Germination Biology of Sesbania (Sesbania cannabina): An Emerging Weed in the Australian Cotton Agro-environment

Weed Science ◽  
2018 ◽  
Vol 67 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Nadeem Iqbal ◽  
Sudheesh Manalil ◽  
Bhagirath S. Chauhan ◽  
Steve W. Adkins

AbstractSesbania [Sesbania cannabina(Retz.) Pers.] is a problematic emerging weed species in Australian cotton-farming systems. However, globally, no information is available regarding its seed germination biology, and better understanding will help in devising superior management strategies to prevent further infestations. Laboratory and glasshouse studies were conducted to evaluate the impact of various environmental factors such as light, temperature, salt, osmotic and pH stress, and burial depth on germination and emergence of two Australian biotypes ofS. cannabina. Freshly harvested seeds of both biotypes possessed physical dormancy. A boiling-water scarification treatment (100±2 C) of 5-min duration was the optimum treatment to overcome this dormancy. Once dormancy was broken, the Dalby biotype exhibited a greater germination (93%) compared with the St George biotype (87%). The nondormant seeds of both biotypes showed a neutral photoblastic response to light and dark conditions, with germination marginally improved (6%) under illumination. Maximum germination of both biotypes occurred under an alternating temperature regime of 30/20 and 35/25 C and under constant temperatures of 32 or 35 C, with no germination at 8 or 11 C. Seed germination of both biotypes decreased linearly from 87% to 14% with an increase in moisture stress from 0.0 to −0.8 MPa, with no germination possible at −1.0 MPa. There was a gradual decline in germination for both biotypes when imbibed in a range of salt solutions of 25 to 250 mM, with a 50% reduction in germination occurring at 150 mM. Both biotypes germinated well under a wide range of pH values (4.0 to 10.0), with maximum germination (94%) at pH 9.0. The greatest emergence rate of the Dalby (87%) and St George (78%) biotypes was recorded at a burial depth of 1.0 cm, with no emergence at 16.0 cm. Deep tillage seems to be the best management strategy to stopS. cannabina’s emergence and further infestation of cotton (Gossypium hirsutumL.) fields. The findings of this study will be helpful to cotton agronomists in devising effective, sustainable, and efficient integrated weed management strategies for the control ofS. cannabinain cotton cropping lands.

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1123
Author(s):  
Shahid Farooq ◽  
Huseyin Onen ◽  
Sonnur Tad ◽  
Cumali Ozaslan ◽  
Samy F. Mahmoud ◽  
...  

Polygonum perfoliatum L. is an aggressive vine, currently invading the Black Sea region, Turkey. However, information about the seed germination biology of this species is scanty. The objective of the current study was to determine the seed germination biology of three naturalized populations of this species. Chemical scarification with 98% sulfuric acid for 30 min followed by cold-wet stratification at 4 °C for 4 weeks effectively released seed dormancy in tested populations. Seeds of all populations required a 12 h photoperiod for the highest germination, while germination under continuous dark and light remained similar. The seeds were able to germinate under a wide range of constant (5–40 °C) and alternating temperatures, pH (3–11), osmotic potential (0 to −1.4 MPa) and salinity (0–500 mM NaCl). However, the peak germination was observed under 20 °C constant and 20/15 °C alternating day/night temperature, and pH 6.8. Seeds of all populations were able to withstand 200 mM salinity and −0.6 MPa osmotic potential. Increasing seed burial depth initially stimulated seedling emergence and then a sharp decline was observed for the seeds buried below >2 cm depth. More than 90% of the seeds were unable to emerge when buried >6 cm depth. Polygonum perfoliatum has a large potential for range expansion; therefore, immediate management of the naturalized populations is warranted. This weed species in agricultural fields can be managed by burying the seeds in deeper soil layers (6 cm), while post-emergence management strategies need to be developed for roadside populations.


Weed Science ◽  
2008 ◽  
Vol 56 (5) ◽  
pp. 722-728 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
David E. Johnson

Southern and India crabgrass are important grass weeds of rice in many tropical countries. Environmental factors influenced seed germination and seedling emergence of these weeds. Seeds of both species germinated at a range of alternating temperatures (25/15, 30/20, and 35/25 C day/night), though the germination of southern crabgrass was reduced at the lowest alternating temperatures (25/15 C). Light stimulated germination of both species; however, a small proportion of southern crabgrass seeds germinated in the dark. Germination of India crabgrass was influenced to a greater degree by increasing salt and water stresses than was southern crabgrass. Seeds of both species germinated over a wide range of pH between 5 and 10. Seedling emergence of both species (98% for southern crabgrass and 94% for India crabgrass) was greatest for seeds placed on the soil surface. Seed burial depth of 2 cm completely inhibited emergence of India crabgrass, whereas for southern crabgrass, this depth was 8 cm. Knowledge gained from this study is expected to contribute to developing components of integrated weed management strategies for these species.


Weed Science ◽  
2021 ◽  
pp. 1-19
Author(s):  
Bhagirath S. Chauhan ◽  
Shane Campbell ◽  
Victor J. Galea

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 other 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 development stage) to commonly available POST herbicides in Australia. Both populations behaved 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 concentrations up to 20 mM and about 50% of seeds could germinate at 160 mM sodium chloride, suggesting its 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 POST herbicides, including 2,4-D + picloram, glufosinate, paraquat and saflufenacil, provided >85% control of biomass of young seedlings compared with the nontreated 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.


Weed Science ◽  
2018 ◽  
Vol 66 (6) ◽  
pp. 752-757 ◽  
Author(s):  
Gulshan Mahajan ◽  
Amar Matloob ◽  
Michael Walsh ◽  
Bhagirath S. Chauhan

AbstractAfrican turnipweed (Sisymbrium thellungiiO. E.Schulz) is an emerging problematic broadleaf weed of the northern grain region of Australia. Laboratory experiments were conducted to evaluate the effects of temperature, light, salinity, pH, seed burial depth, and the amount of wheat crop residue on germination and emergence of two AustralianS. thellungiiweed populations (population C, cropped area; population F, fence line). Both populations behaved similarly across different environmental conditions, except in the residue study. Although the seeds of both populations ofS. thellungiicould germinate under complete darkness, germination was best (~95%) under light/dark conditions at the 20/10 C temperature regime. Both populations ofS. thellungiigerminated over a wide range of day/night temperatures (15/5, 20/10, 25/15, and 30/20 C). Osmotic stress had negative effects on germination, with 54% seeds (averaged over populations) able to germinate at −0.1MPa. Complete germination inhibition for both populations was observed at −0.8MPa osmotic potential. Both populations germinated at sodium chloride (NaCl) concentrations ranging from 50 to 100 mM, beyond which germination was completely inhibited. There were substantial reductions in seed germination, 32% (averaged over populations) under highly acidic conditions (pH 4.0) as compared with the control (water: pH 6.4). Seed germination of both populations on the soil surface was 77%, and no seedlings emerged from a burial depth of 1 cm. The addition of 6 Mg ha−1of wheat (Triticum aestivumL.) residue reduced the emergence of the C and F populations ofS. thellungiiby 75% and 64%, respectively, as compared with the control (no residue). Information gathered from this study provides a better understanding of the factors favorable for germination and emergence ofS. thellungii, which will aid in developing management strategies in winter crops, especially wheat, barley (Hordeum vulgareL.), and chick pea (Cicer arietinumL.).


Weed Science ◽  
2016 ◽  
Vol 65 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Wei Tang ◽  
Jie Chen ◽  
Jianping Zhang ◽  
Yongliang Lu

Triquetrous murdannia is an annual weed commonly found in rice fields in China. Laboratory and screenhouse experiments were carried out to determine the effect of light, temperature, osmotic and salt stress, seed burial depth, amount of rice residue, and depth of flooding on seed germination and seedling emergence of triquetrous murdannia and to evaluate the response of this weed to commonly available POST herbicides in China. Germination was greater than 93% under a wide day/night temperature range of 20/10 to 30/20 C in the light/dark regime. The time to onset of germination decreased as temperature increased. Germination was slightly stimulated when seeds were placed in light/dark conditions compared with seeds placed in the dark. The osmotic potential and NaCl concentration required for 50% inhibition of maximum germination were −0.5 MPa and 122 mM, respectively. The highest germination (68%) was observed from seeds sown on the soil surface, but decreased with increasing burial depth. Only 7% of seedlings emerged from a depth of 4 cm, and no seedlings emerged from seeds buried deeper than 6 cm. Seedling emergence decreased from 93 to 35% with increasing quantity of rice residue (1 to 6 103kg ha−1) applied on the soil surface. Seedling emergence was reduced by 40, 48, 64, and 70% at flooding depths of 1, 2, 4, and 6 cm, respectively, for the seeds sown on the soil surface. Fluroxypyr and MCPA herbicides provided 100% control of triquetrous murdannia at the 2- to 6-leaf stages; however, to achieve 100% control with bispyribac-sodium, MCPA+bentazone or MCPA+fluroxypyr, herbicides had to be applied by the 4-leaf stage. The results of this study could help in developing more sustainable and effective integrated weed management strategies for the control of triquetrous murdannia in rice fields in China.


2013 ◽  
Vol 31 (2) ◽  
pp. 249-257 ◽  
Author(s):  
H.H. Ali ◽  
A. Tanveer ◽  
M.A. Nadeem ◽  
H.N. Asghar ◽  
M.M. Javaid

Rhynchosia capitata is becoming an increasing problem in summer crops, such as cotton, soybean, pearl millet and mungbean in many Asian countries. Laboratory and greenhouse studies have been conducted to determine the effects of several environmental factors on seed germination patterns and seedling emergence of R. capitata. We investigated whether the diverse ecological factors such as temperature, light, salinity, moisture stress, pH, and soil depth affected germination and seedling emergence of R. capitata. Germination increased as temperature increased from 25ºC and significantly reduced at 45ºC. Presence or absence of light did not influence germination. Germination of R. capitata was sensitive to increased salt and moisture stress, as well as to seed burial depth. Only 48% of seeds germinated at 150 mM salt concentration compared to 100% in control (distilled water). Similarly, 15% of seeds germinated at an osmotic potential of ‑0.8 MPa compared to 88% at ‑0.2 MPa. The optimum pH for seed germination of R. capitata was 7 (98% germination), but the seeds also germinated at lower level of pH 5 (85%) and at higher level of pH 10 (75%). In seed burial trial, maximum seedling emergence of 93% occurred at 2 cm depth, and seedling did not emerge from a depth of 12 cm. The high germination ability of R. capitata under a wide range of ecological factors suggests that this species is likely to be the one to cause more problems in a near future, if not managed appropriately.


2021 ◽  
Vol 3 ◽  
Author(s):  
Hanwen Wu ◽  
Md Asaduzzaman ◽  
Adam Shephard ◽  
Xiaoyan Ma

Witchgrass (Panicum capillare L.) is a summer growing grass weed species and is increasing its prevalence in southern Australia. A better understanding of the seed biology is needed to effectively manage this weed. A series of field and laboratory studies were conducted to determine seed germination factors, field emergence patterns, and soil seedbank longevity. Witchgrass germination was stimulated by light and it germinated better at temperature over 20°C, with 93–100% germination at the two constant temperatures of 20 and 30°C, and the two alternating day/night temperatures of 30/25 and 35/25°C. It is highly tolerant to moisture stress at germination, with 2–7% germination even at −0.48 Mpa. Witchgrass seed lost 47–68% viability after 12 months of burial in the soil, however the seed persisted for more than 4 years if buried at 10 cm in the soil. Witchgrass emergence in southern New South Wales (NSW) commenced in mid spring (early October), with peak emergence of 63–83% in November and then significantly reduced to 16–37% emergence in December. Little emergence (<1%) occurred in the summer months from January to February. These results provide useful information for designing effective management strategies and the optimum timing of control. Climate change could favor the phenological development and the further spread of this weed, which present new challenges for its effective management. Further study is needed to investigate the impact of climate change on the biology, spread, and management of witchgrass.


Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 715
Author(s):  
Muhammad Javaid Akhter ◽  
Peter Kryger Jensen ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander ◽  
Per Kudsk

Recently, Vulpia myuros has become a problematic grass weed species in parts of Europe. It is most common in no-till cropping systems. The inherent tolerance to several selective grass weed herbicides is of serious concern to the successful management of V. myuros in arable farming. Here, we reviewed the available knowledge about the biology of V. myuros to identify knowledge gaps and assess management efforts to identify best practices for control. V. myuros is a winter-annual species producing seeds with a short dormancy that can germinate at a wide range of conditions. Seed longevity in the soil is short. Little information is available on the influence of V. myuros on crop yield but some results suggest that yield losses can be significant. The findings provide a better understanding of the weedy characteristics of V. myuros and highlight that management strategies in Europe need to be diversified and integrate preventive and cultural control methods. Finally, we identify some of the management tools that should be considered to minimize the impact of V. myuros on European farming and future needs for research to develop sustainable integrated weed management strategies.


Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 512-516 ◽  
Author(s):  
Bhagirath Singh Chauhan

Crowfootgrass, a C4species, is one of the principal weeds of dry-seeded rice in Asia. Weed management decisions for this species can be derived from knowledge of its seed germination biology. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of crowfootgrass and to evaluate the response of this weed to commonly available selective POST herbicides in the Philippines. Light stimulated seed germination, but it was not an absolute requirement for germination. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C (92%) than at 30/20 (70%) or 35/25 C (44%). The osmotic potential required for 50% inhibition of maximum germination was −0.23 MPa, although some seeds germinated at −0.6 MPa. Seedling emergence was greatest for the seeds placed on the soil surface (64%), and emergence declined with increased burial depth in soil. No seedlings emerged from a burial depth of 6 cm or greater. Seedling emergence of crowfootgrass was reduced by the addition of rice residue to the soil surface at rates equivalent to 4 to 6 Mg ha−1. Fenoxaprop-p-ethyl + ethoxysulfuron at 45 g ai ha−1provided excellent control of crowfootgrass when applied at the four- (99%) and six-leaf (86%) stage. The information gained from this study could contribute to developing components of integrated weed management strategies for crowfootgrass. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence, use of crop residue as mulch, and early application of an effective POST herbicide could serve as important tools for managing crowfootgrass.


Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 657-662 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Marcos J. Oliveira

Laboratory and greenhouse experiments were conducted to determine the effect of light, temperature, moisture stress, solution pH, and burial depth on coffee senna germination and emergence. Seeds germinated equally with or without light, and pretreatment with red or far-red light did not affect germination. Optimum temperature for germination was 25 C, and a high germination percentage (> 70%) occurred from 12.5 to 30 C. The low temperature threshold for germination was between 10 and 12.5 C, whereas the upper threshold was near 45 C. Coffee senna germination in response to moisture stress and solution pH differed at 15 and 30 C. At −0.4 MPa, no germination occurred at 15 C, whereas 15% germination occurred at 30 C. Optimum germination was at pH 6, but further increases in pH had a more negative effect on germination at 15 C than at 30 C. Coffee senna germination ranged from 9 to 12% at pH 3, but was 0% at pH 10, which indicates that coffee senna germination was more tolerant of acidic than basic solutions. Depth-mediated emergence inhibition was sigmoidal, with greatest emergence on the soil surface. Emergence from 2- to 10-cm depths reached 95% of the total emergence 1 to 3 d earlier in a sandy loam than in a sand soil. Mean emergence depth was 1.7 cm in the sand and 2.4 cm in the sandy loam soil. Knowledge gained from this research will be instrumental in developing a better understanding of the requirements for coffee senna germination and emergence, allowing further development and improvement of integrated weed management strategies specific to this troublesome weed.


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