762 EXPERIMENT STATION EECORD. 



ing vineyards on resistant stock. This graft consists essentially of fixing on a green 

 shoot of the year an elliptic scion or shield carrying a bud at its center. In order 

 that it be successfully used, it is necessary that the stock should be in full sap. In 

 the Horwath graft the scion bud is inserted in the place of an eye of the stock. The 

 Besson graft, which is a form of inlaying, has not been a success at the station when 

 tried on green shoots. With ripe canes the results have Ijeen very satisfactory. The 

 Vouzou gi-aft is a Salgues graft made with an old scion l)ud. From 75 to 85 per cent of 

 the grafts of this sort made at the station have commonly taken, and in one instance 

 the success of 95 per cent was reported. " It is a simple graft and gives a perfect 

 union. In case of failure, it is easy to repeat it the same season." The following 

 directions are given for the selection of shoots bearing buds for scions: 



"We should always choose branches growing from eyes which would have nor- 

 mally remained dormant till the following season, in preference to branches grow- 

 ing from buds bursting out normally. Shoots of medium or rather small diameter 

 are to be preferred. These shoots will furnish the scion buds which are to be grafted 

 on the old wood. The diameter of the shoot from which the scion bud is cut must 

 always l)e a little smaller than the diameter of those upon which it is to be grafted. 

 The best shoot is that developed in the shade; branches exposed to direct sunlight 

 must always be rejected; the shoot should be light green in color, but not yellow. 

 The petioles of the leaves of the shoot should be of a whitish-green color, even a 

 little pinkish, slightly transparent at the point of junction with the limb. Shoots 

 bearing leaves with deep green or reddish petioles should be rejected. The eyes of 

 the extremity and base of the shoots, together with those placed at the base of the 

 leaves having a very slender or very long petiole, should not be used." 



In the })reparation of scion buds, scions with half sapwood are considered far su- 

 perior to scions with sapwood. In the station experiments the largest amount of 

 budded wood was ol)tained when the shoots of the mother stocks were tied up in 

 a V shape as soon as hard enough. The axillary buds and tendrils are removed 

 at the time, and this o})eration is repeated 3 times during the season. 



A study of grape pollen and what the results indicate, N. O. Booth (Amer. 

 Gard., 23 {1902), Nos. 414, pp- 767, 768; 415, pp. 784, 785). — Experiments were made 

 during the summer of 1902 to determine, if possible, why certain varieties of grapes 

 were self-sterile. The degree of self-fertility of 169 varieties of grapes has been pre- 

 viously noted (E. S. R., 11, p. 248). The work of the season has centered around 

 two phases of the problem: (1) Whether the pollen on the self-sterile varieties might 

 not be so scanty as to make self-fertilization impossible; and (2) whether lack of via- 

 bility in the i>o]len itself might not be the cause of impotency on its own pistil as 

 well as on all other varieties. As to the amount of pollen present, the investigations 

 of the season showed that "there were greater variations on different clusters of the 

 same vine than normally appeared on different vines of different varieties." The 

 first and last clusters to bloom on the vine are usually not so well supplied with 

 pollen as those blooming at the height of the season. In some cases the amount of 

 pollen found was ajiparently insufficient to make pollination at all certain, but gener- 

 ally with most of the self-sterile sorts pollen was plentiful and apparently suflicient 

 for pollinating purposes. 



The viability of the pollen was studied by germinating the pollen grains in dilute 

 sugar solutions. The percentage of sugar used varied in the different solutions from 

 1 to 20. The smallest percentage was found too weak in some instances, and most of 

 the germination tests were made in 20 per cent solutions. With the self-fertile varie- 

 ties germinations of the pollen varying from 4 to 95 per cent were obtained in these 

 solutions, while with the self-sterile sorts the pollen did not germinate at all or made 

 only a feeble growth, varying from 1 to 5 per cent. Besides these differences in 

 germinating power of the pollen from self-sterile and self-fertile varieties, there was 

 a difference in the behavior of the pollen which seemed to be quite constant. "The 



