Fecundity of Tetraploid × Diploid Crosses and Fertility of the Resultant Triploids in Salpiglossis sinuata

Abstract

<jats:p>Mean seed production in tetraploid × diploid crosses of <jats:italic>Salpiglossis sinuata</jats:italic> R <jats:italic>et</jats:italic> P. was similar to that in diploid × diploid crosses, but germination of the resultant triploid seeds was low (8%). Parental line selection resulted in some germination improvement. Triploid hybrids from these crosses were vigorous, with floral characteristics resembling tetraploids. The fertility indices of self-pollinations of triploids and pollinations by diploid and tetraploid plants were &lt;1, 22, and 6, respectively, compared with 176 for diploid × diploid crosses. Thus, the self-pollinated triploids were virtually sterile.</jats:p>

Pathways, Mechanisms, and Rates of Polyploid Formation in Flowering Plants

“…Further evidence that triploids are often semifertile comes from the few studies that have examined the relative fertility of crosses involving triploids. The available data suggest that some viable progeny are typically obtained from 2x × 3x, 3x × 2x, and 3x × 3x crosses, and that crossing success may vary with the direction of the cross (51,126,152,170).…”

Gametes with the somatic chromosome number: mechanisms of their formation and role in the evolution of autopolyploid plants

“…Secondly, in many cases, tetraploid male-sterile or self-incompatible plants have been used as female parents (McCoy, 1982;McCoy & Rowe, 1986;Veronesi, Mariani & Bingham, 1986;Groose et al, 1988;Van Santen, 1988;Negri & Veronesi, 1989;Maceira, 1990;Freyre et a/., 1991;Van Santen et al, 1991;De Haan et al, 1992;Maceira et al, 1992). In other investigations, the 4x female parents have been emasculated to render them male-sterile (Den Nijs & Peloquin, 1977a, 6;Shoemaker-Megalos & Ballinton, 1988;Sa\a et al, 1989;Jongedijk ei a/., 19916;Ortiz & Peloquin, 1991a, 6;Werner & Peloquin, 1991a;Needham & Erickson, 1992).…”

Effect of triploid fitness on the coexistence of diploids and tetraploids

“…Evidence of lower triploid block is given by the frequent discovery of triploids in contact zones between diploids and tetraploids (Miintzig, 1937;Zohary & Nur, 1959;Lord & Richards, 1977;Felber & Girard, 1986;Felber, in prep. ) and in experimental crosses (Jones & Borrill, 1962;Alexander & Beckett, 1963;Van Dijk, Stegeman & Van Delden, 1991b;Van Santen, Hugessen & Casler, 1991;de Haan et ul., 1992;Maceira et al, 1992;Needham & Erickson, 1992;Felber, in prep.). Triploids may also arise by the fusion of a reduced gamete and a 2n gamete (Rhoades, 1936).…”