Cytology and breeding behavior of some Impatiens hybrids and their backcross progeny

Abstract

Impatiens crosses were made between Plant Introduction (P.I.) 349629 (2n = 16) and cultivar Tangerine (2n = 8), producing a hybrid (2n = 12) that seemed sterile. A large number of pollinations of the hybrid with 'Tangerine' pollen, however, produced only three progeny with 2n numbers of 8, 9, and 12. The backcross with hybrid pollen on P.I. 349629 produced five progeny, all of which were 2n = 20. None of these backcross progeny has shown fertility at present. Backcrosses involving the hybrids between 32 chromosome P.I. accessions and 'Tangerine' have been unproductive. Eleven of the hybrids (2n = 24) between P.I. 349629 and several of the 32-chromosome P.I. accessions occasionally produced viable pollen. When used on a 'Tange-glow' female, which is a 24-chromosome amphidiploid, numerous progeny resulted, some of which proved to be fertile in subsequent crosses.

In vitro pollen germination and viability of a Java × New Guinea Impatiens interspecific hybrid

“…Interspecific hybrids obtained from crosses among New Guinea (2n = 32), Java (2n = 16), or Celebes (2n = 8) Impatiens are often sterile (2,3,7,8,9). Male sterility has impeded the development of hybrids with a combination of desirable characteristics from several species (8).…”

“…Methods for achieving fertility have been pursued with some success ( 1 , 2 , 4, 7 , 8, 9). Colchicine-induced amphidiploids of sterile hybrids were found to produce fertile pollen (2,4,9), whereas naturally occuning pollen fertility has been observed without colchicine induction (7, 8 , 9 , 11).…”

Formation of Unreduced Pollen by an Impatiens Hawkeri × Platypetala Interspecific Hybrid

“…and Java (I. platypetala Lindl.) have been used in crosses with I. hawkeri cultivars and selections, in an attempt to increase heat and drought resistance of New Guinea Impatiens cultivars (PASUTTI et al 1977).…”

“…In spite of the different ploidies amongst these species and the corresponding sterility barriers, some interspecific hybrids have been found pollen fertile (PASUTTI et al 1977;PASUTTI and WEIGLE 1980;HICKS et al 1987;STEPHENS et al 1988). One hybrid seedling in particular, I .…”

Fertility and chromosome number in interspecific Impatiens hybrids

“…Various interspecific hybrids have been produced, but sterility has been a continuous problem (Arisumi, 1973a(Arisumi, ,b, 1974(Arisumi, , 1975(Arisumi, , 1978(Arisumi, , 1980Armstrong, 1976;Beck et al, 1974;Pasutti and Weigle, 1980;Pasutti et al, 1977;. Production of amphidiploids overcomes the problem of sterility, but makes selection for heat tolerance more tedious.…”