Polyacrylamide gel with BNL3279 SSR marker presenting allele segregations in the parental species, the hexaploid, the HTL tri-species hybrids and the BC1 plants. 1 G. hirsutum 2 G. thurberi 3 G. longicalyx 4 the hexaploid (G. hirsutum × G. thurberi)2 5–13 HTL tri-species hybrid plants (G. hirsutum x G. thurberi)2 × G. longicalyx 14–24 BC1 plants (HTL x G. hirsutum). Black arrow: allele of G. hirsutum, Blue arrow: allele of G. thurberi, Red arrow: allele of G. longicalyx.