alternative-dwarfing-genes-in-wheat-can-eliminate-rice-crop-residue-burning-summary

Context: Scientists have mapped two alternative dwarfing genes in wheat, that can help in eliminating rice crop residue burning.

More on the news:

  • 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. 
  • Scientists have mapped the dwarfing genes on chromosome 6A in durum wheat and developed DNA-based markers for a better selection of these genes in wheat breeding lines.
  • These genes are associated with better seedling vigour and longer coleoptiles (sheath protecting the young shoot tip).
  • The research was published in The Crop Journal and Molecular Breeding. 

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
  • Burning of leftover rice crop residue 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, dry environments pose a challenge for the germination of wheat varieties with short coleoptile.

Significance: 

  • The presently available semi-dwarf wheat varieties, explored during the Green Revolution, carry conventional Rht1 dwarfing alleles (variant form of a given gene) and produce optimum yields under high-fertility irrigated conditions. 
  • However, they are not well adapted for deeper sowing conditions in dry environments due to shorter coleoptiles, and low early vigor often results in reduced seedling emergence. 
  • Moreover, crop stands of Rht1 wheat also remain poor where previous crop residues pose a barrier for seedling emergence due to the short coleoptiles.
  • These can, therefore, be utilized as an alternative dwarfing gene to Rht1 for deep sowing conditions or in fields with retained stubble.

Advantages of new findings:

  • This 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 can be used for marker-assisted transfer of these genes in Indian wheat varieties, so as to make them suitable for sowing under rice stubble-retained conditions and dry environments. 
  • Wheat lines with these alternative dwarfing genes, apart from reducing crop residue burning, can allow deeper sowing of wheat seeds to avail advantage of residual moisture in the soil under dry environments.
  • The improved wheat lines will help reduce stubble burning incidences under the rice-wheat cropping system.  

Also, only two dwarfing alleles of Rht1 are predominant in Indian wheat varieties. Therefore, there is a need to diversify the genetic base of dwarfing genes considering diverse wheat growing zones in India.

Stubble Burning

It is a common practice followed by farmers to prepare fields for sowing of wheat (in November) as there is little time left between the harvesting of paddy and sowing of wheat. 

Impact: 

  • Results in emission of harmful gases such carbon dioxide, sulphur dioxide, nitrogen dioxide along with particulate matter.
  • It adversely affects the environment and public health. For example, one of the associated reasons for clouds of smog choking NCR of Delhi is stubble burning in neighbouring states of Punjab,Rajasthan,Haryana,UP.

Why do farmers opt for stubble burning?

  1. Have no alternatives for utilising crop residue/stubble effectively.
  2. Farmers are ill-equipped: To deal with waste because they cannot afford the new technology that is available to handle the waste material.
  3. Cost cutting: Because of  less income due to crop damage, farmers are likely to be inclined to burn residue to cut costs and not spend on scientific ways of stubble management.
  4. It quickly clears the field and kills weeds, slugs and other pests including those resistant to herbicide.
  5. Stubble burning can also reduce nitrogen tie-up.

Alternative solutions:

  1. Wealth from the stubble: There is great potential for making investments in paddy straw-based power plants which can help avoid stubble burning to a large extent and also create employment opportunities.
  2. Improve soil productivity: Adding crop residues in the soil can improve soil moisture and help activate the growth of soil microorganisms for better plant growth.
  3. Generation of organic manure: The removed residues can be converted into enriched organic manure through composting.
  4. Industrial use: Like extraction of yeast protein can be explored through scientific research.

Gauthans:

  • Chhattisgarh has already undertaken an innovative experiment by setting up gauthans.
  • A gauthan is a dedicated five-acre plot, held in common by each village, where all the unused parali (stubble) is collected through parali daan (people’s donations).
  • It is then converted into organic fertiliser by rural youth.
  • The state government supports the transportation of parali from the farm to the nearest gauthan.
  • The state has successfully developed 2,000 gauthans under this model.

 Supreme Court’s observations:

  1. Incentives for those not burning the stubble and disincentives for those who continue the practice.
  2. The existing Minimum Support Price (MSP) Scheme must be so interpreted as to enable the States concerned to wholly or partly deny the benefit of MSP to those who continue to burn the crop residue.

Source: https://pib.gov.in/PressReleasePage.aspx?PRID=1625713

Image Source: HT