Prospective use of barley spike/flower homeotic single and double mutants for ornamental purposes

Abstract

Barley and other cereals only in small portions are used as ornamentals for their attractive spike structure and other features, and thus, there is a need to enhance approaches for the enrichment of their ornamental genetic resources. Homeotic Hooded (Hd) mutants, caused by a 305-bp duplication in intron IV of the BKn3 gene and characterized by ectopic flowers instead of awns, are attractive ornamental plants. However, it has been proposed that the hybridization of Hd mutants with other homeotic mutants may widen resources of attractive forms. Two groups of lines were studied: those resulting from the hybridization of Hooded in cv. Colsess II with other Hd mutants and those resulting from the hybridization of Hd with other homeotic mutant tweaky spike2 (tw2). tw2 has lodicules that are irregularly transformed to reproductive organs and specific spike shapes. Attractive lines were selected, propagated and studied in distinct generations (corresponding to F9–15) for decorative quality and quantitative characters. Variations of vegetation time, weight of grains, resistance to lodging and diseases, protein and starch contents are presented. In total, 231 lines were analysed. Not all selected attractive lines possess the mutant BKn3 allele. Wider and more attractive spectra were revealed when different types of mutants, Hd and tw2, were hybridized. More attractive lines were selected among the offspring of tw2 × Lh and tw2× Br. Several lines are also valuable for high protein content.