Screening of Rice Varieties for their Weed Competitiveness

Weed competition is a major constraint in rice production systems in Africa. This study was conducted at the Africa Rice Experimental Station in Benin in the dry and rainy seasons to screen rice varieties for weed competitiveness. The experiment was factorial under a a split plot design with 14 contrasting cultivars planted under three weeding regimes: 0, 1 and 4 weedings. Agro-morphological characters, growth indeces and weeds were used to evaluate the cultivars. Highly significant differences (P<0.0001) between cultivars were observed. The impact of weeds on agro-morphological traits was expressed through an increasing senescence of plants in relation to the weeding regime. Weed-competitive cultivars typically showed a leaf area index less than 3, a high specific leaf area and a Soil-Plant Analyses development (SPAD) unit less than 30. High affinities between traits were observed and three types of descriptors were identified based on their broad sense heritability. CG20, an O. glaberrima variety was the most competitive against weeds.
Les mauvaises herbes constituent l’une des principales contraintes en riziculture en Afrique Sub Saharienne. Les essais ont été réalisés à la station expérimentale d’AfricaRice. Le dispositif expérimental utilisé est le split plot et le criblage a été réalisé à partir de 14 variétés suivant 3 régimes d’enherbement : 0, 1 et 4 sarclages. Les caractères agro-morphologiques, les indices de croissance et les adventices ont été mesurés. Des effets hautement significatifs (0,0001) ont été obtenus entre variétés. L’impact des adventices sur les caractères agromorphologiques s’est traduit par une dégénérescence croissante des plantes en fonction du régime d’enherbement. Un indice foliaire inférieur à 3, une surface foliaire spécifique grande et une unité SPAD inférieure à 30 caractérisent les plantescompétitives. Les affinités fortes entre variables ont été mises en évidence, trois groupes de variables ont été identifiés par rapport à leur héritabilité et la variété CG 20 (Oryza glaberrima) s’est révélée la plus compétitive.
Extended abstracts submitted under Crop Improvement
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West Africa
RUFORUM Conferences and Workshops
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Open Access
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Printed resource

The 2012 RUFORUM Biennial Conference is the third in the series. The main objective of the Biennial conferences is to provide a platform for agricultural research for development stakeholders in Africa and beyond to actively exchange findings and experiences, while at the same time learning lessons towards improving performance of the agricultural sector and ultimately people’s livelihoods. The biennial conference is RUFORUM’s most comprehensive meeting for the diversity of stakeholers in agriculture. It is especially dedicated to graduate students and their supervisors, grantees in RUFORUM member universities and alumni. It is a platform for peer review, quality control, mentorship, networking and shared learning. The third Biennial Conference was attended by 657 participants.This record contains an extended abstract accepted under the theme of Crop Improvement