English

Njimeni Tchuisse Marlyn,Leonard Magaptche Ngonkeu Eddy,Tekeu Honoré,Hubert Yamdeu Galani Joseph,Boudjeko Thaddée,K Malaa Dorothy,Mballa Thomas,Nji Akindeh

doi:10.5897/ajps2019.1921

Abstract

Rice (Oryza sativa L.) cultivated in Cameroon is appreciated by consumers for its nutritive quality and good taste. Diversity of 68 local rice cultivars was investigated via grain morphology and protein content characterization. The size and shape of grains were determined and used with yield parameters to classify the cultivars and perform Principal Component Analysis (PCA). Total protein content and glutelin content of eight selected cultivars (CMRGNd, CMRGDn, CMRGTi, CMRTBa, CMRDWb, CMRDTc3, CMRDTx5 and CMRDTx6) were evaluated by Bradford assay and correlation analysis of all the parameters studied was performed. Long size grains (42) were predominant over extra-long (16), medium (9) and short (1) grains. Slender shaped grains (36) were distinguished as well as medium (28) and bold (4) grains. The 68 cultivars were grouped into four clusters independent of their origins. PCA revealed three principal components accounting for 74.4% of total variation. Highest total protein content was observed in CMRGNd (14.3%) and highest glutelin content in CMRGDn (10.1 mgEqvBSA/g DW). Pearson correlation of the different variables revealed no significant correlation between total protein and glutelin contents with the agro-morphological parameters evaluated in this study. This suggests that none of these parameters could be descriptor for protein content. Positive correlation between grain length and yield (r = 0.7) suggests grain length as yield descriptor. Key words: Rice, diversity, grain morphology, protein, glutelin.

Highlights

Rice (Oryza sativa L.) is the second most consumed cereal in Cameroon after maize and is presently a staple food for both rural and urban populations
IRRI’s Standard Evaluation System (SES) classifies shape as slender, medium, bold and round (IRRI, 1996)
Kernel shapes were slender (36 cultivars), medium (28) and bold (4). It appeared that majority of the varieties from each of the localities were of long size (Yaoundé-56.6%, Dschang-57.9%, Garoua60% and Tonga-75%), and slender shape (Yaoundé66.7%, Dschang-52.6%, Garoua-53.3% and Tonga-50%)

Summary

Introduction

Rice (Oryza sativa L.) is the second most consumed cereal in Cameroon after maize and is presently a staple food for both rural and urban populations. The national production estimated at about 360000 tons in 2017 (FAO, 2019), remains far below consumption that is estimated at about 635,000 tons (USDA, 2017). While trying to identify the physicochemical characteristics that determine the consumption preferences of local and imported rice in the North-west region, Fon and Fonchi (2016) obtained 83.9% of respondents confirming that locally produced rice tastes better than imported rice. Consumer demand for fine rice varieties is high due to good nutritional quality, palatability, aroma and taste. IRRI classifies brown rice grain length into extra-long (>7.50 mm); long (6.61-7.50 mm); medium (5.51-6.60 mm); and short (≤5.50 mm). IRRI’s Standard Evaluation System (SES) classifies shape as slender (length–width ratio >3.0), medium (ratio 2.1–3.0), bold (ratio 1.1–2.0) and round (ratio

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