Allelopathic effect of black mustard (brassica nigra l.) on germination and growth of wild oat (avena fatua l.)

Increasing global population is a threat to food security and agricultural sustainability. Allelopathy has emerged as a pragmatic approach to solve multiple issues in modern agriculture. Multiple approaches including crop rotations, cover crops, intercropping, mulching, crop residue incorporation and water extracts application are being used to explore allelopathy for pest management, stress mitigation, and growth enhancement in crop production. Allelopathy offers natural control of weeds, insect-pests and diseases. Biosynthesis of secondary metabolites at higher rates and their role in stress signaling provides excellent defense against abiotic stresses. Allelochemicals exuded in plant rhizosphere improve nutrient acquisition through the processes of solublization, biological nitrification inhibition, chelation and selected retention. Allelochemicals promote growth at low concentration; however suppress the growth if applied at high concentration. Allelopathic water extracts of sorghum, brassica, sunflower, rice, wheat, maize and moringa improve crop growth when applied at low concentrations. In this manuscript, potential application of the allelopathic phenomenon in crop production is discussed. If wisely planned, use of this phenomenon is quite effective in managing agricultural pests and improving the productivity of agricultural systems.

Application of allelopathy in crop production

The present study investigated the allelopathic effects of various black mustard (Brassica nigra L.) plant parts on alfalfa germination and seedling growth. Aqueous extracts of black mustard (Brassica nigra L.) leaf, stem, flower and root plant parts were made to determine their effects on germination and dry weights of hypocotyl, and radicle length of 5-day-old alfalfa seedlings over a range of extract concentrations. All aqueous extracts significantly inhibited alfalfa seed germination and seedling growth when compared with the distilled water control. Increasing the aqueous extract concentrations of separated Brassica nigra plant parts significantly inhibited alfalfa germination, seedling length and weight. Based on significant radicle length reactions to aqueous extracts, the toxicity may be classified in the following order of decreasing inhibition: flower, leaf, mixture of all plant parts, root, and stem. Increasing the concentration of aqueous flower extracts significantly inhibited the water uptake by germinated alfalfa seeds. The greatest inhibition in water uptake occurred at a 12 g kg−1 extract concentration for seeds soaked for 8 h.

Inhibitory effects of aqueous extracts of black mustard on germination and growth of alfalfa

Inhibitory Effects of Aqueous Extracts from Black Mustard (Brassica nigra L.) on Germination and Growth of Wheat

The paper presents 32 medicinally important weed species found in different crop fields along with some other plant species believed to have medicinal properties, which are being used by the rural people, particularly the women in Nalbari district, Assam. These weeds, although considered harmful to the crops, and are eradicated from the crop fields during cultural operation, may be fruitfully utilized to serve the medicinal purposes against various diseases. The herbal recipes recorded in the study may provide ample opportunities to study them critically for their efficacy and also for new drug development.

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S. S. Kolhe

Papers

Allelopathic effect of Blumea lacera L. on rice and common kharif weeds.