Evaluating the cost and gain from genetic resistance to Hessian fly (Mayetiola destructor (say)) in durum wheat in Morocco using recombinant inbred lines

Abstract

Durum wheat (Triticum turgidum L. var. durum) is an important food crop in the
Mediterranean region. Hessian fly is the most important insect pest of wheat in the dry land
areas in Morocco. Breeding wheat for genetic resistance to pests is the most sustainable
control strategy because genetic resistance brings yield advantage under pest attack.
However, there are fears that this resistance could have its price in terms of yield potential
under pest free situation. The objective of this study was to quantify the yield gains in the
presence of H. fly and verify the assumption of resistance cost in the absence of the pest.
One hundred and eighty recombinant inbred lines of durum wheat (RILs) derived from the
crosses (CI115 / Bzaiz-AHF/CM829/Cando -H25) segregated for Hessian fly resistance and
adapted to dry areas were planted in two experimental domains of INRA, differing in
Hessian fly infestation levels (Sidi El Aidi and Jemaa-Shaim) in the 2012-2013 season.
Plants were evaluated for agronomic and phenological traits as well as for yield
components. The data indicated that under severe H. fly attacks, the yield losses avoided by
resistant lines may reach 100% and that under pest free situation, the mean values of each
parameter measured are similar between resistant and susceptible groups of lines. These
results indicated that resistance had no negative effect on genetic potential of studied
characters in this case study. In addition, the phenotypic correlations between different
traits are similar between groups under differing situations and this confirms the above
results. The conclusion is that incorporating genetic resistance to Hessian fly has a positive
effect on phenological and agro-morphologic traits, as well as on yield and yield
components under H. fly attack, and has no negative effect on these parameters in a fly free
situation