Jehangir Fardunji Dastur 249 



Glomerella stage. 



Shear and Wood have found that if a culture from any particular 

 acervulus or group of acervuli does not produce the ascogenous stage 

 on corn meal at 75° to 85° F., it is useless to experiment further with 

 material from the source^; and they are of opinion that the perithecial 

 forming faculty in the numerous cases of Glomerella studied by them is 

 a fairly fixed hereditary character; because if once a race or strain which 

 produces perithecia in culture media is obtained other generations from 

 this strain or race continue to produce perithecia indefinitely^. 



Edgerton considers corn-meal-agar the most satisfactory medium 

 for the growth of the fungi belonging to the genus Glomerella. 



Kriiger^ has found partly sterilized potato stems as particularly 

 suitable for the development of perithecia. These and various other 

 media have been tried for the development of the ascogenous stage not 

 only of the chilli fungus but also of the Carica papaya anthracnose. It 

 seems to me doubtful if the medium has any direct influence on the 

 development of perithecia. What seems to be most essential is that a 

 race or strain should be capable of producing the perfect stage. If once 

 such a race or strain is obtained perithecia are formed on almost any 

 medium, especially solid, at least for the first few generations. As will 

 be seen later the perithecia forming faculty is not a fixed hereditary 

 character which would ensure the development of perithecia indefinitely, 

 as stated by Shear and Wood. Perithecial strains completely lose their 

 spore-bearing faculty when their successive generations are cultivated 

 for some length of time on the same medium and at room temperature. 

 But, however, these sterile strains can be induced to form asexual spores 

 by sudden change of food or temperature, e.g., subcultures on corn-meal, 

 corn-meal-agar or sterilized chilli stem produce the conidial form when 

 the transfers are made from a strain that has become sterile, through 

 several generations having been cultivated on glucose-meat-extract-agar. 

 Subcultures from sterile cultures on glucose-meat-extract-agar at room 

 temperature, at times, develop the conidial form if they are kept in a 

 hot incubator at 90° F. in winter, and in a cold incubator at 66° F. 

 in summer. If three or four successive generations of these conidia- 



1 Shear, C. L. and Wood, A. K. Ascogenous Forms of GloRosporium and CoUetotrichum. 

 Bot. Gaz., XLra, p. 262, 1907. 



2 Shear, C. L. and Wood, A. K. Studies of Fungous Parasites belonging to the Genus 

 Glomerella. U.S. Dept. Agric, Bur. PI. Industry, Bull, No. 252, p. 72, 1913. 



^ Kriiger, F. Beitrage zur kenntnis einiger Gloeosporium I und II. Arh. Kais. Biol. 

 An-st. f. Land-u. Forshoirtschaft, rx, 2, p. 217, 1917. 



