构建全基因组导入系所需 BC₁F₁ 群体大小的影响因素分析

Introgression lines are important genetic materials for genetics study and breeding. Development of those lines involves cross and backcross processes between recipient and donor parents. The population size of BC₁F₁ is a critical parameter for fully covering donor genome and successfully obtaining desired introgression lines. However, the minimum sufficient number of BC₁F₁ plants is unknown for each species and can not be obtained experimentally. We have developed a computer program by simulating the recombination process during meiosis to define the ideal BC₁F₁ population size. The reliability of the program was confirmed by mathematics and experimental data. Three factors including linkage groups number, linkage group length and gene density were analyzed and all of them had positive relation with the BC₁F₁ population size. The population size increased from 6.06 to 9.49 when the linkage number increased from 5 to 40. The population size was 7.14 when the linkage group length was 80 cM, while it became 8.64 when the length was 200 cM. The population size was 7.65 with the density of 20 cM per gene and 8.22 with 10 cM per gene. The BC₁F₁ population sizes of rice, wheat, maize and soybean were predicted to be 12, 13, 14–15, and 13 by the program with 95% confident level.