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Associations between endogenous spike cytokinins and grain-number traits in spring wheat genotypes
No full textGenetic variation in grain number has been positively associated with levels of cytokinins in inflorescences in cereals, although studies quantifying endogenous levels in the field are currently lacking. The present study, using a spring wheat association mapping panel (HiBAP II) of 150 lines, quantified associations between spike hormone levels and grain number and associated traits. The HiBAP II panel was grown in the field in NW Mexico under irrigated conditions for one year and a subset of ten genotypes in the glasshouse under well-watered conditions for three years. The spike levels of four cytokinins (trans-zeatin riboside, trans-zeatin, isopentenyladenosine, and isopentenyladenine) were measured by using ultra-high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. In the glasshouse experiments, spike hormone levels were measured at booting and anthesis, and in the field experiment at anthesis. In the glasshouse experiments, cytokinin levels were also measured in the basal, central, and apical spikelets separately in addition to at the whole spike level. The spike cytokinin levels did not differ significantly between the basal, central and apical sections of the spike. or show a spike position × genotype interaction. In the glasshouse experiments, significant genetic variation was detected for the expression of the four cytokinins in spikes at booting. At booting, spike trans-zeatin concentration ranged amongst genotypes from 4.5 to 16.0 ng g−1 FW and was positively correlated with grain number per main shoot (r = 0.77, P < 0.05). In the field at anthesis, the spike levels of each of trans-zeatin, trans-zeatin riboside and isopentenyl adenosine were positively correlated with grains per m2 (r = 0.17–0.19, P < 0.05). Our results indicated that selection for high spike cytokinin levels in wheat germplasm offers scope to raise grain number and yield potential in wheat
Identification of genomic regions associated with Ug99 adult plant resistance on wheat (Triticum aestivum L.)
No full textUg99 is a highly destructive race of stem rust fungus known as Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn. (Pgt). To address this problem, the International Maize and Wheat Improvement Center, Mexico (CIMMYT) has extensively employed adult plant resistance (APR), which combines multiple genes that provide slow rusting resistance. CIMMYT’s advanced germplasm, “Diniza,” has proven to possess a good level of APR for the Ug99 race group. This study identified the genomic regions responsible for providing APR in the PBW343/Diniza RIL population. Study identified four quantitative trait loci (QTLs) that provide slow rusting APR on chromosomes 2B (QSr.cimm-2B), 3BS (QSr.cimm-3BP1 and QSr.cimm-3BP2), and 7DS (QSr.cimm-7D). These QTLs explained phenotypic variances of 17.0, 18, 8.9, and 11.6%, respectively. Three QTLs, QSr.cimm-2B, QSr.cimm-3BP2, and QSr.cimm-7D, were derived from APR parent ‘Diniza’, while QSr.cimm-3BP1 was derived from ‘PBW343’. Further, QTL class analysis revealed the additive and epistatic interaction results of the identified QTL(s), suggesting that combinations of several QTLs can effectively reduce disease severity. Unlike, QSr.cimm-2B, QTLs QSr.cimm-3BP1 and QSr.cimm-7D co-localized with the previously identified stem rust resistance genes. The identified QTL can be combined to enhance stem rust resistance in breeding materials
Sustainable agricultural mechanization in Timor-Leste: status, challenges and further action
No full textDespite many efforts over two decades of independence, Timor-Leste's cereal production and agricultural productivity have decreased dramatically, reflected by high food insecurity and rural poverty. This paper analyses the country's current agricultural mechanization efforts to guide future actions that aim to stimulate growth through sustainable mechanization. We combined information from scientific publications, governmental and international cooperation communications, and data collected during field missions to assess the situation. Our study provides recommendations to reverse a failed tractorization campaign and presents a comprehensive overview of a strategy, in alignment with a proposed and renewed national agricultural mechanization policy, that would enable the modernization and sustainable intensification of current food production systems in a nutrition-sensitive, climate-smart, economically viable, and gender-inclusive fashion. The recommendations suggest a focus on scale-appropriate solutions that respond to upland smallholder farmers' capacities and consider good rural transport options, with the first steps to redirect the situation already taken through a technical cooperation program between FAO and the Ministry of Agriculture. Beyond this, a reform of the current government mechanization hire schemes is needed: integrated approaches, as found from business model analyses and training exercises during field missions, are needed, that entail context-specific solutions for targeted rural communities, with special attention given to participatory extension, inclusive co-validation of technologies, and private sector-led business model development around mechanization service delivery. Finally, the authors hope the presented way forward can serve as a roadmap for smallholder farmers and developing nations in similar conditions elsewhere in the world
Mind the (nutrient supply) gap: An assessment of demand and supply limitations for Nitrogen, Phosphorus and Potassium for major crops in Nepal
No full textThis work is supported by the USAID/Nepal-funded Cereal Systems Initiative for South Asia (CSISA) 'Building food system resilience to global supply chain and climate shocks in Nepal' Activity supported by USAID/Nepal. CSISA aims to enhance the adoption of resource-conserving and climate-resilient technologies while improving farmers' access to market information and enterprise development, particularly for women farmers through modern innovations and entrepreneurial skills. Working in synergy with regional and national efforts, CSISA collaborates with various public, civil society, and private-sector partners to promote widespread adoption of practices that increase yields with reduced water, labor, and input costs. The initiative supports the integration of innovations into government programs, generates and disseminates knowledge on climate-resilient cropping systems, improves the policy environment for sustainable intensification technologies, and builds strategic partnerships to sustain the benefits of increased cereal system productivity. The project is led by CIMMYT and implemented jointly with IFPRI, IRRI, and IWMI, with support from the Institute for Integrated Development Studies (IIDS) and International Development Enterprises (iDE).24 page
TAFSSA stakeholder mapping: The agricultural production systems in Bangladesh
No full textThe network mapping workshop aimed to analyze the agricultural production systems in Bangladesh, focusing on crops, livestock, and aquaculture. The workshop explored the roles and interactions of key stakeholders, including government bodies, NGOs, the private sector, academic institutions, research organizations, and international organizations, in shaping the agricultural landscape. The primary research question guiding this effort was: Who are the main organizations and actors influencing agricultural production systems in Bangladesh? Through this analysis, we aimed to uncover key drivers, barriers, and gaps within the system to guide interventions for enhancing the sustainability and effectiveness of the agrifood systems in Bangladesh.21 page
Testcross performance and combining ability of intermediate maturing drought tolerant maize inbred lines in Sub-Saharan Africa
No full textDrought is a major constraint on maize (Zea mays L.) production and productivity in Sub-Saharan Africa (SSA). The increase in frequency and severity of drought, driven by climate change, is expected to worsen in the future. These occurrences are likely to adversely affect maize production and productivity, threatening the economic and social stability of millions of smallholder farmers. Understanding the genetics of hybrid performance under drought stress is crucial for designing breeding strategies to develop high-yielding hybrids. This study aimed to (i) evaluate the performance of three-way cross hybrids developed from elite inbred lines, including several drought-tolerant lines, using a line-by-tester mating design, and (ii) estimate the general combining ability (GCA) and specific combining ability (SCA) effects of the tropical maize inbred lines under managed drought and optimum conditions. A total of 265 maize inbred lines from the CIMMYT global maize breeding program were used as parents and crossed to six single cross testers to generate 795 testcross hybrids. These hybrids, along with six commercial hybrids as a check, were evaluated under managed drought and optimum conditions. Significant (p < 0.001) variations were observed among genotypes and genotypes-by-environment interactions (GEIs) for grain yield and other traits. There was a preponderance of GCA variance (lines and tester) over SCA variance, indicating that additive effects were more important in determining grain yield and other key traits under both managed drought and optimum conditions. Ten inbred lines (S2_8, S10_1, S6_4, S10_14, S2_14, S10_15, S8_7, S2_3, S8_15, and S13_5) with desirable GCA effects for grain yield and other traits were identified. Fourteen testcross hybrids were identified with high grain yield and desirable agronomic traits under both drought and optimum conditions. The identified lines and hybrids are useful sources to be used in breeding and deploying as stress-tolerant hybrids. High correlations observed between observed and GCA-predicted hybrid performance suggest the possibility to evaluate more hybrids with fixed resources. The study demonstrates that it is feasible to obtain high-yielding and drought-tolerant lines and hybrids. These testcross hybrids should undergo rigorous on-farm trials to ensure consistent performance before commercialization and release. Deploying these hybrids could help in mitigating the effects of drought stress in SSA and contribute to improved maize productivity in the region
Exploring data augmentation algorithm to improve genomic prediction of top-ranking cultivars
No full textGenomic selection (GS) is a groundbreaking statistical machine learning method for advancing plant and animal breeding. Nonetheless, its practical implementation remains challenging due to numerous factors affecting its predictive performance. This research explores the potential of data augmentation to enhance prediction accuracy across entire datasets and specifically within the top 20% of the testing set. Our findings indicate that, overall, the data augmentation method (method A), when compared to the conventional model (method C) and assessed using Mean Arctangent Absolute Prediction Error (MAAPE) and normalized root mean square error (NRMSE), did not improve the prediction accuracy for the unobserved cultivars. However, significant improvements in prediction accuracy (evidenced by reduced prediction error) were observed when data augmentation was applied exclusively to the top 20% of the testing set. Specifically, reductions in MAAPE_20 and NRMSE_20 by 52.86% and 41.05%, respectively, were noted across various datasets. Further investigation is needed to refine data augmentation techniques for effective use in genomic prediction
