What is the yield of crops?

What is the yield of crops? This seemingly simple problem has different understandings and connotations in different times. In the long-term development of agricultural production practice, breeders and farmers have experienced several important changes in their understanding of yield, from experimental field to field, from small environment to large environment, and from a certain year to different years.

All our crops today were originally transformed and evolved from wild "weeds" through the efforts of many generations, and the fruits of crops have evolved from dry and bitter "wild fruits" to today's large and delicious fruits. Therefore, starting from the traditional agriculture developed from intuition and experience, the size of crop fruit has been the most intuitive and core standard to measure yield for thousands of years, and large fruit and "big ear" have become the common pursuit of traditional breeders and agricultural producers. In the 1920s, American geneticists and breeders found that through hybridization and breeding, it was easy to increase the size of maize ears and enhance its ability to resist adversity, so cross breeding has become the mainstream idea of genetics and breeding. In an era when food is scarce, breeders, farmers and consumers must choose crop varieties with large fruit. Therefore, the cognition of traditional breeders is that large fruit is high yield.

With the development of modern agricultural technology, the widespread use of chemical fertilizer technology makes the nutritional demand of crops fully and balanced, and the development of pesticide technology greatly improves the ability of pest control. The development of cultivation technology reveals the inherent law of crop growth, and crops can withstand higher density planting. Breeders, genetic statisticians and farmers have found that the ear has encountered insurmountable bottlenecks in the process of increasing, and it is easier to get more yield through high-density planting. On the contrary, too large fruit can make crops unable to withstand high-density planting. Therefore, modern breeders regard increasing crop planting density as a more important breeding goal. Therefore, the cognition of modern breeders and farmers is that close planting is high yield.

In the production practice of continuous pursuit of high yield, due to the differences in climate, soil, cultivation conditions and planting techniques between years, especially in the case of increasing planting density, the varieties that show high yield in the ideal environment can not show stable high yield in the bad environment, on the contrary, the yield is not very prominent in the ideal environment. But the varieties with better resistance to adversity can show higher yield and stability in different years and different regions. Breeders begin to pay attention to selecting varieties with good adaptability and strong resistance to adversity, while eliminating those varieties with high yield but need to be spoiled. Therefore, breeders and farmers gradually realize in production practice that good resistance is high yield.

With the adjustment of the industrial structure of countries around the world, a large number of agricultural population has been transferred to urban industry and service industries, rural agricultural labor force is becoming less and less, and the aging of agricultural population is also more common. In such a situation, the implementation of mechanization in agricultural production has become inevitable. In this way, some varieties with short growth period, fast fruit dehydration and good lodging resistance have been popularized and popularized in agricultural production, because only the varieties with these characteristics can meet the needs of mechanized harvest. Although varieties with short growth periods of various crops have no advantage in yield, because they are suitable for mechanized operation, they can greatly reduce labor intensity, improve production efficiency, and bring higher benefits to farmers. therefore, such varieties are widely accepted and planted in a large area, while the traditional varieties with long growth period are phased out. After getting rid of the era of food shortage, agriculture, like other industries, is competing for social resources, and industrial social resources without economic benefits will not be favored. Therefore, how to achieve higher efficiency and income through the construction of industrialization is the key to the sustainable development of agricultural industry and the actual high yield. Therefore, in the era of industrialization, people's understanding of output is: efficiency is high yield.

Based on this law of industrial development, a profound change will take place in the direction of crop breeding in China, and breeding with the goal of high yield will be gradually replaced by breeding with the goal of efficiency. The innovation and selection of breeding materials, the design idea of combination and the formulation of promotion criteria, the evaluation of various characteristics and priority evaluation will be changed accordingly.