Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.52

SELECTION FOR FROST TOLERANCE AND ACCLIMATION CAPACITY OF POTATO GENOTYPES DERIVED FROM SOLANUM COMMERSONII (+) S.TUBEROSUM SOMATIC HYBRIDS

T. CARDI, F. CONSIGLIO, F. FIORENTINO, P. PALMIERI

CNR-IGV, Institute of Plant Genetics, Res. Div. Portici

cardi@unina.it

potato, somatic hybrids, frost tolerance, Solanum commersonii

Frost tolerance is a desirable trait in potato, especially for off-season growth in autumn and winter. Genetic variability for both frost tolerance and acclimation capacity, however, is limited within the cultivated gene-pool. S. commersonii (cmm), is a useful source of genes for both traits, but is sexually incongruent with S tuberosum (tbr). Self and backcross progenies derived from a somatic hybrid between the two species were analyzed for agronomic and stress tolerance-related traits. The frost tolerance with and without hardening (LT₅₀AA and LT₅₀NA, respectively) of selected progenies is reported in this study.

The LT₅₀NA of 38 BC₁ and one self clones varied from –1.8 to –3.3 °C. In similar experiments, that of cmm was equal to –4.6 °C, whereas that of a pool of tbr varieties ranged from –1.9 to –2.5 °C. About 60% of tested progenies were significantly better than the control variety Spunta that showed an LT₅₀ equal to –2.2 °C. The LT₅₀AA of self and BC₁ progenies ranged from –2.0 to –5.3 °C, whereas that of cmm and tbr was –8.8 and –2.1 / -3.6 °C, respectively. About 90% of progenies were significantly more tolerant than Spunta. Best clones showed an LT₅₀AA around –5.0 °C, very close to that shown by somatic hybrids.

BC₂ progenies were produced by crossing the best BC₁ clones with two tbr varieties. Seedlings of 34 BC₂ families were tested in a cold chamber at –4 / -4.5 °C (without hardening) and at –5 / -5.5 °C (after hardening at 4 °C for two weeks). On the whole, 116 out of about 2000 seedlings (6%) survived the freezing test w/out hardening, whereas 13 out 527 (2.5%) the test with hardening. The frost tolerance of a sample of about sixty plants survived in the cold chamber was checked again by means of the electrolyte leakage test. Eleven BC₂ clones with LT₅₀NA < -2.5 °C and 13 with LT₅₀AA < -3.5 °C were selected.

Best BC₂ clones will be tested for agronomic performance in off-season growth in autumn-winter.