194 



THE AGRICULTURAL NEWS. 



Jim; 29, 1911?. 



^already existing varieties may be obtained, and through 

 these, strains possessing qualities locally desirable may 

 be produced. 



In the last century, it seems that the systematic 

 breeding of plants may be said to have begun with the 

 ■work of Knight and Van Mons about the beginning 

 of the century. Thomas Andrew Knight, an 

 «minent English plant physiologist, may be calleil the 

 father of plant breeding, smee he was tho first to show, 

 in 180(5, the practical value of hybridization in the 

 production of plant varieties. Of almost eijual impor- 

 tance, however, was the work of a contemporaneous 

 Belgian horticulturist, .lean Baptiste Van Mons, who 

 emphasized mainly the principle of selection. It will 

 thus be seen that the fundamental laws of plant breed- 

 ing were fairly well understood at the beginning of the 

 century, and had been published in horticultural 

 text-books and papers. It requires long years, however, 

 for scientific principles to become thoroughly recognized 

 and widely disseminated. This result, as was noticed 

 before, has largely been due to the universal acceptance 

 -of the laws of heredity expoundetl by Mendel, as a 

 result of his classical experiments on the common pea. 



During the first fifty years of the century almost 

 the sole method of breeding, both in Europe and 

 America, was to select seeds from the best types of 

 plants, and to raise numerous seedlings, of which those 

 were selected for further propagation which seemed 

 to be of better quality than the parent. For instance, 

 when a particularly good fruit was produced, its seeds 

 •were carefully preserved and planted, and some 

 varieties in the main true to type were reproduced, 

 but onlv a few superior or new varieties resulted. 

 Hybridization and cross- fertilization in improving 

 plants wen- very little utilized until during the last 

 half of the century. 



.Since the middle of the century additions to thi.' 

 knowledge of the laws of inheritance have caused a 

 great advance in methods of improving plants. ( )ne 

 important factor in the application <jf hybridization to 

 producing improved strains is the securing of what have 

 been termed 'dilute hybrids', that is hybrids containing 

 more constituents of one <jf the parent varieties than 

 of the other. If in any hybrid the chanjicters of one 

 of the parents are found to be too pronounced to give 

 a s\icces3ful combination, that hybrid may be crossed 

 back with the other parent, and the process repeateij 

 iiniii the desired combinatiun is obtained. 



Ihe primo importance of growing hybrids through 

 several generations in order to fix the characteristics 



aimed at has only been recently recognized as a neces- 

 sary deduction from Memlelian laws. 



The production of varieties which have been ob- 

 tained by careful metho<is of .selection carried through 

 from one to many generations has always had a marked 

 effect on the development of certain agricultural indtis- 

 tries, notably that of cotton. .Scientific hybridization 

 has also had a very marked effect in the de\ eloptuent 

 of many cultivated pirtuts, and in the future there is 

 no doubt that it will lie inore and mop' extensively 

 utilized in securing and perpetuating desired modifi- 

 cations in probably every crop economically valuable. 



A striking instance of the wonderful amelioration 

 that can be accomplished by careful breeding in a 

 plant is the tomato. According to an article in the 

 yearbook of the United States 1 )epartment of Agri- 

 culture, 1899, in the early part of the century the 

 races of tomatoes produced mostly small and lobed 

 fruits. I)r. Hand, of Marylaml, began his work in 

 connexion with it in 18.50. He crossed the smooth 

 tomato, which was filled with juice and seeds, with the 

 compound convoluted tomato generally cultivated at 

 that time. By selection and further hybridization he 

 produced a race of large, smooth, round tomatoes with 

 solid contents, .md the improvement of this fruit has 

 been continuing ever since. 



Another striking instance of the improvement in 

 a plant by selection and hybridization is the maize, 

 very many of the best races of which have originated 

 as carefully produced hybrids, and have been improved 

 and fixed as to characteristics by furthiu- long-continued 

 selection. 



The selection that is regularly practised by all 

 intelligent growers, and which to-day may be regarded 

 as one ot the necessary cultural methods in the pro- 

 duction of cotton, especially Sea Island cotton, has 

 resulted in the increase of length and fineness of fibre, 

 until in places whc;re such selection is rigidly employed 

 the cotton has reached a very high standard in respect 

 of the characters regarded as most desirable. 



Probably in no plants, however, has hybridization 

 giv.'ii such marked results as in those cultivated for 

 their Howers. 'i'his is duo largely to the faotthab in 

 such plants variations of form and colour are th6 

 greatest desiderata, and such modificitions are found 

 to be easily obtained by h_\bridizing different coloured 

 species or varieties. , 



It tnay be observed that the tendency to get rid 

 of existing varieties of commercial plants in favour of 



