Identifying apomixis in matroclinal progeny from an interspecific crossing between Iris domestica and three different colors of Iris dichotoma

In a previous investigation on the reciprocal difference of interspecific hybridization between three different flower colors of Iris dichotoma and Iris domestica in the F1 offspring from crosses where I. domestica was a maternal parent were similar in morphological and cytological characters to their maternal parent. This could be evidence of apomixis; however, matroclinal progeny with complete morphological similarity to the maternal parent could be attributed to the heterozygosity for these characters in the pollen parent. The F1 plants were investigated in order to identify apomixis in I. domestica. Four matroclinal plants were randomly selected from each F1 population produced from Iris domestica × Iris dichotoma that had three different colors of flowers and were allowed to self-pollinate to establish an F2 population. All of the F2 plants had no segregation to I. domestica in their morphological characters. In addition, 13 reciprocal F1 plants were detected by 25,719 single nucleotide polymorphism (SNP) markers. When I. dichotoma plants with three different flower colors were used as maternal parents, all the progenies were genuine hybrids. When I. domestica were used as maternal parents, all the F1 plants were apomictic progenies. Apomixis of I. domestica was successfully identified and SNP markers identified F1 hybrids derived from six interspecific crosses between I. dichotoma and I. domestica, which provides a reference for authenticating offspring identity during Iris cross breeding in the future.