Molecular breeding

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

The role of gene technology in plant breeding

Abstract: Plant breeders have made spectacular progress in the improvement of many crop species over the last 60 years. In wheat, rice and maize for example about 50% of the increase in the yield over the period 1930–1975 has been attributed to improved varieties; the remainder derives from greater and more efficient use of fertilizers and crop management. Recent advances in genetics, cell and molecular biology, particularly recombinant-DNA technology, provide new opportunities for manipulation of the genome to meet the varying demands of breeders.

Identification of functional single-nucleotide polymorphisms affecting leaf hair number in Brassica rapa

Abstract: Leaf traits affect plant agronomic performance; for example, leaf hair number provides a morphological indicator of drought and insect resistance. Brassica rapa crops have diverse phenotypes, and many B. rapa single-nucleotide polymorphisms (SNPs) have been identified and used as molecular markers for plant breeding. However, which SNPs are functional for leaf hair traits and, therefore, effective for breeding purposes remains unknown. Here, we identify a set of SNPs in the B. rapa ssp. pekinenesis candidate gene BrpHAIRY LEAVES1 (BrpHL1) and a number of SNPs of BrpHL1 in a natural population of 210 B. rapa accessions that have hairy, margin-only hairy, and hairless leaves. BrpHL1 genes and their orthologs and paralogs have many SNPs. By intensive mutagenesis and genetic transformation, we selected the functional SNPs for leaf hairs by the exclusion of nonfunctional SNPs and the orthologous and paralogous genes. The residue tryptophan-92 of BrpHL1a was essential for direct interaction with GLABROUS3 and, thus, necessary for the formation of leaf hairs. The accessions with the functional SNP leading to substitution of the tryptophan-92 residue had hairless leaves. The orthologous BrcHL1b from B. rapa ssp. chinensis regulates hair formation on leaf margins rather than leaf surfaces. The selected SNP for the hairy phenotype could be adopted as a molecular marker for insect resistance in Brassica spp. crops. Moreover, the procedures optimized here can be used to explain the molecular mechanisms of natural variation and to facilitate the molecular breeding of many crops.

Resilience of cereal crops to abiotic stress: A review

Abstract: In the last century, conventional selection and breeding program proved to be highly effective in improving crops against abiotic stresses. Therefore, breeding for abiotic stress tolerance in crop plants should be given high research priority as abiotic stresses are the main factor negatively affecting crop growth and productivity throughout the globe. Advancement in physiology, genetics and molecular biology, have greatly improved our understanding of plant responses to stresses. Many studies show that salt tolerance is tightly associated with the ability to maintain ion homeostasis under salinity. Na + transporter SKC1 unloads Na + from xylem; plasma membrane N + /H + antiporter SOS 1 excludes sodium out of cytosol, and tonoplast Na + /H + antiporter NHX 1 sequesters Na + into the vacuole. Silicon deposition in exodermis and endodermis of rice root reduces sodium transport through the apoplastic pathway. A number of transcription factors regulate stress-inducible gene expression that leads to initiating stress responses and establishing plant stress tolerance. Over expression of some transcription factors, including DREB/CBF and NAC, enhances salt, drought, and cold tolerance in rice. A variant of one of ERF family genes, Sub1A-1 , confers immersion tolerance to lowland rice. These findings and their exploitation will hold promise for engineering breeding to protect crop plants from certain abiotic stresses. Although, cereal crops are also quite sensitive to various abiotic stresses, hence in this short review, we will present recent progresses in adaptation of cereal crops to salinity, drought and cold tolerance are emphasized and the future potentials are highlighted. Keywords: Cereal crops, abiotic stresses, food insecurity, molecular breeding, quantitative trait loci (QTLs), salinity, water stress. African Journal of Biotechnology , Vol 13(29) 2908-2921