New microsatellite loci for annatto (Bixa orellana), a source of natural dyes from Brazilian Amazonia

Annatto (Bixa orellana) is a tropical crop native to the Americas with Amazonia as the likely center of origin of domestication. Annatto is important because it produces the dye bixin, which is widely used in the pharmaceutical, food, cosmetic and textile industries. A total of 32 microsatellite loci were isolated from a microsatellite-enriched genomic library, of which 12 polymorphic loci were used to characterize four populations of B. orellana and B. orellana var. urucurana, the wild relative. Higher genetic diversity estimates were detected for the wild populations when compared to the cultivated populations. Also, higher apparent outcrossing rates were found for the two wild than the cultivated populations. These results indicate a mixed mating system for the species. All markers described herein have potential to be used in further studies evaluating the genetic diversity, population dynamics, domestication, breeding, and conservation genetics of annatto. © 2018, Brazilian Society of Plant Breeding. All rights reserved

Chickpea

The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

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