To evaluate the genetic parameters for grain yield and some related trais in a genetically broad base pouplation of sorghum (Sorghum bicolor (L.) Moench). 13 randomly slscted male-strile (A-line) were crossed to sifferent sets of 3 fertility restorer lines (R-line) according to Comstock and Robinson’s design I, and 13 half -sib families were produced. Genotypes. consistins of 13male - fertile (B-lines) , 39 restorer lines (R-lines) and 39 full- sib familites were grown in 1992 at the Isfahan University of Technoligy Research Farm, in two different producttion environments in a randomized complete block design with four replications. Traits studied included grain yield , test weight,plant height, panicle length , panicle weight, number of days to 50% flowering , and crop growth rate.
Significant differences were detected between the two environmental conditions for mosr of the traits studied. An analysis of variance based of design I showed that the mean square of the female parents, wich in genetics terminology is rereferred to asthe variance of general combining ability was significant for all the traits studid except for grainyield the nonsignificance of female x enviroction effecls for grain yield and other trairs indicsated that the halfsib families were more stable across environmental condilions the estimate of broad sense heritability for grain yield was medilm but high for the othertraits the narrow sense herit ability was low for rain yield medium for panicle weight and high for other traits with the exception ofgrain yield result revealed that the other traits were generally controlled by additive gene action this is an indication of the efficiency of direct selection for these traits results also indicated that grain yield is under the control of nonadditive gene action and is highly influenced by environmental conditions. Based on these findings and the presence of high heterosis for grain in some of the crosses, it seems possible to produce hybrid seed.
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