The development of the chemical fertilizer industry, following from the work of von Liebig and early agricultural scientists such as Lawes and Gilbert, had a major impact on agricultural productivity. Railway and steamship lines expanded, opening up new markets. Improved methods of refrigeration and canning made possible the long-distance marketing of perishable agricultural products. An Austrian scientist and monk, Gregor Mendel discovered the basic principles of heredity through carefully controlled experiments in cross breeding. His work paved the way for improving crops through genetics.
Hybrids are the offspring of parents from different breeds, varieties or closely related species.
Hybrids are often superior in many ways to their parents - a phenomenon called hybrid vigour. Hybrid pigs have been bred that grow faster and have more lean meat than earlier breeds. He showed the role of microorganisms in fermentation, devised pasteurization as a way of stopping beer and milk from souring, popularizing sterilization and developed a form of vaccination. The combine harvester, which combined the cutting and threshing of grain crops, came into widespread use in the western United States. It reduced the amount of labour needed to harvest a field of wheat by more than 80 percent.