Pakistan, Aug. 16 -- Seed is the smallest unit of agriculture, yet no other input carries a comparable weight in determining the fortunes of a harvest. Encoded within a single grain is the ceiling of every yield that will follow it: resistance to drought and disease, tolerance of a shifting climate, and ultimately the food security of nations. It is this deceptively modest input that has become the new frontier of geo-economic competition, as the world's leading agricultural powers race to secure genetic advantage over the crops that feed their populations. Certified, high-quality seed alone has been shown to lift crop productivity by twenty to thirty per cent - a margin no fertiliser or irrigation scheme can match on its own. Pakistan's ...