Institute Cytology and Genetics

Laboratory of Plant Cytology and Apomixis

Head V.A.Sokolov, Dr.Biol.Sci.

Research at the Laboratory addresses problems in the genetic control of apomixis and transfer of this reproduction mode to maize. Many year study has been concerned with intergeneric hybrids of maize (Zea mays L.) and Tripsacum (Tripsacum dactyloides L.), a wild relative of maize with apomixis of the Antennaria-type (mitotic diplospory). The laboratory succeeded in transferring the ability for stable apomictic reproduction to the F1 hybrids, 2n=56 (20Zm+36Td) and to derive from the hybrid a unique collection of maize x Tripsacum hybrids with a different ratio of the parental genomes. Forms with 9 chromosomes from Tripsacum (2n=39, 49, 59; 30Zm+9Td, 40Zm+9Td, 50Zm+9Td) were obtained for the first time in the world by backcrossing to the maize forms. The new forms retained the character of asexual reproduction through the seed. Further cytogenetic study of additional maize x Tripsacum hybrid lines justified the conclusion that a subset of 9Tripsacum chromosomes is needed to provide stable expression of apomictic development.

To better understand the problem of paternal sterility in apomictic hybrids, detailed embryological studies are needed. The problem also raised interest in the phenomenon underlying the anomalous development of endosperm.