. Genetics in relation to agriculture. Livestock; Heredity; Variation (Biology); Plant breeding. ON VARIETIES IN PLANTS 311 they include garden and forcing varieties which combine marvellous beauty of form and color with vigor and hardiness (Fig. 12G«). Four or possibly five distinct species enter into the ancestry of the group, as shown by the following pedigree. The Hybrid Perpctuals (Fig. 1266) are of mixed ancestry, all being hybrids of the Damask Hose (Fig. 126c) crossed either with Hybrid Bourbon or Hybrid Chinese varieties. The hardy, disease-resistant Japanese species, Rosa rugosa and
. Genetics in relation to agriculture. Livestock; Heredity; Variation (Biology); Plant breeding. ON VARIETIES IN PLANTS 311 they include garden and forcing varieties which combine marvellous beauty of form and color with vigor and hardiness (Fig. 12G«). Four or possibly five distinct species enter into the ancestry of the group, as shown by the following pedigree. The Hybrid Perpctuals (Fig. 1266) are of mixed ancestry, all being hybrids of the Damask Hose (Fig. 126c) crossed either with Hybrid Bourbon or Hybrid Chinese varieties. The hardy, disease-resistant Japanese species, Rosa rugosa and R. ivichuriana have entered into the ancestry of some of the best modern roses. Thus, the American Pillar variety is a hybrid between a red Hybrid Perpetual crossed with a hybrid between R. ivichuriana and 7^. setigera, the Prairie Rose of America. Again, the Silver INIoon variety is a result , Teas. .derivatives of Rosa cliinennis var. odoratissima Hybrid , Teas. .. Hybrid 'Perpetual si - Hybrid. Chinese - Hybrid Bourbons. \Rosa damascena (Damask Rose) Fig.—127. J'edigree of the hj'brid tea roses. Rosa galUca French or Provence ose). See Fig. 126c?. Rosa chinensis (Chinese Monthly or Bengal Rose). Rosa centifolia (Cabbage Rose). of crossing R. Iwvigata, the Cherokee Rose, with a hj^brid between the Tea Rose, Devoniensis, and R. wichuriana. These will serve to illustrate the composite ancestry of our best roses. The practicability of this method of procuring new varieties has of course been enhanced by the possibility of vegetative propagation. Occasionally valuable varieties have arisen as bud mutations but these usually differ from the parent variety only in some definite character, like flower color or habit of growth. In passing it is of interest to note how extensively tltis method of variety creation has been used by horticulturists, particularly in species which are normally propagated by clonal midtiplication. The hybrid varieties of the rhododendron rival
Size: 1777px × 1406px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksu, booksubjectplantbreeding
