1 Bryan Kindiger USDA-ARS Grazinglands Research Laboratory El Reno, OK 73036 2 Sergey Chalyk Institute of Genetics M. Spataru str. 15, P.O. Box 134 Chisinau 277042 Republic of Moldova
Cytogenetic and molecular evaluations were performed on eight apomictic maize-Tripsacum hybrid families carrying 36, 18, and 9 Tripsacum chromosomes. In addition, one apomictic family possessing a Mz6L-Tr16L translocation was included. Chromosome counts and random amplified polymorphic DNA (RAPD) analyses were used to assess the chromosome constitution, genetic uniformity, and mode of reproduction in nine apomictic lines representing four differing lines of descent. Individuals, regardless of their chromosome constitution, were compared within and among related and unrelated families. The number of progeny generated by apomixis, sexual developmental behaviors, sexual polyploidization, and polyembryony was obtained. Data indicate that apomictic, sexual, BIII derived hybrids and twin offspring occur at similar frequencies regardless of their maize and Tripsacum chromosome constitution. Comparisons on the type and frequency of progeny obtained from identical or closely related families generated during various growing seasons were inconclusive, but suggest that environmental components do not obviously affect apomictic expression. In addition, chromosome and molecular variations were observed in apomictic progeny obtained from apomictic parents, indicating that an infrequent level of partial meiotic activity is occurring in these apomictic individuals.
Plant & Animal Genome VIII Conference Plant & Animal Genome VIII Conference