Natural herbicide resistance (HR) to broad-spectrum herbicide, glyphosate among traditional and inbred-cultivated rice (Oryza sativa L.) varieties in Sri Lanka.
Weeds along with insect pests and plant diseases are sources of biotic stress in crop systems. Weeds are responsible for serious problems in rice worldwide affecting growth and causing a considerable reduction in quality and quantity in yield. High concentrations of pre-emergent-broad-spectrum systemic herbicide, Glyphosate is prevalently applied to control rice weeds which intern causes severe damages to cultivated rice varieties, susceptible to Glyphosate. However, there may be rice varieties with natural Herbicide Resistance (HR) which are so far, has not been evaluated. In this study Six traditional and eighteen developed-cultivated rice varieties (Bg, Bw, At and Ld series developed by Rice Research Development Institute, Sri Lanka) were used to screen their natural HR. RCBD with five replicates and three blocks in each treatment-combination was used as the experimental design. As observations, time taken-to seed germination, time taken to flowering; plant height and number of leaves at 12-weeks after sawing, leaf-length, breadth, panicle-length, number of seeds/panicle of resistant plants and controls were recorded. Plants with > or = 40% resistance were considered as resistant to Glyphosate. Ten inbred-cultivated rice varieties (Bg250, Bg94-1, Bg304, Bg359, Bg406, Bg379-2, Bg366, Bg300, Bw364, At362) and three traditional rice varieties ("Kalu Heenati", "Sudu Heenati", "Pachchaperumal") were naturally resistant to 0.25 g L(-1) Glyphosate concentration and when increased the concentration (0.5 g L(-1)) resistance was reduced. This study showed the usefulness of modern statistical method, classification and regression tree analysis (CART) in exploring and visualizing the patterns reflected by a large number of rice varieties (larger experimental database) on herbicide resistance in future.
Department of Botany, Faculty of Natural Sciences, The Open University of Sri Lanka, Nawala, Nugegoda, Sri Lanka.
S R
SR
Weerakoon
Department of Botany, Faculty of Natural Sciences, The Open University of Sri Lanka, Nawala, Nugegoda, Sri Lanka.
S
S
Somaratne
Department of Botany, Faculty of Natural Sciences, The Open University of Sri Lanka, Nawala, Nugegoda, Sri Lanka.
R G D
RG
Wijeratne
Department of Botany, Faculty of Natural Sciences, The Open University of Sri Lanka, Nawala, Nugegoda, Sri Lanka.
E M S I
EM
Ekanyaka
D000704:Analysis of Variance; D018556:Crops, Agricultural / Q000145:classification / Q000187:drug effects* / Q000254:growth & development; D018525:Germination / Q000187:drug effects; D005998:Glycine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology; D053209:Herbicide Resistance; D006540:Herbicides / Q000009:adverse effects / Q000494:pharmacology*; D015233:Models, Statistical; D012275:Oryza / Q000145:classification / Q000187:drug effects* / Q000254:growth & development; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development; D012044:Regression Analysis; D013188:Sri Lanka; D058728:Weed Control / Q000379:methods*; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate