What is hybrid rice?

With the application and popularization of hybrid rice, the yield per unit area has been increased and the seed consumption has been reduced. So what is hybrid rice?

What is hybrid rice?

Hybrid rice refers to the selection of two rice varieties that have certain genetic differences and their excellent characters can complement each other to cross to produce the first generation of hybrids with heterosis, which is called hybrid rice. Heterosis is a common phenomenon in biology. Using heterosis to improve crop yield and quality is one of the main achievements of modern agricultural science. The first successful rice cross in the world was completed by an American HenryBeachell in Indonesia in 1963 and was awarded the World Food Prize in 1996.

1. Study on two-line hybrid rice.

Compared with three-line hybrid rice, the advantages of two-line hybrid rice are free combination, simplified breeding procedure, shortened breeding cycle and diversification of male sterile lines, while the disadvantages are that the reproduction of male sterile lines and combined seed production are limited by time and space. After the study of two-line hybrid rice was included in the National "863" Plan and Yuan Longping published "Strategic ideas for Hybrid Rice breeding" in 1987, the breeding of two-line hybrid rice was widely carried out in the whole country. In 1988, the first two-line japonica hybrid rice combination was N5047S/R9-1. By the year 2000, there were only 27 two-line hybrid rice varieties approved by provincial and prefectural and municipal levels, with a cumulative extension area of about 3 million hectares, which is a period of slow development. After the four two-line hybrid rice varieties represented by Liangyoupeijiu were approved by the state in 2001, the two-line hybrid rice entered a period of rapid development. By 2015, there were 135 two-line hybrid rice varieties approved by the state and 816 (times) of two-line hybrid rice varieties approved at the provincial level (http://www.ricedata.cn/variety/)). In 1996, the extension area was 180500 hectares, accounting for 0.92 percent of the planting area of hybrid rice. by 2013, the extension area had grown to 5.4404 million hectares, accounting for 33.59 percent of the planting area of hybrid rice. in the past 18 years, the area of two-line hybrid rice has increased 30-fold. Among them, the combination with the largest extension area is Liangyou Peijiu (Peiai 64S/9311), with a cumulative extension area of more than 8 million hectares. At present, two-line hybrid rice is planted in 20 provinces and cities across the country, mainly indica two-line hybrid rice. Hunan, Hubei and Anhui provinces have an annual promotion area of more than 1 million hectares, including Anhui and Hubei. The area of two-line hybrid rice has exceeded that of three-line hybrid rice.

2. Cultivation techniques of hybrid rice

1. Land preparation

Production should be in strict accordance with the requirements of fine soil preparation, so that the border surface is smooth without weeds, smooth drainage and irrigation, no stagnant water. According to the width of the border, a ditch with a width of 0.6 m and a depth of 0.1 m was dug.

2. Timely early sowing

Reasonable arrangement of sowing date is the key measure to ensure the whole seedling and safe panicle of rice direct seeding cultivation.

3. Seed selection

The selection of improved varieties with high yield, disease resistance and high quality can increase the yield and economic benefits. Doing a good job of seed disinfection and germination can reduce the occurrence of diseases and insect pests.

4. Soaking seeds

Generally, it is better to sow seeds directly and raise seedlings by wetting after soaking seeds for 12 hours and 18 hours.

5. Sprouting

In the process of sprouting, proper temperature, proper moisture and timely ventilation should be mastered. The most suitable temperature for rice seed germination is 3035 ℃. It will cause "sprouting" when it exceeds 45 ℃, and more than 80% of the seeds can be sown after breaking their breasts.

6. Sparse sowing and even sowing

Direct seeding cultivation is to sow seeds directly into the field, the sowing rate of conventional rice seeds is 37.5kg/hm2, hybrid rice seeds 18.75kg/hm2, generally 15% to 20% more seeds than normal seedlings. Sowing seeds evenly, burying buds after sowing, gently stepping on boards to make grain buds into the soil, and doing a good job of preventing birds and rats from infestation.

The direct seeding cultivation technology of hybrid rice is a simplified cultivation method which omits the traditional process of raising rice seedlings, soaks and accelerates rice seeds directly into the field, manages them, and makes them grow into seedlings and tiller to maturity.