584 



NATURE 



[December ii, 1919 



not high, in spite of the considectblo efforts made in 

 recent years to improve it. 



Leake's research worlv in the L'nited Provinces, 

 carried on for many years, is regarded as probably 

 the most complete yet attempted with cotton in India. 

 .\ variety known as K.22 has been widely distributed, 

 and the produce in 1916 sold at 31 rupees per maund 

 when local cotton was 25 rupees. Further, the ginning 

 percentage has been raised from 33 to about 40, while 

 the lint is of superior quality. 



Leake has also been successful in raising an early- 

 flowering form of cotton on Mendelian lines. The 

 new form differed from ordinary cotton cultivated in 

 the United Provinces in that it assumed a sympodial 

 instead of a monopodial habit. It not only yielded 

 cotton of high quality, but was found by its early- 

 flowering habit to suit the .special conditions of the 

 L'nited Provinces. 



.\s Egyptian cotton comes next to Sea Island cotton 

 in quality, it may be useful to refer to what has been 

 done, or attempted to be done, on scientific lines to 

 safeguard the industry. Its importance may be 

 gathered from the fact that the area under cultivation 

 is between 1,500,000 and 2,000,000 acres. Balls has 

 fully reviewed the scientific and other problems that 

 had to be .solved in placing the industry- on a satis- 

 factorv footing, .\ccording to Balls, the high-water 

 mark of Egyptian cotton-growing was from 1895 to 

 1899. .Since that time, although the actual area under 

 cotton has been increased bv boo, 000 acres, the benefit 

 measured in terms of cotton alone has been small. It 

 is probable that I he attacks of the pink boll-worm and 

 other pests may have affected the results, but Balls 

 ;ind his colleagues drew the conclusion that " the 

 falling off in yield was due to a rise in the level of 

 the subsoil water or water-table of the country 

 brought about by the extension of the irrigation 

 system during the past decade." The roots of the 

 cotton plant were thus adversely affected at a critical 

 period of growth. This recalls what Howard dis- 

 covered : that one of the causes of the wilt disease 

 in indigo in India was the destruction of the fine roots 

 and nodules during he.ivy monsoon rains. 



Probably the most remarkable instance on record 

 of the successful combination of science and enter- 

 prise in the tropics is the establishment of a cacao- 

 growing industry in the Colony of the Gold Coast, 

 West .\frica. Thirty years ago no cacao of any kind 

 was produced on the coast. Owing, however, to the 

 foresight of the then Governor (Sir William Brandford 

 Griffith), who sought the powerful ;iid of Kew, cacao- 

 growing was started in a small wav among the negro 

 peas.intry. with eventually extraordinarv results. .After 

 selecting the locality for the experiments, seeds and 

 plants were obtained through Kew, and a trained 

 man was placed in charge {Kew BtilL, 1891, p. 169; 

 1895, p. 11). The first exports in 1S91 amounted to a 

 value of 4Z. only. So rapid was the development of 

 the industry that ten years later the exports reached 

 a value of 43,000!. By this time both th(> people and 

 the Government had begun to realise the possibilities 

 of the situation, and systematic steps were taken to 

 organise under scientific control a staff of travelling 

 agricultural instructors to advise and assist the cul- 

 tivators in de.'ding with fungoid and insect pests and 

 improving the quality of the produce. In 191 1 the 

 exports had increased nearly fourfold and reached a 

 total value of 1,613,000/., while in iqi6 what mav 

 possiblv be reifarded as the maximum exports were 

 of the value of 3,1847,720/. 



It should be borne in mind that this Gold Coast 

 cacio industr\', now one of the largest in the world, 

 has been called into being and developed entirelv bv 

 the agencv of unskilled necro labour, and on sm.-dl 

 plots from one to five or ten acres in extent. The 

 NO. 2615, VOL. 104] 



controlling factors were, first, the selection of suit- 

 able land for cacao-growing ; next, the selection and 

 supply of seeds and plants of varieties adapted to 

 local conditions; and, lastly, the advice and assistance 

 of trained Europeans backed by the lesources of 

 science. 



Coining nearer home, Henry, well known from his 

 association with Elwes in the production of "The 

 Trees of Great Britain and Ireland," by historical 

 research and experiment has established the fact that 

 many fast-growing trees in cultivation, such as the 

 Lucombe Oak, Common Lime, Cricket-bat Willow, 

 Black Italian Poplar, Huntingdon Elm, etc., are 

 natural hybrids. It was of high scientific importance 

 to discover the origin of these valuable trees. Further, 

 by artificial pollination Henry has succeeded in rais- 

 ing new- hybrids which display the extraordinarv 

 vigour characteristic of the first-generation cross. 

 Perhaps the most notable so far is a new hvbrid 

 po]jlar {Populiis generosa), which makes the strongest • 

 shoots of all poplars. It is claimed in the case of hvbrid 

 trees that "' it is possible to produce much greater 

 bulk of timber in a given time." The common belief 

 that quickly grown timbers are of inferior qualitv is 

 said not to hold good in respect of any qualitv in 

 ash, oak, and walnut. In fact, according to Dawson, 

 "with oak, ash, and walnut the quicker their growth 

 the better their quality in every way. They are more 

 durable, more elastic, and less difficult to work " 

 (".Science and the Nation," p. 138). It is further 

 claimed that by hybridising it may be possible to pro- 

 duce disease-resisting varieties and varieties carrying 

 with them other desirable characteristics. 



In the tropics breeding experiments in the case of 

 india-rubber trees are likely to prove of great value. 

 In the meantime, selection of seed from the best 

 trees is being carefullv carried out in the hope of 

 increasing the general yield of the plantations. In 

 Java the proportion of alkaloids in the bark of intro- 

 duced cinchona trees (yielding quinine) has nearly 

 doubled bv careful selection on these lines. 



Plant-breeding experiments with india-rubber trees 

 have already been attempted, but they are not likely 

 to be of much value if thev are confined to empirical 

 and hajihazard lines. Work of this kind must b> 

 lengthy and complex, but it is absolutely essential to 

 ensure the safetx of an industry which is estimated 

 to be of the annual v.ilue in the Middle East of about 

 50,000,000/. sterling. The Agricultural Department 

 in Cevlon, which is fully alive to the fundament:! 

 importance of the selection and breeding of india- 

 rubber trees, has alread\ taken some action in the 

 matter. 



Another investigation in hand is to determine 

 whether the latex-yielding quality of Hevea trees can 

 be associated with any definite botanical characters 

 and to what extent such characters arc transmissible^ 

 Twentv trees of the same age growing in a four-acre 

 block have been selected for differences in leaf and 

 bark characters. These are all tapped on the same 

 .system, and the yield of rubber from each tree is 

 recorded separately for each tapping {Keit< BtiUctin, 

 1917, p. i]8). 



The value of these and other experiments of a like 

 nature mav be realised when, according to Varnet, 

 quoted bv Johnson, the yield of rubber from different 

 trees of Hevea growing under similar conditions in 

 the same plantation mav vary as regards volume of 

 I latex from 4 to 48, and in percentage of weight of 

 dry rubber from 1286 to 14-164 (Journ. d'Agric. 

 Trnfiicale, 1907). 



Bateson a few ve-irs ago expressed the opinion that 

 nowhere is the need for wide views of our problems 

 more evident th.m in the study of plant diseases. 

 Biffen and ethers have shown that under certain 



