Establishment And Application Of Marker-assisted Selection For PVY And PVX Resistance In Potato (solanum Tuberosum L.)

In this paper, a marker-assisted selection system on virus-resistance breeding were established.The system was proved to be steady and easy to operate in potato virus-resistance breeding. The mainresults achieved are as follows:1.9markers related to potato virus resistance were collected and analyzed. Among these markers,marker RYSC3and Rxsp were found to be linked to PVY and PVX resistance, respectively. Throughtest and verification, the two markers were amplified clear bands with good repeatibility and detectedeasily. The two marker-linked genes have been identified in S. tuberosum ssp.andigena, which werewidely used in potato breeding. It was concluded that this two markers would be suited for using inmarker-assisted selection.2.22tetraploid materials were further analyzed with marker RYSC3and Rxsp, while they wereinoculated with viruses of PVY and PVX. C120were detected with marker RYSC3and Rxsp, andshowed resistance to PVY and PVX. Whereas, Ca11were detected with neither marker RYSC3norRxsp, and showed susceptible to PVY and PVX. A segregating population for virus-resistance wasconstructed from cross of female parent C120and male parent Ca11.3.139progenies of the population were screened with markers RYSC3and Rxsp, and wereinoculated with PVY and PVX. The results showed that RYSC3and Rxsp were closely linked to PVYand PVX resistance, respectively. Markers RYSC3and Rxsp would be used for further study on theestablishment of the multiplex PCR system.4. A multiplex PCR system to screen RYSC3and Rxsp was established, and was confirmed withvirus-resistance segregating population. The results showed that the system is stable and reliable. Itwould be an efficient and low-cost tool for the virus-resistance genes pyramiding in potato breeding.5.190Chinese approved potato cultivars were screened with marker RYSC3and Rxsp.22cultivars were screened out with RYSC3, and accounted for11.6%in all cultivars tested, while15cultivars with marker Rxsp，acounted for7.9%in all cultivars tested. More than40%of cultivars withmarker RYSC3or Rxsp were progenies of Neo-tuberosum or materials from CIP，and more than50%ofthem were approved after2001．6.699accsessions of exotic germplasm were screened with markers RYSC3and Rxsp.202materials were screened out with RYSC3, and accounted for28.9%in all materials tested, while157materials with marker Rxsp, accounted for22.5%in all materials tested．Materials from CIP made upthe largest proportion of markers RYSC3and Rxsp, which accounted for36.8%and39.9%,respectively．It was concluded that germplasm from CIP would be helpful for the breeding ofvirus-resistance cultivars.