Dwarfism is a frequently occurring congenital disorder in human and farm animals. Defects in endochondral ossification lead to disproportionate dwarfism with abnormal length of the limbs in relation to the size of the trunk. Based on observed skeleton abnormities in general, a short- and long-limbed achondroplasia can be recognized. Short-headed dwarfism often relates to the latter ACH form and comprises a number of head deformities with a characteristic craniofacial shortening. Lethal cases with severe skeleton malformations occur when ACH is inherited in the homozygous recessive mode. A number of different ACH forms were described in Dexter, Holstein Fresian, Jersey, Aberdeen Angus, Hereford, Shorthorn and Japanese brown cattle. Only in the last mentioned breed two causative mutations have been detected causing ACH phenotype in the appendicular skeleton. Extensive efforts are being made to find mutations determining achondroplasia in other cattle breeds.
The article reviews literature relating to the origin and use of Rht1 and Rht2 dwarfing genes in wheat breeding. Moreover, the article deals with problems encountered by breeders and farmers in breeding, certification of seed and cultivation of wheat with the Rht1 and Rht2 genes.
Paper analysed the list of genes determining the dwarfness in selected species of cereal plants. Most of the dwarfness determining genes were described in wheat (25), the two of them (Rht1, Rht2) are utilized in breeding practice all over the world. Much less of the dwarfness genes have been identified in barley (11) and rye (15), and only individual genes, viz. denso and Ddw1, are applied in breeding of short-stemmed varieties of these cereals.