Genecological variation in recently established populations of Abutilon theophrasti (velvetleaf)

1986 ◽  
Vol 64 (8) ◽  
pp. 1632-1643 ◽  
Author(s):  
S. I. Warwick ◽  
L. D. Black
Keyword(s):  
Life History ◽  
Local Environment ◽  
Allozyme Variation ◽  
Morphological Characters ◽  
Abutilon Theophrasti ◽  
Population Differences ◽  
Weed Species ◽  
Wide Range ◽  
Genetic Features ◽  
Multilocus Associations

Life history and electrophoretic variation were examined in 39 populations of Abutilon theophrasti L., velvetleaf, collected from southern Ohio (39° N) to central Ontario (45° N). These collections represent a climatic gradient at the northern extreme of the distribution range of this weed species in North America. Plants from each of the 39 populations were grown from seed in a standard garden trial. A total of 51 growth, germination, and morphological characters were measured for each population. Significant among-population differences (p < 0.05) were found for 33 of the 51 characters. Many of these population differences were correlated with latitude and climate. These patterns of variation may well represent the first stages of differentiation in response to local environment. Of particular importance was the wide range of differences among populations in proportions of seeds exhibiting dormancy. Results from an electrophoretic survey of 16 enzyme systems provided evidence for very low levels of allozyme variation among the 39 populations of A. theophrasti. Only two enzymes were variable and only four multi-locus electrophoretic genotypes were evident among the 39 populations. Velvetleaf exhibited a number of genetic features characteristic of successful colonizers: high levels of fixed heterozygosity as a result of polyploidy, multilocus associations providing a reduced number of genotypes, and high levels of population differentiation in morphometric and life-history traits.

Life history and allozyme variation in populations of the weed species Setaria faberi

1987 ◽  
Vol 65 (7) ◽  
pp. 1396-1402 ◽  
Author(s):  
S. I. Warwick ◽  
B. K. Thompson ◽  
L. D. Black
Keyword(s):  
Life History ◽  
Significant Variation ◽  
Allozyme Variation ◽  
Growth Characteristics ◽  
Population Variation ◽  
Weed Species ◽  
Setaria Faberi ◽  
Single Genotype ◽  
Variable Population ◽  
Low Levels

Life-history features and allozyme variation were examined among and within eight populations of Setaria faberi collected at the northern limits of its distribution range from 39 to 45° N latitude. Statistically significant variation among the eight populations was evident for all 16 characters relating to morphology, phenology, and growth characteristics of the plants. Very low levels of allozyme variation were detected in the eight populations, i.e., only 3 of the 22 loci surveyed were polymorphic. Nine multilocus genotypes were present. Six of the eight populations contained a single genotype, whereas the most variable population (A) contained eight genotypes. Estimates of within-population variation of nine life-history features indicated that population A was the most variable with 7 of 9 characters showing statistically significant among-family variation.

scholarly journals Use of Raman spectroscopy for determining the effects of herbicides on the carotenoid content in Chenopodium album and Abutilon theophrasti leaves

2020 ◽  
Vol 29 (1) ◽  
pp. 63-72
Author(s):  
Filip Vranješ ◽  
Ilinka Pećinar ◽  
Steva Lević ◽  
Sava Vrbničanin ◽  
Dragana Božić
Keyword(s):  
Raman Spectroscopy ◽  
Chenopodium Album ◽  
Abutilon Theophrasti ◽  
Carotenoid Content ◽  
Growth Stages ◽  
Weed Species ◽  
Leaf Analysis ◽  
Wide Range ◽  
Significant Difference ◽  
Adequate Method

Raman spectroscopy has so far proved to be a suitable method for the analysis of carotenoids in a wide range of plant samples. This study aimed to determine whether the influence of mesotrione on the changes in carotenoid content of leaves in treated weed species Chenopodium album and Abutilon theophrasti can be detected using Raman spectroscopy. When the plants reached the targeted growth stages (C. album: 4 leaves, A. theophrasti: 2 leaves), Skaut herbicide (a.i. mesotrione 480 g l-1, SC) was applied in the amount of 120 g a.i. ha-1 in the tank mix with the adjuvant Alteox wet 40 (a.i. mineral oil (500 g L-1) + polyoxy alcohol (500 g L-1)), in the amount of 1 L ha-1. Leaf analysis, using Raman spectroscopy, was performed four times: on the 1st, 2nd, 3rd, and 7th day after the application of mesotrione. The intensity of the bands in the obtained Raman spectra, at positions 1007, 1155, and 1522 cm-1 in untreated and treated plants was analysed to determine the relative carotenoid content. The obtained results have shown that changes in the relative carotenoid content in the leaves of treated C. album plants can be detected as early as 3 days after the application of mesotrione, compared to the leaves of untreated plants of the same age. Meanwhile, a statistically significant difference for the same parameter in the leaves of treated A. theophrasti plants was evident at a later stage than in C. album, on the 7th day after the application of mesotrione. Consequently, this study has confirmed that Raman spectroscopy can be used as an adequate method for the rapid detection of the effect of herbicides on the content of carotenoids in the leaves of treated weed species.

Key to the currently recognized species of Limnias Schrank, 1803 (Rotifera, Monogononta, Gnesiotrocha, Flosculariidae)

Zootaxa ◽  
2018 ◽  
Vol 4442 (2) ◽  
pp. 307 ◽  
Author(s):  
ROBERT LEE WALLACE ◽  
AZAR KORDBACHEH ◽  
ELIZABETH J. WALSH
Keyword(s):  
Life History ◽  
Morphological Characters ◽  
Ecological Information ◽  
Genetic Features ◽  
Species Groups

Although the most widely used key to the Rotifera subsumes six species of the sessile genus Limnias within two species groups (L. ceratophylli and L. melicerta), the original descriptions of these forms are sufficiently different to recognize them as distinct entities. We used these descriptions and all available literature on these species to develop dichotomous and formula keys to the six species based on easily recognizable morphological characters. As part of our review we added relevant ecological information from published sources, as well as our own data. We also discuss the need for additional observations of morphological, behavioral, life history, and genetic features to better understand the diversity of this widespread genus.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

scholarly journals Overview of the Genetic Diversity of African Macrotermes (Termitidae: Macrotermitinae) and Implications for Taxonomy, Ecology and Food Science

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 518
Author(s):  
Bronwyn Egan ◽  
Zwannda Nethavhani ◽  
Barbara van Asch
Keyword(s):  
Negative Impact ◽  
Phylogenetic Reconstruction ◽  
Morphological Characters ◽  
Food Science ◽  
Cryptic Diversity ◽  
African Species ◽  
Genetic Groups ◽  
Wide Range ◽  
Coi Sequences ◽  
High Level

Macrotermes termites play important ecological roles and are consumed by many communities as a delicacy and dietary complement throughout Africa. However, lack of reliable morphological characters has hampered studies of Macrotermes diversity in a wide range of scientific fields including ecology, phylogenetics and food science. In order to place our preliminary assessment of the diversity of Macrotermes in South Africa in context, we analysed a comprehensive dataset of COI sequences for African species including new and publicly available data. Phylogenetic reconstruction and estimates of genetic divergence showed a high level of incongruity between species names and genetic groups, as well as several instances of cryptic diversity. We identified three main clades and 17 genetic groups in the dataset. We propose that this structure be used as a background for future surveys of Macrotermes diversity in Africa, thus mitigating the negative impact of the present taxonomic uncertainties in the genus. The new specimens collected in Limpopo fell into four distinct genetic groups, suggesting that the region harbours remarkable Macrotermes diversity relative to other African regions surveyed in previous studies. This work shows that African Macrotermes have been understudied across the continent, and that the genus contains cryptic diversity undetectable by classic taxonomy. Furthermore, these results may inform future taxonomic revisions in Macrotermes, thus contributing to advances in termitology.

Oscillatory Dynamics in Populations of an Annual Weed Species Abutilon Theophrasti

1989 ◽  
Vol 77 (4) ◽  
pp. 1135 ◽  
Author(s):  
P. H. Thrall ◽  
S. W. Pacala ◽  
J. A. Silander
Keyword(s):  
Abutilon Theophrasti ◽  
Weed Species ◽  
Oscillatory Dynamics

Seed germination biology of sweet acacia (Vachellia farnesiana) and response of its seedlings to herbicides

Weed Science ◽  
2021 ◽  
pp. 1-19
Author(s):  
Bhagirath S. Chauhan ◽  
Shane Campbell ◽  
Victor J. Galea
Keyword(s):  
Sodium Chloride ◽  
Seed Germination ◽  
Development Stage ◽  
Hot Water ◽  
Control Treatment ◽  
Similar Species ◽  
Weed Species ◽  
Physical Dormancy ◽  
Seed Biology ◽  
Wide Range

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.

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
Keyword(s):  
Seed Germination ◽  
Management Strategies ◽  
Moisture Stress ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Weed Species ◽  
Physical Dormancy ◽  
Sesbania Cannabina ◽  
Wide Range ◽  
The Impact

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.

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