Genetic control of cone clusters and precocious flowering in Pinus sylvestris

Abstract

A Scots pine clone bearing cone clusters transmitted precocity to a portion of its progeny resulting from crosses to clones having normal cone distribution. Inheritance appeared to be governed by a single major gene whose expression was dominant or recessive depending upon which clone it was mated to. Differences of reciprocal crosses indicated maternal or cytoplasmic influence. This genetic variation in precocity can be used to reduce the generation interval, thereby facilitating genetic studies and breeding programs. Seed yield per pollination bag was several times greater for cone clusters than for normally distributed cones although viable seed per cone was 20% less. This can reduce the cost of producing hybrid seed if artificial pollination is required.

Hormonal Aspects of Phase Change and Precocious Flowering

“…Selection and breeding can thus be used to produce progeny with a shorter juvenile phase. This has been done with apple (SAURE 1970, SCHANDER 1962, SCHMIDT 1970, VISSER 1965, WAY 1971, pear (VISSER 1976, ZIMMERMAN 1977, Prunus species (SCHMIDT 1976), birch (JOHNSSON 1949, STERN 1961, and several Pinus species (HEIMBURGER and FOWLER 1969, SCHRÖCK 1949, TEICH and HOLST 1969 among others (ef. ZIMMERMAN 1972 for further discussion on this point).…”

A New Record on Flowering in Harar (<i>Terminalia chebula</i> Retz.) Seedling

“…Flowering control is exercised by single dominant gene [15]. Single major gene for precocious flowering in Dalbergia sissoo has been reported [16].…”

Aggregated Cones in Pinus Halepensis

“…Thus, their position was considered only in clusters formed during the current year. The position in P. halepensis is the same as in P. sylvestris (Teich and Holst 1969;Frankis 1980), and in some instances in P. ponderosa, in which clusters of female cones either replace dwarf shoots, or are formed in the position of male cones at branch bases (Zobell952). Cone clusters also appear in the position of male cones in P. contorta (Black 1961 ), P. claus a, P. massoniana, P. mugo, P. rigida, and P. thunbergii (Frankis 1980), and P. banksiana (Rudolph et al 1986).…”

“…(Zobel 1952), P. rigida Mill. (Frankis 1980), P. sylvestris L. (Keslercanek 1880;Mullins 1881;Kirchner, Loew, and Schroter 1908;Schrock 1957;Carlisle 1958;Teich and Holst 1969;Frankis 1980) and P. thunbergii Pari. (Frankis 1980;Lemoine-Sebastian 1982).…”

“…Others attribute aggregate cones to changes in endogenous hormone levels (Frankis 1980;LemoineSebastian 1982;Rudolph et al 1986). Only a few studies have been devoted to the genetics of cone clustering (Teich and Holst 1969;Rudolph et al 1986). Nevertheless, several authors suggest a genetic control of cone clustering (Zobel 1952;Carlisle 1958;Frankis 1980).…”