Understanding smallholder farmers’ access to maize seed and seed quality in the drought-prone Central Rift Valley of Ethiopia

Despite efforts made by the Ethiopian research and extension system during the past 40 years to disseminate improved maize (Zea mays L.) variety seeds for increased crop production, the diffusion and use remained low, particularly in moisture-stressed areas. The topic of smallholder farmers’ access to quality seed is an ongoing issue in Ethiopia. The purpose of this paper is to identify and explain maize seed sources for smallholder farmers and assess the seed quality status in the drought-prone Central Rift Valley (CRV) of Ethiopia. Data for this study were obtained from farm households and other stakeholders survey in 2011 from East Shewa Zone, Oromia Regional National State. The survey results indicated that informal seed sources contributed 84% of annually planted maize seed. Sixty percent of maize growers obtained improved seed through farmer-to-farmer seed exchange and the informal seed market (ISM). Regarding the socioeconomic characteristics and maize seed acquisition behavior of the farm-household heads, a higher proportion of female-headed households and resource-poor farm households depended on other farmers and ISM than male-headed farm households. A quarter of the better-off maize-grower households also used ISM. Formal seed sources were found to be key in new variety introduction. The quality of the seeds obtained from informal sources was found to be acceptable relative to purity and germination. The effectiveness of the seed-supply system tended to rely on the complementary integration of formal and informal seed systems, as both systems had their own peculiarities in serving the farm community to enhance food security.     

Has the introduction of modern rice varieties changed rice genetic diversity in a high-altitude region of Nepal?

We surveyed the uptake of three modern rice varieties by farmers in high-altitude villages in the Kaski district of Nepal and found that their uptake had displaced some traditional landraces in the district. The three varieties, Machhapuchhre-3 (M-3), Machhapuchhre-9 (M-9) and Lumle 2, were developed using client-oriented, participatory plant breeding methods and the first was introduced to farmers in 1996. By 2004 up to 60% of the land area was used to grow these modern varieties. Molecular markers (SSR) were used to assay levels of genetic diversity to test if adoption of modern varieties in the place of landraces had changed genetic diversity. The modern varieties were found to contain diverse alleles with a high proportion from the local parent variety, Chhomrong Dhan. We found a high level of allelic richness in the landraces, and although seven had been dropped in favour of the modern varieties, other diverse landraces were still being cultivated by farmers in the study villages on up to 40% of the rice area. Genetic diversity may be maintained even when landraces are displaced by modern varieties. Using a model we found that the partial replacement of landraces increased genetic diversity if the modern varieties were adopted on up to 65% of the area. Only above these levels did overall diversity decline.     

Conditional genes for grain yield in rice

Grain yield in cereal crops was an eternal theme. The number of panicles per plant (PN), filled spikelets per panicle (FSP), and 1000-gram weight (TGW) were the three important yield components. Some QTLs for rice yield had been mapped, but conditional QTLs for grain yield had not been analyzed. Phenotypic values of yield traits, which had no influence on the given components, were used for QTLs conditional analysis. This study was to uncover conditional QTLs for rice yield in a RIL population, and to search for evidences on the genetic basis of yield QTLs.     

Characteristics of growth and quality,and factors contributing to high yield in newly developed rice variety ‘Akidawara’

The newly developed rice variety ‘Akidawara’ (AKI) combines the traits of high yield and highly palatability, and its cultivation is expected to spread. We examined characteristics of growth and quality, and factors contributing to high yield in AKI by comparing with ‘Nipponbare’ (NIP). Grain yield for AKI were 703 g m^?2 (9% more than NIP) and 781 g m^?2 (14% more than NIP) under the standard and heavy fertilizer regimes. It was also suggested that increase in the sink capacity was the key contributors to the high yield in AKI resulting from a conspicuous increase in the number of spikelets, which is likely due to introgression of the high-yielding variety allele. Furthermore, AKI achieved the similar degree of sink filling in spite of its larger sink capacity. In this point, panicle dry weight increase during ripening (ΔP) was significantly higher for AKI than for NIP despite the fact that no differences in shoot dry weight increase were observed between varieties. The greater ΔP in AKI might be derived from its larger sink capacity and the difference between varieties involves the translocation of nonstructural carbohydrate. In the grain quality, the reduction in perfect grain ratio was negligible and regarded as a small trade-off for AKI’s 14% increase in yield, and grain protein content increased to a lesser degree in AKI at the same yield level. These results suggest that over 700 g m^?2 high yield can be achieved with relative high grain quality and lower protein content in AKI.     

Markers for pollen fertility in intersubspecific hybrid rice

Since an allele S_5~n was identified and used to overcome the sterility in hybrid rice breeding, many intersubspecific hybrids harbored the S_5~n allele had been tested for their yield potential. Such hybrids showed pronounced heterosis and high yield potential, but some of them had an unstable or low seed set. The reason for the low seed set was attributed to the partial pollen sterility.     

PAGE electrophoresis systems for 8 isozymes in rice

Discontinuous polyacrylamide gel electrophoresis(PAGE) systems for eight isozymes in rice including malic enzyme (Mal) phosphogluconate dehydrogenase (Pgd), phoshoglucose isomerase (Pgi), alanine aminopeptidase(Amp), catalase (Cat), peroxidase (Pox), acid phosphatase (Acp), and esterase (Est) were established in our laboratory. Eighteen known loci and some unknown loci of the 8 isozymes have been detected with     

Hybrid rice technology for food security in the world

The current world population is over 6 billion and will reach 8 billion in 2030. Meanwhile, the annual loss of land to other use is 10 to 35 million ha, with half of this lost land coming from cropland.Facing such severe situation of population growth pressure plus cropland reduction, it is obvious that the only way to solve food shortage problem is to greatly enhance the yield level of food crops per unit land area through advance of science and technology.……     

Chromosome location of a gene for aroma in rice

Scented or aromatic rice (Oryza sativa L.) is highly valued in many areas of the world. The development of high yielding scented cultivars has been limited because of lacking information on the inheritance of scent such as linkage of genes for aroma with other genes. We report here our studies on the determination of the chromosomal location of an aroma gene. Twenty-nine marker stocks, including 14     

An incompletely dominant suppressor for dominant earliness in rice

An early maturing maturing TGMS rice line 6442S-7 hascompletely dominant earliness mainly controlled by twodominant major genes, but heading dates Of F1 progenies of6442S-7 crossed with some of medium or late maturing va-rieties were close to the mid-parent values under long day[see CRRN, 2000,8(3): 3 - 4] .In this study, an in-completely dominant suppressor for the dominant earliness of 6442S-7 was detected.In F2 populations of 6442S-7 crossed with fivelate-maturing varieties, heading d…     

QTLs for ovicidal response to whitebacked planthopper in rice

Ｊａｐａｎｅｓｅ ｊａｐｏｎｉｃａｒｉｃｅｃｏｍｍｏｎｌｙｐｒｏｖｉｄｅｓｗｉｔｈａｎｏｖｉｃｉｄａｌｒｅｓｉｓｔａｎｃｅａｇａｉｎｓｔｔｈｅｗｈｉｔｅｂａｃｋｅｄｐｌａｎｔｈｏｐｐｅｒ（ＷＢＰＨ）．Ｓｉｍｉｌａｒｌｙ，ｏｖｉｃｉｄａｌａｃｔｉｖｉ ｔｙｗａｓａｌｓｏｆｏｕｎｄｔｏｐｌａｙａｓｉｇｎｉｆｉｃａｎｔｒｏｌｅｉｎａｓｔａｂｌｅｆｉｅｌｄｒｅｓｉｓｔａｎｃｅｔｏＷＢＰＨｉｎｓｏｍｅＣｈｉｎｅｓｅ ｊａｐｏｎｉｃａｒｉｃｅ．Ｒｉｃｅｖａｒｉｅｔｉｅｓｗｉｔｈｏｖｉｃｉｄａｌｒｅ ｓｉｓｔａｎ…     

Path analysis for grain yield and its components in rice

Rice yield, its components and their relations are one of the most important research objects for genetics, cultivation, and breeding. This study was to investigate the genetic relationships between yield and yield components by using the methods of correlation analysis and path analysis with a set of 241 RIL population of Shanyou 63.     

On-farm soil N supply and N nutrition in the rice–wheat system of Nepal and Bangladesh

On-farm research to evaluate the productivity and nitrogen (N) nutrition of a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system was conducted with 21 farmers in the piedmont of Nepal and with 21 farmers in northwest Bangladesh. In Nepal, two levels of N-fertilizer (0–22–42 and 100–22–42 kg N–P–K ha⁻¹) and farmers’ nutrient management practices were tested in the rice season, and three levels of N (0–22–42, 70–22–42, and 100–22–42) and farmers’ practices were evaluated in the wheat season. The treatments in Bangladesh included a researchers managed minus-N plot (0–22–42) and the farmers’ practices. Rice and wheat yields were higher in all treatments than the 0–22–42 control plots, with the exception of rice with the farmers’ practices at one location in Bangladesh. The researchers’ treatment of 100–22–42 in Nepal resulted in larger yields of both rice and wheat than the farmers’ practices, indicating that farmers’ rates of N-fertilizer (mean 49 kg N ha⁻¹) were too low. Delaying wheat seeding reduced yields in the fertilized plots in both countries, especially as N-fertilizer dose increased. Soil N-supplying capacities (SNSC), measured as total N accumulation from the zero-N plots (0–22–42), and grain yields without N additions were greater for rice than for wheat in both Nepal and Bangladesh. Higher SNSC in rice was probably due to greater mineralization of soil organic N in the warm, moist conditions of the monsoon season than in the cooler, drier wheat season. However, SNSC was not correlated with total soil N, two soil N availability tests (hot KCl-extractable NH₄⁺ or 7-day anaerobic incubation), exchangeable NH₄⁺ or NO₃⁻. Wheat in Nepal had greater N-recovery efficiency, agronomic efficiency of N, and physiological efficiency of N than rice. Nitrogen internal-use efficiency of rice for all treatments in both countries was within published ranges of maximum sufficiency and maximum dilution. In wheat, the relationship between grain yield and N accumulation was linear indicating that mobilization of plant N to the grain was less affected by biotic and abiotic stresses than in rice.     

Multidisciplinary assessment of agricultural innovation and its impact: a case study of lowland rice variety WITA 9 in Côte d’Ivoire

ABSTRACT

Information on comprehensive evaluation of agricultural innovations is often limited. This study provides an overview of multidisciplinary evaluation of a lowland rice variety, WITA 9 (released in Côte d’Ivoire in 1998), with respect to its agronomic performance, grain quality, resistance to diseases, adoption by farmers, impact on productivity and farmers’ income, and marketability. WITA 9 had the highest paddy yield among the tested varieties including an international check (IR 64) and recently developed varieties adapted to this country. WITA 9 had a higher amylose content (26–28%) than others tested. This study confirmed its resistance to bacterial leaf blight, Rice yellow mottle virus (RYMV), and rice blast. A household survey showed that the adoption rate was 24%, its paddy yield advantage was 0.7 t ha^–1, and its adoption increased farmer’s income by US$ 91 ha^–1 per season. A market study showed that consumers’ willingness to pay was higher for WITA 9 than any other locally produced rice variety and comparable to imported rice in one of two markets. We conclude that WITA 9 is an ideal innovation for enhancing productivity and rice import substitution in Côte d’Ivoire. An effective seed delivery system and enhancing farmers’ and consumers’ awareness of this variety are vital for accelerating impact.     

Quantitative trait loci responsible for the difference in γ-oryzanol content in brown rice between japonica-type and indica-type rice cultivars

γ-Oryzanol is a main oleophilic component in rice bran oil and has been well recognized as a good dietary supplement for human health, as well as having uses in industrial materials. japonica-type rice cultivars generally showed significantly higher contents of total γ-oryzanol in brown rice compared with indica-type cultivars, although within-group variation was significant. The objective of this study was to explore quantitative trait loci (QTLs) responsible for the difference in the γ-oryzanol content between japonica-type and indica-type rice cultivars, using recombinant inbred lines (RILs), backcross inbred lines (BILs), and corresponding chromosome segment substitution lines (CSSLs) derived from crosses between japonica-type and indica-type. Results from RILs and BILs showed that eight QTLs were detected with R² from .09 to .16. Nine candidate regions for QTL were also suggested from corresponding CSSLs. These QTLs from RILs and BILs and the candidate regions from CSSLs were not overlapped, although one QTLs was mapped near the boundaries of the respective candidate region. At four QTLs and three candidate regions, alleles or segments from japonica-type caused higher contents than those from indica-type. On the other hand, at the other four QTLs and six candidate regions, alleles or segments from indica-type caused higher contents than those from japonica-type, which is a reverse result to the parental differences. This result strongly suggested that alleles with increasing effects on γ-oryzanol content could be accumulated not only from japonica-type but also from indica-type, leading to a potential for increase in γ-oryzanol content in future breeding programs.     

Measuring farmers’ preferences for weather index insurance in the Ayeyarwady Delta,Myanmar: a discrete choice experiment approach

Paddy and Water Environment - This study examines farmers’ preferences for weather index insurance (WII) in the Ayeyarwady Delta, Myanmar, using discrete choice experiments. It employs data...     

Evaluation of a model recommended for N fertilizer application in irrigated rice

The response of rice to N fertilizer application has shown that high rates of N application do not always ensure a proportional increase in yield due to high N losses. A model, ORYZA-0 was developed by ten Berge for designing optimum N fertilizer management strategy inrice . We evaluated the performance of ORYZA-0 in Jinhua. Zhejiang Province.