Frequency of Occurrence and Types of Branching Spikes in Triticale Cultivated in Different Time of Sowing

Abstract

The frequency of occurrence and types of branching spikes and spikelets were examined in one octoploid and eleven hexaploid lines or varieties of triticale (X Triticosecale WITTMACK). Among the plants sown in five different months, i.e., February, September, October. November and December 1986, the plants sown on September 10, as a whole, showed the highest frequency of branching. This phenomenon may be attributed to a daily mean temperature as low as about 5°C at the time of ear formation that provides long period for inflorescence development which gives favourable time for bh (branching) gene to be active longer for branched development. The sensitivity to low temperature seemed to differ from one to another variety or line in triticale. Octoploid line Tcl 18 showed a higher frequency of branching than the hexaploid ones. Commercial varieties of hexaploid triticale including Welsh, Rosner, Yoreme and Currency did not show any type of branching. The varietal difference in the frequency of branching was not clearly associated with the chromosome constitution or cytoplasrnic characteristics of the lines or varieties. Branching occurred mainly on the lower 1/3 of the spikes. Branching spikes with hay-fork shape, Y-fork shape, and branching from the flag leaf node as well as branching spikelets of banana twin type, face to face twin type, compact type, whorl and square head types were recorded. The number of spikelets per spike and the number of florets per spike in most of the branching spikes were significantly larger. The number of grains per spike in the branching spikes of the octoploid line Tcl 18, hexaploid varieties Beaver, Rosner (Mono-1B) and Beagle was significantly larger than of the normal spikes, but opposite results were obtained for the hexaploid varieties Camel/Pato, Camel and Bronco. This observation suggests that it may be possible to select a high yielding line with a large number of spikelets, florets and grains per head in triticale.