Isolation of five new monosomic alien addition lines of Gossypium australe F. Muell in G.hirsutum L. by SSR and GISH analyses

With 2 figures and 3 tables Gossypium australe F. Muell (2n=2x=26) is a wild perennial species possessing agronomic useful traits that would be interesting to introgress into G. hirsutum L. (2n=4x=52), the main cultivated cotton species. To isolate monosomic alien addition lines (MAALs) of G. australe in G. hirsutum, the [2(G. hirsutumG. australe) G. hirsutum] pentaploid (2n=5x=65) was backcrossed as male parent to G. hirsutum. Analysis of 42 BC1 plants and seven alien addition lines, already available, with 150 SSR markers developed from G. hirsutum revealed a cross-species amplification rate of 100% and a polymorphism rate of 56%. Eighty polymorphic SSR markers generated 87G. australe-specific loci that have been assigned by a hierarchical cluster analysis to 13 linkage groups corresponding to the 13 chromosomes of G. australe. Analysis by SSR markers and genomic in situ hybridization of the self-progeny of disomic alien addition lines, backcross progeny of the pentaploid, allowed the isolation of five new MAALs.