INTERNATIONAL CONFERENCE ON PLANT BREEDING?^ 427 



tion are not available. Hitherto, seedlings appear to have been raised by 

 chance fertilisation in the field, so that only the seed parent is usually 

 known. Of these probably only 1 in 10,000 survive the severe field and 

 chemical tests to which they are subjected for four years. In future 

 experiments in the West Indies it is intended to raise cross -fertilised 

 seedlings by the use of certain ingenious contrivances whereby both 

 parents can be definitely known. This has already been done in Java by 

 Dr. Kobus by using a variety with infertile pollen as the seed parent and 

 planting alternate rows with a distinct variety with fertile pollen. By 

 this method good results have been obtained as far as high sugar content 

 and disease-resisting power are concerned. 



Some Cytological Aspects of Hybrids. By W. A. Cannon, of 



New York. 



Mr. Cannon introduces the important question of the relationship 

 between cytological studies and the experimental work of hybridists, with 

 special reference to the discoveries of Mendel and his successors. In the 

 present state of knowledge this relationship cannot be definitely stated, 

 but as a result of his cytological experiments with Cotton hybrids Mr. 

 Cannon believes : — 



1. That the normal divisions of the male nuclei lead to fertility in 

 hybrids, while the abnormal divisions lead to sterility. 



2. That variation of the hybrids may or may not be associated with 

 variation in spermatogenesis. 



3. That in certain cases the chromosomes derived from the original 

 parent tend to preserve their individuality. 



Hitherto, cytological and expsri mental research has gone on inde- 

 pendently, and Mr. Cannon suggests that it would be better in the future 

 for cytological work to be done on forms that give marked experimental 

 results. 



The Improvement of Roses by Bud Selection. By L. C. Corbett, 



of Washington. 



The recorded results are based on a series of tests with Rose cuttings 

 made from "blind " and "flowering " wood, and cover a period of five 

 years. The cuttings were all grown under the same conditions, and were 

 potted up to flower under glass ; five varieties of the Tea section were 

 used, principally ' Bride ' and ' Bridesmaid.' 



In the following year cuttings were taken from these plants on the 

 same lines, i.e. " blind " from " blind," and " flowering " from " flowering " 

 wood, and so on throughout the experiments. The general result was 

 that while the plants propagated from "flowering " wood gave an average 

 of 29^ blooms per plant for the season, those propagated from "blind" 

 wood produced on the average only 11| blooms per plant for the season. 

 Professor Corbett concludes, therefore, that the tendencies manifested in 

 a branch are perpetuated from generation to generation by cuttings. It 

 is equally demonstrated that cumulative results are not to be expected by 

 selecting parts showing like tendencies through successive cutting genera- 

 tions. The flowering habit of plants produced from " flowering " wood 



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