The Canadian Horticulturi^ 



Floral Edition 



FVol. XLV. 



PETERBORO, ONT., SEPTEMBER, 1922 



No. 9 



BEFORE plant breeding can be in- 

 telligently performed, a knowl- 

 edge of several essentials is neces- 

 sary. These essentials are : (a) A knowl- 

 edge of the natural orders. Plants can- 

 not or can rarely be crossed with others 

 outside of the natural order to which 

 they belong, (b) A knowledge of the 

 structure of the flowers and the func- 

 tions of their parts. The breeder must 

 know what constitutes the male and the 

 female organs of reproduction, (c) The 

 meaning of self-polination, cross-pollin- 

 ation, and fertilization, (d) A knowl- 

 edge of the cultural requirements of 

 plants. This from a practical stand- 

 point. 



Instruments. 

 The instruments required are of a 

 simple and inexpensive nature. Finely- 

 pointed scissors, fine-pointed forceps, a 

 small bottle of alcohol to sterilize in- 

 struments, a number of small tags, to 

 record data, and small envelopes to con- 

 tain the seeds. 



Stnxcttire of the Flowers. 



j Flowers are sometimes composed of 

 j the four parts, petals, sepals, stamens or 

 I male organs, and the pistil or female 

 i organ. The pistil is composed of style, 

 ' stigma, and ovary ; examples are primu- 

 la and geranium. Other flowers may 

 have either the male or female organs, 

 but not both. The begonia is an ex- 

 I ample, though both male and female 

 I flowers may be borne on one plant. Still 

 ! another form may have the male flowers 

 , on one plant and the female on another 

 of the species; example is the Tree of 

 'Heaven. 



Pollination. 



There are two forms of pollination: 



f'-poUination, when the pollen nat- 



■illy reaches the stigma. A flower 



may also be said to be self-pollinated 



when its pollen is artificially placed on 



its own stigma; cross-pollination, the 



act of placing the pollen of the flower 



of one plant upon the stigma of the 



flower of another plant of another 



species or variety. 



Fertilization. 

 This is the act of impregnation of the 

 le (female cell) within the ovary by 

 "lale cell from the pollen grata. 



*ven before the Canndiiia PlorisU' and 



Plant Breeding* 



Henry J. Moore, Islington, Ont. 



Seedlings like the parent are pro- 

 duced by self-pollinated plants. 

 Hybrids are the result of cross-pollina- 

 tion, when species are crossed with 

 species, as for instance, geraniums, with 

 geraniums. They are known as specie 

 hybrids. "When, howeveir, plants of dif- 

 ferent genera are crossed the progeny 

 are known as generic hybrids. 

 Selection. 



This is the practice of selecting seeds 

 from the most desirable plant or plants 

 of the hybrids with a view to improving 

 them. 



Mendel's Law. 



Mendel crossed a tall and a dwarf 

 variety of a culinary pea. The progeny 

 of the first generation were all tall. He 

 allowed these plants to produce seeds, 

 and when sown they produced plants of 

 two kinds, tall and dwarf in the propor- 

 tion respectively of 75 and 25 per cent 

 (three-fourths tall and one-fourth 

 dwarf). In the third generation, the 

 dwarfs produced 100 per cent pure 

 dwarf. Of the tails, one part was found 

 to breed pure in the third generation. 

 The other two parts which were impure- 



ly tall, gave, as did the oripuial hybrid 

 of the first generation, pure awarf , pure 

 tall, and impure tall. 



Mendel called the factor for tallness, 

 a dominant factor, and that for dwarf- 

 ness a recessive factor. He also discov- 

 ered that a dark color is dominant over 

 a light color, and that in crossing, darks 

 and lights will be produced in exactly 

 the same proportion in the same genera- 

 tions as the tails and dwarfs. Mendel 's 

 Avork was looked upon with disfavor by 

 the scientific societies of his day, and 

 so he hid his manuscript. It is to Pro- 

 fessor Balison of Cambridge University, 

 that we largely owe the re-discovery of 

 Mendel's Law and all that it means to 

 civilization. 



Divme Guiding EUnd 

 This law, scientific though it is said to 

 be, but proves the existence of a divine 

 hand in guiding and controlling the 

 production of life. Marvellous, yet con- 

 stant in its application, we are forced to 

 ask ourselves, why we should ever 

 doubt the existence of a divine and con- 

 trolling hand. Darwin, great scientist 

 as he was, was badly off the track in 



Th« Hand Wheel Hoe la an EflecUvc Labor-aaTini Davlcc. 

 Prequeot culUvalion of the (ardcn destroys the weed.i aiul maintains the best growinu conditioiu in the aod. The wheel 

 hoe allows for frequent applications at a minimum of labor. 



