Breeding potential of Solanum tuberosum–S. commersonii pentaploid hybrids: fertility studies and tuber evaluation

Abstract

Twenty-one (near) pentaploid hybrids between sexually incompatible Solanum commersonii [2x(1EBN)] and cultivated S. tuberosum [4x(4EBN)] were characterized for tuber traits and fertility. A number of genotypes resembled the S. tuberosum type in terms of stolon length and eye depth and produced tubers under long day conditions. Tuber yields were not as high as expected, probably due to lack of adaptation of the S. commersonii genome to the environmental conditions in southern Italy (on average 325 gÁpt -1 and 285 gÁpt -1 in 2003 and in 2004, respectively). Compared to 2004, in the summer of 2003, characterized by extremely high temperatures, hybrids gave a higher tuber yield than the S. tuberosum control, suggesting that in our environmental conditions the wild S. commersonii genome, rather than resulting in heterosis for tuber yield, provides better adaptation to harsh environments. Although aneuploidy has often been associated with reduced fertility, several hybrids were fertile in crosses with S. tuberosum when used as female parents. In particular, the average berry set and number of seeds per berry were 38.2% and 31.8%, respectively. Based on significant relationships between ploidy levels and all yield and fertility data measured, the presence of extra chromosome affected the parameters considered: tuber yield in 2003 and 2004, percentage of fruit set, number of seeds per berry and number of seeds per pollinated flower. Regression analysis also indicated that ''Residuals'' were significant for all parameters measured. Therefore, additional factors (e.g. the genetic makeup of hybrids) may be key to fertility and yield.

Resistance to Ralstonia solanacearum of Sexual Hybrids Between Solanum commersonii and S. tuberosum

“…Due to the good fertility of (near) pentaploids (Caruso et al 2008), there should be no further barrier to the introgression of resistance genes into cultivated varieties. This plant material is also suitable for further studies on the genetics and nature of R. solanacearum resistance of wild S. commersonii.…”

Are We Getting Better at Using Wild Potato Species in Light of New Tools?

“…2 will hybridize with cultivated potato, producing generally fertile aneuploids. Several variations of this scheme have been published (Ehlenfeldt and Hanneman, 1984; Camadro and Espinillo, 1990; Adiwilaga and Brown, 1991; Carputo et al, 1997; Carputo and Barone, 2005; Caruso et al, 2008). Ploidy reduction can also be used to manipulate EBN.…”

Flower Forms and Ploidy Levels Impact Fertility in Althea

“…Although triploids are often sterile or nearly so, odd ploidy levels are not always a guarantee of seedlessness. Higher-level polyploids, such as pentaploids, vary in fertility levels, as observed in crops such as Solanum (Caruso et al, 2008), Lantana (Czarnecki et al, 2014), and Vaccinium (Laverty and Vorsa, 1991). For example, Lantana triploids had only 9.3% pollen stainability compared with 34.6% in pentaploids (Czarnecki et al, 2014).…”

“…For example, Lantana triploids had only 9.3% pollen stainability compared with 34.6% in pentaploids (Czarnecki et al, 2014). In Solanum, Caruso et al (2008) found that several pentaploid hybrids were female fertile when crossed with the tetraploid S. tuberosum. In addition, they found that the number of extra chromosomes in their aneuploid accessions had a significant effect on most of their fertility parameters, including berry set, number of seeds per berry, and number of seeds per pollinated flower (Caruso et al, 2008).…”

“…In Solanum, Caruso et al (2008) found that several pentaploid hybrids were female fertile when crossed with the tetraploid S. tuberosum. In addition, they found that the number of extra chromosomes in their aneuploid accessions had a significant effect on most of their fertility parameters, including berry set, number of seeds per berry, and number of seeds per pollinated flower (Caruso et al, 2008). Their results agree with previous work in Vaccinium (Laverty and Vorsa, 1991), which showed a positive linear relationship between chromosome number and fertility in aneuploids.…”