The relationship between seed weight and crop yield
The evolution trend of wheat yield traits since the founding of the People’s Republic of China: the increase in grain weight was the largest, from 29.6 g in the 1950s to 42.06 g in the 1980s, an increase of 41.66%. By the 1990s, the wheat grain weight increased to around 50 g. . There is little change in the biomass of contemporary wheat varieties, mainly due to the significant increase in grain weight and the simultaneous increase in the harvest index, resulting in an increase in yield. The same is true for rice. Studies have shown that for every 1 g increase in 1000-grain weight, 400.1 kg/hm2 can be increased. The measurement of seeds' grain weight requires the use of an electronic automatic counting instrument (seed particle counting machine) to perform mistakes in the process of reducing the number of artificial grains.
Through the research and demonstration of scientists, the yield of rice is directly composed of the three yield factors of panicle number, grain number and grain weight. Different periods and different ecological conditions should have different emphasis on yield factors. Before the promotion of hybrid rice, most of the conventional varieties had high stem pods and fewer panicles. Increasing the number of panicles was the main way to increase yield. After the promotion of hybrid rice, the rice yield has been greatly improved because of its superiority of strong tillering ability and effective panicle. With the increase of fertilization level, the effect of increasing the number of panicles and increasing yield is becoming smaller and smaller. In recent years, super high yield breeding has placed more emphasis on the increase of grain number. However, with the development of rice varieties with large panicles, based on the stabilization of a certain number of panicles, increasing the grain weight should be the focus of rice breeding strategies for super-high yield. For the large panicle type (combination), the number of grains per panicle is still a favorable factor for the increase of yield, but when the number of panicles per panicle reaches a certain amount, the increase in panicles per plant and the increase of 1000-grain weight are even more important for obtaining rice super-high yield. important. Both of these increases mean an increase in storage capacity, and must be based on good plant morphology and physiological functions as a prerequisite to ensure a higher seed setting rate and fullness.
The following are the 1000-grain weights of several conventional rice grains: 1,000-grain rice grains, 18-34 grams, 29400-55,000 grains per kilogram. The grain weight of japonica rice ranges from 25-321 grams to 31200-40,000 grains per kilogram. The grain weight of japonica rice ranges from 18-25 grams to 40000-55000 grains per kilogram. In the process of measuring 1000-grain weight, balance and electronic automatic particle counting instrument (seed particle counting instrument) are indispensable. Although the seed counting instrument changes the number of pots according to the size of the seed particles in the measurement process, the error is relatively small at the time of measurement, and there is no damage at the same time.
Cold Drawn Smls Steel Pipe
The cold working methods of steel pipes mainly include cold drawing and cold rolling. The raw materials of cold-rolled steel pipes can be hot-rolled seamless steel pipes or Welded Pipes. The common characteristics of the cold working method of steel pipes are high dimensional accuracy and good surface roughness. It can produce very thin (up to 0.05~0.01mm) thin-walled tubes and very thin (up to 0.3~0.1 mm in diameter) capillaries.
Seamless Steel Pipe is a kind of pipe with hollow section, which is widely used to transport fluids, such as oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, steel pipe is light in weight when its bending and torsional strength is the same. It is a kind of economic Section Steel, which is widely used in pipeline engineering.
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