Molecular breeding

About: Molecular breeding is a research topic. Over the lifetime, 2120 publications have been published within this topic receiving 56908 citations.

Development of molecular marker and introgression of Bph3 into elite rice cultivars by marker-assisted selection.

Abstract: The brown planthopper (BPH) is a serious insect pest of rice and a substantial threat to rice production. Identification of new BPH resistance genes and their transfer into modern rice cultivars are effective breeding approaches to reduce the damage caused by BPH. In this study, we mapped a BPH resistance gene to a 50-kb genomic interval between two InDel markers 4M03980 and 4M04041 on the short arm of chromosome 4 in indica rice cultivar BP60, where the BPH resistance gene was mapped in Rathu Heenati by Liu et al. (2015) and named "Bph3". This region contains two annotated genes Os04g0201900 and Os04g0202300, which encode lectin receptor kinases responsible for BPH resistance. We also developed a molecular marker "MM28T" for Bph3, and introgression Bph3 into susceptible rice restorer lines Guihui582 and Gui7571 by the marker-assisted selection (MAS) approach. The BPH resistance level is significantly enhanced in the Bph3-introgression lines, the resistance scores decrease from 8.2 to 3.6 for Guihui582 and decrease from 8.7 to around 3.8 for Gui7571. Therefore, developing molecular markers for the BPH resistance gene Bph3 and using them for molecular breeding will facilitate the creation of BPH-resistance rice cultivars to reduce damage caused by BPH.

Genome Mapping and Map Based Cloning

Abstract: Genome mapping has emerged as a potential tool that provides the complete depiction of the genomes of plants and animals and thereby the means for their further manipulation. It involves elucidation of the nuclear genome of higher plants and animals as well as the smaller cytoplasmic genomes as chloroplasts and mitochondria. It involves basically linkage mapping employing molecular markers and using mainly segregating populations. First generation or primary genetic linkage maps have been constructed in several plant and animal systems, particularly those of fundamental or of economic interests. An array of markers have been used for such purposes, those included mainly isoenzyme, RFLP, RAPD, AFLP and SSR. The mostly used mapping populations included F2, recombinant inbred lines, backcross, doubled haploid lines and CEPH. The second generation genetic maps, such as high density, high resolution and saturated linkage maps have also been developed in several plants and animals mainly by enriching the primary maps locally or globally. Molecular mapping has paved the way for positioning of simply inherited trait loci (SITL) controlling oligogenic characters and quantitative trait loci (QTL) controlling polygenic characters. These have in turn facilitated marker assisted breeding (MAB) or molecular breeding (MB) for improvement in these traits. It has also recently been possible to mendelize the QTLs for precise monitoring of the gene clusters. Construction of molecular maps of two or more species/genera using a common set of markers and characters have resulted in comparative mapping that provides valuable information on genome homology and thus could illuminate on phylogenetic relationship and evolution in several taxa. Genome mapping has also provided the platform for chromosome walking or chromosome landing for isolating the chromosomal fragment containing a target gene and its (map based) cloning (MBC) for use in genetic transformation.

Development of EST-SSR markers through data mining and their use for genetic diversity study in Indian accessions of Jatropha curcas L.: a potential energy crop

Abstract: Jatropha curcas L. is gaining importance as a potential energy crop. However, lack of sufficient numbers of molecular markers hinder current research on crop improvement in Jatropha. The expressed sequences tags (EST) sequences deposited in public databases, offers an excellent opportunity to identify simple sequence repeats (SSRs) through data mining, for further research on molecular breeding. In the present study 42,477 ESTs of J. curcas were screened, out of which 5,673 SSRs were identified with 48.8 % simple (excluding mononucleotide repeats) and 52.2 % compound repeat motifs. Amongst these repeat motifs, dinucleotide repeats were abundant (26.5 %), followed by trinucleotide (23.1 %) and tetranucleotide repeats (0.8 %). From these microsatellites, 32 EST-SSR (genic microsatellite) primer pairs were designed. These primers were used to analyze the genetic diversity among 42 accessions collected from different parts of India. Out of the 32 EST-SSR primers, 24 primer pairs exhibited polymorphism among the genotypes, with amplicons varying from one to eight, giving an average of 2.33 alleles per polymorphic marker. Polymorphic information content value ranged from 0.02 to 0.5 with an average of 0.402 indicating moderate level of informativeness within these EST-SSRs markers. The EST-SSR markers developed here will serve as a valuable resource for genetic studies, like linkage mapping, diversity analysis, quantitative trait locus/association mapping, and molecular breeding. The current study also revealed low diversity in the screened Indian Jatropha germplasm. Therefore, the future efforts must be made to broaden the gene pool of Jatropha for the creation of genetic diversity that can be further used for crop improvement through breeding.

Advances in Plant Breeding Strategies:Industrial and Food Crops

Abstract: The book is an excellent reference source for plant breeders and geneticists engaged in breeding programs involving biotechnology and molecular tools together with traditional breeding. It is suitable for both advanced undergraduate and postgraduate students specializing in agriculture, biotechnology, and molecular breeding as well as for seed companies and policy-makers Chapter 1 Genetics and Breeding of Tropical Acacias for Forest Products: Acacia mangium,A. auriculiformis and A. crassicarpa / Arif Nirsatmanto and Sri Sunarti

Transgenic technologies for enhanced molecular breeding of white clover (Trifolium repens L.)

Abstract: White clover is an important pasture legume of temperate regions, generally through co-cultivation with a pasture grass in a mixed-sward setting. White clover provides herbage with high nutritional quality to grazing animals, along with the environmental benefit of biological nitrogen fixation. Several key agronomic traits are amenable to modification in white clover through use of transgenic technology. Efficient methods for Agrobacterium-mediated transformation of white clover have been developed. The current status of transgenic research is reviewed for the following traits: resistance to viruses and insect pests; aluminium tolerance and phosphorus acquisition efficiency; control of leaf senescence and seed yield; biosynthesis of flavonoids and rumen bypass proteins for bloat safety and enhanced ruminant nutrition; cyanogenesis; and drought tolerance. Future prospects for transgenic technology in molecular breeding in white clover are also discussed.