Allelopathic Effects of Some Selected Tree Species on the Germination and Growth of Cowpea (<i>Vigna unguiculata</i> L. Walp.)

Abstract

The allelopathic effect of three tree species (Azardiracta indica, Vitellaria paradoxa, and Parkia biglobosa) on germination and growth of cowpea was investigated in the Southern Guinea Savannah agro ecological zone of Nigeria. The experiment was laid out in Randomized Complete Block Design (RCBD) with three (3) replicates. Data were collected on germination, plant height, stem diameter, number of leaves, number of branches, root length, the above grand biomass and the below grand biomass and were subjected to statistical analysis using Analysis of Variance (ANOVA) while the significant mean was separated using Duncan's Multiple Range Test (DMRT) at 5% possibility level. Results showed that the tree species brought about considerable inhibition in the germination of cowpea seeds and in its growth parameters. The statistical germination value of the cowpea seeds under the tree species had decreased value thus indicating that growth inhibitions were seriously felt. It was apparent that Parkia biglobosa (53.33) and Vitellaria paradoxa (60.00) had more inhibitory effect on cowpea seeds germinability than that of Azardiracta indica. (63.33) while all the treatments are lower than that of control (100). The tree species had similar inhibition capability in the cowpea plant height, stem circumference, number of leaves, above grand biomass and below grand biomass. However, in all treatment, statistic showed that there is no significant difference (p < 0.05) among the means.

Influence of Shea tree (Vitellaria paradoxa) on maize and soybean production

“…We also attribute the yield decline due to Vitellaria paradoxa , to the presence of phytochemicals referred to as allelo chemical that have inhibitory effects on the growth and production of other plants. For instance, Aleem et al ., 2014 [11] and Alamu and Aleem, 2014 [10] in separate studies of cowpea and maize respectively reported that Vitellaria paradoxa had allelopathic effects on Cowpea and Maize. However, the influence of Vitellaria paradoxa on maize was more pronounced than in cowpea.…”

“…The influence of planting season and crop productivity under Shea has not been widely reported. Majority of the studies on inhibitory effects of Shea tree are single season studies such as those of Aleem et al, 2014, [11] or bioassays that involve planting the experimental crops in soils incorporated with extracts of mature Shea tree components such as those of Folarin et al, 2015, [12]. It is widely accepted that variations in seasons have significant influence on crop productivity [1].…”

“…Physiological stages of Shea is also expected to have significant influence on crop production. These influences are expected to vary with the crop in question, for instance, Alamu and Aleem, 2014, [10]; Aleem et al, 2014 [11] reported differential responses of cowpea and maize to Shea tree. This study was therefore done to investigate the seasonal variations in the influence of Vitellaria paradoxa on production of Zea mays L. (Maize) and Glycine max (L.) Merrill .…”

Allelopathic effects of Androstachys johnsonii Prain on germination and growth of Zea mays L. and Vigna subterranea (L.) Verdc.

“…Findings of other researches indicated allelopathy of tropical tree species as detrimental to germination and growth of paramount crop plant species. 3 Additionally, Abugre et al 4 concur that inhibitory effects of allelochemicals pose a serious crop reduction.…”

“…varied across all the treatments employed (Figure 3 and 4). Aleem et al 3 provided evidence that germination of Cowpea seeds planted both in the field and in pot experiment was significantly affected by the tree species which are allelopathic to their understories or neighbours. Further evidence attested availability of allelochemicals in all parts of plants, for example, in the alfalfa plant: they are found in leaves, stems, flowers, seeds and roots 24 .…”