Durum Wheat Mediterranean Landraces: A Valuable Source for Resistance to Tan Spot Disease

Marwa Laribi,Sarrah Ben M’Barek,Amor Hassine Yahyaoui,Moez Fakhfakh,Khaled Sassi

doi:10.3390/agriculture11111148

Abstract

Tan spot (TS), caused by Pyrenophora tritici-repentis (Ptr), has gained significant importance in Tunisia. In this study, a Mediterranean durum wheat collection of 113 accessions were evaluated under field conditions, during the 2018–2019 cropping season, for resistance to Ptr at Koudia experimental station in Bou Salem (Tunisia). The disease progress curve (AUDPC) was used to screen this collection, and the effect of days to heading (DH) and plant height (PH) were evaluated in relation to TS resistance. No significant correlation of PH with AUDPC was found, yet a significant correlation (r = 0.212, p ≤ 0.05) was established between DH and AUDPC scores, suggesting that DH may have an effect on TS development. Moreover, correlation between seedling and adult reactions was significant (r = 0.695, p ≤ 0.001). Although susceptible accessions clustered separately from resistant accessions, the clustering was independent of the country of origin and the status of improvement of the wheat accessions. In total, 67% and 80% of resistant and moderately resistant accessions, respectively, were landraces, suggesting therefore the possible presence of novel sources of resistance to Ptr in some landraces, which can be used to establish a breeding program for resistance to tan spot disease.

Highlights

Published: 16 November 2021Durum wheat (Triticum turgidum L. subsp. durum) has a significant agricultural importance and represents the third most important cereal crop worldwide, accounting for 8%of the wheat planted area and provides 5% of the total wheat production worldwide [1,2].It originated in the Fertile Crescent and spread west of the Mediterranean basin to NorthAfrica 9000 years ago
Wheat production is threatened by the emergence of high-yielding elite cultivars grown in large areas that led to the loss of genetic diversity that are more vulnerable to newly emerging strains of pathogens [8,9,10,11,12]
All Mediterranean durum wheat accessions evaluated against tan spot responded differentially to Pyrenophora tritici-repentis (Ptr) under field conditions at both seedling and adult stages, exhibiting reactions that ranged from susceptible (S) to moderately susceptible (MS) and moderately resistant (MR) to resistant (R)

Summary

Introduction

Published: 16 November 2021Durum wheat (Triticum turgidum L. subsp. durum) has a significant agricultural importance and represents the third most important cereal crop worldwide, accounting for 8%of the wheat planted area and provides 5% of the total wheat production worldwide [1,2].It originated in the Fertile Crescent and spread west of the Mediterranean basin to NorthAfrica 9000 years ago. Durum) has a significant agricultural importance and represents the third most important cereal crop worldwide, accounting for 8%. Of the wheat planted area and provides 5% of the total wheat production worldwide [1,2]. It originated in the Fertile Crescent and spread west of the Mediterranean basin to North. Most of the durum wheat is grown in the Mediterranean region (75% of the world’s durum wheat production) because of its adaptation to the environment and its end-use products such as semolina, pasta, couscous, and burghul [5,6]. In Tunisia, durum wheat is cultivated in over half a million hectares, representing 87% of the area dedicated to wheat production [7]. The adoption and widespread of reduced or no-till practices in the 1970s

Objectives

Methods

Results

Conclusion