Vegetative and reproductive growth of weedy rice in Selangor, Malaysia: a comparative study with commercial rice varieties

Malaysia has been facing weedy rice problem in the rice granaries. A random sampling was done in 2010 to collect the weedy rice populations from eight sites of Selangor rice granaries in Malaysia. The study was done to understand the chronology of vegetative and reproductive growth of weedy rice found in Selangor rice granaries. A total of 360 plant accessions were collected and scored in twelve weedy rice morphotypic group on the basis of plant height, panicle type, lemma and palea colour, presence of awn and apiculus colour. Data from different growth stages of these along with four commercial rice varieties (MR84, MR185, MR211 and MR219) were recorded and analyzed. Most of weedy morphotypes were observed having vigorous growth at early growth stage. Most of weedy morphotypes were found 10 to 84% taller with 29 to 61% higher leaf area indexes at all the growth stages. Tillering ability initially was comparatively 69% higher in weedy morphotypes at 14 days after planting and was decreased at later growth stages. Wide range of flowering and maturity periods were observed in weedy morphotypes, where some flowered earlier and some flowered at the same time or later than the commercial varieties. All these characteristics of weedy rice might help to identify them for better control in the rice granaries.