Molecular Markers and Marker-Assisted Selection in Rice

Abstract

Abstract:The status of rice as a model crop and the sequencing of the indica and japonica genomes have provided breeders with the necessary tools for marker assisted breeding. Simple Sequence Repeat (SSR) markers are easily available for any region of the genome, and candidate gene markers are being developed rapidly. The likely targets of MAS include yield and agronomic traits, cooking and nutritional quality, and resistances to abiotic and biotic stresses. MAS for gene pyramiding for disease and insect resistances is being widely used. For major genes and QTLs of larger effect, marker assisted backcrossing (MAB) is an effective method for developing improved versions of widely-grown "mega" varieties. Developing submergence tolerant mega varieties is a good example of how the MAB approach can result in significantly improved mega varieties within two to three years. The use of markers in more conventional breeding nurseries has been limited by cost, but is beginning to be applied for some traits like grain quality. Lower-cost marker methods combined with large-scale gene discovery will increase the use of MAS over the next decade.

Quantitative Trait Loci and Crop Performance under Abiotic Stress: Where Do We Stand?: Table I.

“…The systematic dissection of QTLs governing the naturally occurring variation relevant for crop yield and its sustainability will facilitate a more targeted and effective tailoring of cultivars with an improved performance under abiotic constraints (Baum et al, 2007;Dwivedi et al, 2007;Mackill, 2007;Xu and Crouch, 2008). Nonetheless, it is difficult to predict to what extent QTL-based MAS will affect breeding practices aimed at improving tolerance to abiotic stresses.…”

Assessment of Rice Sorts and Hybrids on the Salt Tolerance Using Laboratory Methods

“…Because markers are chained with the certain signs of interest they can be used as biotechnological instrument for transferring the value genes of rice tolerance to the salt stress without undesirable adhesion [18].…”

Genetic Diversity Studies on Selected Rice (Oryza sativa L.) Genotypes based on Gel Consistency and Alkali Digestion

“…They are popularly known in the determination of the genetic diversity, generating gene map for tagging traits of interest, germplasm conservation and crop improvement [13]. Microsatellites also known as simple sequence repeats (SSR) markers have been applied in various studies to study rice genetic diversity [14][15][16], marker assisted selection [17,18] and in mapping of the QTLs [19,20]. In Kenyan and Tanzanian rice genotypes SSRs have been used to study diversity studies gelatinization temperature and amylose content [15].…”