| The occurrence of new color of glumes and awns in the
Triticum vulgare and Triticum dicoccum cross Slavko BOROJEVIC Institute of Plant Breeding and Genetics, Faculty of Agriculture, Zagreb, Yugoslavia Triticum vulgare var. lutescens Al. (variety "Graf Torring") and T. dicoccum var. farrum Korn. (Emmer from Trebinje, Yugoslavia) were crossed, both having white color of glumes and dicoccum as a bearded variety with white color of awns as well. In the F1, red color of glumes has occurred. In the F2 and later generations the color of glumes and awns was found to be inherited on the basis of at least two factor difference segregating for red and white in 9:7 ratio. The red color varied from intensive red to light-red. Glumes were completely red whereas palea exterior was red only on the part which is not covered by the glume. This fact warned to check whether the red color depends upon the presence of sunlight or not. Therefore the experiment with bagging of ears has been performed. The ears of some segregates homozygous for red color were bagged just before heading and immediately after heading. The same was done with another vulgare variety with red glumes. Unbagged ears were used as control. The red color was not developed at all on the ears bagged before heading while those bagged after heading were light-red. The same was true for vulgare variety. Thus, the conclusion was drawn that red color is genetically controlled but it can be developed only in the presence of sun-light. In principle, the color of awns was the same as that of glumes. Many segregates however, had more intensive color of awns, i.e. dark-red or black. These colors occurred particularly in the F4 during the hot and dry growing season. Quite a number of segregates which had red color of glumes and awns in early genetations, in the F4 gave progenies with black color of awns and in some cases black glumes as well. Even plants with white color gave progenies with white glumes and black awns or with blue-black glumes and black awns. In majority of the plants black color disappeared in the F5 and succeeding generations, especially black color of glumes while that of awns remained in some segregates. The occurrence and disappearance of black color has been explained to be primarily due to the influence of environmental factors, particularly the strength and duration of sunlight, even though its genetic basis can not be neglected. The red and white color were present in all species-type segregates, black color being linked only to 14-chromosome types. This shows that D genome inhibits the development of black color. |