Explore key concepts about Plant Growth Regulators (PGR) and Plant Growth Promoters (PGP) used in cumin cultivation. Learn scientific principles behind boosting cumin yield and quality in modern agriculture.
Which plant growth regulator is most commonly used to promote uniform flowering in cumin crops?
Explanation: Gibberellic acid stimulates uniform flowering and stem elongation in cumin, improving yield consistency. Abscisic acid is involved in dormancy and stress response, not active promotion of flowering. Ethylene primarily induces fruit ripening and can cause premature senescence. 2,4-Dichlorophenoxyacetic acid is a synthetic auxin more often used as a herbicide than for regulated flowering in cumin.
How do plant growth-promoting rhizobacteria (PGPR) benefit cumin plants when applied to their root zone?
Explanation: PGPR, such as certain Bacillus and Rhizobium species, fix atmospheric nitrogen, enhance nutrient availability, and promote cumin plant growth. They do not directly kill pests; that is a role for biocontrol agents or pesticides. They generally improve, rather than increase, soil health and do not increase salinity. Inducing wilting is a negative effect and not associated with PGPR.
At which growth stage is foliar application of plant growth regulators like NAA (Naphthalene Acetic Acid) most effective in cumin cultivation?
Explanation: Applying PGRs at the flower initiation stage maximizes their effect on cumin yield and uniformity. At seedling emergence, plants are too immature for yield-related PGR benefits. Late maturity is too late for effective physiological changes, and after harvesting offers no benefit to the current crop.
Which of the following substances can act as a bio-stimulant (PGP) in cumin, improving growth and yield?
Explanation: Seaweed extract contains natural growth hormones and nutrients, widely used as a PGP to support cumin development. Charcoal dust and alum powder do not provide growth-promotion and table sugar, while an energy source, is not effective as a field-applied PGP.
What is a potential risk of over-applying synthetic plant growth regulators in cumin cultivation?
Explanation: Excessive PGR use can disrupt normal plant development, causing abnormal morphology and reducing yield. Immediate crop death is unlikely from typical over-application. PGRs do not cause pest resistance nor do they induce permanent soil infertility if used improperly.