Molecular and Phenotypic Characterization of Advanced Backcross Lines Derived from Interspecific Hybridization of Durum Wheat

ABSTRACT

Development, production, identification and evaluation of novel crop plant phenotypes is a fundamental issue addressed to food security, environmental change and bioenergy at a global scale. One of the major approaches used is wide hybridization and introgression breeding.

In this study molecular markers and phenotype evaluation were used to characterize eight backcross lines obtained from interspecific hybridization of six Bulgarian durum wheat cultivars (Triticum durum Desf.) (2n = AABB) with eight alien species of the family Gramineae, using a backcross strategy.

Thirty-three SSRs mapped on the A, B and D genomes and chromosomes of common wheat and three ISSRs were used to assign the alien chromosomes introgressed in the durum wheat chromosomes. The SSR markers showed introgression of several segments of T. carthlicum, T. dicoccoides, T. dicoccum, T. polonicum, T. macha and T. spelta donor genomes, with the highest number of introgressions from T. polonicum, T. dicoccum, and T. macha. This study reflects easy introgression of the genomes of T. dicoccum, T. polonicum and T. macha in cv. Progress and a full compatibility between their genomes. Only one introgression was found from Ae. tauschii in cv. Victoria with the employed set of SSR markers, while such ones from T. timopheevi were not detected. The ISSR markers (GA)₉C and (AC)₈G showed introgression of T. polonicum, T. macha and T. timopheevi chromosome fragments into the genomes of cvs. Progress and Vazhod, respectively.

The phenotypic evaluation of the backcross lines and their durum wheat parents was conducted in 2010–2011 under field conditions, for several important agronomic and grain quality traits. The studied lines were found to differ statistically from the recurrent parents for some traits either in a positive direction, or in a negative one. Higher grain protein and gluten content was identified in all backcross lines in comparison with the recurrent durum wheat cultivars. Backcross lines BL₃from the cross with T. dicoccum, BL₄ from the cross with T. polonicum, and BL₇ from the cross with T. macha, and cv. Progress as a recurrent parent possess the best combination of agronomic traits related to spike productivity and grain quality.

Keywords:

• interspecific hybridization
• alien introgression
• durum wheat
• molecular markers (SSR, ISSR)
• phenotype evaluation