Morphological analysis of spikes and grouping of accessions of Triticum turgidum ssp. dicoccon

H. Stoyanov

Abstract. Triticum turgidum ssp. dicoccon, is one of the oldest cultivated plants. Its wide distribution throughout the three continents (Asia, Europe and Africa) is the reason to differentiate this species into many groups. Under the influence of different environmental conditions and the effect of stress factors different genotype and phenotype forms have evolved. Simultaneously, under the influence of natural and artificial selection typical forms with valuable agronomic properties are preserved. To establish the group diversity, 152 accessions of the species Triticum turgidum ssp. dicoccon (cultured emmer) are tested. Morphological evaluation of the spikes of each accession is made by 4 quantitative (length of spike, length of spike with awns, spike weight, number of spikelets per spike), 4 index (awns index, weight distribution along the length of spike, number of spikelets per length of spike, average weight of spikelet) and six quality properties (glume colour, awn color, spike brittleness, spike hairiness, spike shape, spike branching). The accession’s influence on the formation of quantitative traits is assessed. All samples were grouped by the relevant studied characteristics. The largest number of accessions (72 accessions) belongs to the group of typical emmer – bearded, yellow glumes and awns, glabrous, prismatic shape, unbranched spikes with an average weight between 59 and 69 g and an average number of spikelets per spike between 15 and 20. The smallest number of accessions are these with black glumes (3 accessions), strong hairness (5 samples) and awnless accessions (3 accessions). There are 5 accessions with pyramid-shaped spikes, 2 accessions with a triangular cross section and 7 accessions with branched (complex) spikes (two typically branched, and the remaining 5 – similar to Triticum turgidum ssp. turgidum). Some samples exhibit atypical morphology of the species – non-brittle rachis spikes, better threshing, very low mean spikelet weight) and should be related to other wheat species (Triticum aestivum, Triticum turgidum ssp. durum, Triticum monococcum ssp. monococcum). Many samples show widely and similarly variation of spikes length, spike weight and number of spikelets per spike, which determines the presence of significance of the factor ‘accession’ for the formation of these properties. Proper grouping on intraspecific level of accessions and referral to a particular species is crucial for the selection of source breeding material for the wheat species.