Estimation of Actual and Potential Adoption Rates and Determinants of Improved Rice Variety Among Rice Farmers in Nigeria: The Case of NERICAs

The article used the ATE estimation framework to derive consistent semi-parametric estimators of population adoption rates and their determinants of the NERICA (New Rice for Africa) rice varieties in Nigeria. Empirical evidence shows that the observed sample adoption rate does not consistently estimate the population adoption rate even if the sample is random. NERICA awareness was found to be a major constraint to NERICA adoption in Nigeria. Several socioeconomic/demographic characteristics were found to be important determinants of NERICA awareness and adoption. Among those factors are age, gender, major occupation, year of experience and vocational training. In particular, we have found that the NERICA adoption rate in Nigeria would have been up to 76% in 2008 instead of the actually observed 20% joint exposure and adoption rate, if the whole population were exposed to the NERICAs in 2008 or before. This justifies investing in the dissemination of the NERICA varieties; considering that the 76% is bound to increase significantly in the future as farmers learn more about the characteristics of the NERICAs and become comfortable with their performances.NERICAs Adoption, awareness, Average Treatment Effect, Nigeria, Crop Production/Industries,

Physiological and Agronomic Responses of Four Rice Varieties to Drought in the Rainforest.

The present investigation tested the hypothesis that there would be variation in physiological responses to water deficit among rice varieties from different production ecologies, with contrasting tolerance to water deficit under repeated cycle of soil moisture deficit, at reproductive growth stage. A screen house and a field trial were conducted at International Institute of Tropical Agriculture, Ibadan and Ikenne (Latitude 6° 52' N, Longitude 3° 43' E) respectively. Both experiments had rice varieties ('IR 64', 'WAB 56-104', 'IR 77298-1-2-B-10' and 'NERICA 4') and stress status (stress and control) as treatment factor's, arranged in a randomised complete block design with three replicates. In both trials, the physiological mechanism that underpins varietal differences with repeated cycles of water deficit at the reproductive growth stage was more balanced water status, improved foliar characters, efficient photosynthetic capacity and higher grain yield in comparatively drought tolerant upland rice varieties ('NERICA 4' and 'WAB 56-104'), as opposed with the results for the drought susceptible cultivar 'IR 64'. A converse pattern was observed on water stressed rice, despite fewer cycles of water deficit on the field. The results could have suggested that the initiation of water deficit is the rate limiting step rather than its intensity at the reproductive growth stage

Alternate phenotype–genotype selection for developing superior high-yielding irrigated rice lines

Increase grain yield potential is one of the most important objectives of any cereal crop breeding program. To efficiently develop superior rice lines by the introgression of favorable alleles for yield and yield component traits, a strategy of alternate phenotype–genotype selection was used. The present study aimed to (i) investigate the allelic diversity of loci associated with major yield-component traits and (ii) phenotype and genotype advanced populations derived from crosses between NERICA-L-20 and Giza178 for yield component traits using agro-morphological descriptors and GRiSP polymorphic markers to select superior high-yielding rice lines. A total of 100 F2:3 progeny were selected from 1000 F2 plants and genotyped with 16 polymorphic markers linked to four major yield- component traits. Four promising F2:3 lines (ARS 563–14, ARS 563–62, ARS 563–286, and ARS 563–41) bearing combinations of desirable alleles were selected. A selected set of 20 F2:4 lines showed moderate to high heritability for all target traits. Fourteen F2:5 lines derived from ARS 563–14 and 17 F2:5 from ARS 563–286 families were evaluated in preliminary trials to estimate yield gain. The three top lines, ARS 563–286–16-1-1, ARS 563–286–5-1-1, and ARS 563–14–10-1-1, showed an increase of more than 10% grain yield over the best check, Sahel 108, which is widely cultivated in the Senegal River valley. The 16 markers linked to the target yield component traits can be used to fast-track breeding programs targeting rice productivity

EFFECTS OF MOISTURE CONTENTS AND TEMPERATURE ON THE THERMAL PROPERTIES OF SOME NERICA VARIETIES RELEVANT TO ITS PROCESSING

The thermal properties of NERICA (New Rice for Africa) was investigated on differing moisture content levels and temperatures. The NERICA varieties studied includes; FARO 44, FARO 52, FARO 57, FARO 60 and FARO 61. The variety samples were later categorized into two; NERICA Raw-Paddy and NERICA Parboiled-Milled samples. The thermal properties studied were; thermal conductivity, specific heat, and thermal diffusivity. The thermal conductivity and the specific heat were determined using the thermal conductivity probe method and a digital scanning calorimeter, respectively. The thermal diffusivity was determined from the obtained results of the specific heat and the thermal conductivity. Results indicated that, increase in moisture content and temperature results to increase in the specific heat, thermal conductivity and thermal diffusivity of NERICA varieties and these ranged from 4.245 to 39.976 kJ/kgoC; 0.042 to 1.403 W/moC; and 1.236 x 10-5 to 5.933 x 10-5 m2/s respectively for NERICA Raw-Paddy and 7.033 to 81.657 kJ/kgoC; 0.067 to 1.876 W/moC; and 1.413 x 10-5 to 5.219 x 10-5 m2/s respectively for NERICA Parboiled-Milled. Bulk density decreased with an increase in moisture contents and temperature and the obtained results ranged from 760.3 to 698.7 kg/m3 for NERICA Raw-Paddy and 720.4 to 652.4 kg/m3 for NERICA Parboiled. Regression analysis were carried out on the thermal properties of NERICA varieties and moisture content, and there was positive correlation between the parameters. There were significant effects of moisture content (p < 0.05) on all the parameters studied

Management of Striga asiatica in the vulnerable uplands of Central Madagascar: combining zero-tillage rice-maize cover-crop rotations with resistant varieties

Una de las principales dificultades que se tienen actualmente para diseñar localmente máquinas y herramientas para la extracción de gel de la planta de Aloe Vera, es el desconocimiento de las propiedades mecánicas de sus hojas. En este documento se presenta de manera general la metodología y los resultados obtenidos en el proceso de diseño y construcción de una máquina para la evaluación de la resistencia a la penetración y la resistencia a la compresión de las hojas de Aloe Vera

Combining High Yields and Blast Resistance in Rice (Oryza spp.): A Screening under Upland and Lowland Conditions in Benin

The future security of the supply of rice for food in Africa depends on improving the level of local production to achieve self-sufficiency. In order to cope with the existing gap between production and actual demand, combining a high level of rice blast tolerance and a high-yield potential is necessary. The current study was conducted under upland and lowland conditions in Benin to gain insight into the performance of selected blast-resistant accessions along with some currently grown varieties. This study revealed a high phenotypic variability among these accessions. Furthermore, differences in the performance of these accessions under lowland and upland conditions were observed. Principal component analysis showed their grouping in three clusters. The analysis also demonstrated a high yield potential among the blast-resistant rice accessions whether they were Oryza sativa or O. glaberrima. Furthermore, there was a significant correlation between yield and both spikelet fertility and growth cycle duration. In conclusion, the present study identified promising rice accessions for future breeding. High phenotypic variability in combination with interesting traits can help to develop new resilient varieties. Finally, when the traits correlate with yield, they can be used as markers for an early screening method for identifying promising accessions at an early stage

Scale Efficiency and Determinants of Productivity of New Rice for Africa (NERICA) Farmers in Kaduna State, Nigeria

Rice productivity is low in Nigeria, and NERICA was introduced by West Africa Rice Development Agency (WARDA) to solve this problem. This study focused on NERICA productivity and efficiency in Kaduna State. A three-stage sampling technique was used with Kaduna State being purposively selected. Igabi and Soba Local Government Areas (LGAs) were randomly selected. Five villages were randomly selected from each LGA, with a total of 129 NERICA farmers selected and used for the analysis. There were technical and managerial inefficiencies among the farmers. NERICA production is characterized by increasing returns to scale with a value of 1.4954. The farmers were cost inefficient, hence there was room for improvement in NERICA production in the study area. The average productivity (AP) was 26.30. The average marginal productivity (MP) is 9.213. The average total factor productivity (TFP) is 12.87. Farmer’s age and access to credit had negative influence on both AP and MP. Extension contact and adoption of NERICA technology positively influenced the AP and MP. Farmer’s age had negative influence on total factor productivity. Formal education, farming experience, extension contact, farm commercialization and adoption of NERICA technology had positive influence on the total factor productivity of the NERICA farmers. Improvements in the supply of NERICA seed, extension services and level of farm commercialization are recommended.Keywords: Scale efficiency, productivity, NERICA, Kaduna State, Nigeri

Leaf Eh and pH: A Novel Indicator of Plant Stress. Spatial, Temporal and Genotypic Variability in Rice (Oryza sativa L.)

A wealth of knowledge has been published in the last decade on redox regulations in plants. However, these works remained largely at cellular and organelle levels. Simple indicators of oxidative stress at the plant level are still missing. We developed a method for direct measurement of leaf Eh and pH, which revealed spatial, temporal, and genotypic variations in rice. Eh (redox potential) and Eh@pH7 (redox potential corrected to pH 7) of the last fully expanded leaf decreased after sunrise. Leaf Eh was high in the youngest leaf and in the oldest leaves, and minimum for the last fully expanded leaf. Leaf pH decreased from youngest to oldest leaves. The same gradients in Eh-pH were measured for various varieties, hydric conditions, and cropping seasons. Rice varieties differed in Eh, pH, and/or Eh@pH7. Leaf Eh increases and leaf pH decreases with plant age. These patterns and dynamics in leaf Eh-pH are in accordance with the pattern and dynamics of disease infections. Leaf Eh-pH can bring new insight on redox processes at plant level and is proposed as a novel indicator of plant stress/health. It could be used by agronomists, breeders, and pathologists to accelerate the development of crop cultivation methods leading to agroecological crop protection