Effects of photoperiod on the phenological development of redroot pigweed (Amaranthus retroflexus L.)

Abstract

. 2000. Effects of photoperiod on the phenological development of redroot pigweed (Amaranthus refroflexus L.). Can. J. Plant Sci. 80: [929][930][931][932][933][934][935][936][937][938]. Mechanistic weed models focus on determining the outcome of weed and crop interference. An understanding of weed phenology is essential for simulation model development. Phenological development is a major factor determining the outcome of weed-crop competition. Growth cabinet studies were conducted to characterize the influence of photoperiod on the phenological development of redroot pigweed (Amaranthus retroflexus L.). Results indicated that redroot pigweed is a quantitative short-day species. Four development phases of redroot pigweed were described according to its response to photoperiod: (1) a juvenile phase of 1.1 d; (2) a photoperiod-sensitive inductive phase of 7.9 d; (3) a photoperiod-sensitive post-inductive phase of 39.9 d; and (4) a photoperiod-insensitive phase of 2.2 d. This information is useful for the development of mechanistic models and for comprehending the distribution and competitive ability of redroot pigweed with crops. The utilization of these results could help in predicting the phenological development of redroot pigweed.Key words: Phenology, mechanistic weed models, juvenile phase Huang, J. Z., Shrestha, A., Tollenaar, M., Deen, W., Rahimian, H. et Swanton, C. J. 2000. Effets de la photopériode sur la phénologie de l'amarante à racine rouge (Amaranthus retroflexus L.). Can. J. Plant Sci. 80: 929-938. Les modèles mécanistes des infestations de mauvaises herbes se concentrent sur la résultante de la compétitivité entre mauvaises herbes et cultures. La compréhension de la phénologie des mauvaises herbes est un préalable essentiel à la construction de modèles en simulation car le développement phénologique est un facteur de première importance pour l'issue de la compétition mauvaises herbes-cultures. Nous avons conduit des travaux en armoire de croissance pour caractériser l'influence de la photopériode sur la phénologie de l'amarante à racine rouge (Amaranthus retroflexus L.). L'amarante apparaît comme une espèce de jour court quantitative. Nous avons dégagé quatre phases de développement de l'amarante selon sa réaction à la longueur de la photopériode : 1) une phase juvénile de 1,1 j; 2) une phase d'induction florale sensible à la photopériode de 7,9 j; 3) une phase post-induction, sensible à la photopéri-ode de 39,9 j; 4) une phase photo-apériodique de 2,2 j. Ces renseignements sont utiles pour la construction de modèles mécanistes et pour comprendre le mode de répartition spatiale de la mauvaise herbe ainsi que sa compétitivité envers les cultures. Ils pourraient également faciliter la prédiction de son développement phénologique. Mots clés: Phénologie, mécaniste, modèles d'infestation de mauvaises herbes, phase juvénileIntegrated weed management (IWM) is a multidisciplinary approach that utilizes various methods of weed control within a cropping system Swanton and Murphy 1996). The success of IWM ca...

Living Mulch as a Tool to Control Weeds in Agroecosystems: A Review

“…Because FR is a determinant of photoperiod, within a dense crop canopy (FR enriched), long-day weed species may have accelerated phenological development, whereas short-day weeds (i.e., pigweed) will take longer to complete their life cycle (Huang et al, 2000). Branching and tillering are also influenced by FR light ( Begonia et al 1988;Davis and Simmons 1994;Ghersa et al 1994;McLachlan et al 1993).…”

The biology of Canadian weeds. 130. Amaranthus retroflexus L., A. powellii S. Watson and A. hybridus L.

“…Populations of the three species growing in temperate regions have a facultative short-day flowering response (Weaver and McWilliams 1980;Huang et al 2000;Rajcan et al 2002). Plants of A. retroflexus grown under short-day conditions (8, 10, 12 h) at 20ºC in growth cabinets required only 13 d to initiate flowering, whereas plants grown under long-day conditions (14 and 16 h) required 41 d (Huang et al 2000).…”

Effects of hydrologic modifications to riparian plant communities in a large river system in northern China

“…In the present study, annuals had the highest percentage at seasonal flow sites, resulting from the unique hydrological ''disturbance'' along seasonal reaches and annuals' response strategy. Riparian annuals like Chenopodium glaucum and Digitaria sanguinalis are fastgrowing, widespread summer-annual weeds that show high phenotypic plasticity to changes in environmental conditions (Wulff et al 1999;Huang et al 2000;Rajcan et al 2002;Causin and Wulff 2003). Both have intermediate strategies between R and C-R (C, S and R are short for competitive, stress-tolerant and ruderal respectively) in the established phase, according to Grime's C-S-R model (Grime et al 1988;Zelnik and Č arni 2008).…”