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

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

RESISTANCE TO LOW TEMPERATURE AND GLYCOALKALOID CONTENT OF INTERSPECIFIC HYBRIDS BETWEEN SOLANUM TUBEROSUM AND S. COMMERSONII

TERRA A.*, FOGLIANO V.*, ESPOSITO F.*, PARISI M.**, CARPUTO D.**

* Department of Food Science, University of Naples “Federico II”, Via Università 100, 80055 Portici, Italy

** Department of Agronomy and Plant Genetics, University of Naples “Federico II”, Via Università 100, 80055 Portici, Italy

carputo@unina.it

ploidy manipulations, LT₅₀, acclimation capacity, HPLC, mass spectroscopy

Wild Solanum species represent an excellent source of useful traits lacking in the cultivated potato Solanum tuberosum (tbr). Resistance to biotic as well as abiotic stresses, several quality traits, and allelic diversity can be easily found in these species. Along with useful traits, however, the use of wild species in potato breeding can cause the appearance of undesired traits and/or chemical changes of tuber composition. Thus, chemical analyses should be carried out to assess the value of newly produced genotypes. To introgress freezing resistance and capacity to cold acclimate from the incongruent species S. commersonii (cmm) into tbr form, a breeding scheme based on ploidy bridges h been developed. F₁ triploids, BC₁ (near) pentaploids and BC₂ (near) tetraploids characterized by various wild to cultivated genomic ratios have been produced. F₁ triploids (2:1 cmm to tbr genomic ratio) were those with freezing resistance and capacity to cold acclimate closer to those of the wild parent (on average LT₅₀ were -4.4°C and -6.3°C, respectively). In the BC₁ and BC₂ generations the average resistance for the two traits was reduced and distributed between the two parents. However, resistant genotypes, expecially in terms of acclimation capacity, were identified. Unfortunately, cmm has also a number of undesired traits. Its glycoalkaloid content, for example, is very high both in tubers and leaves. HPLC and mass spectroscopy were used to assess if glycoalkaloid from cmm were transmitted to the various hybrid generations. Interestingly, we found that F₁ and BC₁ hybrids analyzed contained all the tbr (solanine and chaconine) and cmm (demissine, deidrotomatine and commersonine) glycoalkaloids. By contrast, some BC₂ hybrids completely lost the glycoalkaloids of the wild species, having only solanine and chaconine. These results are felt very important, indicating that the glycoalkaloids of cmm can be lost after only two backcross generations, and thus hybrids combining resistance traits from the wild species and low glycoalkaloid content can be selected.