Inhibition of Germination and Growth Behavior of Some Cowpea Varieties Using Neem (Azadiracta Indica) Leaf Water Extracts

Abstract

The experiment was conducted to observe the inhibitory effects of the leaf extract derived from neem (Azadiracta indica) on germination and growth behavior of some cowpea varieties (receptor). Experiments were set on sterilized petridishes with a photoperiod of 24 hours at room temperature of 27-30 o C. The effects of the different concentrations of aqueous extracts were compared with distilled water (control). The aqueous extracts of leaf caused significant inhibitory effects on germination, root and shoot elongation and development of lateral roots of treated plants. Bioassays indicated that the inhibitory effect was proportional to the concentrations of the extract, as concentration increased the extent of inhibition also increased. The study also revealed that inhibitory effect was much pronounced in root and lateral root development rather than germination and shoot growth.

ALLELOPATHIC PROPENSITY OF THE AQUEOUS LEAF EXTRACT AND LEAF LITTER OF Melia dubia CAV. ON PULSE CROPS

“…The filtrate was centrifuged and supernatant was decanted (Prasad et al, 2011). The filtrate was defined as 100 per cent extract and was further diluted with distilled water at 25 , 50, 75, 100 per cent concentrations (Nikneshan et al, 2011) while distilled water was used as control T1 (0 %) (Lawan et al, 2011).…”

Evaluation of Allelopathic Effects of Neem, Azadirathta indica A. Juss (Sapindales: Meliaceae) Seed Powder on the Viability of Stored Maize, Zea mays L. Seeds

“…A) General view of normal maize germination (B) Abnormal germination: note the maize kernel emerging above soil level Elsewhere, [9,10] working on Arapu leaf powder (Albizia amara) and Moringa oleifera found that Arapu leaf powder maintained good seed viability and seedling vigour for scented rice stored for up to 20 months however, Moringa oleifera had serious allelopathic effects on the viability and germination of Vigna radiata where germination decreased with increasing concentrations of Moringa leaf extracts. [11] Also, working on cowpea found that Neem leaf water extracts inhibited germination as well as suppressed the growth and development of some cowpea varieties with increasing concentrations of neem leaf extracts. These findings agree with the work of [12,[16][17].…”

“…Furthermore, these plant materials offer an ecologically safer means of controlling insect pest infestations in stored cereals and grains in the tropics where the resource poor farmers are generally found [8]. Such materials include powders and extracts from several plant species namely, drumstick tree Moringa oleifera [9][10][11][12][13]. These materials have been established to be environmentally friendly bio-pesticides and possess many desirable properties.…”

“…Neem, a well-known tree for its insecticidal properties attributed to the presence of alkaloids as Azadiractin, Selanin and Meliontriol and several other less important minor alkaloids are known to be very effective against a wide range of insect pests including S. zeamais [15]. However, these desirable pest control properties of neem have often been associated with toxicity and other adverse allelopathic effects in some crop grains/ seeds treated with either the leaf, seed or bark preparations to some crops namely, cowpeas Vigna unguiculatta Walp., which exhibited significant reductions in seed viability [11,12,[16][17]. No such investigative studies have been undertaken to evaluate the effects of neem materials/ seed powder on stored maize.…”

Allelopathic Influence of Leaf Aqueous Extract and Leaf Litter of Indian Lilac (Melia azedarach L.) on Germination, Growth, Biomass and Grain Yield of Green Gram (Vigna radiata L.) and Black Chickpea (Cicer arietinum L.)

“…The filtrate was defined as 100 per cent extract (Nikneshan et al, 2011). From this 25, 50, 75, 100 per cent concentrations were prepared and distilled water was used as control (Lawan et al, 2011). The treatments were replicated five times in completely randomized design (CRD).…”