دانلود رایگان ترجمه مقاله زیست شناسی و مدیریت کتان صحرایی قرمز

زیست شناسی و مدیریت کتان صحرایی قرمز – یک تهدید جدید برای صنعت غلات

Biology and management of red dodder – a new threat to the grains industry

Summary

Seed dormancy release, host species preference, the effect of parasitisation on pods or burrs of host plant species, the effect of crop sowing time and control of red dodder ( Cuscuta planiflora) by selective herbicides were investigated in a series of experiments under laboratory and glasshouse conditions in 2005 at Northam, WA. About 88% of untreated seeds of red dodder were dormant but soaking seeds in concentrated sulphuric acid for 10 minutes improved seed germination from 12 to 45%. Treated seeds of red dodder germinated over a range of temperature regimes. This weed species successfully parasitised lupin, lentil, chickpea, field pea, faba bean, sub-clover and canola plants in order of decreasing preference. Parasitisation reduced pods or burrs per plant by 20% in lentil, 50% in faba bean, 60% in lupin, 75% in chickpea, and 100% in sub-clover. Pre-sowing herbicides such as trifluralin, simazine, Kerb®, diuron, Spinnaker® and Lexone® controlled 90 to 100% of red dodder plants. Post-emergent herbicides such as atrazine, Spray.Seed® (paraquat + diquat), Lexone® and Sniper® controlled 83 to 100% of red dodder plants. Delay in sowing time of crops by two to four weeks effectively reduced red dodder plants.

1 Introduction

Red dodder (Cuscuta planiflora Ten.) is widely distributed in the Mediterranean and central Asia but it has been introduced in many other countries (Parker and Riches 1993). It is known to attack lucerne and clovers (Al-Menoufi and Hassan 1976) and some species of dodder are mildly toxic to animals (Movesian and Azaria 1971). Cooke and Black (1987) reviewed the biology and control of Cuscuta campestris Yuncker and other Cuscuta spp. including Cuscuta planiflora which was referred to as red dodder. That review highlighted the lack of information available on red dodder. Red dodder was found in a canola crop in the Northern Agricultural region of WA in 2001; the first record of parasitisation of canola. The presence of dodder has the potential to contaminate produce and may exclude this produce from markets which have zero tolerance for dodder seed.Very little information is available on the biology and management of this parasitic weed under WA wheatbelt conditions. The aims of this study were to investigate red dodder seed dormancy release, the preference of red dodder for host plant species, the effect of parasitisation on the pods or burrs of host plant species, the effect of crop sowing time on red dodder and its control by selective herbicides.

MATERIALS AND METHODS

A series of experiments were conducted in a completely randomised design with 50 seeds per Petri dish or pot replicated three to five times under laboratory or glasshouse conditions at Northam in 2005. An untreated control was maintained in each experiment. Release of red dodder seed dormancy Seeds were treated with concentrated sulphuric acid for 10 minutes and then allowed to germinate at three temperature regimes (5/15, 10/20, and 15/30°C night/day) with or without prior chilling. Germination of seeds was recorded either daily or every alternate day for 3–6 weeks. Data were averaged over the temperature regimes. Host preference for red dodder plants Treated seeds of red dodder were sown with seven species of crops and pastures in 10 L pots with three replications. An untreated set of three pots species was maintained without red dodder seeds. The crop and pasture species are canola (Brassica napus L.), chickpea (Cicer arietinun L.), faba bean (Vicia faba L.), field pea (Pisum sativum L.), lentil (Lens culinaris Medik.), lupin (Lupinus angustifolius L.), and sub-clover (Trifolium subterraneum L.). Emergence and survival of dodder plants were recorded for up to seven weeks after sowing. Preference was determined by the extent of parasitisation and survival of red dodder on different species. Red dodder effect on the pods or burrs Treated seeds of red dodder were sown on the surface of pots and covered with a thin layer of sandy soil. In the pots where natural parasitisation did not occur, artificial parasitisation was performed by wrapping an 8 cm long fragment of red dodder shoot around the stem of the target host plant. Pods produced by host crop plants both in the absence and presence of red dodder were counted. Time of sowing effect on red dodder Treated red dodder seeds were sown in pots four times at weekly intervals. Emergence and survival of red dodder plants were recorded for each time of sowing (TOS) up to 31 days after sowing. Red dodder control by herbicides Selected presowing herbicides recommended for each host species were sprayed on the surface of pots and covered with a thin layer of sandy soil. Emergence and mortality of red dodder plants were recorded for seven weeks after sowing. Selected post-emergence herbicides recommended for each host plant species were sprayed at the label rate and at the recommended growth stage of each host plant species. Density and mortality of red dodder plants were recorded four weeks after spraying