Relationship between grain yield and its components and grouping of rice (Oryza sativa L.) recombinant inbred lines

To determine the relationship between grain yield and yield components and grouping of 150 F8 recombinant inbred lines derived from a cross between two Iranian rice varieties; Gharib and Sepidroud, a field experiment was conducted using Augmented design in the research field of Faculty of Agriculture, University of Guilan, Rasht, Iran, in 2013. Correlation coefficients showed positive and significant correlation between grain yield with number of panicle per plant, number of filled grain per panicle, number of spikelet per panicle and panicle length. Path coefficient analysis for grain yield also showed that maximum positive direct effect belonged to flag leaf length and number of panicle per plant that implies these traits are important characteristics associated with grain yield. These traits can be used as selction criteria for indirect selection for genetic improvement of grain yield in rice breeding programs in Iran. Rice recombinant inbred lines were classified in three distinct groups by cluster analysis using ward method with 94% confidence. Recombinat inbred lines in third cluster had higher tiller number per plant, panicle number per plant, panicle length, spikelet fertility, thousand grain weight, grain yield, RWC and chlorophyll content were identified as highly valuable sources to be incorporated in rice breeding programs. These lines can also be used for selection of high yielding cultivars with desirable traits.