Création et sélection de populations diploïdes de pomme de terre (Solanum tuberosum L)

Abstract

L). A large number (3 027) of dihaploids (2 n = 2 x = 24) has been obtained from 445 tetraploid (2 n = 4 x = 48) potato clones by means of in situ parthenogenesis. These pollinations gave about 2 to 3 seeds per fruit. Of the seedlings 27% were dihaploid. The dihaploids had weak vigour and were all male sterile, but showed a wide variability for plant aspect, tuber characteristics, processing quality (dry matter content and ability to be fried) and disease and pest resistance. They were subsequently included in hybridizations with 4 diploid related species (S phureja, S stenotonum, S chacoense and S vernei). First generation hybrids were intercrossed or crossed with other dihaploids and different combinations were then obtained. Hybrid groups were distinguished depending on the species used. These hybrids were very vigourous and exhibited enough male fertility, the latter depending on the dihaploid used. They were described for characters such as dry matter content and chipping quality. The advanced diploid populations prove to be adapted to French cropping conditions and show interesting variability. They constitute a basis for the resynthesis of tetraploid clones and they will be used for the application of biotechnology and the introduction of new related species.Solanum tuberosum = potato / breeding / diploid / related species INTRODUCTION

Homozygote Depression in Gamete-Derived Dragon-Fruit (Hylocereus) Lines

“…Further support comes from the study of Plume et al ( 2013 ), which showed a low level of polymorphism within or among H. megalanthus accessions, meaning an autopolyploid rather than an allopolyploid origin. Their findings, in turn, are corroborated by the almost insignificant gametoclonal variation (namely, variation in plant morphology) observed in our study in the di-haploid H. megalanthus lines in comparison with the donor plant: the only difference lay in the size of the floral organs (bud length and width) of the di-haploid lines, which was smaller than that of the tetraploids (Figures S3 , S4 ) These findings contrast with the wide variability in plant morphology reported for a di-haploid potato by Rousselle-Bourgeois and Rousselle ( 1992 ).…”

Overcoming hybridization barriers in potato

“…1958). These 2x (2EBN) haploids cross readily to 2x (2EBN) wild species, often producing hybrids with good yield, adaptation and fertility (Hermundstad and Peloquin 1986, Yerk and Peloquin 1989, Rousselle‐Bourgeois and Rousselle 1992, Serquén and Peloquin 1996, Tucci et al. 1996).…”

Root and Tuber Crops

“…When they also produce 2n gametes by FDR (first division restitution), much of the genetic diversity of the wild species can be efficiently transferred to the tetraploid offspring from 4x × 2x crosses and results in about 25% of the wild species genes in the final product (Tai, 1994;Jansky, 2009). Tai (1994) concluded, however, that haploid-wild species hybrids need to be improved before they are used in 4x × 2x crosses, for example, through population improvement by recurrent selection (Rousselle-Bourgeois and Rousselle, 1992). In contrast, diploid hybrids with S. raphanifolium with resistance to cold-sweetening after storage for 3 months at 2 • C have been used by Hamernik et al (2009) to produce commercially acceptable tetraploid offspring without extensive backcrossing to cultivated germplasm.…”