Identification of Genotypic Similarities Having QTLS for Drought Tolerance by Using SSR Markers

Abstract

Rice is one of the most important crops, providing staple food for about half population of the world. Rice production must be increased 60% so as to meet for the contention by the year 2025.Rice belongs to the genus Oryza and has two cultivated and 22 wild species. The cultivated species are Oryza saliva and Oryza glaberrima. Oryza saliva is grown all over the world while Oryza glaberrima has been cultivated in west Africa for the last -3500 years. Rice is the principal food for over half of the production of the world. Drought is the most important abiolic stress limiting rice y ields in almost all major ecosystems where ii is presently grown. Drought is a critical abiolic stress that severely restrict crop production, under drought conditions plant accumufate reactive oxygen speciesAbiotic stress is defined as the negative impact of non-living factors on the living organisms in a specific environment. The region within genome that contains gene associated with a particular trait are known as quantitative trait loci (QTLs).DiJferenl SSR markers are associated with different QTLs for drought tolerant.RM 3825 is associated with QTL DTY 11,RM 2 79 is associated with QTL DTY 22- Microsatellites are simple repeated motifs consisting of I to 6 base pairs, and they can be found in both coding and non-coding regions. The mutation rate of this type of genetic marker has been estimated to be between I 0- 2 and I 0- 4 per generation. The primary advantage of microsatellites as genetic markers is that they are inherited in a Mendelian fashion as co dominant markers. High polymorphism rates, high abundance and a broad distribution throughout the genome have made microsatellites one of the most popular genetic markers for use in plant breeding programs. Microsatellites are also known as simple sequence repeats (SSR), and they are typically composed of 1- 6 nucleotide repeat/161.Recent advances in rice genomics have now made ii possible lo identify and map a number of genes through linkage to existing DNA markers. The ideal type of genetic marker should be highly polymorphic, show