Biology subjects

Haile, T.

Publications and source records attributed to Haile, T..

6 recordsLinked to original sources

bioRxiv2025

Development of a Nested Association Mapping (NAM) population for untangling complex traits in lentil (Lens culinaris Medik.)

Understanding the genetic basis of complex traits remains a key challenge in crop improvement. This study aimed to develop a structured, multi-parental mapping population to enhance the resolution of quantitative trait dissection, based on the hypothesis that a Nested Association Mapping (NAM) design would enable the detection of minor-effect loci often overlooked by traditional biparental or diversity panel-based approaches. A lentil (Lens culinaris Medik.) NAM population was developed by crossing the Canadian cultivar CDC Redberry with 32 diverse genotypes sourced globally from three major lentil-growing macro-environments: Northern temperate, Mediterranean, and South Asia. The resulting recombinant inbred lines were phenotyped for key phenological traits, days to emergence (DTE), flowering (DTF), and maturity (DTM), under field conditions, and genotyped using exome capture sequencing. Genome-wide association studies for DTF identified 14 significant loci across six chromosomes, including the known FTb locus and novel associations near AP3a, HUB2a, and PIF6 genes. These results demonstrate the utility of the NAM design in detecting both major and minor-effect loci that underlie complex trait variation. To our knowledge, this is the first publicly available NAM population in lentil. It provides a high-resolution, globally representative platform for trait discovery, pre-breeding, and collaborative genetic improvement of this nutritionally and agronomically important legume.

plant biology↗

bioRxiv2024

Harnessing genome prediction in Brassica napus through a nested association mapping population

Genome prediction (GP) significantly enhances genetic gain by improving selection efficiency and shortening crop breeding cycles. Using a nested association mapping (NAM) population a set of diverse scenarios were assessed to evaluate GP for vital agronomic traits in B. napus. GP accuracy was examined by employing different models, marker sets, population sizes, marker densities, and incorporating genome-wide association (GWAS) markers. Eight models, including linear and semi-parametric approaches, were tested. The choice of model minimally impacted GP accuracy across traits. Notably, two models, rrBLUP and RKHS, consistently yielded the highest prediction accuracies. Employing a training population of 1500 lines or more resulted in increased prediction accuracies. Inclusion of single nucleotide absence polymorphism (SNaP) markers significantly improved prediction accuracy, with gains of up to 15%. Utilizing the Brassica 60K Illumina SNP array, our study effectively revealed the genetic potential of the B. napus NAM panel. It provided estimates of genomic predictions for crucial agronomic traits through varied prediction scenarios, shedding light on achievable genetic gains. These insights, coupled with marker application, can advance the breeding cycle acceleration in B. napus. Core ideasO_LIGenome prediction (GP) enhances genetic gains by improving selection efficiency and shortening breeding cycles. C_LIO_LIFactors influencing GP accuracy include model choice, marker types, and population size. C_LIO_LIInclusion of SNaP markers and highly significant GWAS markers improves prediction accuracy, shedding light on achievable genetic gains. C_LI Plain SummaryGenome prediction (GP) is a powerful tool that helps us improve crops more efficiently. In this study, we assessed how well GP works for predicting important traits in Brassica napus plants. We tested different models and marker sets to see which ones were most accurate. We found that two models, rrBLUP and RKHS, were consistently the best. Also, including certain types of genetic markers, like SNaP markers and highly significant GWAS markers, improved the predictions. Overall, our study shows that GP can help us understand the genetic potential of B. napus plants and improve breeding strategies, which can be exploited to develop better varieties more quickly, which is good news for farmers and the food supply.

genomics↗

bioRxiv2021

Genomic rearrangements have consequences for introgression breeding as revealed by genome assemblies of wild and cultivated lentil species

Understanding the genomic relationship between wild and cultivated genomes would facilitate access to the untapped variability found in crop wild relatives. We developed genome assemblies of a cultivated lentil (Lens culinaris) as well as a wild relative (L. ervoides). Comparative analyses revealed large-scale structural rearrangements and additional repetitive DNA in the cultivated genome, resulting in regions of reduced recombination, segregation distortion and permanent heterozygosity in the offspring of a cross between the two species. These novel findings provide plant breeders with better insight into how best to approach accessing the novel variability available in wild relatives.

plant biology↗

bioRxiv2021

Identification of anthracnose (Colletotrichum lentis) race 1 resistance loci in lentil by integrating linkage mapping and a genome-wide association study

Anthracnose, caused by Colletotrichum lentis, is a devastating disease of lentil in Western Canada. Growing resistant lentil cultivars is the most cost-effective and environmentally friendly approach to prevent seed yield losses that can exceed 70%. To identify loci conferring resistance to anthracnose race 1 in lentil, biparental quantitative trait loci (QTL) mapping of two recombinant inbred line (RIL) populations was integrated with a genome-wide association study (GWAS) using 200 diverse lentil accessions from a lentil diversity panel (LDP). A major-effect QTL (qAnt1.Lc-3) conferring resistance to race 1 was mapped to lentil chromosome 3 and co-located on the lentil physical map for both RIL populations. Clusters of candidate nucleotide binding-leucine-rich repeats (NB-LRR) and other defense-related genes were uncovered within the QTL region. A GWAS detected 14 significant SNP markers associated with race 1 resistance on chromosomes 3, 4, 5, and 6. The most significant GWAS SNPs on chromosome 3 supported qAnt1.Lc-3 and delineated a region of 1.6 Mb containing candidate resistance genes. The identified SNP markers can be directly applied in marker-assisted selection to accelerate the introgression of race 1 resistance in lentil breeding.

genomics↗

bioRxiv2020

Sero-prevalence of anti-SARS-CoV-2 Antibodies in Addis Ababa, Ethiopia

BackgroundAnti-SARS-CoV-2 antibody tests are being increasingly used for sero-epidemiological purposes to provide better understanding of the extent of the infection in the community, and monitoring the progression of the COVID-19 epidemic. We conducted sero-prevalence study to estimate prior infection with with SARS-CoV-2 in Addis Ababa. MethodsA cross-sectional study was done from April 23 to 28, 2020 among 301 randomly selected residents of Addis Ababa; with no known history of contact with confirmed COVID-19 person. Interviews on socio demographic and behavioural risk factor followed by serological tests were performed for SARS-CoV-2 IgM, and IgG antibodies, using COVID-19 IgG/IgM Rapid Test Cassette. The test has sensitivity of 87{middle dot}9% and specificity of 100% for lgM; and a sensitivity of 97{middle dot}2% and specificity of 100% for IgG. RT-PCR test was also done on combined nasopharyngeal and oropharengeal swabs as an important public health consideration. FindingsThe unadjusted antibody-based crude SARS-CoV-2 prevalence was 7{middle dot}6% and the adjusted true SARS-CoV-2 prevalence was estimated at 8{middle dot}8% (95% CI 5{middle dot}5%-11{middle dot}6%) for the study population. Higher sero-prevalence were observed for males (9.0%), age below 50 years (8.2%), students and unemployed (15.6%), those with primary education (12.1%), smokers (7.8%), alcohol consumers (8.6%), chatt-chewers (13.6%) and shish smokers (18.8%). Seroprevalence was not significantly associated neither with socio-demographic not behavioral characteristics. According to the findings, possibly more individuals had been infected in Addis Ababa than what was being detected and reported by RT-PCR test suggestive of community transmission. The use of serological test for epidemiological estimation of the extent of SARS-CoV-2 epidemic gives a more precise estimate of magnitude which would be used for further monitoring and surveillance of the magnitude of the SARS CoV-2 infection.

microbiology↗

bioRxiv2020

Understanding photothermal interactions will help expand production range and increase genetic diversity of lentil (Lens culinaris Medik.)

O_LILentil (Lens culinaris Medik.) is cultivated under a wide range of environmental conditions, which led to diverse phenological adaptations and resulted in a decrease in genetic variability within breeding programs due to reluctance in using genotypes from other environments. C_LIO_LIWe phenotyped 324 genotypes across nine locations over three years to assess their phenological response to the environment of major lentil production regions and to predict days from sowing to flowering (DTF) using a photothermal model. C_LIO_LIDTF was highly influenced by the environment and is sufficient to explain adaptation. We were able to predict DTF reliably in most environments using a simple photothermal model, however, in certain site-years, results suggest there may be additional environmental factors at play. Hierarchical clustering of principal components revealed the presence of eight groups based on the responses of DTF to contrasting environments. These groups are associated with the coefficients of the photothermal model and revealed differences in temperature and photoperiod sensitivity. C_LIO_LIExpanding genetic diversity is critical to the success of a breeding program; understanding adaptation will facilitate the use of exotic germplasm. Future climate change scenarios will result in increase temperature and/or shifts in production areas, we can use the photothermal model to identify genotypes most likely to succeed in these new environments. C_LI

plant biology↗