عنوان مقاله [English]
Monogerm and multigerm seed varieties are used in sugar beet cultivation. Singling is inevitable and mechanization almost impossible when multigerm seed varieties are used. For this and for some other reasons, economically sound and fully mechanized cultivation of sugar beet calls for the use of monogerm seed varieties. Throughout Europe, only monogerm varieties are used in sugar beet production. In sowing monogerm seeds, special types of machineries are implemented and land preparation techniques play a very important rule. In the past, lack of suitable machineries and well prepared lands discouraged farmers from sowing monogerm varieties and therefore, monogerm seed production showed no improvement in quality, quantity and diversity for many years. In recent years, with the growing interest of sugar beet producers, Sugar Beet Research Institute of Iran has focused on monogerm seed production. With the development of varieties suitable for different climatic areas, this institute has reached a high level of commercial success in monogerm seed production. In a multigerm seed production field, some fraction of the crop is monogerm. One way of monogerm seed production, called technical monogerm, is the separation of this fraction of monogerm seed from the multigerm seeds using a combination of round and slotted screens. Another type of monogerm seed is hybrid monogerm and its production is rather complex and requires special tools and material with a growing demand for monogerm seed, Sugar Beet Seed Research Institute has been focusing on the production and development of high quality basic seeds of monogerm type in recent years and the increasing level of commercial production of hybrid monogerm is a clear indication of its success. Table 1 shows the trend of commercial hybrid monogerm seed production in an interval of 5 years. Each year, field performances of domestic varieties are compared with top quality foreign varieties by researchers and technical staffs of SBSI, agricultural organizations and agricultural sectors of sugar refineries. Data gathered from 70 sugar beet production farms with a total of 203 hectares in Western Azerbaijan province for the production year of 2002 is shown in Table 2. At a large scale, average root yield is 5 tons per hectare with 9.01 tons of gross sugar. Domestic varieties show unique superiorities over foreign varieties and in some cases 40% yield increase is observed. Sugar Beet Seed Research Institute has developed Rhizomania and Nematode resistant lines and farmers will have access to the new varieties in the coming years.