Marker assisted selection in vegetable crops
Author: Leela Bhatt

Marker assisted selection in vegetable crops

Molecular marker-assisted selection (MAS) is an approach that has been developed to avoid the problems connected with conventional plant breeding changing the selection criteria from selection of phenotypes towards selection of genes, either directly or indirectly. molecular marker is dependent from its capability in revealing polymorphisms in the nucleotide sequence allowing discrimination between different molecular marker alleles. These polymorphisms are revealed by molecular techniques such as restriction fragment length polymorphisms (RFLP), amplified fragment length polymorphisms (AFLP), microsatellite or simple sequence length polymorphisms (SSR), random amplified polymorphic sequences (RAPD), cleavable amplified polymorphic sequences (CAPS), single strand conformation polymorphisms (SSCP), single nucleotide polymorphisms (SNPs) .

Marker Assisted Selection How It is useful in Vegetable Breeding:

• Selection of plant carrying genomic regions that are involved in the expression of traits of interest through molecular markers.

• Marker is a piece of genetic material that bears or produces distinctive feature.

• A marker is usually a mutant gene and can be either dominant or recessive.

• A marker must be polymorphic.

Application of Marker Assisted Selection in vegetable crops

• SCAR markers linked to Or ,a gene including beta -carotene accumulation in Chinese cabbage.

• Identification of an ISSR Marker for 2-propenyl glucosinolates content in brassica.

• QTL increasing soluble solids content has recently been introgressed in cultivated tomato from L. chmielewskii chromosome 1, generating a NIL with a 56-cM introgression (Frary et al., 2003).

• Testing specific traits where phenotypic evaluation not possible e,g. Disease resistance Black rot of a cauliflower and source of germplasm MGS2-3 ,Pua Kea ,BR-161,BR-207, Pusa subhra ,B. carinata,B,juncea,B.nigra.

The recent progress in the area of plant molecular biology and plant genomics have the potential to initiate a new Green Revolution.Marker assisted selection (MAS) has been advocated as a highly efficient breeding tool, wherein genetic marker(s) (especially DNA-based markers) tightly linked with the desired trait/gene(s)/QTLs are utilized for indirect selection for that trait in segregating/nonsegregating generations. The use of MAS can be justified when it replaces more expensive or tedious assays, or results in increased precision in the identification of the desired genotypes. different approaches are improving the strategies on which MAS rely on, an increased complementarity between molecular technologies and conventional breeding is expected in the near future for a more efficient improvement of the crop plants.

References:

Fraray A,Doganlar S,Frampton A,Fuiton T, Uhlig J,Ytes H and Tanksley S(2003) fine mapping of quantative traits loci foe improved fruit characteristic from lycopersicon chmielewskii Chromosome 1.Genome 46:235-245

About Author / Additional Info:
I am currently pursuing Ph.D. in Horticulture (Vegetable Science) from GBPAU&T Pantnagar