Abstract
Rotation of sorghum (Sorghum bicolor L. Moench) with sesame (Sesamum indicum L.) in drought prone areas of Zimbabwe has raised concerns on whether these two crops are compatible in the rotational system. This is because sorghum is known to exhibit strong allelopathic effects on both crop and weed species. A greenhouse experiment was conducted to assess the effect of soil incorporated sorghum residues on the emergence and seedling growth of sesame and weeds. The emergence and early seedling growth of sesame and the weed significantlyp<0.05increased with increases in the amount of soil incorporated sorghum residues. Incorporating 27.7 g of the ground sorghum herbage caused a stimulatory effect on the emergence and early seedling growth of the test species. Liquid chromatography-mass spectrometry revealed the presence of 6 probable allelochemicals in sorghum residues, namely, 4-methylaminobutyrate, C16 sphinganine, oleamide, tauroursdeoxycholic acid, pisatin, and anhalonidine. From this study, it can be concluded that dry sorghum residues do not have an inhibitory effect on sesame emergence and growth at mulch rates that retard emergence and growth of weeds.
Highlights
Allelopathy is defined as the ability of a plant to cause either a suppressive or stimulatory effect on the growth and development of another plant, this term is loosely used to describe inhibitory effects on the susceptible plant species [2]
Research Station (RARS) is in ecological region II, which is 1314 meters above sea level and receives an annual rainfall of above 750 mm. e stem and leaf portions were separated, chopped into 2 cm long pieces using secateurs, and dried in the oven at 70°C for 48 hours. e different plant parts were ground into powder using a hammer mill grinder. e ground powder was kept in the Weed Science Laboratory at the University of Zimbabwe (UZ) for three days at room temperature before being used in experiments
Beggarticks final emergence percentage increased with increasing concentration of soil incorporated sorghum residues (Figure 1(a)). ere were no significant differences between the other treatments except 27.7 g pot−1, which resulted in significantly higher final emergence than the other treatments
Summary
Sorghum has become one of the most studied allelopathic crop, and research work focused on isolating allelochemicals responsible for the suppressive effects [3]. Allelopathic activity of sorghum is attributed to sorgoleone and dhurrin, two important allelochemicals that are produced in the roots and shoots of sorghum, respectively [4, 5]. Previous studies have reported that sorghum exhibited allelopathic activity on the growth and development of both crop and weed species [10]. Hussain et al [16] reported that sesame produces allelochemicals that inhibited growth and development of the purple nutsedge (Cyperus esculentus L.). E objective of the study was to identify the sesame varieties that are tolerant to allelochemicals released by sorghum mulches at rates that are lethal to weeds of divergent morphology, namely, goose grass Gaertn) and beggarticks (Bidens pilosa L.). e present study sought to profile possible allelopathic compounds from dry sorghum leaf and stem herbage using liquid chromatography-mass spectrometry (LC-MS)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
