Evaluation of Leaf Rust Resistance in the Spanish Core Collection of Tetraploid Wheat Landraces and Association with Ecogeographical Variables

Fernando Martínez-Moreno,Magdalena Ruiz,María Del Mar Cátedra,Patricia Giraldo

doi:10.3390/agriculture11040277

Abstract

Spain has a great landrace diversity of the subspecies of the tetraploid species Triticum turgidum L., namely, durum (or durum wheat), turgidum (or rivet wheat) and dicoccon (or domesticated emmer wheat). These wheats have to confront several foliar diseases such as the leaf rust. In this work, a core collection of 94 landraces of tetraploid wheats were inoculated with three leaf rust isolates. Besides, a larger collection (of 192 accessions) was evaluated in the field. Although the majority of landraces were susceptible, approximately 20% were resistant, especially domesticated emmer wheat landraces. Several variables, such as late heading and red coat seeds were associated to resistant accessions. Regarding ecogeographic variables, a higher rainfall from October to February and more uniform temperature were found in the area of origin of resistant landraces. Based on these results, several resistant landraces were identified that potentially may be used in durum wheat breeding programs. In addition, a predictive model was elaborated to develop smaller subsets for future screening with a higher hit rate for rust resistance.

Highlights

IntroductionLeaf (or brown) rust is a foliar disease caused by the fungus Puccinia triticina Eriks
Several tetraploid wheats (2n = 4x = 28) of the species Triticum turgidum L. are cultivated
Several resistant landraces were identified that potentially may be used in durum wheat breeding programs, especially durum wheat accessions (e.g., BGE045670 Colorado de Cabra for hypersensitive resistance, and BGE047515 Claro de Balazote for partial resistance) and rivet wheat (BGE047509 Blanco de Vegadeo), and domesticated emmer (BGE048901 Escaña doble)

Summary

Introduction

Leaf (or brown) rust is a foliar disease caused by the fungus Puccinia triticina Eriks. It is the most constant disease globally out of the three rusts diseases (yellow rust, leaf rust, and stem rust). It affects to bread wheat, durum wheat, and triticale. Durum wheat was generally deemed more resistant to leaf rust compared to bread wheat, from 1998 to 2006 severe leaf rust outbreaks on durum wheat were recorded at many locations in southern Spain. Other resistant cultivars carry the complementary genes Lr27 + Lr31 (that originated from bread wheat but transferred to several durum wheat cultivars such as Jupare C2001, and LrCamayo (present in cultivar Camayo), but the resistant stock is scarce

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