Understanding GM mustard: what is it, and how has it been achieved?

Last Updated28/10/2022

Recently, GEAC recommended “environmental release” of hybrid mustard DMH-11 for seed production and conduct of field demonstration studies w.r.t. its effects on honey bees & other pollinating in sects.

Involves crossing 2 genetically dissimilar plant varieties that can even be from the same species.
First-generation (F1) offspring tend to have higher yields than what either parent can individually give.

In mustard, its flowers have both female (pistil) and male (stamen) reproductive organs, making the plants largely self-pollinating.
The eggs of one plant cannot be fertilised by the pollen grains from another.
Limits the scope for developing hybrids where this can be done through simple emasculation/ physical removal of anthers.
Barnase-barstar GM technology
Used to develop DMH-11 by crossing an Indian mustard variety ‘Varuna’ ( barnase) with East European ‘Early Heera-2’ mutant (barstar).
Showed an average 28% yield increase over Varuna in contained field trials carried out by the ICAR.

A body responsible for appraisal of proposals relating to the “release” of GM organisms and products (ordinarily considered hazardous) into the environment.
Gave green signal for commercial cultivation by farmers with production of seed material being the first step.
Also recommended the environmental release of DMH-11’s parental lines for them to be used to develop new hybrids.
Could give even higher yields than DHM-11.
Mustard varieties in India have a narrow genetic base.
Barnase-barstar system enables breeding of hybrids from a wider range of mustards.

Presence of a third ‘bar’ gene
Makes GM mustard plants tolerant to the spraying of glufosinate ammonium, a chemical used for killing weeds.
Will cause displacement of manual labour engaged in weeding by promoting use of chemical herbicides.
DMH-11 developers, however, say that bar is only a marker gene.
Threatening the population of honey bees.
Mustard flowers are a source of nectar for honey bees and many other pollinator insects.
GEAC recommended that the applicant (CGMCP) should conduct “field demonstration studies w.r.t. the effect on honey bees and other pollinators.