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The direct and indirect effects of mobile phone ownership on maize yields in Tanzania
No full textThe study uses the Living Standards Measurement Study–Integrated Surveys on Agriculture to evaluate mobile phone ownership’s direct and indirect effect on yields in Tanzania. The results indicate that transitioning from not owning to owning a mobile phone improves maize yields by about 16%. Mobile phones indirectly affect maize yield by facilitating farmers’ access to extension services – regardless of the type of provider – but only account for about 2% of the total effects. Considering both direct and indirect effects, this study suggests that extension services partially moderate this causal relationship. Further, the impact of mobile phones is stronger among male-headed farm households.371 - 39
Optimizing genomic diversity assessments for conservation of Bromus auleticus (Trinius ex Nees) using individual and pooled sequencing
No full textBromus auleticus, a valuable forage grass native to the Pampa biome, is currently undergoing genetic erosion. Therefore, it is essential to assess appropriate methodologies for developing population genomic studies that will contribute to the conservation of this genetic resource. In this study, we evaluated five accessions using two genotyping strategies: individual sequencing (ind-seq) and pooled sequencing (pool-seq). To assess methodologies effectiveness, the correlation between allele frequencies calculated using each approach was investigated, as well as genetic diversity and population structure. These comparisons explicitly accounted for the potential effects of factors such as sample size, missing data, sequencing depth, and minor allele frequencies. The highest values of frequencies concordance and percentage of SNPs in common between ind-seq and pool-seq were achieved using a sample size of 30-60 plants per accession. These values were obtained with a maximum missing data threshold of 10% and a less strict minimum allele frequency threshold for pool-seq (0.01) compared to ind-seq (0.05). Pool-seq required a higher sequencing depth per accession (4.8 million reads) compared to ind-seq (0.9 million reads) to achieve similar allele frequencies. Pools of 50 individuals yielded the highest number of polymorphic sites, averaging over 9,000 per accession at a sequencing depth of 4.8 Mr. Under these conditions, pool-seq consistently resulted in an average of 0.09 higher expected heterozygosity and a 0.24 lower allelic richness compared to ind-seq in all accessions. Population structure inferred with both methodologies confirmed the outcrossing nature of B. auleticus and aligned with the geographical origin of each accession. The average inbreeding coefficient of 0.2 evidence inbreeding, which highlights the importance of conservation efforts for this valuable plant genetic resource. Based on these findings, we propose two workflows for conducting population genomics studies on Bromus auleticus
Environmental data provide marginal benefit for predicting climate adaptation
No full textClimate change poses a major challenge for both natural and cultivated species. Genomic tools are increasingly used in both conservation and breeding to identify adaptive loci that can be used to guide management in future climates. Here, we study the utility of climate and genomic data for identifying promising alleles using common gardens of a large, geographically diverse sample of traditional maize varieties to evaluate multiple approaches. First, we used genotype data to predict environmental characteristics of germplasm collections to identify varieties that may be pre-adapted to target environments. Second, we used environmental GWAS (envGWAS) to identify loci associated with historical divergence along climatic gradients. Finally, we compared the value of environmental data and envGWAS-prioritized loci to genomic data for prioritizing traditional varieties. We find that maize yield traits are best predicted by genome-wide relatedness and population structure, and that incorporating envGWAS-identified variants or environment-of-origin provide little additional predictive information. While our results suggest that environmental data provide limited benefit in predicting fitness-related phenotypes, environmental GWAS is nonetheless a potentially powerful approach to identify individual novel loci associated with adaptation, especially when coupled with high density genotyping
TaPUB57 confers drought tolerance, governs grain size and salt sensitivity by ubiquitinating TaEXPB3 in rice
No full textWheat (Triticum aestivum L.) is the widest cultivated crop in the world. Abiotic stress, such as drought and high salinity, dramatically impacts the growth and development of wheat and leads to remarkable yield loss. Understanding the underlying mechanisms of abiotic stress tolerance is of great importance to develop high yield varieties with wide adaptability. Ubiquitination is a major type of post-translational modification in eukaryotes. The plant U-Box (PUB) protein is the smallest family in the E3 ligase superfamily, and involved in the responses to various environmental stimuli. Currently, TaPUB57 has been cloned from wheat. It was induced by multiple abiotic stresses and phytohormone. Its ectopic expression increased grain size and drought tolerance, but caused hypersensitive to salt stress in rice. TaPUB57 interacted with and ubiquitinated TaEXPB3. Constitutive expression of TaEXPB3 resulted in small grain size and remarkably enhanced salt tolerance. Moreover, TaPUB57/ TaEXPB3 co-expressing rice plants exhibited phenotypes of salt sensitivity and larger grain size relative to TaEXPB3 transgenic lines. Therefore, it is speculated that TaPUB57 acts on grain size and the salt tolerance by ubiquitinating TaEXPB3
Macrofauna accelerates nutrient cycling through litterfall in cocoa agroforestry systems
No full textThis study aimed to better understand nitrogen (N), phosphorus (P), and potassium (K) cycling through litterfall in smallholder cocoa agroforestry systems and to assess if these nutrient flows can be measured using standard litterbags. Annual litter production, relative mass loss, and nutrient loss rates from cocoa leaf litter were evaluated in three farms in south-western Nigeria with and without macrofauna access. Litterfall was measured fortnightly close to the base of the cocoa tree and at the edge of the tree canopies from January 2020 to December 2021. Leaf litter decomposition rates were determined over 388 days in 2 mm mesh litterbags to exclude macrofauna and in frames open to the soil surface to allow macrofauna access. Concentrations of C, N, P, and K were measured in the remaining litter at 180, 244, 314, and 388 days after incubation. Annual estimates of litterfall (10.62 Mg DM ha−1) did not significantly differ between the traps close to and away from the cocoa tree trunk. Nutrient cycling from litter was estimated at approximately 101 kg N, 5 kg P, and 89 kg K ha−1 year−1. Relative litter decomposition rates (k) significantly differed between frames and litterbags. Macrofauna access significantly reduced the C:N ratio in the remaining litter and increased N and P loss from the litter layer by 28 and 69%, respectively. In conclusion, nutrient flows through litterfall are considerable, and N and P transfer rates to soil are likely underestimated in litterbag experiments that exclude macrofauna.427–44
Know your men and women farmers: Ensuring host farmers in participatory trials represent heterogeneity within the target environment
No full textSocietal Impact Statement: Gender responsive and more socially inclusive breeding strategies are needed to ensure new crop varieties, which offer greater yields in an increasingly variable climate, meet the needs of a diverse range of smallholder farmers. Participatory varietal selection actively involves farmers in testing and selecting new varieties at the end of the breeding process. We evaluated the inclusivity of a participatory maize breeding program in Zimbabwe. Our analysis found that setting targets for women farmer participation ensured adequate representation, but participatory research should move beyond simple targets and ensure the inclusion of different types of women and men farmers. Summary: There is growing interest in participatory varietal selection and gender-responsive breeding in research and development initiatives. On-farm testing is increasingly used to ensure that new varieties perform within the target environments. However, there are few established approaches for selecting host women and men farmers who reflect the diversity of the overall target population of smallholder farmers. This study sought to evaluate ex-post if recruited farmers within a participatory breeding network in Zimbabwe were representative of the surveyed population and pilot an approach to developing comprehensive farm typologies to ensure more gender-responsive and socially inclusive breeding. A sample of over 2,000 randomly selected women and men farmers, including those hosting breeding trials, were surveyed. A typology was constructed to group farms with similar characteristics associated with household demographics, maize production and resource endowments. This facilitated the subsample of trial-hosting farmers characteristics to be compared with the broader typology.The distribution of farm types selected by extension agents to host trials closely reflected the distribution of farm types within the surveyed population. Two farm types associated with women household heads and three types associated with men-headed households were identified, highlighting the heterogeneity within these groups. Other important factors of differentiation included farm assets, livestock ownership and maize production features. Sampling strategies that explicitly incorporate agronomic and socio-economic diversity within the target population should be used in the selection of host women and men farmers for participatory research to ensure appropriate gender and social inclusion
Genetic structure of Ethiopian finger millet landraces and genome-wide association mapping for agronomic and nutritional traits
No full textFinger millet (Eleusine coracana subsp. coracana) (2n = 4x = 36) remains one of the most important millets in East Africa (EA), where it was most likely domesticated along the highlands of Ethiopia and Uganda. The goal of the current study was to understand the population structure of the Ethiopian finger millet landraces and identify quantitative trait nucleotides (QTNs) and haplotypes associated with agronomic and nutritional traits. In a field evaluation across three environments, 448 genotypes were assessed for days to flowering (DTF), days to maturity (DTM), thousand seed weight (TSW), grain yield (GY), stay-green score (STG), and drought score (DrtSc). The harvested grain was analyzed for Fe and Zn contents. A subset of 391 genotypes was skim-sequenced, generating 24,112 high-quality SNPs that were employed for population structure, association mapping, and haplotype analysis. Seventy marker-trait associations were detected including 15 major QTNs with more than 30% phenotypic variance explained (PVE) for all traits except STG and GY. Pleiotropic major QTNs were identified for DTM/DTF and Fe/Zn on chromosomes 9B and 2B, respectively. Haplotype analysis of major QTNs identified 54 significant haplotype blocks and 2 additional haplotypes for a multidrug ABC transporter gene family like protein on chromosome 4A that was associated with PTH. Favorable haplotypes from pleiotropic DTM/DTF and Fe/Zn QTNs were present in 13 and 12 genotypes respectively, majority from Tigray region. Two genotypes from Tigray and one from Amhara harbored favorable haplotypes for DTM/DTF and Fe/Zn. These findings provide invaluable insights for targeted breeding to enhance finger millet resilience, nutritional profile, and yield
Wheat genotypes selected for their high early daytime stomatal conductance under elevated nocturnal temperatures maintain high yield and biomass
No full textGlobal night-time temperatures are increasing and correlate with a decline in crop yield. Various aspects of nocturnal physiology in plants are understudied, one of which is the independent influence on daytime processes. Twelve elite wheat genotypes were field grown in plots with artificially increased night-time temperatures (+ 2 degrees C). The stomatal conductance on the adaxial and abaxial leaf sides were measured during the morning and the night, and stomatal morphological traits were assessed during the same period of plant growth. To determine whether an increase in early daytime stomatal conductance provides a growth and/or yield advantage under high temperature, the biomass (Bm), grain number (Gn), thousand-grain weight (TGW), and grain yield (Yld) were measured. Genotypes exhibiting the highest early daytime stomatal conductance also showed higher Bm, Gn, and Yld. An increase of 19% in early daytime stomatal conductance led to a Yld increase of 86 and 65 gm-2, in heated and control conditions respectively, translating to 43 and 35% Yld enhancement. Irrespective of the environment, the adaxial leaf side showed the highest diurnal and nocturnal conductance, mirroring direct stomatal aperture (SA) measurements. The high night-time temperature treatment increased daytime stomatal conductance but reduced nocturnal conductance. SA varied with growing conditions; in the morning, plants under high night-time temperatures showed larger SA than those from the control independently of the leaf side, conversely, the opposite trend was observed in the night. Stomata on the adaxial leaf side showed higher density and larger size. Results from this study show that early daytime conductance increased productivity in hot-irrigated environments studied here. Previous studies showed that high pre-dawn conductance improves morning photosynthesis, and here we find that high nocturnal temperatures increased early morning conductance but reduced night-time conductance and this may be a factor that contributed to minimize Yld losses
