Rht14 and Rht18 dwarfing genes

Recently the scientists at Pune based Agharkar Research Institute (ARI) have mapped two alternative dwarfing genes Rht14 and Rht18 in wheat.

About the dwarfing genes

• These genes are associated with better seedling vigour and longer coleoptiles (sheath protecting the young shoot tip).
• They have mapped the dwarfing genes on chromosome 6A in durum wheat, and DNA-based markers were developed for a better selection of these genes in wheat breeding lines.
• The DNA-based markers will help wheat breeders to precisely select wheat lines carrying these alternative dwarfing genes from a massive pool of wheat breeding lines. These DNA based markers are being used at ARI for marker-assisted transfer of these genes in Indian wheat varieties.

Benefits

• It helps in controlling pollution because in India, close to twenty-three million tonnes of leftover rice residues are annually burnt by farmers to get rid of the straw and prepare their fields for sowing wheat.
• The dry environments pose a challenge for the germination of wheat varieties with short coleoptile.

Research work

• ARI scientists have mapped ‘dwarf genes’ on chromosome 6A in durum wheat grown in arid regions. A good quality variety of wheat was developed using the dwarf gene based on the ‘deoxyribo nucleic acid’ based marker method.
• DNA based marker techniques will help wheat breeders to select the wheat variety that is the carrier of the ‘alternative dwarf gene’.
• Scientists are trying to transfer these genes to Indian wheat varieties using DNA based markers.

Features of new wheat variety

• Wheat variety prepared on the basis of transfer of genes will be suitable for sowing in rice residues and dry soil.
• Producing the developed wheat variety using these alternative dwarf genes will not require burning of rice crop residue.
• It is worth noting here that the residue of rice is burnt by farmers before sowing the wheat crop, which is a major cause of pollution in Delhi National Capital Region.
• Sowing of these wheat seeds can be done to a greater depth so that this crop can use residual moisture even in dry soil.

Why was there a need for research

• Currently only semi-dwarf wheat varieties are available. These varieties of wheat were produced during the Green Revolution.
• These semi-dwarf wheat varieties have Rht1 allele (variant variant of a given gene), which gives maximum yield only in high fertility and irrigated lands.
• The coleoptile potential (protection of newcomers from weeds) is low in these crops. For this reason, these semi-dwarf varieties of wheat are not more suited to deep sowing conditions in dry environments.

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