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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.32

TUBER YIELD AND MORPHOLOGICAL CHARACTERISTICS OF TETRAPLOID SOLANUM PHUREJA – S. TUBEROSUM HYBRIDS OBTAINED THROUGH UNILATERAL SEXUAL POLYPLOIDIZATION

ALBERINO S., IOVENE M., CARUSO G., CARPUTO D.

Departmentof Soil, Plant and Enviromental Science, School of Biotechnology Sciences, Via Università 100, 80055 Portici, Italy

heterosis, earliness, potato, 2n pollen, allelic diversity

Unilateral sexual polyploidization with 4x x 2x crosses is an alternative breeding strategy available for the improvement of cultivated potato via the introgression of genetic diversity from the diploid gene pool. Twenty-four 4x x 2x families from crosses between 20 tetraploid cultivated varieties/advanced clones with different backgrounds and two diploid S. phureja – S. tuberosum hybrids (I and UP88P5) producing 2n pollen were obtained. Clones of each family were evaluated for tuber yield and number, morphological characteristics and earliness, at Camigliatello Silano, Southern Italy. High variably was found between families and clones within each family in terms of morphological tuber characteristics. Most of the clones showed long stolons (64%) and deep eyes (76%), confiming that the inheritance of undesired traits is often a problem of interspecific hybridization, and that further breeding efforts are needed. Considerable variability was observate for earliness but, most of the clones analyzed were later maturity than the tetraploid parents. Significant differences in terms of tuber yield and number were found between families and clones. In particular, out of 203 clones tested, 12% and 85% gave a higher tuber yield than the avarage value of tetraploid and diploid parental groups, respectively. An estimate of the degree of heterosis for tuber yield was obtained by comparing the field performance of the progenies with their respective diploid and tetraploid parents. Twelve 4x x 2x families showed a positive heterosis, and for four of them the value of heterosis was higher than 100%. Our results indicate that selection of new genetic material potentially adapted to the environmental conditions of southern Italy is feasible with the 4x x 2x breeding scheme.