Cytological characterization of potato -Solanumetuberosumsomatic hybrids and their backcross progenies by genomic in situ hybridization

Abstract

Four somatic hybrids derived from a diploid wild species Solanum etuberosum and a diploid tuber-bearing Solanum clone 463-4, together with five BC1 and three BC2 plants, were analyzed by genomic in situ hybridization (GISH). None of the four somatic hybrids had the expected chromosome constitutions, i.e., 24 chromosomes from each fusion parent. Either one chromosome from S. etuberosum or one from the potato parent 463-4 was lost in the hybrids. Three BC1 plants had exactly one set of S. etuberosum chromosomes. The other two BC1 plants either had one extra or one fewer S. etuberosum chromosome, possibly because their somatic hybrid parents had an extra or had lost one S. etuberosum chromosome. The presence of one set, or close to one set, of S. etuberosum chromosomes in all BC1 plants suggests a preferential pairing and segregation of the S. etuberosum chromosomes in the somatic hybrids. Two of the three BC2 plants had 52 chromosomes, deviating significantly from the expected chromosome number of 48. These results suggest poor pairing between S. etuberosum and S. tuberosum chromosomes in the BC1 plants. The present study demonstrates the importance of combining GISH and DNA marker analysis for a thorough characterization of potato germplasm containing chromosomes from different species.Key words: potato germplasm, Solanum etuberosum, molecular cytogenetics.

Reproduction and cytogenetic characterization of interspecific hybrids derived from Cucumis hystrix Chakr. × Cucumis sativus L.

“…Our observations indicate that the majority of C. hystrix chromosomes are about one-half the length of those of C. sativus, and also stain poorly. GISH has proven useful for determining the parentage of chromosomes in somatic hybrids (Dong et al 1999), and was effective in our studies for the assessment of chromosome constitution after interspecific hybridization.…”

“…Shared C. sativus DNA (0.5 µg/µl) was added to the hybridization mixture. GISH experimentation proceeded according to Dong et al (1999) such that 40 µl of hybridization mixture containing 100 ng of the C. hystrix probe (2 to 5 µl), and 4 µg of blocking DNA (about 8 µl), were applied to chromosome preparations. Post-hybridization washing and signal detection procedures were according to those described by Jiang et al (1995).…”

Comparative Oligo-FISH Mapping: An Efficient and Powerful Methodology To Reveal Karyotypic and Chromosomal Evolution

“…S. etuberosum: S. etuberosum is a nontuberizing wild species that has been used in potato breeding due to its resistance to various potato diseases (Dong et al 1999;Novy et al 2002Novy et al , 2007. Phylogenetically, S. etuberosum is more distantly related to potato than tomato is to potato (Lou et al 2010).…”

Identification of mitotic chromosomes of tuberous and non-tuberousSolanumspecies (Solanum tuberosumandSolanum brevidens) by GISH in their interspecific hybrids

“…For the genetic enhancement of potato using alien genomes, the application of GISH for detailed analysis of interspecific hybrids has great potential. Of the hybrids between S. brevidens containing the E genome and S. tuberosum containing the A genome, there are no previous reports of chromosome complements detected by GISH except Dong et al (1999) who were able to discriminate the A and E parental genomes in a related combination (S. tuberosum × S. berthaultii + S. etuberosum).…”

“…Since the demonstration of genomic in situ hybridization (GISH) using total genomic DNA probes (Schwarzacher et al 1989), cytological analyses of wide hybrids, such as intergeneric Solanum + Lycopersicon (Wolters et al 1994;Jacobsen et al 1995;Garriga-Calderé et al 1997;Gavrilenko et al 2001), and analysis of hybrids between species that belong to different subgenera (Solanum tuberosum + Solanum nigrum) (Horsman et al 2001) have been carried out. However, in GISH analysis there are only a few reports (Wilkinson et al 1995;Dong et al 1999) of hybrids between phylogenetically more-related Solanum species that belong to the section petota (Hawkes 1990).…”