ABSTRACT

Non classé

Rice (Oryza spp.) is becoming one of more cultivated cereals through the world. The
knowledge of agro-morphological characters could be an invaluable in germplasm
management and crop improvement strategies. In 2011, 128 accessions collected from all
agro-ecological zones of Benin were assessed using 14 quantitative and 8 qualitative traits.

This study was conducted at Africarice Ouèdèmè site in Lokossa and its aim is to access the
variability existing in rice accessions from Benin. The accessions were evaluated on the field
using an augmented design in randomized complete block with nine replicated checks.
The phenotypic frequency analyze of the qualitative traits showed that the collection is
predominantly extra vigorous (72.66 % of accession). Basal leaf sheath color is 82.81 % green
and is 17.19 % purple. The accessions have in majority 2-cleft ligule (95 %), and the
pubescence of their leaves is 88.28 % intermediate.

Analysis of variance showed that significant block effects were observed for 8
quantitative characters whereas blocks effects were non-significant for the 6 others
quantitative traits, meaning that blocking was not important for these traits. The first five
principal components which explained 76.46 % of the total variation were used as variables
for the clustering of accessions. Eight groups were identified. Canonical discriminant analysis
revealed that traits such as lodging, days to heading, leaf length, flag leaf length, plant height,
number of tillers and number of panicle per plant were the main discriminatory
characteristics. A descriptive analysis of the different groups of accession showed that cluster
7 only composed of accessions from O. glaberrima is characterized by its susceptibility to
lodging and are early heading. The accessions of the cluster 8 are mostly tall and have long
leaf. Those from cluster 4 and 6 have the highest number of tiller and panicle per plant.

Key word:

rice accession, characterization, multivariate analysis, agro-morphological
diversity, Benin.

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