Weedy rice ( Oryza sativa
L.) is a noxious form of cultivated rice (O. sativa
L.) associated with
intensive rice production and dry seeding. A cost-efficient strategy to control this weed is the Clearfield rice
production system, which combines imidazolinone herbicides with mutant imidazolinone-resistant rice
varieties. However, imidazolinone resistance mutations can be introgressed inweedy rice populations by natural
outcrossing, reducing the life span of the Clearfield technology. Timely and accurate detection of imidazolinone
resistance mutations in weedy rice may contribute to avoiding the multiplication and dispersion of resistant
weeds and to protect the Clearfield system. Thus, highly sensitive and specific methods with high throughput
and low cost are needed. KBioscience’s Allele Specific PCR (KASP) is a codominant, competitive allele-specific
PCR-based genotyping method. KASP enables both alleles to be detected in a single reaction in a closed-tube
format. The aim of this work is to assess the suitability and validity of the KASP method for detection in weedy
rice of the three imidazolinone resistance mutations reported to date in rice.
Validationwas carried out by determining the analytical performance of the newmethod and comparing
it with conventional allele-specific PCR, when genotyping sets of cultivated and weedy rice samples. The
conventional technique had a specificity of 0.97 and a sensibility of 0.95, whereas for the KASP method, both
parameters were 1.00.
The new method has equal accuracy while being more informative and saving time and resources
compared with conventional methods, which make it suitable for monitoring imidazolinone-resistant weedy
rice in Clearfield rice fields.