Cytoplasmic male sterility (CMS) systems are based on the nuclear-cytoplasmic incompatible interaction which are frequently used for hybrid seed production in many crops. Tbe msHl CM ystem results from the incompatibiJity between the nuclear genome of wheat and the cytoplasmic geno me of the wild bar ley species Hordeum chilense (Martín et al. 2008). Chromosomal reorganizations are frequently observed in interspecific bybrids. In a descent obtained from octoploid tritordeum x common wheat, the addition of a modified extra chromosome (acrocentric type) from H chilense with fertility restoring ability in the msHl system was found. Molecular marker and GISH characterization revealed that it was composed by parts from both short arms ofchromosomes lH and 6H (Castillo et al. 2014).

In the descent of plants harboring this acrocentric chromosome, smaller modified Chromosomes, also capable of restoring fertility in a single dose, were originated. On of this minichromosomes was characterized by GISH and molecular markers confirming that it was a reorganization of H. chilense chromosome 1H and 6H. It was also isolated and sequenced to identify candidate genes for fertility restoration. Two other lines with minichromosomes derived from the acrocentric were obtained in different events. Preliminary characterizations derived from the acrocentnc with molecular markers show that these minichromosomes are different, being an excellent material to identify putative restoring genes along with their fertility restoration ability.

Trabajo presentado en el 8th International Triticeae Symposium y la 13th Gatersleben Research Conference, celebrados en Wernigerode/Gatersleben (Alemania) del 12 al 16 de junio de 2017.

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