Leake and ram PRASAb. 43 



while such fertiUsation is readily effected between certain plants 

 and will give rise to fertile progeny, in other cases it is totally un- 

 productive. Between these extremes lie those cases in which 

 offspring is produced but in which such offspring is wholly or 

 partially sterile. 



Observations as to this latter form of sterility are not niune- 

 rous. As far as they go, however, these tend to show that the 

 Indian forms of cotton constitute a fairly definite group, the 

 members of which show complete sterility when crossed with other 

 forms of Gossjrpia. Gamraie* records failure in his attempts to 

 cross G. hirsutum, Mill., by the Indian cottons and the authors have 

 similarly been met by a like failure. Among the Indian cottons, how- 

 ever, there appears to exist considerable divergence in the degree 

 of fertility when they are crossed inter se. In some cases no dimin- 

 ution of fertility results, while in others various degrees of steri- 

 lity are developed. As examples of the former case may be cited 

 all crosses between Types 5-9 {G. neglectuni, Tod., and G. roseum, 

 Tod.) ; between Type 3 (6^. arboreum, Linn.) and Type 4 {G. indicum, 

 Lamk.), Types 5-9, Type 10 {G. sangumeuin, Hassk.) and Type 11 

 (6r. cernum, Tod.) and also between Type 4 and Tjrpes 5-9. In 

 all these cases crosses have been effected and fully fertile offspring 

 raised. Crosses have also been made between Type 3 and Type 1 

 (G. obiusifoUum Roxb.) and Type 2 {G. herbaceum, Limi.), and these 

 offspring are apparently fully fertile. Owing, however, to the late 

 flowering habit of these types considerable difficulty attaches to the 

 cultivation of these crosses in Northern India and they were dis- 

 carded after the F,, generation. 



Crosses between Type 2 and the sympodial forms, of which 

 Types 4, 5 and 9 were selected for the purpose, showed a consider- 

 able degree of sterility. This is indicated by a comparison of the 

 figures given in Table II. In the second generation of the cross 

 between Types 2 and 4 the percentage of boHs which set was reduced 

 to less than 11 and the plants of this generation set practically no 



♦ 'I'he Indian Cottons, 1005, 



