Rice grain quality: A comparison of imported varieties, local varieties with new varieties adopted in Benin

Agro-morphological and physiochemical studies of upland rice (Oryza sativa L.) varieties for variability with yield and quality related parameters in south Gondar district, Ethiopia

Study was conducted during the main cropping season of 2016 in Fogera and Libo Kemkem District, South Gondar, Ethiopia to evaluate agro-morphological and physiochemical studies of upland rice (Oryza sativa L.) varieties for variability and their association with yield and their quality. A total of ten up land rice varieties namely NERICA13, NERICA12, NERICA4, SUPERICA1, HIDASE, ADET, ANDASA, TANA, KOKIT and GETACHEW laid down in a randomized complete block design with three replications were used. The study revealed significance (P < 0.05) difference in ago-morphological parameters like plant height, number of spike lets, biomass yield, straw yield, grain yield and harvest index in Fogera district, and productive tillers, number of spike lets, grain yield and harvest index in Libo Kemkem District. At Fogera district the highest yield were recorded in NERICA13 (4738 kg/ha), GETACHEW (4614 kg/ha), NERICA4 (4092 kg/ha), NERICA12 (4020 kg/ha) and Adet (3557.4 kg/ha) varieties, and NERICA12 (4583 kg/ha), NERICA13 (4013 kg/ha) NERICA4 (4002 kg/ha) and Adet (3380 kg/ha) varieties at Libo Kemkem districts. Five varieties (NERICA (4, 12 and 13), GETACHEW and ADET) at both locations had been tested for physicochemical analysis. The result showed that such rice varieties grain have a cooking grain length of 7.39 mm (ADET), 7.68 mm (NERICA4), 7.65 mm (NERICA12), 7.88 mm (NERICA13) and 6.76 mm (GETACHEW); cooking grain width of 2.61 mm (ADET), 2.64 mm (NERICA4), 2.70 mm (NERICA12), 2.79 mm (NERICA13) and 2.91 mm (GETACHEW); Grain thickness of 1.91 mm (ADET), 2.73 mm (NERICA4), 2.69 mm (NERICA12), 2.72 mm (NERICA13) and 2.23 mm (GETACHEW. and grain length/width (L/w) ratio 2.67 mm (ADET), 1.85 (NERICA4) 1.80 (NERICA12), 1.92 (NERICA13) and 2.09 (GETACHEW) were revealed and determination of grain shapes. Broken density was obtained 85.74mg/cm3 (ADET), 83.47mg/mm3 (NERICA4), 84.38mg/mm3 (NERICA12), 87.5mg/mm3 (NERICA13) and 73mg/mm3 (GETACHEW). Also investigations showed that upland rice grains contained 11.63-14.27% moisture; 1-1.24%, ash; 2.90-3.62% fiber and 8.07-10.35% protein. Gelatinization Temperatures ranged from 58.33 to 72.67% and grain contents of carbohydrates 73.57-75.65% were shown and significantly affected among their five upland rice grains varieties. Among the treatments of upland rice varieties were gained 35.79% of grain yield advantageous over all treatments at both locations. The results revealed in relatively morphologically and physicochemical properties of the three types of upland rice varieties NERICA (4, 12 and 13) were recommended to maximizing grain yielding for rice producing farmers.

Differences in physicochemical properties of commercial rice from urban markets in West Africa

Rice consumers in West Africa (WA) have an acquired preference for imported rice. Enhancing consumption of local rice requires matching the grain quality attributes of the imported benchmarks in addition to increasing productivity of local rice cultivars. Thus, there is a need to develop screening tools that will aid breeding programs select for high-yielding and stress-tolerant cultivars whose grain quality are at par with imported rice. Hence, this study evaluated various grain quality characteristics of 316 commercial milled rice samples from urban markets in three WA countries (Benin, Cameroon, and Ghana) and developed linear discriminant models (LDAs) to classify rice according to their origins and to predict the imported rice classification of local germplasm based on their grain quality attributes. More than half of the commercial rice samples that were collected originated from Thailand (60%); in contrast, only a small fraction was locally grown (2%). The commercial rice from different origins were distinguishable based on the quality attributes evaluated, contributing to the relatively high classification rates achieved by the fitted LDAs. These results indicate that multivariate models could be useful during varietal improvement as tools for screening for cultivars that can match the quality of imported rice.

Novel and Automatic Rice Thickness Extraction Based on Photogrammetry Using Rice Edge Features

The dimensions of phenotyping parameters such as the thickness of rice play an important role in rice quality assessment and phenotyping research. The objective of this study was to propose an automatic method for extracting rice thickness. This method was based on the principle of binocular stereovision but avoiding the problem that it was difficult to directly match the corresponding points for 3D reconstruction due to the lack of texture of rice. Firstly, the shape features of edge, instead of texture, was used to match the corresponding points of the rice edge. Secondly, the height of the rice edge was obtained by way of space intersection. Finally, the thickness of rice was extracted based on the assumption that the average height of the edges of multiple rice is half of the thickness of rice. According to the results of the experiments on six kinds of rice or grain, errors of thickness extraction were no more than the upper limit of 0.1 mm specified in the national industry standard. The results proved that edge features could be used to extract rice thickness and validated the effectiveness of the thickness extraction algorithm we proposed, which provided technical support for the extraction of phenotyping parameters for crop researchers.

Evaluation of physical properties of rice used in traditional Kyrgyz Cuisine

Eight staple rice cultivars consumed in Kyrgyzstan were evaluated for physical properties in this study. The dimensions of investigated grains correspond to 5.29-6.99 mm for length, 2.52-3.10 mm for width, and 1.88-2.13 for thickness. Equivalent diameter was in range of 3.14 - 3.47 mm, surface area took 25.35-31.90 mm². The sphericity analysis values varied from 0.480 to 0.559, aspect ratio from 0.39 to 0.55, volume of the grain was measured in range from 16.25 to 22.02 mm3, bulk density values were 0.77-0.87 g/cm3, and solid density from 1.17 to 1.41 g/cm3. The porosity of grain was equal to 28.27-39.83%, thousand kernel weight correspond to 19.67 to 27.15 g, rupture force of grain was measured in range of 63.47-155.50 N, color characteristic varied in parameters L*, a* and b*, 37.58-72.19, -0.22-10.17, and 9.65-21.12, respectively. Optimum cooking time ranged from 19.33 to 33.00 min. The water uptake ratios for 30 min of soaking were 1.21-1.28, 1.18-1.45, and 1.14-1.57 for 30, 45, and 60°C, respectively. While the water uptake ratios for 60 min of soaking were 1.22-1.42, 1.19-1.54, and 1.25-1.75 for 30, 45, and 60°C, respectively. Optimal cooking time showed that imported varieties needed lower interval for full grain cooking compared to the local Kyrgyz varieties. It was found that Kyrgyz rice varieties staying more firm after cooking as compared to imported varieties and therefore more suitable for the local traditional dish such as plov.