Weed Science (2021) 69, 681-686

Bhagirath S. Chauhan, Shane Campbell and Victor J. Galea (2021)
Seed germination biology of sweet acacia (Vachellia farnesiana) and response of its seedlings to herbicides
Weed Science 69 (6), 681-686
Abstract: Sweet acacia [Vachellia farnesiana (L.) Willd.] is a problematic thorny weed species in several parts of Australia. Knowledge of its seed biology could help to formulate weed management decisions for this and similar species. Experiments were conducted to determine the effect of hot water (scarification), alternating temperatures, light, salt stress, and water stress on seed germination of two populations of V. farnesiana and to evaluate the response of its young seedlings (the most sensitive developmental stage) to commonly available postemergence herbicides in Australia. Both populations responded similarly to all the environmental factors and herbicides; therefore, data were pooled over the populations. Seeds immersed in hot water at 90 C for 10 min provided the highest germination (88%), demonstrating physical dormancy in this species. Seeds germinated at a wide range of alternating day/night temperatures from 20/10 C (35%) to 35/25 C (90%), but no seeds germinated at 15/5 C. Germination was not affected by light, suggesting that seeds are nonphotoblastic and can germinate under a plant canopy or when buried in soil. Germination was not affected by sodium chloride (NaCl) concentrations up to 20 mM, and about 50% of seeds could germinate at 160 mM NaCl, suggesting high salt tolerance ability. Germination was only 13% at –0.2 MPa osmotic potential, and no seeds germinated at –0.4 MPa, suggesting that V. farnesiana seeds may remain ungerminated until moisture conditions have become conducive for germination. A number of postemergence herbicides, including 2,4-D + picloram, glufosinate, paraquat, and saflufenacil, provided >85% control of biomass of young seedlings compared with the non-treated control treatment. Knowledge gained from this study will help to predict the potential spread of V. farnesiana in other areas and help to integrate herbicide use with other management strategies.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Bhagirath Singh Chauhan, Victor J. Galea

Research topic(s) for pests/diseases/weeds:
control - general
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Vachellia farnesiana (weed)		Australia (NT+QLD)