Insight in Mapping Quantitative Trait Loci Associated with Disease Resistance in Crops: Sensed and Reached Seethapathy Parthasarathy1,*, Sannasi Thirumal Raj2, Jayaraman Rajalakshmi1, Kuppusamy Prabakar1 1Department of Plant Pathology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India 2Department of Fruit Crops, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India *Email: spsarathyagri@gmail.com
Online published on 2 January, 2017. Abstract The transition to a new era of disease resistance research is underway, and both the public and private sectors are moving to exploit the new tools and opportunities presented by genetics and molecular biology. Most disease resistance traits are polygenic innature and controlled by many genes residing at so called quantitative trait loci (QTLs). In addition, sources of resistance are usually found in wild relatives or cultivars with lower agronomical value, so introgression of resistance characters into commercial peach cultivars usually requires several generations of backcrossing to reinstate the favorable genotype. Molecular-assisted breeding (MAB), however, allow the pre-selection of traits long before they are expressed. Plant scientists have used disease resistance genes (R genes) to control plant disease since the turn of the century. Molecular cloning of R genes that enable plants to resist a diverse range of pathogens has revealed that the proteins encoded by these genes have several features in common. These findings suggest that plants may have evolved common signal transduction mechanisms for the expression of resistance to a wide range of unrelated pathogens. Characterization of the molecular signals involved in pathogen recognition and of the molecular events that specify the expression of resistance may lead to novel strategies for plant disease control. Top Keywords Defence response gene, Disease resistance, Map based cloning, Mapping gene loci, R genes. Top |