%) as the major constituents. The important components of the leaf sheath oil were 1,8-cineole (23.2%) and humulene epoxide I (10.6%). The stem oil had β-pinene (11.2%) and 1,8-cineole (33.2%) as the major compounds. On the other hand, the root oil showed camphene (13.6%), 1,8-cineole (15.6%) and α-fenchyl acetate (37.6%) as the main constituents.

Pre-Flowering Harvesting of Ocimum gratissimum for Higher Essential Oil and Eugenol Yields Under Semi-Arid Tropics

Abstract In spice basil (Ocimum gratissimum L.), contribution of leaves, stalks and inflorescences were 59%, 23% and 18% to total plant biomass and 80%, 1% and 19% to total oil yield, respectively. The leaf oil was richer in eugenol but simultaneously had lower (E)-β-ocimene, compared to the inflorescence oil. Harvesting at pre-flowering produced 12.5%, 24.1%, 35.5% and 50.0% higher biomass yield compared to harvesting at 25%, 50%, 75% and 100% flowering, respectively, in the first year of cropping. The respective increase was 16.8%, 22.0%, 38.2% and 63.2% in the second year. Late harvested crop (100% flowering) contained the highest amount of essential oil and it decreased in the order of harvesting at 100% flowering > 75% flowering > 50% flowering > 25% flowering > pre-flowering treatment. The total oil yield was, however, significantly higher (15.8–19.9% and 12.7–33.6% in first and second years, respectively) with pre-flowering compared to all other harvest treatments. Pre-flowering harvested crop produced oil containing the highest amount of eugenol and it decreased in the order of harvesting at pre-flowering > 25% flowering > 50% flowering > 75% flowering > 100% flowering treatment.

Chemical Weed Control in Japanese Mint (Mentha arvensis L.)

Field experiment conducted at the Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar during 1985 and 1986 revealed that unrestricted weed growth reduced the herbage and oil yields of Japanese mint by 86.6 and 87.8%. respectively. Pendimethalin at 1.5 and oxyfluorfen at 0.3 kg/ha as pre-eme. application recorded the highest weed control efficiency and also produced the green herbage, oil and menthol yield compared to the yield of weed free treatment. Fluchloralin as preplant soil incorporation was toxic to mint crop. mint oil.

Influence of Co-distillation with Weed Biomass on Yield and Chemical Composition of Rose-Scented Geranium (Pelargonium Species) Oil

Abstract A laboratory experiment was performed to study the influence of distilling rose-scented geranium (Pelargonium species) biomass together with different proportions (0, 5, 10, 15 and 30% by weight of rose-scented geranium biomass) of biomass of weed species growing in rose-scented geranium fields, on the yields % and compositions of oils of cultivars Algerian, Bourbon and Kelkar. Crop:weed mixtures reduced oil yields of all the three cultivars in comparison to control (pure crop biomass). Combined distillation of biomass of cv. Algerian with weed biomass decreased the concentrations of linalool, geraniol, geranyl formate, 10-epi-γeudesmol and increased the contents of isomenthone, citronellol and citronellyl formate in its oil. This distillation method resulted in enhancements in isomenthone, citronellol and reductions in geraniol and geranyl formate in the oil of cv. Bourbon. In cv. Kelkar, the percentages of linalool and isomenthone increased, but that of citronellol and geraniol decreased in crop:weed mixed distillations.

Comparative Composition of Cornmint Oils Produced in North and South India

Abstract The chemical composition of two North Indian (freshly distilled and a commercial oil samples) and four South Indian cornmint oils produced from different cultivars (‘Gomti,’ ‘MAS-1,’ ‘HY-77’ and ‘Shivalik’) were compared. All the oils contained menthol as their major constituent which varied from 70.4% in commercial North Indian oil to 87.2% in cultivar ‘MAS-1’ of South Indian origin. The North Indian oils contained minor quantities of camphene, (E)-β-ocimene, isopulegol and were richer in isomenthone, isomenthol + αterpineol and menthyl acetate compared to the South Indian oils. Among all the oils, one cultivar (‘MAS-1’) oil was unique with its high menthol content (87.2%).

Effect of Hay Storage on Oil Yield and Quality in Three Cymbopogon Species (C. winterianus, C. martinii and C. flexuosus) during Different Harvesting Seasons

ABSTRACT Hay storage of Cymbopogon martinii and C. winterianus, either in the shade or in the open, was found to be advantageous during summer and rainy seasons, respectively. Maximum enhancements of 31.4% and 18.0% in oil content over the fresh distilled herbs were recorded in 5 and 7 days respectively. The safe limit of herb storage varied according to the species and storage conditions. Storage of C. flexuosus herbage always caused a reduction in oil content except during the summer when it was not affected for three days under shade storage. Temperature and humidity were found to play a vital role in biosynthesis/accumulation of essential oils in stored herbs.

Critical periods of weed interference in Japanese mint (Mentha arvensis L.)

Abstract Results from two sets of field experiments carried out during 1984 and 1985 revealed that Japanese mint (Mentha arvensis L.) was associated with both broad‐leaf and grass weeds dominant in summer and rainy seasons representing the period of first and second harvests, respectively. The weed biomass exceeded that of the crop from the very beginning of the crop cycle, and the most rapid increase in weed biomass was noted between 30 and 45 days after planting in first harvest and the first 45 days in second harvest. Unrestricted weed growth significantly reduced Japanese mint oil yield by 74.4% and 70.0%, respectively in first and second harvests. The critical period of weed interference was between 30 and 75 days in first harvest and 15 and 45 days in second harvest. Weed infestation during the critical periods caused significant reduction in plant height and herb and oil yields, and weed infestation beyond the critical periods did not have any significant influence on these parameters. The leaf:ste...

Suitability of organic mulch (distillation waste) and herbicides for weed management in perennial aromatic grasses

Abstract Poor economic return from perennial aromatic grasses during a planting year results from the high cost of cultivation, on account of planting, and lower yields, largely due to slow crop growth rate and high vulnerability of aromatic grasses to weeds, which are poorly managed In the absence of suitable weed control measures. Field experiments were established in July 1982 to examine the suitability of organic mulch (distillation waste of citronella Java) and herbicides in three important perennial aromatic grasses, citronella Java (Cymbopogon winterianus Jowitt), lemongrass (C. flexuosus (D.C.) Stapf) and palmarosa (C. martinii Stapf var. motia) for two harvest years (1981–82 and 1982–83) under a subtropical climate at Lucknow. Weeds caused an average 40% reduction in herb and oil yields in the first harvest year as against 6% In the second. Organic mulch 3 t/ha, oxyfluorfen 0–5 kg/ha, diuron 1.5 kg/ha and simazine 1.5 kg/ha gave herb and oil yields equal to weed‐free check, and proved superior to...