Genetic worth and stability of selection indices in rice (Oryza sativa L.)

Document Type : Original Research Papers


Crop Science and Plant Breeding Department, College of Agriculture, Shahed University, Tehran, Iran


Improvement of one trait on its own will affect the performance of other traits because of
genotypic correlations between traits. Index selection is one of the tools used by plant breeders
to overcome this problem. The purpose of this paper is to evaluate selection indices developed
for improving grain yield in rice (Oryza sativa L.). Forty-nine rice genotypes were cultivated at
Tonekabon Rice Research Station, Iran, in 2009 and 2010. Selection indices were developed
based on phenotypic and genotypic correlations, path coefficients, broad-sense heritability of
traits and stepwise multiple linear regression coefficients. Assessment of indices revealed that
the stability decreased concurrently with increase in the genetic worth, and hence an inverse
association existed between stability and genetic worth of indices. The results also suggested
that selection for TP, GW, GP and GL and against PH using their multiple linear regression
parameters as economic weights was an effective criterion for improving grain yield in rice
genotypes. On the other hand, the most stable indices were those that were developed based on
heritability of traits as well as genotypic path coefficients.


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