Genetic Structure Analysis of a Collection of Tunisian Durum Wheat Germplasm.

Amine Slim,Luciana Piarulli,Houda Chennaoui Kourda,Domenico Pignone,Giacomo Mangini,Mustapha Rouaissi,Cinzia Montemurro,Ramzi Chaabane,Cyrine Robbana

doi:10.3390/ijms20133362

Abstract

The Tunisian durum wheat germplasm includes modern cultivars and traditional varieties that are still cultivated in areas where elite cultivars or intensive cultivation systems are not suitable. Within the frame of a collection program of the National Gene Bank of Tunisia (NGBT), durum wheat germplasm was collected from different Tunisian agro-ecological zones. The collected samples were studied using simple sequence repeats (SSRs) markers to explore the genetic diversity and evaluate the genetic structure in Tunisian germplasm. The results demonstrated significant diversity in the Tunisian durum wheat germplasm, with clear differentiation between traditional varieties and modern cultivars. The population structure analysis allowed the identification of five subpopulations, two of which appear to be more strongly represented in germplasm collected in central and southern Tunisia, where environmental conditions at critical development phases of the plant are harsher. Moreover these subpopulations are underrepresented in modern varieties, suggesting that traits of adaptation useful for breeding more resilient varieties might be present in central and southern germplasm. Moreover, our results will support, the activity of in situ on farm conservation of Tunisian durum wheat germplasm started by the National Gene Bank of Tunisia along with the ex situ approach.

Highlights

IntroductionDurum wheat, which originated in the Fertile Crescent, spread west of the Mediterranean basin, reaching the Iberian Peninsula and North Africa ca
Durum (Triticum turgidum L. subsp. durum, genome AABB, 2n = 4× = 28) and common (Triticum aestivum L. subsp. aestivum, genome AABBDD, 2n = 6× = 42) wheats are species with significant agricultural importance as cereal grains throughout much of the world
During the second half of the last century, a significant increase in wheat yield was observed in Tunisia

Summary

Introduction

Durum wheat, which originated in the Fertile Crescent, spread west of the Mediterranean basin, reaching the Iberian Peninsula and North Africa ca. From the south of the Italian peninsula through the Sicily region, wheat reached the coasts of Tunisia, Morocco and Algeria [3] This migration process, combined with both natural and human selection, led to the creation of local varieties along the Mediterranean basin that were well adapted to its different agro-ecological zones. Contrasting environmental conditions of North Africa triggered a wide diversification of the durum wheat genome determining the development of several local populations. Durum wheat cultivation has continued to the present day as a staple food for local populations and possesses an outstanding socio-economical value as an important basic constituent of the diet in Maghreb countries [7,8]

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