Abstract:

The good acceptors for maize transgenic engineering are insufficient in our country, especially in the southwest mountain areas of China. The hereditary variation regularity of maize culture capacity is not very clear. The efficiency of embryonic callus induction and the number of regenerated plantlet were used as the characters of the maize culture capacity in this research. A genetic linkage map was constructed using 88 simple sequence repeat (SSR) markers on a maize (Zea mays L.) population consisting of 202 F2 individuals derived from the cross between the inbreds 18-599 (red) (higher culture capacity) and R15 (lower culture capacity). The SSR map covers 1 636.6 cM over the ten chromosomes, with an average interval length of 18.60 cM (Fig.3) with software MAPMAKER version 3.0b. The immature embryos from the population of 202 F₂﹕3﹕4 lines were evaluated in two traits which were in a normal distribution based on the investigated values (Table 1, Fig.1 and Fig.2). With the method of composite interval mapping (CIM) described in QTL Cartographer V2.0 procedure, 5 quantitative trait loci (QTL) were identified for efficiency of embryonic callus induction, on chromosomes 1, 3, 7 and 8 respectively, accounting for phenotypic variation from 5.25% to 23.4% (Table 2); one QTL was revealed for number of regenerated plantlet on chromosome 3 and explained the phenotypic variation of 13.42%. Combining the marker assisted selection (MAS) method, the necessity and possibility will be enhanced greatly to transferring the high-culture capacity as well as to accurately location, clone and transformation of the main effect QTL of these two characters.

Key words: SSR marker, Genetic map, Immature embryo culture capacity, QTL, Maize