Understanding the dynamic of rice farming systems in southern Mozambique to improve production and benefits to smallholders

Rice farming systems (RFSs) in southern Mozambique are very heterogeneous and diversified, which has implications for smallholders’ adoption of each RFS, as well as on rice production and productivity in the region. In this regard, it is important to understand: (i) which RFS typologies can be leveraged to improve rice production and productivity; (ii) the drivers for smallholder farmers’ decisions to adopt an RFS; and (iii) which policies/incentives could enhance existing RFSs. The present study was based on surveys of 341 smallholder rice farmers in the Chókwè Irrigation Scheme (CIS), southern Mozambique. Data on the productivity of rice, size of the herd, and total other crop types were used to frame the RFS typologies. A multinomial logit model (MLM) and multiple linear regression (MLR) were applied to determine the driver for each RFS, and predict the constraints for production and yield. Based on cluster analysis, four typologies of RFSs were identified: the subsistence farming system (FS), specialised rice FS, mixed crops FS, and rice–livestock FS. Farms with longer experience reported applying more fertiliser and seedlings per unit hectare. The availability of labour increased the likelihood of adopting the mixed crops FS and rice–livestock FS. Older households were more likely to adopt the subsistence FS, and live closer to the farming fields. Yield of rice was positively associated with inputs such as fertilisers, pesticides, and seedlings, as well as years of experience of the household. Our results suggest that smallholder farmers need more assistance and technical support to identify and adopt more productive and less costly RFSs in this regioninfo:eu-repo/semantics/publishedVersio

Screening for aroma in rice genotypes with African and Asian backgrounds

Aromatic rice is highly preferred by consumers and has an important market worldwide. The demand for aromatic rice is high in East African countries, mainly in urban areas. Among the rice varieties that are grown in Burundi, few of them have a slight aroma which is not enough to satisfy the consumers’ demand and preference. There is no published report on the status of aroma in locally grown varieties and breeding lines in Burundi yet. This study aimed to identify aromatic genotypes that can be used in the breeding program to meet preferences of consumers. Two hundred fifteen genotypes were subjected to kompetitive allele-specific PCR genotyping and sensory evaluation methods. Fifty-three genotypes had the betaine aldehyde dehydrogenase (BADH2) gene for fragrance and displayed different levels of aroma expression. The sensory evaluation revealed two strongly aromatic genotypes, 43 moderately aromatic genotypes, 131 slightly aromatic genotypes, and 32 nonaromatic genotypes.The results of this study showed that BADH2 gene is significantly associated with rice aroma in accordance with previous reports. Furthermore, aroma and taste were positively and significantly correlated. Strongly aromatic genotypes (SUPA KATRIN and SUPA DE NYANZA –LAC) having the BADH2 gene for fragrance are of great interest for use in the breeding program to improve rice varieties to meet consumers' preferences in Burundi

Breeding for Rice Aroma and Drought Tolerance: A Review

Aroma is one of the main characteristics that guide rice purchases worldwide. Aromatic rice varieties are generally less adapted to biotic and abiotic stresses. Among the abiotic constraints, drought stress causes considerable yield losses. This review describes advances in breeding for aroma and drought tolerance in rice and investigates the possibility of combing these traits in one variety. Some of the major quantitative trait loci that have been discovered for drought tolerance were recently introgressed into aromatic varieties. However, more details on the performance of developed lines are still needed. Furthermore, there are not yet any published reports on the release of aromatic drought-tolerant rice varieties

Effectiveness of hermetic containers in controlling paddy rice (Oryza sativa L.) storage insect pests

Naturally infested paddy rice was used to compare the effectiveness of polypropylene bags and hermetic storage containers over 12 months of storage in a warehouse. Insect pest identification as well as the infestation level, percentage of damaged grain, weight loss, and moisture content were evaluated. Five insect species associated with stored rice were identified during the storage period, namely lesser grain borer (Rhyzopertha dominica), red flour beetle (Tribolium castaneum), rice/maize weevil (Sitophilus spp.), angoumois grain moth (Sitotroga cerealella) and flat grain beetle (Cryptolestes ferrugineus). The lesser grain borer was the most predominant species with an average incidence above 70% after twelve months of storage, followed by the rice/maize weevil with an incidence of 17%. When compared to hermetic storage containers, polypropylene bag showed the highest mean infestation level with 233.3 individuals/ kg after six months of storage, representing about 8-fold of the number of insects recorded in hermetic containers after six months of storage. In polypropylene container, the percentage of damaged grain and weight loss increased significantly achieving a maximum of 6.98% and 5.56% respectively, whereas using hermetic containers the highest percentage of damaged grain reached was 3.24% in polyethylene drum and the weight loss was 1.62% in GrainSafe bag. The results from the study show that the use of hermetic storage containers is a green alternative for safe storage of paddy rice, for 12 months without application of pesticides, bringing multiple advantages for smallholder farmers, lever food security and income generation for smallholder farmers and rice milling companiesinfo:eu-repo/semantics/publishedVersio

Rice biofortification with zinc and selenium: a transcriptomic approach to understand mineral accumulation in flag leaves

Original ResearchHuman malnutrition due to micronutrient deficiencies, particularly with regards to Zinc (Zn) and Selenium (Se), affects millions of people around the world, and the enrichment of staple foods through biofortification has been successfully used to fight hidden hunger. Rice (Oryza sativa L.) is one of the staple foods most consumed in countries with high levels of malnutrition. However, it is poor in micronutrients, which are often removed during grain processing. In this study, we have analyzed the transcriptome of rice flag leaves biofortified with Zn (900 g ha1), Se (500 g ha1), and Zn-Se. Flag leaves play an important role in plant photosynthesis and provide sources of metal remobilization for developing grains. A total of 3170 differentially expressed genes (DEGs) were identified. The expression patterns and gene ontology of DEGs varied among the three sets of biofortified plants and were limited to specific metabolic pathways related to micronutrient mobilization and to the specific functions of Zn (i.e., its enzymatic co-factor/coenzyme function in the biosynthesis of nitrogenous compounds, carboxylic acids, organic acids, and amino acids) and Se (vitamin biosynthesis and ion homeostasis). The success of this approach should be followed in future studies to understand how landraces and other cultivars respond to biofortificationinfo:eu-repo/semantics/publishedVersio

Assessing the impact of rice cultivation and off-season period on dynamics of soil enzyme activities and bacterial communities in two agro-ecological regions of Mozambique

Soil ecosystem perturbation due to agronomic practices can negatively impact soil productivity by altering the diversity and function of soil health determinants. Currently, the influence of rice cultivation and off-season periods on the dynamics of soil health determinants is unclear. Therefore, soil enzyme activities (EAs) and bacterial community compositions in rice-cultivated fields at postharvest (PH) and after a 5-month off-season period (5mR), and fallow-fields (5-years-fallow, 5YF; 10-years-fallow, 10YF and/or one-year-fallow, 1YF) were assessed in two agroecological regions of Mozambique. EAs were mostly higher in fallow fields than in PH, with significant (p < 0.05) differences detected for -glucosidase and acid phosphatase activities. Only -glucosidase activity was significantly (p < 0.05) different between PH and 5mR, suggesting that -glucosidase is responsive in the short-term. Bacterial diversity was highest in rice-cultivated soil and correlated with NO3 , NH4 + and electrical conductivity. Differentially abundant genera, such as Agromyces, Bacillus, Desulfuromonas, Gaiella, Lysobacter, Micromonospora, Norcadiodes, Rubrobacter, Solirubrobacter and Sphingomonas were mostly associated with fallow and 5mR fields, suggesting either negative effects of rice cultivation or the fallow period aided their recovery. Overall, rice cultivation and chemical parameters influenced certain EAs and shaped bacterial communities. Furthermore, the 5-month off-season period facilitates nutrient recovery and proliferation of plant-growth-promoting bacteriainfo:eu-repo/semantics/publishedVersio

Assessing the benefits of green super rice in sub-Saharan Africa: Evidence from Mozambique

In Mozambique, smallholder farmers commonly grow rice under rainfed systems with limited fertilizer application; thus, productivity remains very low. Moreover, the adoption rate of improved rice varieties is as low as 3 per cent, partly because these varieties usually require an irrigated environment with the use of fertilizer. Green super rice (GSR) varieties are expected to sustain high yield potential under severe stress conditions. This article used farm-level survey data collected in Mozambique to assess the benefits of the adoption of a GSR variety (Simão) on the yield and cost efficiency of smallholder rice producers. The econometric approach involves propensity score matching and a simultaneous equation model with endogenous switching regression to account for observable and unobservable factors that affect adoption and outcome variables. The results indicate positive and significant benefits from adopting GSR on rice yield and cost efficiency for adopters. These benefits are observed not only in irrigated environments where fertilizer is applied together with some more advanced farming practices (i.e. Gaza province), but also in Nampula and Sofala provinces where farmers grow rice under rainfed conditions with no fertilizer application. Our findings suggest that GSR varieties have the potential to bring some positive changes in the development of rice production in Mozambique

Multi-environment genomic selection in rice elite breeding lines

Abstract Background: Assessing the performance of elite lines in target environments is essential for breeding programs to select the most relevant genotypes. One of the main complexities in this task resides in accounting for the genotype by environment interactions. Genomic prediction models that integrate information from multi-environment trials and environmental covariates can be efficient tools in this context. The objective of this study was to assess the predictive ability of different genomic prediction models to optimize the use of multi- environment information. We used 111 elite breeding lines representing the diversity of the International Rice Research Institute (IRRI) breeding program for irrigated ecosystems. The lines were evaluated for three traits (days to flowering, plant height, and grain yield) in 15 environments in Asia and Africa and genotyped with 882 SNP markers. We evaluated the efficiency of genomic prediction to predict untested environments using seven multi-environment models and three cross-validation scenarios. Results: The elite lines were found to belong to the indica group and more specifically the indica-1B subgroup which gathered improved material originating from the Green Revolution. Phenotypic correlations between environments were high for days to flowering and plant height (33% and 54% of pairwise correlation greater than 0.5 ) but low for grain yield (lower than 0.2 in most cases). Clustering analyses based on environmental covariates separated Asia’s and Africa's environments into different clusters or subclusters. The predictive abilities ranged from 0.06 to 0.79 for days to flowering, 0.25 to 0.88 for plant height, and -0.29 to 0.62 for grain yield. We found that models integrating genotype-by-environment interaction effects did not perform significantly better than models integrating only main effects (genotypes and environment or environmental covariates). The different cross-validation scenarios showed that, in most cases, the use of all available environments gave better results than a subset. Conclusion: Multi-environment genomic prediction models with main effects were sufficient for accurate phenotypic prediction of elite lines in targeted environments. The recommendation for the breeders is to use simple multi-environment models with all available information for routine application in breeding programs