Correspondence: HlongoaneT@arc.agric.za

As the demand for wheat grows rapidly across the globe, Ug99 responsible for tremendous economic losses continuously evolve and spread threatening food security. Developing wheat varieties with moderately effective slow rusting genes and race specific genes is useful in developing more stable and long lasting resistance to curtail the evolution of Ug99 and newly aggressive stem rust races.

This study aimed to pyramid diverse sources of resistance, Sr25, Sr26 and a slow rusting resistance gene Sr2, in the background of three locally adapted bread wheat cultivars because of their effectiveness against Ug99 and other stem rust races. Specific markers for each gene; csSr2, BF145935 and Sr26#43 and BE518379 for Sr2, Sr25 and Sr26 respectively were used to confirm the presence of all the three genes that help to expedite breeding technologies through marker assisted selection (MAS). F1 lines carrying the pyramided genes were selected and crossed to the recurrent parents.

These lines were checked for homozygosity for the three genes up to the BC3F2 generation.

A total of 64 lines carrying all the three stem rust resistant genes were obtained and screened at both seedling and adult plant stage for their infection response and disease severity to the currently prevalent Pgt races in South Africa. Marker assisted background selection accelerated recovery of the recurrent parents.

The lines developed in the present study provide improved versions of the three recurrent parents with good disease resistance of stem, leaf and stripe rust and desirable agronomic performance. The balance between desirable agronomic traits and excellent disease resistance would promote the use of these lines and to provide immediate useful germplasm for disease resistance.