Improvement of high quality and yield variety is the main goal of Rice Research Institute of Iran. More than 60% of rice cultivation is alocated to the local cultivars with low yield but high quality. So the total rice production does not fit to the annual demand and therefor a considerable of rice has to be importet every year. In a precise breeding program , some local high quality cultivars. (Hassan sarai and Sang - Tarom) crossed with improved high yield varieties (Amol3 ,PND 160-2-1 and RNR 1446) in all possible Combination [ P(P-1) ]. Genetic studies were done at Fl according to the Hayman (1954) and Griffing’s (1956) approaches.Further genetic analysis were also applied according to the 6 Parameter method at P1, P2, Fl, F2, Bi and B2 generation, using single grain analysis for quality characters (J.uliano 1979, Cagampange et al, 1973, Sood and Siddique 1977).Accessing to the genetic stracture of quantitative and qualitative characters helped us to chaose an efficient breeding method and selection at segregating generations. Several high yield, good quality, resistant to the blast and sheet blight disease and tolerant to the stemborer purelines optanied. Primarily and main yielding trails including stability analysis of yield were done. In all these process, the superiority of yield and quality of new promissing line (now it is registered as a Nevat variety) to the others improved varieties proved.The average yield of Nemat variety is 8 Ton/ha wich twice as much as that of the local varieties. In addition, it’s quality is more acceptable to the consumer, and is complety resistant to Blast and tolerant to the Stem Borer (two most common disease and pest at the region). So, due to it’s superior characteristics, It was spread more than 10000 ha at the year of releasing.Now (2 nd year), The area under it’s cultivation has reached more than 30000 ha and is introduced to the other rice production area. this break through is the result of 11 years intensive genetics studies and its application in a precise breeding program. The author of this paper was awarded the 2nd Prize of applied researches of the 9th kharazmj International Festival (on 8th Feb. 1996) Tehran, Iran , due to releasing this new variety that will highly affect the economic of farmers and national yield production.
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