(ind Magazine of the Ceylon Agricultural Society. 



89 



THE IMPROVEMENT OF CULTIVA- 

 TION OF CROPS BY PLANT 

 BREEDING. 



Now that wo have amongst us an export in 

 Plant Breeding (in the person of Mr. R. H. 

 Lock, who is known to the scientilie world as 

 the author of " Recent Rosoarches in Heredity, 

 Variation and Evolution,'') it will be of interest 

 to inquire shortly into the significance of the 

 work which Mr. Lock is engaged on. Looking 

 only at the agricultural aspect of this question 

 of breeding we may state that there are throe 

 ways in which improved strains of plants can be 

 secured— (1) ny selection, (2) by mutation and 

 (3) by hybridization. 



Selection is the picking out for further 

 breeding of those individuals which approach 

 most nearly to the type forming the breeder s 

 ideal. Selection, of course, presumes variation. 

 Individuals, possessing the desired characters in 

 the highest degree, are picked out, and by 

 breeding through many generations, improve- 

 ment in the direction sought is secured. It 

 should be stated, however, that variation may 

 bo of two kinds due to : (1) acquired characters 

 brought about by external causes and, there- 

 fore, distinguished as acquired variation, 

 being neither inherited nor heritable ; (2) in- 

 herited characters brought about by causes 

 inherent in the individual oi-ganism and hence 

 sometimes distinguishable as genetic variation. 

 Practically we have no means of distinguishing 

 between these tvro, save by the test of actual 

 breeding. The object of such test should be to 

 discover the existence of inherited (and herit- 

 able) characters ; selection being made depen- 

 dent not on the excellence of'the individual, 

 but on that of its progeny. 



Mutations are what are more familiarly known 

 as " sports/' due, so far as we know, to acci- 

 dental and uncontrolled causes, though be- 

 lieved to be possibly induced by changes of 

 environment. These sudden and striking varia- 

 tions must be constantly watched for, and re - 

 ported to Mr. Lock at the earliest opportunity, 

 as on thorn depend great possibilities in the 

 improvement of plants. 



Hybridization or cross-breeding may be de- 

 fined as a "reshuffling of the various unit charac- 

 ters present in. individuals, so as to bring about 

 re-combinations of characters already in exis- 

 tence." The possibilities of evolving permanent 

 results by this means have been greatly in- 

 creased by the discovery of the Mendelian law. 

 The principles of scientific breeding, are the 

 outcome of the work of Gregor Mendel, an 

 Austrian monk, in the garden of his Monastery; 

 and it was not until 1900 that his records 

 were unearthed, and biologists began to 

 realise their value and recognise that a new 

 avenue to scientific research— of the utmost 

 importance to agriculture and stock-breeding 

 —had been opened to them. 



Plants and aninialsare now regarded as built up 

 of distinct unit characters, each pair of which is 

 inherited accordingto certain definite principles, 

 the different pairs being generally inherited 

 independently of one another. New characters 

 resulting from a cross, if capable of fixation, 



may bo fixed in tho second generation after 

 the cross —no elaborate process of selection 

 being required, provided that tho members 

 of the generation are tested individual by 

 individual. It need hardly be said that it is 

 no easy matter to distinguish an individual 

 which will breed true from one which will 

 not, since it may be pure or impure as re- 

 gards its dominant character ; and tho point 

 can only be satisfactorily settled in plants by 

 growing a further generation. 



It is this preliminary but indispensable pro- 

 cess of " analysis ' that constitutes the chief 

 difficulty in plant breeding operations, for the 

 process is often of great complexity, demanding 

 accurate work and familiarity with the subject. 



Upon the results of such investigations as 

 Mr. Lock is engaged in does the progress of 

 practical agriculture depend, and it is to be 

 hoped that before long tho island will have 

 good reason to congratulate itself upon the 

 work of its expert in plant breeding. 



TESTING SOILS, 



The Bureau of Soils of the United States 

 Department of Agriculture has during the 

 last few years been making experiments with 

 a view to improve and simplify the pot met- 

 hod of testing soils. They have evolved tho 

 paraffined wire basket method, which is des- 

 cribed as a promising method of investigat- 

 ing soils, either as to present fertility or 

 as to the effect of additions of fertilisers. 

 The process is as follows :—" Into small 

 baskets made of wire netting they put less 

 than a pint of soil. The basket is then 

 dipped into molten paraffin to coat the sides 

 and bottom of the soil with paraffin, so as to 

 exclude the air. Six seeding wheat plants are 

 set out in this soil, and the surface of the soil 

 covered with paraffined paper, excepting a nar- 

 row slit, through which the wheat plants pro- 

 ject. Thus the evaporation from the soil is 

 almost completely prevented, excepting such 

 evaporation, called transpiration, as takes place 

 through the plants. The leaves continually give 

 off water which the plants keep continually 

 drawing up through roots and stem from the 

 soil. The amount of this transpiration can 

 readily be determined by occasionally weighing 

 the soil. They found that the more fertile the 

 soil, the more rapid this transpiration. Within 

 from three to six weeks this has gone far 

 enough to give the necessary indications." 

 It seems hopeful that we have in this a 

 method whereby we can test a- coil within one 

 or two months' time and learn whether it is 

 fertile, or to what fertilisers it responds best. 



SIMPLE AGRICULTURAL 

 IMPROVEMENTS. 



For Rice Growers and Otheks. 

 The Eastern Bengal and Assam Department 

 of Agriculture has just issued a pamphlet on 

 "A Few Simple Agricultural Improvements" 

 which experience has shown to bo practicably 

 profitable and within the means of the ryots. 

 These are : (f^ The use of bone-meal and salt- 

 petre as manure for transplanted winter rice; 



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