Transcriptome profiling and validation of gene based single nucleotide polymorphisms (SNPs) in sorghum genotypes with contrasting responses to cold stress

Primer sequences for validation of bi-allelic variant calls. (DOCX 15 kb

Dhurrin: a potential endogenous nitrogen turnover source for early seedling growth in sorghum

Dhurrin is a cyanogenic glucoside found in all vegetative tissues of Sorghum bicolor, functioning as a herbivore repellent, antifungal agent, osmoprotectant, and nitrogen (N) storage. Dhurrin concentration is usually highest in young seedlings, where it rapidly accumulates following germination, after which its biosynthesis decreases and its turnover increases as the seedling ages. To avoid prussic acid poisoning from dhurrin catabolism in cattle grazing or foraging on sorghum, numerous research studies now focus on breeding for dhurrin-free or acyanogenic sorghum using EMS (Ethyl methanesulfonate) mutants with a non-functional dhurrin biosynthetic pathway. However, there has been limited and conflicting research investigating the role dhurrin plays as a potential nitrogen source in sorghum’s early seedling growth, especially under N deficiency. It is plausible that the presence of background mutations in dhurrin-free sorghum mutants could mask or confound how the absence of dhurrin affects early seedling growth. Using a naturally occurring (non-mutant) ultra-low dhurrin genotype and known low and high dhurrin genotypes, the current research investigated the importance of dhurrin as a potential endogenous nitrogen source for early seedling growth in simulated non-marginal (N-available) and marginal (N-deficient) media. Dhurrin was implicated to be an N source for seedling growth from 8 to 13 days after planting under deficient N conditions. In N-deficient media at 13 days after planting, high-dhurrin-level genotypes accumulated more seedling fresh shoot biomass than low-dhurrin-level genotypes. Thus, while acyanogenic sorghum will be beneficial in expanding sorghum’s economic value, the use of dhurrin knock-out mutants can prove problematic since the complete lack of dhurrin may affect field germination and stand establishment, particularly under N-deficient or low-N-input conditions

Assessment of Photoperiod Sensitivity and the Effect of Sowing Date on Dry-Season Sorghum Cultivars in Southern Chad

The cultivation of dry-season sorghum on residual moisture in West and Central Africa is highly affected by sowing dates and ecotypes used. Fifty-five dry-season sorghum ecotypes collected from three zones in southern Chadian were sown on two dates, early and late, in 2013 and 2014, in an α-Lattice, and replicated five times to evaluate the effect of sowing date on potential yield, flowering time, and other agro-morphological traits and to determine their photoperiod sensitivity. Trials were conducted in the research fields at the Agricultural Research Extension Farm in Youé, Chad. Year, sowing date, and their interaction significantly affected most of the assessed traits. Delaying sowing significantly decreased potential yield, duration of vegetative phase, and other agro-morphological traits, except staygreen. All cultivars were photoperiodic with late sowing requiring a lower cumulative growing degree unit to flower. The flowering window was not affected by sowing dates across cultivars; however, the flowering time was affected by a decrease in daylength, but not low night temperatures. Generally, late sowing decreased potential yield across cultivars. However, this decrease varied with the region of origin, with seven cultivars having average potential yields at or above the regional potential yield of 1 t/ha, irrespective of year or sowing dates

Effect of elevated CO2 on peanut performance in a semi-arid production region

With the intensification and frequency of heat waves and periods of water deficit stress, along with rising atmospheric carbon dioxide [CO2], understanding the seasonal leaf-gas-exchange responses to combined abiotic factors will be important in predicting crop performance in semi-arid production systems. In peanut (Arachis hypogaea L.), the availability of developmental stage physiological data on the response to repeated water deficit stress periods in an elevated [CO2] (EC) environment is limited and necessary to improve crop model predictions. Here, we investigated the effects of season-long EC (650 µmol CO2 m−2 s−1) on the physiology and productivity of peanut in a semi-arid environment. This study was conducted over two-growing seasons using field-based growth chambers to maintain EC conditions, and impose water-stress at three critical developmental stages. Our results showed that relative to ambient [CO2] (AC), long-term EC during water-stress episodes, increased leaf-level light-saturated CO2 assimilation (Asat), transpiration efficiency (TE), vegetative biomass, and pod yield by 58%, 73%, 58%, and 39%, respectively. Although leaf nitrogen content was reduced by 16%, there was 41% increase in maximum Rubisco carboxylation efficiency in EC, indicating that there was minimal photosynthetic down-regulation. Furthermore, long-term EC modified the short-term physiological response (Asat) to rapid changes in [CO2] during the water-stress episodes, generating a much greater change in EC (54%) compared to AC (10%). Additionally, long-term EC generated a 23% greater Asat compared to the short-term EC during the water-stress episodes. These findings indicate high levels of physiological adjustment in EC, which may increase drought resilience. We concluded that EC may reduce the negative impacts of repeated water-stress events at critical developmental stages on rain-fed peanut in semi-arid regions. These results can inform current models to improve the projections of peanut response to future climates

Characterization of semi-arid Chadian sweet sorghum accessions as potential sources for sugar and ethanol production

Sweet sorghum (Sorghum bicolor (L.) Moench) is an important crop in Chad that plays an economic role in the countryside were stalks are produced mainly for human consumption without any processing. Unfortunately, very little information exists on its genetic diversity and brix content. Studies performed in 2014 and 2015 showed that there were significant variations (p < 0.001) for all assessed quantitative traits. Potential grain yield (0.12–1.67 t ha−1), days to 50% flowering (68.3–126.3 days), and plant height (128.9–298.3 cm) were among traits that exhibited broader variability. Brix content range from 5.5 to 16.7% across accessions, was positively correlated to stalk diameter and plant height, but negatively correlated to moisture content in fresh stalk and potential grain yield. Fresh stalk yield range from 16.8 to 115.7 Mg ha−1, with a mean value of 58.3 Mg ha−1 across accession. Moisture content in fresh stalk range from 33.7 to 74.4% but was negatively correlated to fresh stalk yield. Potential sugar yield range from 0.5 to 5.3 Mg ha−1 across accession with an average of 2.2 Mg ha−1. Theoretical ethanol yield range from 279.5 to 3,101.2 L ha−1 across accession with an average of 1,266.3 L ha−1 which is significantly higher than values reported under similar semiarid conditions. Overall, grain yields were comparatively low. However, two accessions had grain yield of more than 1.5 t ha−1; which is greater than the average 1.0 t ha−1 for local grain sorghum varieties in Chad. These could have multi-purpose uses; grains, sugar and bioenergy production

Peanut leaf transcriptomic dynamics reveals insights into the acclimation response to elevated carbon dioxide under semiarid conditions

IntroductionElevated atmospheric carbon dioxide [CO2] increases peanut carbon assimilation and productivity. However, the molecular basis of such responses is not well understood. We tested the hypothesis that maintaining high photosynthesis under long-term elevated [CO2] is associated with the shift in C metabolism gene expression regulation.MethodsWe used a field CO2 enrichment system to examine the effects of elevated [CO2] (ambient + 250 ppm) across different soil water availability and plant developmental stages on the molecular responses in a peanut runner-type genotype. Plants under both [CO2] treatments were grown in semiarid conditions. We evaluated a comparative leaf transcriptomic profile across three periodic water deficit/re-hydration (well-watered/recovery) cycles throughout the growing season using RNAseq analysis.ResultsOur results showed that the transcriptome responses were influenced by [CO2], water availability, and developmental stages. The traditional Mercator annotation analysis based on percentage total revealed that lipid metabolism, hormone biosynthesis, secondary metabolism, amino acid biosynthesis, and transport were the most regulated biological processes. However, our new approach based on the comparative relative percentage change per individual category across stages revealed new insights into the gene expression patterns of biological functional groups, highlighting the relevance of the C-related pathways regulated by elevated [CO2].DiscussionThe photosynthesis analysis showed that 1) The light reaction was the most upregulated pathway by elevated [CO2] during water stress, 2) Photorespiration was downregulated across all stages, 3) Sucrose synthesis genes were upregulated by elevated [CO2] before stress, 4) Starch synthesis genes were upregulated by elevated [CO2] under drought periods, and 5) CO2 regulation of sucrose and starch degradation was critical under drought periods. Our findings provide valuable insights into the molecular basis underlying the photosynthetic acclimation response to elevated [CO2] in peanuts

Impact of Micro Credit on the Growth of Women-Owned Small Businesses in Limbe I, Cameroon

Purpose -- This study aims to analyze the impact of microcredit on the growth of women-owned small businesses in Limbe I Cameroon. More specifically, to identify, map and characterize the women-owned small businesses in Limbe I that have benefited from micro-credit, to assess the extent to which microcredit has assisted in the expansion of their businesses, and to investigate the challenges faced by the women small businesses in Limbe I. Design /Methodology/Approach – The research design adopted for this study was ex-post facto or causal-comparative research design. A sample of 30 women-owned small businesses that have ever benefitted from microcredit was selected using a purposive sampling technique. The instrument used for this study was a well-structured and validated questionnaire and data for the study was analyzed and presented on tables, bar charts, using descriptive and inferential statistics assisted by SPSS software version 20 and the hypothesis was tested using a regression. Findings – The findings revealed that microcredit has a very low level of impact on the growth of women-owned small businesses in Limbe I. The findings also unveiled the major challenges faced by women entrepreneurs viz. the pledge for collateral security, the lack of marketing skills and knowledge, the absence of proper training and support, the cumbersomeness of documents for the acquisition of loans, the high-interest rate, the long period of time taken before granting their loans and an absence of knowledge and awareness amongst women about budgeting control resource management and commercial functions. Practical Implications- The study recommends that the women-owned businesses of Limbe I should unite them by creating an association on which to debate about their challenges. The Delegation of the small and medium scale enterprise should organize training to enhance their business management skills

Water for All (<i>Har Ghar Jal</i>): Rural Water Supply Services (RWSS) in India (2013–2018), Challenges and Opportunities

Sustainable delivery of drinking water of adequate quantity/quality sits at the core of rural development paradigms worldwide. The overarching goal of this study was to assess operational performance of rural water supply services (RWSS) in India to help authorities understand challenges/shortfalls vis-à-vis opportunities. Data on habitation-level coverage, aggregated by states between 2013 and 2018, were obtained from the National Rural Drinking Water Programme (NRDWP) database, against two water supply norms, namely, 40 lpcd and 55 lpcd (litres per capita per day). Results indicate that certain states are faring better (providing full coverage to over 90% habitations) while others are lagging (e.g., the north-eastern region, and Kerala and Karnataka in the South, for both norms). Several states yet fail to provide 55 lpcd to over half of their rural habitations. Overall, RWSS is marked by high spatial heterogeneity, inequality and recurrent slip-backs (decline in year-to-year habitation coverage) that thwart the basic motto of NRDWP— Har Ghar Jal (Water for All). Ground-level experience reveals a mismatch between theoretical systems’ output (40 lpcd and 55 lpcd) and on-site delivery, and highly intermittent services. Moreover, frequent scheme failure/abandonment adds to systems’ uncertainties and water users’ plight. A multitude of operational/organisational flaws, associated with government waterworks bodies, at different levels of systems’ hierarchy, limit RWSS operational performance. To that end, the concluding section argues for a demand-driven RWSS model (bottom-up systems’ governance) and highlights the core tenets of the same that call for integration of environmental, social, cultural, ethical and political perspectives in RWSS systems’ thinking/design. </jats:p