Quantitative and geoecological Study on the Spatial Diffusion of Hybrid-variety (F_1) of Vegetables

种子和苗木行业向农民提供和分发种子，现在已经成长为大企业。种子公司杂交种子新品种(F_1)的产销在农田种子比较中迅速增长，本研究的目的是从定量和地质生态角度阐明蔬菜杂交新品种(F_1)的扩散过程。因此，以下几点就很清楚了。一般来说，蔬菜连作受害严重。因此，具有优良抗病、抗虫性能的杂交种(F_1)越来越受到菜农们的青睐。其中一个例子是日本最大的种子公司Takii生产的抗病F_1品种大比乌甜菜，青头萝卜，最早在冈山郊区引进，后来扩散到北国和近海，然后传播到四国和九州。在那之后，它扩散到北海道、东北和高原地区。最后，在低地关东地区耕种。青菜口感好，销售价格高，在许多种子公司生产，在日本各地种植，作者鉴定了青菜通过大型种子公司及其支流网络的多核扩散。在一个地区，它在4年内完全扩散。鲜食玉米(F_1品种)和玉米(F_1品种；Haney Bandl=和甜玉米)的生产也出现了相同的规律。

Seed and Seedling Industry, which provides and distributes the seed to farmers, grows now to Big business. Production and marketing of new variety of Hybrid-seeds(F_1)by seed companies increased rapidly in compasating the farm seeds.The purpose of this study intend to clarify quantitatively and geoecologically the diffusion process of Hybrid-variety(F_1)of vegetables. As a results, following items make clear.Generally speaking, vegetables were received severe damage with successive cropping. Thus, vegetable farmers tend to try the cultivation of new variety of Hybrid-seeds(F_1), which show superior property of anti-disease and insects. One of these example is the Taibyo soubuto(disease-resistance F_1 variety), Aokubidaikon(radish with green head)produced by Takii, the biggest seed company in Japan.Aokubidaikon, which introduced at first in suburban area of Okayama, diffuse to Hokuriku, and Kinki, then to Shikoku and Kyushuu. After that, it diffused to Hokkaido, and Tohoku and highland regions. Lastly it cultivated in lowland Kanto district. Aokubidaikon with good taste and high marketing price, produced at many seed companies, and cultivated throughout Japan.The authur identify the multi-nuclear diffusion of Aokubidaikon through big seed companies and their tributary networks. In a area it diffused fully within 4 years. Same patterns were observed in fresh tcmhato(F_1 variety ; Momotarou)and maize(F_1 variety ; Haney bandl= and sweet corn)production.