Reasons for Low Germination Rate of Rice Seeds and Preventive Measures

Ansheng Yang (Hanjiang District Seed Company, Putian City)

The seed germination rate is determined by the vitality of the seed's embryo and the storage of sufficient endosperm. Highly viable embryos with sufficient endosperm nutrition ensure that the seed germination rate is high; otherwise it is low. According to my many years of practice, I would like to talk about the causes of the low germination rate of rice seeds and preventive measures.

1 The reasons that affect the low germination rate of rice seeds

1.1 High temperature and high humidity conditions cause sprouting on the ear. In general, the higher the maturity of seeds, the higher the germination rate (with a few exceptions). It takes about 25 days for a full and abundant seed to mature from pollination. The minimum temperature for germination of rice seeds is 10-15°C, and the optimum temperature is 30-35°C. Since seeds on the same plant or even on the same ear differ in flowering and maturation at the site of planting, all fully matured seeds are more likely to germinate when they are dormant, and those that are not fully mature dormancy are often not easy to germinate. The rainfall in various areas of the Yangtze River basin is very high. The temperature of mature early rice is very high, so it is suitable for seed germination. When the late rice matures, it is a season when the temperature in the late autumn and early winter is relatively high. The weather in the rainy season will sprout in the field. Some species, especially those that are susceptible to lodging, are susceptible to sprouting or sprouting on the ear.

1.2 The seeds were harvested too early and too late. Since rice seeds do not have a significant period of dormancy, prematurely harvested seeds are not fully mature, and if they are not fully dried, vigorous respiration is still required and nutrients are consumed, resulting in a significant reduction in germination rate. When the seeds are harvested too late, on the one hand, in the event of high temperature and high humidity in the field, it is easy for the seeds to germinate and germinate, resulting in a lower germination rate; on the other hand, the seed moisture is high, and the seeds do not age quickly, the germination rate is reduced, and the harvest rate is reduced. Too late to miss the best drying period, mildew during the drying period, will also affect the germination rate.

l. 3 The seed is not harvested in time and it is not timely. Breeding units have a large number of breeds, due to restrictions on the conditions of the drying yard, warehouses, etc., and lack of necessary drying equipment. In addition, southern rice harvest season has more rain and the seasons are tight. After the seeds are harvested, they are not promptly spread or turned into the sun. Libraries, at this time, generally have a high seed moisture content, which leads to steaming of the stuffing cultivars, and the husk is black and moldy. In addition, the high-temperature drying in the cement texture field without turning in time will also seriously affect the seed germination rate.

1.4 mechanical damage. Some species have thin seed husks or cracked seeds. These cultivars are easily husked into brown rice after harvesting and processing. Due to the removal of the protective layer, these brown rice are generally difficult to germinate, even if they can germinate it is difficult to become seedlings (easily rotted in Putian).

1.5 seeds have high moisture content when they are put into storage. Due to the lack of strict control, the seeds were not sun dried or stored before storage, and the seeds were damp during the storage process, so that the moisture content of the seeds was significantly higher than the quality standard (13.5% in early rice and 14.5% in late rice). At this moment, the seeds breathe very vigorously. On the one hand, the water vapor is released. After the water vapor is released, it is absorbed again by the seeds to make the seeds more moist. On the other hand, the respiratory heat is released and accumulates in the seed pile, so that the temperature of the seeds gradually increases and the animals breathe. The role of strengthening, resulting in the emergence of local mildew, insects, fever, sweating, condensation and other phenomena, which is the main reason for reduced germination rate.

1.6 Impact of pests and diseases. If the pests are seriously harmed, the control measures are not timely, and the functional leaves or transport channels are damaged. If the corresponding functions are reduced or lost, the function of seed embryo development will be insufficient, the nutrient of the endosperm will be insufficient, and the fullness of the seeds will be insufficient. The power is low, even if it can germinate and become weak and sick, it is difficult to grow seedlings.

2 Countermeasures to increase the germination rate of rice seeds

2.1 Select good varieties and strictly control the sowing date. Eliminate species with high aging rates and try to select varieties that are not easy to germinate on the ear, resist lodging, and resist pests and diseases. In terms of cultivation and management, attention should be paid to the selection of pesticides to prevent and control pests; refer to local climatic data for timely sowing, and seek advantages and avoid disadvantages, and arrange the maturation of seed grouting in a relatively suitable and favorable ecological environment to ensure that the seeds are fully mature and the seed maturity is improved.

2.2 Control the amount of panicle fertilizer. Increasing the use of multiple panicle fertilizers will help increase grain weight, make the grain plump, and have a high germination rate. However, for varieties that are susceptible to cracking and shelling, the amount of panicle fertilizer should be appropriately controlled to prevent cracking of the husks and shelling into brown rice during threshing, sun drying, and selection processing.

2.3 Add drying equipment. In view of the fact that there is a lot of rain in the Yangtze River Basin, it is necessary to add necessary drying equipment to prevent it from happening.

2.4 timely harvest, dried. Generally, rice seeds should be harvested at the later stage of the yellow ripening stage. At this time, most of the plant leaves turn yellow, and only the upper part remains green. The seeds show the inherent color of the varieties. The contents of the seeds are like waxes, and the clam shells show the inherent colors of the original varieties. At this time, the dry matter accumulation of rice reached the maximum and the moisture was the lowest. At the same time, we must pay attention to listening to the local weather forecast, catch the bad weather to harvest, and dry in time. If the number of breeding is large and the area is relatively large, drying equipment should be used to prevent the accumulation of heat and seeds from the wet seeds and cause sprouting. On sunny days, pay attention to the temperature of the drying field, turn over the sun in time, and directly affect the vitality of the seeds by overheating the solar protection field.

2.5 seed selection, safe storage. The moisture content must be determined before the seeds are put into the storage, and then the selected processing is carried out to remove the grains, damaged grains, impurities and part of the smut particles to ensure that the seeds have stronger vitality and higher potential germination rate. Closed fumigation should be carried out in time after storage, and the source of pests and diseases should be completely removed.

2.6 Intensify storage management. The storage and storage environment of rice seeds has a direct impact on its germination rate. Maintaining a low-temperature, dry, pest-free, and rodent-free environment is the overall principle of seed storage. Therefore, during seed storage, the seed moisture content is controlled within 13%, the seed temperature is within 20°C, and the seed temperature, moisture, germination rate, and insect pests are periodically checked. Unusual conditions are found and prompt remedial measures are taken to ensure seed safety.

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