Molecular markers linked to apomixis in Paspalum notatum

MARTÍNEZ, ERIC J.; ORTIZ, JUAN P. A.; HOPP, HORACIO E.; QUARIN, CAMILO L.

Victoria, Australia

Congreso; Second International Symposium Molecular Breeding of Forage Crops 2000; 2000

Apomixis, asexual reproduction by seeds is a mode of reproduction of Paspalum notatum, a forage grass native to Central and South America. Diploid cytotypes are sexual while tetraploids are apomictic. Sexual tetraploid plants were induced from diploids. Manipulation of apomixis may have a great impact in agriculture. Our objective was the identification of molecular markers linked to apomixis. A segregating population for the reproductive mode of about 200 individuals was generated by crossing a sexual tetraploid plant with an apomictic one. F1, progenies were classified in sexual or apomictic by direct observation of embryo sacs in 60 clarified ovaries for each plant. Bulked segregant analysis was used to identify RAPD and AFLP markers associated with the trait. Ten plants were included in each group (sex, ape). Four hundred RAPD primers of British Columbia University were tested. AFLP experiments were carried out using EcoRI and Msel in combination with 10 pairs of oligonucleotides. Two RAPD and 2 AFLP markers showed clear differences between the groups. All markers resulted specific to the apo group and were present in the apo parent. Linkage analysis performed on a sample of the population (50 sex and 48 apo individuals) showed a high degree of co-segregation (2 %< r < 3%) between the apo locus and the 4 molecular markers detected.