107 



Thursday, 10th July. 



Morning Session. 



The Congress assembled at 9.30 a.m. 



Dr. Chmelaf read a paper of which the following is an Enghsh 

 summary : — 



Determination of the Botanic Identity of Varieties in Laboratories 

 and in Experimental Fields. 



BY 



De. F. CHMELAli, BRUNN. 



The more the intensity of plant cultivation develops and the utility of 

 selected strains realized, the greater the necessity for guarantees of the 

 genuineness and purity of seed becomes, as well as that of determining all 

 the signs of identity in the laboratory and in the field. The testing of 

 seeds and the determination of identity of common varieties in a number 

 of European States requires the establishment of the authenticity and 

 purity of varieties in field growths and also in the samples of seeds and 

 bulba, &c., sent to different institutes. 



In addition, this determination is reqtiired when the identity or origin 

 of selected varieties intended for exportation has to be established. 



The methods which are used to establish the botanical identity of 

 varieties are not yet fully studied, inasmuch as it is mainly the most 

 striking signs giving a guarantee of a good crop and quality which attract 

 the attention of selectors, while it is often important to observe also 

 practically insignificant factors. 



A good method for the determination of varieties of the sugar 

 Ibeet and the mangold is observation of the colour of the shoots which 

 develop in a temperature of 15° C. under diffused hght in the course 

 of two weeks (Pieper). Determination of the colour of the shoots, 

 particularly of the intermediate forms, is facilitated by the use of chromatic 

 filters (Vitek). To establish the saccharine richness of the root it is 

 necessary to analyse, at least three times in succession, 40 beets developed 

 in a normal culture and to make use of a quantity of mdsh~four times 

 larger than normally if the saccharine richness is to be established to a 

 ' 1 per cent, exactness. (Method of the Sugar Research Station at Prague. ) 

 In Denmark an analogous method (Hallquist's method) is followed to 

 determine the colour of the root according to the colour of shoots of 

 cruciferous plants. 



An excellent means for determining the different varieties of potatoes 

 is the observation of the colouring of the cymes of shoots sprouted in 

 diffused light (Snell) or indeed observation of the colour of shoots developed 

 in obscurity (Viknorin). Recently it has been ascertained that the size 

 of starch grains (Parow), established by the Lindner method, is the sign 

 of such and such a variety. If the variety must be estabhshed on the 

 fields, it is necessary to ascertain not only the qualities of the tubers but 

 Also of the plant in its entirety. As regards the tubers, it is most 

 important to observe : the shape, the colour of the skin and that of the 

 flesh and the eyes ; as to the plant, the height, thickness and coloxir of the 

 stem; as regards the leaves, the shape, the colotir of the foUoles, the 

 position of the terminal foliole, the shape of the point, the colour of the 

 petiole, the coalescence of the leaflet ; as to the inflorescence, the quantity 

 of flowers, the bractea, the shape and length of points of the sepals of 

 the calyx, the size and colour of the coroUa, as well as flowers with double 

 corolla, and, finally the position of stamens and pistil. 



