Zhang Jiashi attaches great importance to some key scientific research projects that do not have a large degree of leapfrogging. Pen × fun × Pavilion www. ｂｉｑｕｇｅ。 info Nature.2 After all, it's not impossible to do. It's just that for him, he also knows that with the current level of science and technology, it will be a long time to achieve accurate results in this regard, and it may even be impossible to get the expected results.

After all, even in the cross-breeding of wheat, millet and other crops, which has already been invested in for a long time, it can be said that there has been no breakthrough exhibition, which can be said to be a normal thing.

As far as the facts are concerned, even when the later generations still have a certain advantage over the current level of science and technology, the research process of hybrid rice is also tortuous and has not achieved corresponding results for a long time.

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In later generations, hybrid rice was not first advocated by the Chinese.

In the history of hybrid rice, its basic ideas and techniques, as well as the realization of the second success, were completed by the Americans in Indonesia, and henr?beache11 is also known as the father of hybrid rice by some in the academic community, for which he won the World Food Prize in 1996.

In fact, the title of the father of hybrid rice is not unavoidable, but in terms of the exact results in this regard, henr?beache11 makes people sigh helplessly.

The original hybrid rice concept was flawed, and the technology was not widely used around the world.

In Japan at that time, some scientists proposed the three-line breeding method to cultivate hybrid rice, although after many years of hard work, the Japanese found wild male sterile strains, but the effect was not very good; in addition, a series of new rice breeding methods were proposed, but in the end due to various reasons could not complete the industrialization of hybrid rice.

Later, as the father of "real hybrid rice", Academician Yuan Longping made a research process in this regard.

In 196o, Yuan Longping learned from some journals that hybrid sorghum, hybrid corn, seedless watermelon, etc., have been widely used in domestic and foreign production. As a result, Yuan Longping jumped out of the circle of asexual hybridization theory and began to conduct sexual hybridization experiments on rice.

In July 196o, he found a unique rice plant in the experimental field of the conventional varieties of early rice. In the spring of the following year, he sowed the seeds of this variant in the experimental field, and the results proved that the rice plant that "stood out from the crowd" last year was an authentic "natural hybrid rice". Yuan Longping broke through the shackles of the traditional concept that rice is a self-pollinating plant without heterosis from practice and reasoning, and immediately turned his energy to the new topic of cultivating artificial hybrid rice.

Since 1964, when the current "natural male sterile strain" was born, Yuan Longping and his assistants spent 6 years, successively using more than 1ooo varieties and making more than 3ooo hybrid combinations, but still did not cultivate an sterile line with a sterility rate and sterility of 1oo%. Yuan Longping summed up the lessons learned in the past six years, and based on the sterility phenomenon he observed, he realized that it was necessary to jump out of the small circle of cultivated rice, re-select the parental materials, and put forward a new idea of using "distant wild rice and cultivated rice hybridization".

Under the guidance of this ideology, Yuan Longping led his assistant Li Bihu to present a male flower abortion plant in the ordinary wild rice community on Hainan Island on the 23rd, and used the square dwarf, Jingyin 66 and other varieties to measure the crossing, and now it has the ability to maintain the wild sterile plant, which opens a breakthrough for the cultivation of rice sterile lines and the subsequent "three lines" matching, and brings a new turning point to the research of hybrid rice.

In the 70s, China listed hybrid rice as a key scientific research project.

In 1972, the Ministry of Agriculture listed hybrid rice as a key scientific research project in China, forming a China-wide cooperation network for tackling key problems.

In 1973, on the basis of breaking through the "sterile line" and "maintenance line", the majority of scientific and technological personnel selected more than 1ooo varieties for cross-testing and screening, and found more than 1ooo varieties with recovery ability. Zhang Xiancheng and Yuan Longping took the lead in finding a group of "restorer lines" with strong advantages, large pollen volume and recovery degree of more than 9o% represented by IR24.

In January, Yuan Longping presented a paper entitled "Progress in the Breeding of Three Lines Using Wild Defeat", officially announcing the success of the "three lines" of China's indica hybrid rice. This is a major breakthrough in rice breeding in China. Subsequently, he and his colleagues successively conquered the "dominance barrier" and "seed production barrier" of hybrids, paving the way for the utilization of heterosis in rice.

China's hybrid rice technology has been developed by leaps and bounds in the 9o years of the last century:

In 1986, Yuan Longping proposed in his paper "Breeding Strategy of Hybrid Rice" that the breeding of hybrid rice should be divided into three stages from the selection method, that is, the breeding procedure is developing in the direction of increasing efficiency from complex to simple, and from the utilization of heterosis level, it is divided into three development stages: the utilization of heterosis between varieties, subspecies and distant heterosis, that is, the utilization of heterosis is developing in the direction of getting stronger and stronger. According to this assumption, each new stage of hybrid rice is a new breakthrough, which will push rice yield to a higher level.

In August 1995, Yuan Longping announced that China's nine-year research on two-line hybrid rice had made a breakthrough and could be popularized on a large scale in production.

In August 1998, Yuan Longping proposed the research topic of selective hybrid rice. The government allocated 1ooo yuan to support it. Yuan Longping was deeply encouraged by this.

At the Sanya Farm Base in Hainan, Yuan Longping led a collaborative research army with the participation of more than 10 member units of China's provinces and regions to overcome the difficulties of two-line hybrid rice. After nearly a year of hard work, the grade hybrid rice has been successfully planted in a small area, with a yield of 8oo kg per mu, and has been successfully introduced in Southwest Agricultural University and other places.

At present, grade hybrid rice is moving towards large-scale trial planting.

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From the research process of hybrid rice by Academician Yuan Longping, even if it began in 1972 and received corresponding support from the state, it was finally around 1995 that a key breakthrough was made, and then it entered the foundation of formal planting.

And if we calculate the corresponding time, from 196o to 1995, almost a full 35 years of time, as well as incalculable human and material support, finally made a breakthrough in this regard......

Well, Zhang Jiashi really couldn't imagine that his persistence in this aspect in the Qin Empire would eventually become a luxury in his lifetime......

Zhang Jiashi can only say that only God knows about this matter.

But even so, Zhang Jiashi's determination to cross-breed crops such as wheat and millet will not change. Because there is no doubt that the advantages of hybrid rice and hybrid wheat in later generations made Zhang Jiashi have to strengthen his determination in this regard.

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In terms of the cultivation research of hybrid rice, hybrid rice is produced by the crossing of different rice varieties with each other, and rice is a self-pollinating crop, which is not conducive to the preparation of hybrid seeds.

To carry out the crossbreeding of two different rice varieties, the stamens of one variety must be artificially emasculated or killed, and then the pollen of the stamens of the other variety should be transferred to the emasculated variety, so that there will be no false hybrid rice with self-pollination of the emasculated variety.

However, if technicians manually pollinate tens of thousands of rice flowers, it is a huge amount of work, and it is not possible to solve the problem of producing a large number of seeds. Therefore, research has bred a kind of rice as a female parent, which has a special personality, its stamens are thin and degenerate, and the anthers are shriveled and deformed. You can't fertilize and produce seeds on your own pollen.

In this regard, Zhang Jiashi can only say hehe, because at present, the lack of corresponding personnel with advanced computing methods is more to repeat such steps in the past few years, and then gradually observe the corresponding results.

It can be said that this is a very inefficient practice......

Zhang Jiashi is naturally very aware of the shortcomings in this regard, but under the premise of sufficiently advanced scientific means, this is a more feasible way.

In the later generations, in order not to cut off the offspring of the mother, it is necessary to find two objects for it, and the characteristics of these two objects are different:

The first object resembles the female parent in appearance, but has sound pollen and a stigma, and when its pollen is given to the female parent, it is a daughter who is produced. It looks exactly like its mother, and it is also the female parent with thin and degraded stamens, shriveled and deformed anthers, and no fertility;

The other object is very different from the female parent in appearance, generally taller than the female parent, and also has sound pollen and a stigma, and after giving the female parent its pollen, it produces a son, who is stronger than both father and mother.

This is the hybrid rice that technicians need, a female parent and its two objects, people according to their different characteristics, respectively, three names: the female parent is called sterile line, two objects, one is called the maintenance line, the other is called the recovery line, referred to as the "three lines".

With the "three lines" matching, the technicians know how to prepare hybrid rice in production: the production to plant a breeding field and a seed field, the breeding field planting sterile line and the maintenance line, when they are all flowering, the maintenance line pollen is transmitted to the sterile line with the help of the wind, the sterile line gets normal pollen and fruit, and the offspring produced are still sterile lines, so as to achieve the purpose of breeding sterile lines.

Technicians can reproduce the sterile line seeds, keep a part of the next year to continue to reproduce, the other part of the same restorer line seeds, when the sterile line and the restorer line are flowering, the pollen of the restorer line is transmitted to the sterile line, and the offspring produced by the sterile line is to provide hybrid rice seeds for field planting. Since both the maintainer and restorer lines themselves have normal stamens and are self-pollinating, the seeds produced by each are still the offspring of the maintainer and restorer lines.

In fact, in the current Qin Empire, there is still a big problem in this aspect of research, that is, the survival guarantee of the plant itself.

In later generations, many times more advanced pesticides or fertilizers are more likely to have a favorable basic premise for the survival of the corresponding plants under the influence of this aspect. But in the current Qin Empire, it is very difficult to do this. It can even be said that all the resources that Zhang Jiashi can think of in this regard are basically invested in it.

But in this respect, the "welfare" of the crops of the Qin Empire is simply incomparable with that of later generations.

Under this influence, Zhang Jiashi is well aware that the survival rate of the experimental plants is low, which will also affect the final performance in many ways.

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In later generations, hybrid rice had two subspecies, indica and japonica.

Theoretically, the yield of interspecific hybrid rice can be increased by more than 3o% compared with interspecies hybrid rice.

At present, the main problem of using the heterosis of subspecies has been basically solved, and the newly bred interspecific hybrid rice has many large grains and excellent quality, and the yield of the newly bred inter-species hybrid rice is more than 2o% higher than that of the existing inter-variety hybrid rice in the production test and demonstration.

But for Zhang Jiashi, he is very interested in the existence of these two subspecies, but this thing is probably not something that can be achieved by thinking about it, because this subspecies was excavated after the emergence of hybrid rice. That is to say, before the emergence of hybrid rice, Zhang Jiashi had little hope for this subspecies of hybrid rice.

The Qin Empire was already growing rice along the Yangtze River valley for now, but Zhang Jiashi focused more on hybrid wheat.

Later generations also have some experience in hybrid wheat technology, but relatively speaking, Zhang Jiashi can also be said to be blind in this regard......

According to the experience of later generations, when wheat blooms, the scale cells absorb water and expand rapidly, causing the inner and outer wings to open. The opening angle is 2o-3o°.

The size of the opening angle varies depending on the species and climatic conditions. When the weather is sunny and the water is sufficient, the angle can reach 4o°, and in drought conditions, it can be as small as 1o°, and the filaments elongate quickly during flowering to push out the anthers.

The average time for a flower to bloom is 15~2o minutes, which varies depending on the variety and climatic conditions. Soon after the inner and outer flowers open, as the filaments elongate, the anthers begin to break, and the pollen falls on its stigma, and the rest of the pollen is scattered in the air by the wind.

The flowering order of wheat is that the ears on the main stem open first, the ears on the tillers open later, in the case of one ear, the middle spikelet opens first, the upper and lower spikelets open later, and in the case of one spikelet, the flowers at the base bloom first, and the flowers on the upper part bloom later. It takes about 2~3 days for an ear of wheat from flowering to finishing, and 3~8 days for a few ears. The flowering period is shortened in dry weather, and can be extended in wet weather.

The pollination method of hybrid wheat, wheat is a self-pollinating crop, but there is a certain natural hybridization rate, and its natural hybridization rate is less than 1%. The hybridization rate varies with temperature and variety. The most suitable temperature for wheat flowering is 18-2oC, and the lowest temperature is 9-11C.

If there is high temperature or drought during flowering, the natural hybridization rate is prone to increase. Because under high temperature and drought conditions, pollen is easy to lose vitality, and the fertilization ability of the stigma can often be maintained for a period of time, and the stigma life can be maintained for about 7 days under normal conditions, but the seed setting rate will decrease significantly after 3-4 days. Once the temperature drops or the drought subsides, it can accept foreign pollen and produce natural hybridization.

Some wheat varieties have larger flakes at flowering and have a longer opening time, which increases the chance of natural hybridization. After 1-2 hours after pollination, the pollen grains begin to germinate, and fertilization is completed after about 4o hours.

If Zhang Jiashi knew the above records, he would probably cry and faint next to the pit of Maokeng:

"I know how come it seems like there hasn't been any movement in a few years?"