Rht5 is a gibberellin-sensitive dwarfing gene and reduces plant height without affecting early growth. In this study, the effects of dwarfing gene Rht5 on coleoptile length, some agronomic and seed traits were revealed in an F4 population obtained from a cross between Marj12 (semi-dwarf, Rht5) and Scholar (tall). The genotypes of F4 individuals were screened using SSR marker BARC102 linked with the Rht5 gene and the dwarf, tall and heterozygous individuals were identified. Analysis of variance in the F4 population indicated highly significant differences among the lines for all traits studied, suggesting genetic differences existed for all traits among these lines. In general, the Rht5 dwarfing gene was associated with plant height and peduncle length reduction of 25.44 and 22.28 %, respectively, as well as decreases in spike length, number of spikelets, and kernels per spike. Higher values of kernel weight, seed width and seed length could be observed in the tall lines when compared to the dwarf lines. The dwarfing gene Rht5 increased coleoptile length by 6.03 % in dwarf lines and also increased primary root number and first leaf length. The results of the study could contribute to the proper use of dwarfing gene Rht5 in breeding programs aimed at modifying plant height and coleoptile length in wheat.

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