CURRENT LITERATURE. 213 



Plant disease 



Blakeslee, A. F- A graft infectious disease resembling a vegeta- 

 tive mutation. Jour, of Gentics II. 1st April, 1921. 



In this paper is described a disease of Datura stramonium which causes 

 profound changes in leaf, flower and fruit. The leaves become narower and 

 incised, the corolla is split down to the base and frequently fails to become 

 free of the calyx, the stamens are devoid of pollen, the capsules are less spiny 

 or quite smooth, and the colour of the plant is usually darker. The disease 

 appears in the field to the extent of about 16 % of all the plants, but up to 26% 

 in an experimental plot where the plants were more widely spaced. This the 

 author thinks was due to the plants growing larger and therefore having a 

 larger area liable to infection. It is transmitted by seed produced by healthy 

 pollen to the extent of about 79%, the remaining 21% of plants raised from 

 diseased stock being entirely free from it. It is transmitted by pollen, that is 

 when pollen is used from normal or nearly normal flowers of plants that are 

 beginning to show the disease, and lastly it is transmitted by grafting: a 

 diseased branch used as scion will affect a healthy stock and even a healthy 

 scion grafted on to the same healthy stock. 



It is suggested that vegetative segration and mosaic inheritance in other 

 plants may sometimes be due to some such disease. To the writer of this 

 abstract it appears possible that this disease is similar to the spike-disease of 

 Sandal and other plants in this country, which so far have been studied only 

 on the physiological side, not as far as he knows genetically. 



P. F. F. 



Plant-breeding, Heredity, etc. 



Batcson, W. Root-cuttings and chimaeras II Jour, of Genetics. 

 II., 1st April, 1921. 



The author continues his investigation into the product of root-cuttings 

 of certain variegated cultivated plants, of Bouvardia, Pelargonium, and 

 Spiraea ulmaria. In these plants there appears to be a core of one kind over- 

 laid by a cortex of another, the latter giving the varietal character of the 

 plant. Many such herbaceous plants are liable to give rise by root-cuttings to 

 shoots composed entirely of either their external or their internal constituent. 

 Such shoots are probably formed by adventitious buds, which clearly are not 

 always endogenous, but may arise from the cortical layer. The instance of 

 a core character appearing in patches on a leaf are difficult to explain, the 

 growing point apparently has both elements in it. 



Kefering to " reversal," described in Vol. IV (see this journal Vol. I, p. 63) 

 while several instances have been seen of white-over-green turning to green- 

 over-white, none have been found of the oposite. 



P. F. F. 



Rangaswami Aiyangar, G. N. Some rice breeding experiences. 

 Agri. Jour. India, XVI, 2nd March, 1921. 



The author who has been for several years engaged in breeding varieties 

 of rice with, F. R. Parnell, gives here some of his experiences and much sound 



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