Title: Selection of rice varieties adapted to the environment through Evolutionary Participatory, Breeding
Author: Maryam Hosseini Chaleshtori
Abstract: The stages of rice breeding and releasing of new cultivars include creating diversity, selecting suitable lines resulting from the existing diversity and segregation, purification, and finally examining the adaptability and stability of the selected lines. This is a common method that has been used for many years in the breeding of self-pollinated plants. What is very important in rice breeding in Iran is the quality of cooking, flavor, and taste of rice, which is influenced by many genes and many quantitative traits that play a role in controlling it. Therefore, to breed new rice cultivars, the genome of local cultivars is always used as one of the parents in the crosses. The usual method of crossing and purifying the lines causes a great loss of diversity and ignores the desired traits, so this study was conducted to evaluate the adaptability of cultivars in a new way (evolutionary and participatory combination) and select the adaptable cultivars. For this purpose, the population of local cultivars of the 1940s, which had a great variety, was used. At first, all agronomic and cooking quality traits were measured in these cultivars, and analysis of variance of traits showed that there is a very high diversity in all traits. On the other hand, cultivars were grouped based on agricultural and quality characteristics. The seeds of 198 local cultivars were mixed evenly (100 seeds) and exposed to natural selection (three different farms) and artificial selection (breeder and farmer) during 5 cropping years. The results showed that natural selection in organic conditions had a higher selection intensity than conventional farms. The high-height and high-grain cultivars of group Sadri had a great advantage over the cultivars of groups Champa and Gardeh. Natural selection on a typical farm resulted in a population with low mean amylose content and high gelatinous temperature. While on the organic farm, natural selection resulted in populations with average amylose levels and moderate gelatinous temperatures. In spite of the great differences between the farmers and breeder choice, commonly selected cultivars were chosen for complementary stages of cultivar introduction. The final results of this project included: pure initial population, three mixed populations resulting from natural selection, populations selected by the farmer and breeder, and selected cultivars. The final selected cultivars can be considered for introduction to the farmers’ community and replace the current local cultivars. Due to the fact that these cultivars were the result of simultaneous selection of natural and artificial, they have good adaptability and stability. Mixed populations derived from the natural selection can also be used to continue this project and use the natural selection for another 4 years up to achieving the relative purity and final selection or to select suitable parents for the crosses. The genetic diversity in this germplasm is available in pure and mixed form, it can help breeders to choose and transfer desirable traits. Preserving this diversity in local cultivars and trying to take advantage of this diversity and its application in introducing rice cultivars is essential.
Keywords: Adaptability, Artificial selection, Evolutionary breeding, Genetic diversity, Natural selection, Participatory selection, Rice.