ARS | Publication request: EXPRESSION OF FREEZING TOLERANCE IN SOMATIC HYBRIDS BETWEEN HARDY WILD AND CULTIVATED POTATO SPECIES

Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: May 16, 1996
Publication Date: N/A

Technical Abstract: Somatic hybrids (SH) with balanced genomes from fusion parents can retain the intragenomic heterozygosity and bypass the effect of allelic segregation occurred in sexual F1 hybrids. In order to explore the genic interaction between hardy and nonhardy genomes, this study was undertaken to characterize the expression of nonacclimated freezing tolerance (NA) and acclimation capacity (ACC) in two kinds of SH: 1) hexaploid SH from S. tuberosum and S. brevidens (tbr-brd) and 2) tetraploid SH from haploid S. tuberosum and S. commersonii (tbr-cmm). Our data showed that the freezing tolerance in brd mainly came from ACC. However, ACC of tbr-brd SH was similar to tbr, indicating that ACC of brd was poorly expressed in the tbr-brd SH. The tbr-cmm SH, NA was also as low as the sensitive parent, while ACC did increase significantly and approximated that of the parental mean. These results along with the information from a parallel study in interspecific F1 hybrids suggest that the suppressed expression of freezing tolerance of brd and cmm in the SH was probably due to the dominance effect of homoeoallelic genes present in the nonhardy parent. Some of the tbr-cmm SH had acclimated freezing tolerance similar to hardy species and these SH were found to be crossable with a potato cultivar. Therefore, to use these materials in breeding for cold hardiness is encouraging.