FERTILE BREEDING STOCKS 



18-4 



with No. 1426 to produce No. 2882. A mating of No. 2882 and No. 

 2791 introduced adenine dependence into the methionine dependent 

 stock. The mating of No. 3091 x No. 3228 produced a hybrid het- 

 erozygous for at least 9 alleles, all of which showed regular 2:2 

 segregation in nearly every ascus. 



Saccharomyces chodati (fig. 18-2 ) is ordinarily described as 

 a slow fermenter of sucrose. The culture which we obtained from 

 Dr. L. J. Wickerham was a slow fermenter and the only copulat- 

 ing haplophase (No. 4839) which we derived from it was also a slow 

 fermenter. The original culture produced only two spores per as- 



5ACCHAR0MYCE5 CHODATI (2-5P0RED>\5Cj) 



46^39 cL 6(5L0W6DArc5) 9AX05PORL6 GRE^ n?OM 

 ^ 'ABOUT JO ISOLATED 



ONLY ONE MATED 



3 3-5P0REDA5C! 

 4886.1 



4066 ng 



^9vS&oy 



4891 ng 



489^5 



4893 r^ 



4894 ng 



(^3 



3 f<SpEDA5CI 



4896W 



48976 



48985 



W9a 

 4900 ng 

 49015 

 4902 r^ 



49055(5LCM 



4904 ng 



4905 r^ 

 49066 



490^ 

 49065 

 4909S 

 49J05 



4911/ 

 491Z5 

 4913/ 



4914 r^ 



4915 og 



4916 r^ 

 49175 

 4918 ng 



4?19n9 

 492)r^ 

 49Zlng 

 ^9lln9 



4923 5 



4924 r^ 



4925 5 



4926 r^ 



4927 ng 

 49285 

 49295 

 49305 



4931 DIED 



4932 ng 

 4933 



Id 



4934 



4935 ng 

 49365 



4937 ng 



4938 ng 



49395 

 49405 



494U 

 4942 ng 



49435 

 4944 5 



Fig. 18-2 Pedigree Showing the Origin of a Non-Fe rmenter of 

 Sucrose by Mating a Haplophase of S. Chodati with our Fertile 

 Haplophase . 



cus but its descendents of it eventually produced hybrids from which 

 asci containing 4 viable spores were obtained. A hybrid (No. 4839 

 X No. 3543) produced a 4-spored ascus from which 3 viable spores 

 were isolated. Two were non-fermenters of sucrose. Five other 

 asci isolated from the hybrid are shown in fig. 18-2. One con- 

 tained 4 sucrose fermenters but many irregularities in viability 

 occurred. In the figure "n.g." means that the spore did not germ- 



