CIMMYT Publications Repository
Not a member yet
7809 research outputs found
Sort by
Nitrogen use efficiency in bread wheat: genetic variation and prospects for improvement
No full textNitrogen (N) is one of the primary macronutrients required for crop growth and yield. This nutrient is especially limiting wheat yields in the dry and low fertile agro-ecologies having low N in the root zone soil strata. Moreover, majority of farmers in India and South Asia are small to marginal with meagre capacity to invest in costly nitrogen fertilizers. Therefore, there is an immense need to identify lines that use nitrogen efficiently. A set of 50 diverse wheat genotypes consisting of indigenous germplasm lines (05), cultivars released for commercial cultivation (23) and selected elite lines from CIMMYT nurseries (22) were evaluated in an alpha-lattice design with two replications, a six-rowed plot of 2.5m length for 24 agro morphological, physiological and NUE related traits during two consecutive crop seasons in an N-depleted precision field under two different N levels of 50%-N50 (T1) and 100%-N100 (T2) of recommended N, i.e., 100 kg/ha. Analysis of variance revealed significant genetic variation among genotypes for all the traits studied. About 11.36% yield reduction was observed at reduced N levels. Significant correlations among NUE traits and yield component traits were observed which indicated pivotal role of N remobilization to the grain in enhancing yield levels. Among N-insensitive genotypes identified based on their yielding ability at low N levels, UASBW13356, UASBW13358, UASBW13354, UASBW13357 and KRL1-4 showed their inherent genotypic plasticity toward N application. The genotypes with more yield and high to moderate NUtE can be used as parents for the breeding of N efficient genotypes for marginal agro-ecologies. Low N tolerant genotypes identified from the current investigation may be further utilized in the identification of genomic regions responsible for NUE and its deployment in wheat breeding programs. The comprehensive data of 24 traits under different nitrogen levels for diverse genotypes from India and global sources (mainly CIMMYT) should be useful for supporting breeding for NUE and thus will be of great help for small and marginal farmers in India and South Asia
A combination of joint linkage and genome-wide association study reveals putative candidate genes associated with resistance to northern corn leaf blight in tropical maize
No full textNorthern corn leaf blight (NCLB), caused by Setosphaeria turcica, is a major fungal disease affecting maize production in sub-Saharan Africa. Utilizing host plant resistance to mitigate yield losses associated with NCLB can serve as a cost-effective strategy. In this study, we conducted a high-resolution genome-wide association study (GWAS) in an association mapping panel and linkage mapping with three doubled haploid (DH) and three F3 populations of tropical maize. These populations were phenotyped for NCLB resistance across six hotspot environments in Kenya. Across environments and genotypes, NCLB scores ranged from 2.12 to 5.17 (on a scale of 1-9). NCLB disease severity scores exhibited significant genotypic variance and moderate-to-high heritability. From the six biparental populations, 23 quantitative trait loci (QTLs) were identified, each explaining between 2.7% and 15.8% of the observed phenotypic variance. Collectively, the detected QTLs explained 34.28%, 51.37%, 41.12%, 12.46%, 12.11%, and 14.66% of the total phenotypic variance in DH populations 1, 2, and 3 and F3 populations 4, 5, and 6, respectively. GWAS, using 337,110 high-quality single nucleotide polymorphisms (SNPs), identified 15 marker-trait associations and several putative candidate genes linked to NCLB resistance in maize. Joint linkage association mapping (JLAM) identified 37 QTLs for NCLB resistance. Using linkage mapping, JLAM, and GWAS, several QTLs were identified within the genomic region spanning 4 to 15 Mbp on chromosome 2. This genomic region represents a promising target for enhancing NCLB resistance via marker-assisted breeding. Genome-wide predictions revealed moderate correlations with mean values of 0.45, 0.44, 0.55, and 0.42 for within GWAS panel, DH pop1, DH pop2, and DH pop3, respectively. Prediction by incorporating marker-by-environment interactions did not show much improvement. Overall, our findings indicate that NCLB resistance is quantitative in nature and is controlled by few major-effect and many minor-effect QTLs. We conclude that genomic regions consistently detected across mapping approaches and populations should be prioritized for improving NCLB resistance, while genome-wide prediction results can help incorporate both major- and minor-effect genes. This study contributes to a deeper understanding of the genetic and molecular mechanisms driving maize resistance to NCLB
InnovaHub - Herramientas esenciales: guía para socios y asistentes agrícolas en la red
No full text78 page
Capacity building, Sorghum varieties evaluation and seed production in Cameroon in 2024
No full text1 graphi
Genetic variability and character association among maize (Zea mays L.) Inbred lines
No full textGenetic analysis of variability, heritability and character association was studied among 25 maize inbred lines for eleven traits. The ANOVA indicated significant variation among the inbred lines chosen for the study for all the traits. Wide range of variability was observed for all the traits among them grain yield varied from 16.03 to 62.52 q/ha with an average mean value of 45.75 q/ha. Phenotypic variance was higher as compared to genotypic variance and highest phenotypic variance was observed for plant height followed by grain yield. However, the difference between phenotypic and genotypic variance was very narrow for majority of the traits. Similarly, phenotypic coefficient of variation (PCV) was marginally higher than the genotypic coefficient of variation (GCV) and highest GCV and PCV was recorded for grain yield (37.03, 38.12) followed by ear height (24.12, 26.48) indicating that these characters are under genetic control and have high potential for selection. High amount of broad-sense heritability coupled with high genetic advance as a percent of mean (GAM) was observed for grain yield (0.94 and 74.12) followed by number of kernels per row (0.90 and 32.88) indicating that phenotypic based selection for these traits would be successful. Hundred grain weight had the highest genotypic correlation (0.834) with grain yield followed by number of kernels per row (0.623).57–6
Increasing productivity and profitability: Evaluating diverse and intensifying cropping systems. A field study in Rajshahi District in Bangladesh
No full textThe Barind Tract in the Rajshahi region of Bangladesh spans 160,000 hectares and experiences high temperatures, limited soil moisture storage, and low, erratic rainfall. The land is characterized by poor drainage, low organic matter content, and a high susceptibility to drought, leading to low crop productivity (Rashid et al., 2019). A farmers' participatory research trial was conducted on diversified, intensified, and climate-resilient cropping system options, comparing farmers’ traditional cropping systems with those developed in collaboration with the Bangladesh Agricultural Research Institute and the Bangladesh Wheat and Maize Research Institute. A research brief has been prepared to summarize the results of the study, focusing on productivity and economic efficiency from 2022-23 in the Rajshahi district, Bangladesh.16 page
Outmigration and the rural-urban transition: Challenges and opportunities to crop-livestock interactions in Nepal - A systematic review
No full text22 page
Flour blending can mitigate food insecurity and economic stress
No full textCereal flour blending can reduce food insecurity risks, as well as contribute to economic and nutrition goals. Yet, the potential for blending has not been realized, and new products have not become scalable commercial propositions. Numerous experiments have shown the potential to produce acceptable foods derived from blended flours of diverse crops including wheat. An important question is whether the incentives, capacities and needs of farmers, processors and consumers have been considered. We argue that technical solutions must be developed within a specific agroecological, commercial, economic, and political environment. Innovations must address the clearly defined objectives of a wheat flour blending policy, if the potential benefits of blending for addressing food insecurity and economic stress are to be achieved
