What are the factors that determine the growth period of rice varieties?

The growth period of rice varieties is mainly determined by the response of rice varieties to environmental temperature and sunshine length. Under normal cultivation conditions, the length of rice reproductive growth time did not change much, and the length of vegetative growth period varied greatly due to the maturity period of the cultivar. The "three sexes" of rice determine the length of the growth period of rice varieties.

Rice is planted from the northern rice area at high latitudes to the southern rice areas at low latitudes, and the growth period is generally shortened, especially in the early japonica in the northeast, the accumulated temperature required for the whole growth period is less, and it is sensitive to high temperatures. Rice is planted from the southern rice area at low latitude to the northern rice area at high latitude, and the growth period is prolonged, and the early rice introduction is easy to be successful, while the late rice may not be able to mature normally in the rice season, so the early maturing varieties must be selected as the introduction object. The introduction of rice areas with the same latitude and different altitudes, and the introduction of rice areas at low altitude to rice areas with high altitude prolonged the growth period, and the introduction of early-maturing varieties was more likely to be successful. On the contrary, the introduction of seeds from high altitude to low altitude rice area shortens the growth period, and it is easy to obtain stable yield and high yield by selecting late-maturing varieties.

The success rate of rice introduction between rice areas at the same latitude and altitude was relatively high.

The growth period of rice varieties is determined by the response factors of rice varieties to environmental temperature and the length of sunlight. The three sexes of rice determine the length of the growth period of rice varieties.

The "Three Sexes" of Rice Varieties The three sexes are the genetic characteristics of photosensitivity, temperature sensitivity, and basic vegetative growth. In different regions and different cultivation seasons, the length of the growth period of rice varieties (from sowing to heading) is basically determined by the comprehensive effect of the "three sexes" of the variety. Therefore, the three sexes of rice varieties are the essence that determines the length of the growth period and its changes.

The three sexes of rice are formed under the influence of climatic conditions and cultivation seasons, and for any specific variety, the three sexes are an interrelated whole.

1. Growth period of rice varieties The life cycle of rice includes two stages: vegetative growth and reproductive growth, and the beginning of the differentiation of young panicles is generally used as a sign of the beginning of reproductive growth. The vegetative growth stage is the growth of the vegetative body of rice, which is divided into the seedling stage and the tillering stage. In terms of production, it is divided into the seedling field stage and the large (original) field stage (from transplanting.

Rice is an annual herbaceous plant with the following main fertility characteristics:

1) Short daylight: During the growing season, the shorter the number of days and the earlier the flowering and fruiting. Therefore, when the sunshine hours increase and the heading maturity will be significantly delayed. On the contrary, the sunshine hours are reduced and the heading maturity is significantly improved, so we must pay attention to this characteristic when introducing seeds, and do not blindly introduce seeds and cause losses.

2) Thermophilicity: It has high temperature requirements in its life, and the minimum temperature of seed germination is 12-14, so we must choose an average temperature of more than 12 in breeding and cultivation to sow seeds, otherwise it will rot seedlings or not germinate.

3) Semi-aquatic: Although rice needs more water, not the more water, the better, and the rice will grow poorly and the yield will not be high if it has been flooded or lacking water throughout its life. Therefore, in the management of aquifers, the method of alternating dry and wet should generally be adopted to ensure growth and development.

<> rice is an important cereal widely cultivated in the Asian hot spot, with southern China as the main rice-producing area and northern China. So what are the stages of rice growth divided into several periods, and what is the rolling time?

The growth period of rice is about 90 days, which can be divided into four periods: seedling stage (about 35 days), transplanting stage (7-10 days), tillering stage (about 30 days), jointing stage (about 15 days); The reproductive growth stage of rice is about 70 days, including booting stage (about 15 days), heading stage (about 15 days), flower pollination stage (15-20 days), and grain filling stage (about 20 days).

The main factors that determine the sowing date of rice are ().

a.Seed purity.

b.Climatic conditions.

c.Cropping system.

d.Rockside characteristics of the variety.

Correct Answer: Climatic rough oak conditions; planting checks and balances; Breed characteristics.

Rice is a kind of herbaceous rice, and it is also the most important and longest-standing one of the rice genus as a grain. Native to China, rice has been cultivated in the Yangtze River basin of China 7,000 years ago.

Cultivated rice (oryzasativa) rice grows very fast, the longest is one year, the fastest is three to four months, and the growth period is about 130-140 days, which can be from germination, flowering, and fruiting to complete the process. It only takes two or three days for the seeds of rice to sprout and another three days for the sprouts to pull out the first leaves, so in areas with mild climates, three rice can be planted in a year. When farmers choose rice seeds, they often soak them in water, and the light and floating rice seeds are eliminated, and the remaining ones are cultivated into rice seedlings.

Generalized rice is different from upland rice; Narrow rice refers to light rice, which is different from seawater rice.

According to the type of rice, rice can be divided into indica and japonica rice, early rice and middle and late rice, glutinous rice and non-glutinous rice. There are other classifications, rice is generally cultivated in paddy fields, and soilless cultivation is water rice. Rice is generally not one meter tall, and about 2 meters is newly cultivated giant rice.

Chinese scientist Yuan Longping has made great contributions to the research of hybrid rice and is known as:"The father of hybrid rice"。The fruit of rice is rice, and the rice is called brown rice after removing the glume husk, and the brown rice can be obtained by grinding off the rice bran layer. Nearly half of the world's population feeds on rice.

In addition to being edible, rice can also be used as industrial raw materials for brewing and sugar, and rice husks and rice stalks can be used as feed. The main rice producing areas in China are mainly the Northeast region, the Yangtze River basin and the Pearl River basin. It is a direct cash crop.

It is also the staple food of one-third of the world's human race. It is also the main organic food of the people of the north. In September 2017, Yuan Longping announced a new achievement in the elimination of cadmium, a heavy metal, from rice.

The definition of the whole growth period refers to the sum of the number of days in the seedling stage and the honda stage of the rice transplanted with seedlings.

The whole growth period of early rice is less than 125 days.