Allelopathy: an eco-friendly approach to control palmer amaranth using allelopathic sweetpotato

Abstract

Palmer amaranth (PA) is one of the major weeds in sweetpotato reducing its quantity and quality. The widespread and repeated use of chemical herbicides has led PA to develop resistance for such chemicals. In addition, chemical herbicides are incompatible with the organic production system. It is imperative to find sustainable weed management strategies to provide weed control suitable for organic cultivation and detain the development of herbicide-resistant weeds under conventional crop production. In the present study, seventeen sweetpotato varieties were screened for their allelopathic (weed-suppressing) effect on the growth of PA. The experiment was conducted in a greenhouse using a stair-step system. Each plant in the stair-step system had its height (cm), chlorophyll concentration (cci) and shoot biomass (g) measured. The variation in the height, chlorophyll and shoot biomass reduction of PA was significant after the third week of transplanting. Three weeks after transplanting (WAT), only three varieties, i.e., Morado (75%), Bayou belle (62%), and Vardaman (61%), reduced PA’s height by >60% compared to the control. While 5 WAT, four varieties, i.e., 529 (93%), Morado (93%), Heartogold (85%), and Centennial (81%), reduced PA height by >80%. Hatteras, Centennial, and 529 reduced the chlorophyll content of PA by >50%. In the presence of Beauregard, the commercial cultivar, there was no reduction in shoot biomass of PA. Cluster analysis also demonstrated that the four allelopathic sweetpotato varieties, i.e., Heart-O-Gold, Centennial, 529, and Morado, were clustered together, indicating that these varieties have similar potential to suppress the growth and development of PA. Combining allelopathic sweetpotato cultivars (Heart-O-Gold, Centennial, 529, and Morado) with other sustainable weed control measures, such as cover crops and hand-weeding, can improve the weed management, espicially in organic farming. However, field experiments should be conducted to confirm the allelopathic as well as yield potential of these varieties in an agronomic setting. The availability of the allelopathic sweetpotato cultivars will benefit organic producers by enhancing crop productivity and decrease reliance on chemical herbicides in conventional farming systems.

Assessing the allelopathic effect of Chrysopogon zizanioides (L.) Roberty root methanolic extract on Brassica rapa subsp. chinensis var. parachinensis using an untargeted metabolomic approach

“…The decrease in chlorophyll levels can be linked to reduced mineral absorption and disruptions in the regulatory mechanisms responsible for chlorophyll synthesis (Siyar et al, 2019). The reduction of chlorophyll content in target plants due to the allelopathy effect was similar to those reported by Ma et al (2020), Li et al (2022) and Singh et al (2022). In addition, the experiment revealed that the length of stomata in the choisum compared to the control decreased by up to 34.21% when subjected to 100 mg mL -1 (Figures 2A-2B).…”

Assessment of Allelopathic Potential of Cotton Chromosome Substitution Lines

“…PCA and clustering have been used to group allelopathic weed-suppressive cotton lines based on their weed-suppressive potential, which can aid in gaining a deeper insight into breeding material for crop enhancement (Fuller et al, 2021) [2]. Similarly, the grouping of rice cultivars by Schumaker et al (2020) [19] and sweet potato varieties by Singh et al (2022) [25] has been carried out using similar strategies. Allelopathy often occurs as a response to challenging conditions, as noted by Kruse and a group of researchers in their study published in 2000.…”

“…Using the stairstep structure created an avenue for determining the possible allelopathic effect of the donor plant (cotton lines) on the recipient plant (PA seedlings). In previous studies, the stairstep structure has been used to assess the allelopathic potential of Oryza sativa in relation to Echinochloa crus-galli [ 19 ] and Gossypium hirsutum against A. palmeri [ 2 ] and Ipomoea batatas against A. palmeri [ 25 ].…”