Context: Recently, scientists at Pune based Agharkar Research Institute (ARI), have mapped two alternative dwarfing genes Rht14 and Rht18 in wheat that can help in reducing rice crop residue burning i.e. stubble burning.
Background

• 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, which is the next crop, resulting in air pollution. 
• Also, dry environments pose a challenge for the germination of wheat varieties with short coleoptile.
• To overcome these problems, Scientists at Pune based Agharkar Research Institute (ARI), an autonomous institute of the Department of Science and Technology, have mapped two alternative dwarfing genes Rht14 and Rht18 in wheat.

Key Points

• Rht14 and Rht18 genes are associated with better seedling vigour and longer coleoptiles (sheath protecting the young shoot tip).
• The researchers 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.
• The dwarfing genes Rht14 and Rht18 in wheat conferred a plant height reduction comparable to the Rht1 alleles while retaining early vigour in wheat seedlings, but do not affect coleoptile length and seedling shoot length.
• The improved wheat lines which are being developed at ARI will help reducing stubble burning incidences under the rice-wheat cropping system.
• They will also allow deeper sowing of wheat seeds to avail advantage of residual moisture in the soil, therefore, saving valuable water resources and reduce the cost of cultivation to farmers.

Significance

• The wheat lines with these alternative dwarfing genes will help in reducing stubble burning incidences under the rice-wheat cropping system.
• The improved lines will make it possible for farmers to sow wheat under rice stubble-retained conditions.
• It means farmers won't have to resort to stubble burning for preparing their ground for the sowing of the next crop.
• Burning of leftover rice crop residue (stubble burning) has serious implications for the environment, soil, and human health. Therefore, there is a need to include alternative dwarfing genes in wheat improvement programs.
• Also, only two dwarfing alleles of Rht1 are predominant in Indian wheat varieties; therefore, it is required to diversify the genetic base of dwarfing genes considering diverse wheat growing zones in India.
• Also there is a need for rigorous Research and Development related to the gene varieties of crops so that productivity of the crops can be enhanced.