Multiflorous cereals – history and state of studies

Abstract

The spike performance or grain weight per spike is the main element of the yield structure in spiked cereals. It is believed that 25–35 grains per wheat spike can ensure yields of up to 30–50 cwt/ha. If there are up to 70 grains per spike, it is possible to double the plant performance. Some researchers think that the use of unique forms with greater numbers of spikelets, flowers and grains in crosses may be a way to increase the yields of cereals.

We could only achieve yields of bread wheat of > 8 t/ha due to fully functional 4-seed spikelets in the spike and of >10 t/ha –due to a fifth caryopsis in the middle or lower part of the spike, whereas 3-seed spikelets are normal for the same variety giving a lower yield. An idea of creating breeding material with genetically fixed multi-seeded spikelets (4–5 seeds per spike for rye, 5-6 seeds for bread wheat) and high penetrance of this trait started up.

This review investigates the state of this problem in Ukraine and in the world and analyzed the search for sources and possibilities to insert genes determining multiflorous condition into the bread wheat and rye genomes. The review includes a brief insight into the history of studies of multiflorous condition, peculiarities of the organogenesis of branched cereals and the body of knowledge on the genetics of spike formation.

Over the last ten years, the number of studies of multiflorous cereals, in particular wheat, using methods of molecular genetics has considerably increased in the world, especially in Asia. Sufficient numbers of wheat mutants and landraces which confirm a possibility of the existence of genetically determined multiflorous condition have been found. Studies aimed at insertion of orthologic genes determining multiflorous spikelets in other crops into the wheat genome are underway. Valuable features of these mutants demonstrate a huge potential for increasing the yields of cereals.