Genetic mapping in rice using isozyme and RFLP markers

Abstract

Four isozyme loci were assigned to linkage groups through primary trisomic analysis: Got-3 on chromosome 2, Enp-1 on chromosome 6, Est-1 on chromosome 7, and Fdp-1 on chromosome 11. Amp1 and Got-3, located on chromosome 2, were found to be independent of each other. Enp-1 was independent of Est-2 and Pgi-2, and Est-1 of Est-9. Linkage relationships between isozyme and RFLP markers were determined from IR36/Ma Hae F₂ segregation. IR36 and Ma Hae show polymorphism for Adh-1, Amp-1, Amp2, Amp-3, Amp4, Est-1, Est-2, Est-9, Fdp-1, Mal-1, Pgd-1, Pgi-1, Pgi-2, and Sdh-1. The single-copy DNA probes of the rice genomic library (RG probes) were labeled with nonradioactive digoxigenin-deoxyuridine triphosphate. The DNA was digested with seven restriction enzymes (EcoRI, EcoRV, BamH1, Pst1, HindIII, Xba1, Dra1) and hybridized with six polymorphic RG probes belonging to chromosomes 6, 7, and 11. RG213 was shown to be linked with Est-2, Amp3, and Pgi-2, with distances of 1.7, 1.7, and 7.9 map units, respectively. RG64 was linked with these 3 markers with distances of 22.5, 22.5, and 11.5 map units, respectively. RG118 was linked with Adh-1 with a distance of 7.3 map units. Mal-1 was located on chromosome 7 through linkage with RG173.