Evaluation of crossability between triticale (XTriticosecaleWittmack) and common wheat, durum wheat and rye

Abstract

Development of transgenic triticale as a platform for novel bio-industrial products is predicated on an environmental biosafety assessment that quantifies the potential risks associated with its release. Pollen-mediated gene flow to related species and conventional triticale varieties is one pathway for transgene movement. A tier 1 quantification of triticale hybridization was conducted by emasculating and hand pollinating flowers under greenhouse conditions. Approximately 2000 manual pollinations were conducted for each cross and its reciprocal between two triticale genotypes: a modern triticale cultivar (AC Alta) and primary triticale (89TT108), and common wheat, durum wheat and rye. The frequency of outcrossing, hybrid seed appearance and weight, and F 1 emergence and fertility were recorded. Outcrossing, F 1 emergence and fertility rates were high from crosses between triticale genotypes. Outcrossing in inter-specific crosses was influenced by the species, and the genotype and gender of the triticale parent. In crosses to common and durum wheat where triticale was the male parent, outcrossing was ≥ 73.0% and ≥ 69.5%, respectively, but ≤ 23.9% and ≤ 3.0% when triticale was the female parent. Overall, outcrossing with rye was lower than with common and durum wheat. F 1 hybrid emergence was greater when triticale was the female parent. With the exception of a single seed, all wheat-triticale F 1 hybrid seeds were non-viable when triticale was the male parent in the cross. Only seven durum wheat-triticale F 1 hybrids emerged from 163 seeds sown, and all were produced with triticale 89TT108 as female parent. With rye, 8 F 1 hybrids emerged from 38 seeds sown, and all were produced from crosses to AC Alta; five with AC Alta as the female parent and three as the male. Interspecific F 1 hybrids were self-sterile, with the exception of those produced in crosses between common wheat and triticale where triticale was the female parent. Tier 2 hybridization quantification will be conducted under field conditions.

Male sterility of triticale lines generated through recombination of triticale and rye maintainers

“…In the present study, crosses conducted among maintainers of triticale and rye showed low efficiency. This contrasts with studies of other authors (Tarkowski & Otl -owska, 1968;Guedes-Pinto et al, 2001;Hills et al, 2007), who obtained higher seed set, although crossability in these studies depended on the parental genotype and environmental conditions (Guedes-Pinto et al, 2001).…”

Pollen-mediated gene flow in flax (Linum usitatissimum L.): can genetically engineered and organic flax coexist?

“…Several markers have been used in other crops to detect pollen-mediated gene flow in donor-receptor experiments including molecular markers based on quantitative PCR (Weekes et al, 2005(Weekes et al, , 2007Pla et al, 2006;Weber et al, 2007) or micro-satellite markers (Chaix et al, 2003;Dje et al, 2004;Isagi et al, 2004). Other techniques like green fluorescent protein (Halfhill et al, 2003) and blue aleurone seed color in wheat (Hanson et al, 2005) and triticale (Hills et al, 2007) ) (Kenaschuk and Rashid, 1994) and low ALA 'Solin' (o3% ALA) cultivars have been developed (Dribnenki et al, 2003). Two independently inherited genes, LuFA-D3A and LuFAD3B control the ALA trait in flax (Vrinten et al, 2005).…”

Potential Hybridization of Genetically Engineered Triticale with Wild and Weedy Relatives in Canada

“…These examples underscore the need for detailed environmental risk assessments before release of new genetically engineered crops. Genetically engineered triticale (tribe Triticeae, = Poaceae) is being examined for a range of uses, including bioproducts (CTBI, 2008;Hills et al, 2007;Zimny et al, 1995). Relatively new to agriculture, triticale is an intergeneric hybrid between wheat and cultivated rye (Secale cereale L.).…”