84 Reduplication Series in Sweet Peas 



The zygotic series (a) is evidently a "coupling" form of reduplica- 

 tion, and is most nearly approached by the gametic series 10 : 1 : 1 : 10, 

 on which the expectation of the 4 forms is 2984 : 184 : 184 : 873. It 

 is clear that in this case, as in the BEL and bel cross, the normal value 

 of the pollen-colour reduplication series is upset, and that instead of 

 being on a 7:1 basis it approximates to a 10 : 1 basis. It is possible 

 that this upsetting of the normal value may be true also of the 

 standard-pollen, and of the standard-colour series, but at present the 

 point must remain undecided. For we do not know the normal value 

 of the standard-pollen series, and in the case of the standard-colour 

 series the data are insufficient for determining even its approximate 

 value. 



B. The D, F, N Series. 

 (1) The relation between D and F in plants homozygous for N. 



(a) Nature of mating FD x fd. 



Evidence has already been given ((3), p. 16) for regarding the re- 

 duplication in this case as on a 15 : 1 basis, and to the figures previously 

 set out we can now add a few more families (cf Table VII). As the 

 figures shew, the numbers of the two classes, dark sterile and light 

 fertile, are rather below expectation. Certain of the families (marked 

 * in Table VII) were also heterozygous for B and L and it is possible 

 that this may have influenced the result. Certainly when these families 

 are deducted the discrepancy in the remainder between reality and 

 expectation is not so marked (cf. Table VII). 



(yQ) Nature of mating Fd x f D. 



The experimental data for this mating are given in Table VIII. 

 So far no light axilled sterile has occurred among 2252 plants, though 

 2 such plants were to be expected if the gametic series is on the 

 1 : 15 basis. At present therefore the value of the reduplication is un- 

 decided. 



(2) The relation between F and N. 



Details of 9 F^ families derived from the mating Nf x nF have 

 been given elsewhere ((5), p. 295) and it was clear that the nature of 

 the gametic series produced by the F^ plant was INF : 3Nf : 3nF : Inf. 

 In the same paper it was suggested that the value of the reduplication 

 affecting two factors might be the same for both the " coupling " and 



