Characterisation and genetic diversity analysis of selected chickpea cultivars of nine countries using simple sequence repeat (SSR) markers

The genomic DNA profiles of 48 chickpea cultivars released in nine countries and of historical significance to the chickpea breeding programs at ICRISAT and in Ethiopia were evaluated using 48 simple sequence repeat (SSR) markers. Across the cultivars, a total of 504 alleles representing the 48 SSR loci were detected with frequencies ranging from three to 22 (mean 10.5) alleles per locus. The polymorphism information content (PIC) for the SSR markers varied from 0.37 to 0.91 (mean 0.77). A subset of only three highly informative SSR markers (TA176, TA2, TA180) enabled complete discrimination among all 48 chickpea cultivars tested. Hierarchical neighbour-joining UPGMA cluster analysis based on simple matching dissimilarity matrix resolved the 48 cultivars into two major clusters representing desi and kabuli types. These cluster groupings of the cultivars were consistent with the pedigree information available for the cultivars as to the phenotypic classes of chickpea types. Analysis of the temporal patterns of the SSR diversity by classifying 48 chickpea cultivars into four periods of release revealed increasing tendencies in the overall genetic diversity from 0.42 for the earliest varieties developed in the 1970s to 0.62 for those released in the 1980s, and reached a maximum and equivalent level of 0.72 for the varieties developed in the 1990s and 2000s. Overall, the study ascertained that SSRs provide powerful marker tools in revealing genetic diversity and relationships in chickpeas, thereby proving useful for selection of parents in breeding programs and also for DNA fingerprint identification of cultivars

Characterisation and genetic diversity analysis of selected chickpea cultivars of nine countries using simple sequence repeat (SSR) markers

The genomic DNA profiles of 48 chickpea cultivars released in nine countries and of historical significance to the chickpea breeding programs at ICRISAT and in Ethiopia were evaluated using 48 simple sequence repeat (SSR) markers. Across the cultivars, a total of 504 alleles representing the 48 SSR loci were detected with frequencies ranging from three to 22 (mean 10.5) alleles per locus. The polymorphism information content (PIC) for the SSR markers varied from 0.37 to 0.91 (mean 0.77). A subset of only three highly informative SSR markers (TA176, TA2, TA180) enabled complete discrimination among all 48 chickpea cultivars tested. Hierarchical neighbour-joining UPGMA cluster analysis based on simple matching dissimilarity matrix resolved the 48 cultivars into two major clusters representing desi and kabuli types. These cluster groupings of the cultivars were consistent with the pedigree information available for the cultivars as to the phenotypic classes of chickpea types. Analysis of the temporal patterns of the SSR diversity by classifying 48 chickpea cultivars into four periods of release revealed increasing tendencies in the overall genetic diversity from 0.42 for the earliest varieties developed in the 1970s to 0.62 for those released in the 1980s, and reached a maximum and equivalent level of 0.72 for the varieties developed in the 1990s and 2000s. Overall, the study ascertained that SSRs provide powerful marker tools in revealing genetic diversity and relationships in chickpeas, thereby proving useful for selection of parents in breeding programs and also for DNA fingerprint identification of cultivars

Chickpea Genomics

As precise phenotyping is essential and the cost of generating phenotyping data at every generation is very expensive, recent advances in genomics technologies and the availability of a wide range of genotyping platforms have made the cost of genotyping much less expensive compared with phenotyping. The recent developments in sequencing technologies have manifold increased the repertoire of various types of markers that are available in chickpea including SSRs, SNPs, DArTs, hundreds of thousands transcript reads and BAC-end sequences saturated genetic maps, QTL maps as well as physical maps, and the sequencing of both kabuli and desi type has greatly helped in using marker-assisted technologies to be applied in plant breeding. Germplasm resequencing for identification of genome-wide SNPs and their subsequent utilization in genomic selection has the potential to break the yield barrier being experienced in chickpea and many other crops. Genomic-assisted breeding for marker-assisted backcrossing (MABC) for introgressing QTL region, marker-assisted recurrent selection, gene pyramiding, marker-assisted selection (MAS), and genomic selection can now be taken up in chickpea. The conventional plant breeding should take these tools to make greater genetic gains, increase selection potential, and have faster breeding cycles so that the genetic improvement gains are increased in chickpea

Chickpea Genomics

As precise phenotyping is essential and the cost of generating phenotyping data at every generation is very expensive, recent advances in genomics technologies and the availability of a wide range of genotyping platforms have made the cost of genotyping much less expensive compared with phenotyping. The recent developments in sequencing technologies have manifold increased the repertoire of various types of markers that are available in chickpea including SSRs, SNPs, DArTs, hundreds of thousands transcript reads and BAC-end sequences saturated genetic maps, QTL maps as well as physical maps, and the sequencing of both kabuli and desi type has greatly helped in using marker-assisted technologies to be applied in plant breeding. Germplasm resequencing for identification of genome-wide SNPs and their subsequent utilization in genomic selection has the potential to break the yield barrier being experienced in chickpea and many other crops. Genomic-assisted breeding for marker-assisted backcrossing (MABC) for introgressing QTL region, marker-assisted recurrent selection, gene pyramiding, marker-assisted selection (MAS), and genomic selection can now be taken up in chickpea. The conventional plant breeding should take these tools to make greater genetic gains, increase selection potential, and have faster breeding cycles so that the genetic improvement gains are increased in chickpea

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.The aim of this study was to inform vaccination prioritization by modelling the impact of vaccination on elective inpatient surgery. The study found that patients aged at least 70 years needing elective surgery should be prioritized alongside other high-risk groups during early vaccination programmes. Once vaccines are rolled out to younger populations, prioritizing surgical patients is advantageous