Morphology and Cytogenetics of some New Macro-Mutants in Barley

Four new macromutants, ‘reduced leaf-blade’, ‘entire anther’, ‘grooved culm’ and ‘reverse palea’, induced in barley ‘C 164’ by different mutagens, were studied for their morphological and cytological behaviour. Only the latter two mutants could be maintained in homozygous state. The ‘reduced leaf-blade’ mutant was characterised by a progressive reduction in the size of leaf-blade, dark green leaf-sheath and culm, typical extension of auricles over the leaf margin upto about 2 cm, very late heading and maturity and very short, hooded and sterile spike. The characteristic feature of the ‘entire anther’ mutant was the transformation of filaments into flattened anther-like structures. It was male sterile but female fertile and had open florets. The ‘grooved culm’ mutant was characterised by reverse orientation of leaves in the seedling stage, a distinct longitudinal groove in the culm, very broad leaf sheath enclosing the culm loosely, and coiled neck. The palea of the central florets of the ‘reverse palea’ mutant got twisted, trifurcated and tended to come in between the lemma and the sex organs. All the mutants also exhibited distinct pleiotropic effects on various other plant parts. The mode of inheritance and cytological behaviour revealed that all these were monogenic recessive macromutants. The gene symbols proposed for ‘reduced leaf-blade’, ‘entire anther’, ‘grooved culm’ and ‘reverse palea’ are rlb, ena, gc and rp, respectively. These mutants are not of immediate practical value but could prove valuable material for studies on linkage, pleiotropy and taxonomy. The ‘entire anther’ mutant might be useful in the production of hybrid barley.