Analysis on Genetic Recombination of an F3 Population in Rice Using SSR Markers

• Main Authors: Wen-Tsung Hsieh, 謝汶宗
• Other Authors: 林順福
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/92277496523287624988

碩士 === 國立臺灣大學 === 農藝學研究所 === 94 === A total of 230 individuals attributed to 19 F3 lines, were used to study segregation distortion, genetic recombination, genetic contribution from female or male parent, and homozygosity in the F3 population. In addition, comparison of genetic recombination between F3 and F2 (previous study) was discussed. The 19 lines with at least one pair of entire homologous chromosomes from each parent were identified using SSR DNA markers from 93 F2 plants of an inter-subspecific cross population, Taichung-Sen 10 (indica type) x Koshihikari (japonica type). The experimental results indicated that the averaged crossing over frequency was 1.47 times for a pair of homologous chromosomes and 17.64 (1.47 x 12) times for an F3 individual bred through F2 generation. The chromosomes 2 and 7 respectively had the highest (2.11 times) and the lowest (0.93) frequencies of crossing over in the F3 generation, and similar results were found in the F2 generation of the same cross. Four SSR DNA loci, including OSR26 on chromosome 2, RM340 and OSR21 on chromosome 6, and RM202 on chromosome 11, accounted for 5% of 80 analyzed loci were detected. In comparison with the F2 generation (46.08%), apparent decline in the frequency of segregation distortion was observed in the F3 generation. This result supports the hypothesis that the segregation distortion is not controlled by a single gene. Segregation distortion to indica genetic background in the F2 generation was obviously reduced in the F3 generation. The segregation distortion in the RM340 and OSR21 loci was mainly caused from the deviation of homozygous genotypes. However, segregation in the OSR26 and RM202 loci was mostly resulted from the increase of heterozygous genotypes. The systematic study results of genetic recombination and genotypic segregation in the F2 and F3 generations of an inter-subspecific cross population would provide information for early generation selection in rice breeding.