Scientific plant breeding activities in Iran has initiated in early 1920s, and was carried out in some part of the country including Karaj, 40 Km northwest Tehran and Varamin, 40 Km east Tehran. The development of plant breeding and agronomy research in Iran can be divided into five distinct periods:The first period (1927 to 1945): Establishment of Higher School of Agriculture followed by the foundation of Faculty of Agriculture in 1927, in Karaj, were the two most prominent initiatives. Many obstacles were experienced during this period, since shifting from traditional and old approaches needed educated and trained man power in new agriculture. Technical infrastructures and experimental fields for conducting field experiments were also constructed and established. From 1932, seed multiplication and purification were practiced in the experimental field of Higher School of Agriculture. Seed samples of cereals (wheat, barley), food legumes (beans, chickpea), vegetables, and cotton were collected from all around the country and were sown in the experimental fields and evaluated. Sugar beet varieties were imported from Germany, Belgium and Denmark and evaluated under Iranian conditions. In 1933, preliminary field experiments and seed multiplication schemes were carried out for cereals, cotton and sugar beet, in the experimental fields of Higher School of Agriculture. The first plant breeding enterprise was established in Karaj, in 1935, with the main mandate of improvement and multiplication of sugar beet seed. Concurrently, primary facilities for cereal improvement and seed multiplication were also made available in Karaj. In 1936, in Varamin as one of the main cotton growing areas in Iran, a plant breeding enterprise was established to improve and produce elite seeds of cotton and wheat. The second period (1945 to 1960): This period commenced as concurrent with the end of the Second World War and continued until the establishment of Seed and Plant Improvement Institute in 1960. In fact this period was in coincidence with the development and rapid expansion of new agricultural approaches, techniques and equipments in developed countries. This period of time can be termed as the period of training of plant breeders and preparation and development of required infrastructures for seed and plant improvement in the country. Many of researchers initiated and conducted some studies and preliminary yield trials in Karaj and Varamin which were better equipped. Horticultural crops improvement began in 1946, by the establishment of collection gardens of different cold and temperate fruit species in Karaj, collected either from different part of Iran or imported from other countries. This was also done for citruses in the north (Ramsar, Mazandran province) and date palm (Ahwaz, Khuzestan province) in the south. In 1948, with the separation of Faculty of Agriculture from the Ministry of Agriculture, all duties, related equipments and facilities for collection, evaluation and experimenting of wheat and barley landraces and local populations were transferred and concentrated in Karaj Plant Breeding Enterprise. Cotton seed improvement was followed more seriously from 1951, and initiative of establishment of General Office of Certified Seed Supply was formed and took place in 1956. This office was established to supervise and control the seed producing fields of cereals and cotton in Karaj and Varamin, and certified seeds were, then, distributed to the farmers. By organizing the scattered plant breeding research activities in the country, the rice breeding research commenced in Lahijan Agricultural Enterprise in 1957 and developed by establishment of Rice Research Field Station in Rasht in 1959. All this endeavors led to the approval of the law of Seed and Plant Improvement Institute by legislative body (Senate Assembly) in 1959, and its establishment in 1960. The third period (1960 to 1978): Scattered research in different sections of the Ministry of Agriculture, and the then General Office of Crop Production with limited organization and facilities could not directly lead the national research system. Hence, the establishment of a new and independent institute with wide legal authorities was a necessity. Therefore, Seed and Plant Improvement Institute was established in 1960, and the following areas of research and development were determined as its mandates- Breeding and agro-technique research for most of the field crops such as: wheat, barley, cotton, rice, oil seed crops, maize, forage crops, and hemp. - Production of registered and certified seeds to meet seed requirements of the country. Propagation and distribution of grafted seedlings suitable for different climatic conditions.- Control of field and certification of seed produced by seed producer farmers, based on rules and regulations determined in the then Ministry of Agriculture and Natural Resources.
Lack of required infrastructures and facilities were the most serious hurdles to be handled and developed at the beginning. To implement and materialize the described mandates the institute formed four general offices as follows:1- General office for horticulture crops research for preliminary propagation of fruits, vegetables and potato varieties.2- General office for field crops research and preliminary seed increase of wheat, barley, cotton, maize, rice, forage crops, food legumes, and other field crops. 3-General office for seed multiplication and certification to supervise and control seed multiplication fields and issuing seed certificates. 4-General office for multiplication and distribution of seed to provide and distribute improved seed. To facilitate the civilities of these offices the institute also established: cereal improvement laboratory, sugar beet seed improvement laboratory, fruits improvement laboratory, in Karaj as well as seed improvement laboratory in Varamin, rice improvement laboratory in Rasht, palm date improvement laboratory in Ahwaz, and seed specialized glass-houses in Karaj and Varamin. In addition to plant breeding centers in Karaj and Varamin, three other main field research stations were also established in Mashhad in Khorasan, Moghan in East Azarbaijan and Darab in Fars.
As the required infrastructures and facilities, particularly human resources were developed and provided, the work load also considerably increased. Therefore, the institute went into a change in its organization as the Oil Seed Crops Research Department was established in 1969 followed by formation of Maize Research Department in 1970. In 1971, the general office for horticulture crops research changed into Horticultural Crops Research Department, and the vegetable crops unit was separated as to form Vegetable Crops Research Department in 1978. The forth period (1978 to 1993): To proceed with amendment of its organization, Seed and Plant Improvement Institute followed the strategy of the formation of new research departments. Food Legumes Research Department was formed in 1980, and with the development in the science of crop physiology, the Physiology, Biochemistry and Biotechnology Research Department was established in 1983. To enhance the utilization of plant genetic resources in crop breeding programs and increase their efficiency, the Genetic and Plant Genetic Resources Research Department was also formed and established in the second half of 1983. This organization scheme was in place until a dramatic shift occurred in this mother plant breeding and agronomy institute, when new commodity research institutes were separated from it and formed new independent research institute, in early1990s .The fifth period (1993 to present): This period is known as the period of formation and establishment of commodity research institutes. The first institute that separated from SPII and established as an independent institute in 1992, was Dryland Agricultural Research Institute (DARI). This was followed by separation and establishment of Pistachio Research Institute in 1992, Date Palm and Tropical Fruits Research Institute in 1993, Rice Research Institute in 1994, Citruses Research Institute in 1996, Cotton Research Institute in 1997, Agricultural Biotechnology Research Institute in 2000 and Seed and Plant Certification Research Institute in 2004. All these new commodity research institutes are carrying-out breeding and agronomy research for the concerned crops.