Androgenesis using amphidiploid cultivars of Festuca pratensis × Lolium multiflorum as parents, overcame earlier problems that gave rise to widespread plant sterility amongst androgenic Festulolium populations. Two Festuca pratensis × Lolium multiflorum (2n=4x=28) cultivars, Sulino and Felopa, were highly amenable to androgenesis and 10% of plants, including some novel androgenic genotypes, had sufficient fertility to produce progeny and further generations. The genomes of amphidiploid cultivars, which represent the F8 generation, were the result of considerable intergeneric chromosome recombination. Moreover, during cultivar development, natural and breeders’ selection pressures had led to the assembly of gene combinations that conferred good growth characters and fertility with the removal of putative deleterious gene combinations. Over 80% of the androgenic plants derived from the amphidiploid F. pratensis × L. multiflorum (2n=4x=28) had 14 chromosomes and were likely to be dihaploids with a single genome of Lolium and of Festuca. In contrast, hybrids of F. pratensis × L. multiflorum (2n=2x=14) found naturally are invariably sterile. Structural reorganization within the genomes of the androgenic Festulolium plants had restored fertility in genotypes expected to contain the haploid genome of Lolium and Festuca. This provided opportunities for their future incorporation in breeding programmes and the development of fertile diploid Lolium–Festuca hybrids. Amongst the androgenic plants, Festulolium genotypes were recovered that conferred excellent drought resistance or freezing tolerance and were thought to be highly suitable for entry into plant breeding programmes.

The aim of the present study of triticale x maize crosses was to find an appropriate growth regulator treatment to improve the yield of triticale haploids and the subsequent production of doubled haploids. The growth effect in unpollinated ovaries of triticale was examined after treatment with 1000 mg/1 indole-3-acetic acid (IAA) or 100 mg/1 solutions of the following auxin analogues: 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-o-anisic acid (dicamba), 4-chloro-o-tolyloxyacetic acid (MCPA), phenylacetic acid (PAA), 4-amino-3,5,6-trichloropicolinic acid (picloram) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), respectively. Dicamba stimulated growth of the ovaries significantly more than picloram and both stimulated more growth than the other growth regulators tested. Neither dicamba nor picloram induced embryo development in unpollinated pistils. Dicamba and picloram solutions, at concentrations of 25, 50, 75 and 100 mg/1, were subsequently apphed to pistils of triticale poUinated with maize. On average, between 17.1 and 21.5 embryos/100 fiorets were excised after treatment with 75 or 100 mg/1 solutions of picloram or dicamba but the concentrations of 20 and 50 mg were less effective. The frequencies of excised embryos did not differ between genotypes. Seventy-six green haploids were obtained from 100 embryos rescued in vitro on the 190-2 and modified B5 media, the first medium being superior. The plants were subjected to colchicine treatment at the 3^ tiller stage. Out of 68 plants brought to maturity, 25 exhibited fertile sectors. In comparison with previous studies, picloram and dicamba significantly improved the efficiency of the triticale x maize crossing. The low dependence on the mother germplasm makes triticale x maize crossing an efficient alternative to the androgenetic methods of doubled haploid production in triticale.

To create a framework for genetic dissection of hexaploid triticale, six populations of doubled haploid (DH) lines were developed from pairwise hybrids of high-yielding winter triticale cultivars. The six populations comprise between 97 and 231 genotyped DH lines each, totaling 957 DH lines. A consensus genetic map spans 4593.9 cM is composed of 1576 unique DArT markers. The maps reveal several structural rearrangements in triticale genomes. In preliminary tests of the populations and maps, markers specific to wheat segments of the engineered rye chromosome 1R (RM1B) were identified. Example QTL mapping of days to heading in cv. Krakowiak revealed loci on chromosomes 2BL and 2R responsible for extended vernalization requirement, and candidate genes were identified. The material is available to all parties interested in triticale genetics.Electronic supplementary materialThe online version of this article (10.1007/s11032-018-0804-3) contains supplementary material, which is available to authorized users.