Practice question

Despite expanding gene pools, introduction carries inadvertent adverse consequences representing demerits. Along with desired cultivars, weed seeds such as Phalaris minor, Avena fatua, Parthenium hysterophorus introduced with PL-480 wheat shipments from USA in 1960s became dominant weeds competing for light, nutrients and space, producing allelochemicals like parthenin suppressing crop growth. Pathogens such as coffee rust, potato late blight and diseases like downy mildew also hitchhike as dormant mycelium. Invasive ornamentals outcompete native flora reducing biodiversity index. Economic costs escalate due to increased herbicide use, mechanical weeding and yield losses estimated in billions. Hence strict sampling, seed cleaning, and certification protocols mandatory to minimize ecological disruption accompanying germplasm exchange programs. This understanding supports competitive exam preparation for NEET, GATE and CSIR NET concepts linking genotype with phenotype through molecular pathways involving transcription factors, hormones and metabolic enzymes that regulate development, adaptation and reproductive biology in applied breeding programs. Additional insights from genomic studies reveal QTL clusters, epigenetic modifications and protein interactions that influence trait expression under varied agro-climatic conditions and management.