Breeding Technology of Broccoli

Broccoli is the main exporting vegetables of Zhejiang, and in the province the perennial planted area is about 10,000 hectares, but because of the high temperatures in July-September and typhoon activities, how to use the limited period to foster robust seedlings is the key to cultivate broccoli. Here are some effective and efficient solutions:
First, the environmental requirements of the seedlings
There are three stages for the growth of seedlings of broccoli: germination period, basic nutrition period and fast growth period.
Broccoli is semi-cold-resistant vegetable. The minimum germination temperature is 3 ℃, and the optimal temperature is 20-25 ℃; the maximum temperature is 35 ℃; the proper temperature of plant growth is 20- 22 ℃, the ballflower will be affected and damaged by the low temperature in -5? -3 ℃. Broccoli has strict requirement in the sowing period.
Broccoli needs adequate sunlight, and it likes the soil with moisture. But it is not tolerate to drought and waterlog, so it has strict requirement to water condition. It needs loose soil with adequate fertilizer and good ventilation.
2. The ways of breeding the seedlings. Ways of nursery period are different according to the characteristics of varieties.
3. The standard of robust seedlings
The age of the seedling is 30-35 days, 5-6 leaves, robust growth, no plant disease and insect pests, sturdy stems, shorter internodes, large and thick leaves, normal leave color, good development of roots, developed fibrous roots, uniformed plant.
4, preparation for seedbed
1. Choose the seedbed with higher topography, good drainage, fine ventilation and translucence, loose soil with rich organic matters.
2. Disinfection of the seedbed should strictly enforce the pollution-free vegetable production practices. Use 25％ Milburn 500 times solution to spray the seedbed and kill the insect pests in the soil.
3. Chemical weeding before sowing to reduce weeds in the fields. Choose a broad spectrum herbicide to spray the seedbed and water the seedbed to be totally wet.
4. Adjust soil moisture of the seedbed, soil moisture deficiency will affect the germination of the seeds and excessive moisture will decline the ventilation of the soil and lead to rotten seeds. So the water contents of the soil is positively relative to the germination of the seeds.
5, Sowing
1. Determine a reasonable sowing time according to the characteristics, weather conditions and cultivation purposes.
2. Determine a reasonable sowing quantity of the seeds. The seeds of broccoli are small, so scientific calculation of the field seeds is necessary in order to ensure that the field has enough number of seedlings and the seedlings have ample space to grow.
The formula is as the following: seed dosage (g/667 m2) = [seedlings / 667 m2 x (1 + safety factor)] x 1000-grain weight ÷ seed germination rate.
3. Sowing. Choose sunny or cloudy evening to sow.
6. Seedbed management
1. Regulate temperature and moisture is the key to manage the seedbed, the two main factor. During the germination period, field survey is necessary. Make soil temperature maintain 25-30 ℃. Pay attention to the weather condition and the soil condition.
2. The basic nutritional management. Strengthen water management. Timely clear the drainage ditch after the rain. Prevent typhoons, rainstorms. Pay close attention to typhoons, rainstorms and other adverse weather conditions. Strengthen the prevention of insect pests and plant diseases. (Reproduced)