Genetic and phenotypic diversity of triticale in relation to yellow rust resistance

Abstract

Triticale (x Triticosecale Wittmack), a cross between wheat and rye, has the potential to become a valid alternative to other small cereals and could thus diversify crop rotations and increase biodiversity in agricultural production. As a multi-purpose grain-forage species it has the reputation of performing well on marginal soils, even with reduced nutrient input. Although triticale was considered as a healthy crop compared to e.g., wheat, in recent years disease susceptibility is one of the main issues limiting its introduction into cropping systems. The most urgent targets of triticale breeding are therefore durable resistance against diseases of which yellow (stripe) rust caused by Puccinia striiforimis f. sp. tritici (Pst) is one of the biggest problems given the presence of some very aggressive isolates (e.g,, ‘Worrior race’). In this study, 280 triticale accessions were grown in an augmented design, during two growing seasons in four different agro-ecological zones. These accessions were evaluated for their resistance to yellow rust, but also other phenotypic characteristics such as soil cover, plant height, flowering time and grain yield were noted. The variation in genetics was mapped using DAFT (Diversity Arrays Technology) markers. The phenotypic screening of the triticale revealed that there is a considerable variation in yellow rust incidence between years, locations and triticale genotypes. In addition, the tolerant genotypes originated from different breeders, which can be an indication of the presence of different sources of resistance within this population. Also, on the genetic level, there was a great variation between the genotypes, which is essential to continuously improve triticale by breeding efforts. In the next phase, a GWAS study willlink the genetic data to the phenotypic data to find informative markers for future breeding. The data collection and analyses are currently running. Results will be analyzed, and conclusions drawn.