162 



AMERICAN BEE JOURNAL, 



March IS, 1900 



ffag-e. The new owner thoug-ht he had a bonanza in that 

 pear-orchard, and he, too, cared for it until his ability to do 

 so failed, when it past into the hands of another person ; 

 but still it failed to yield a crop of fruit. I take it that the 

 last owner had some faith in '•book-farming'," for he sent 

 to the Department of Agriculture at Washington for a solu- 

 tion of the problem of an unproductive orchard of Bartlett 

 pears. Mr. M. B. Waite, of the Department, was sent down 

 to study the subject on the ground. He guest the trouble 

 to be the lack of cross-pollination with other varieties, and, 

 fortunately, he guest right. More or less of the orchard 

 was grafted with other varieties ; but before it came into 

 profitable bearing it was struck with " blight " and ruined. 

 But it had served a useful purpose. A new interest was 

 taken in the subject of the effects of self and cross pollina- 

 tion of fruit-blossoms, and the scientific study of the sub- 

 ject began. This was carried out by taking pear and apple 

 blossoms just before they open, and removing a part of the 

 blossom and then applying either pollen of the same variety 

 or some other variety, and covering at once to prevent in- 

 sects from interfering. In this way it could be told whether 

 a given variety would prove fertile with its own pollen or 

 not, and just the effects of crossing with other varieties. 



As a result of these studies Mr. Waite says : " Many of 

 the common varieties of pears require cross-pollination, 

 being partially or wholly incapable of setting fruit when 

 limited to their own pollen. Some varieties are capable of 

 self-fertilization. Self-pollination takes place, no matter 

 whether foreign pollen is present or not. The failure to 

 fruit with self-pollination is due to sterility of the pollen, 

 and not to mechanical causes, the impotency being due to 

 lack of affinity between the pollen and ovules of the same 

 variety." 



"Varieties that are absolutely self-sterile may be per- 

 fectly cross-fertile. The normal typical fruits, and in most 

 cases the largest and finest specimens from both the so- 

 called 'self-sterile ' and ' self-fertile ' varieties, are crosses." 



" Self- fecundated pears are deficient in seed, and the 

 seeds produced are usually abortive. The crosses are well 

 supplied with sound seeds." . 



He gathered most of the cross and self-poUmated fruits 

 resulting from most of his experiments for study and com- 

 parison, and found, as a rule, a decidedly better develop- 

 ment of the blossom-end of the fruits of those cross-pollina- 

 ted than those self-pollinated. He found, also, a disposition 

 or tendency in self-pollinated late varieties of pears to 

 wither before ripening, while those resulting- from crosses 

 ripened perfectly. My son has offered to copy several of 

 Mr. Waite's illustrations. 



Fig. 1 shows a Bartlett pear crost with pollen of Easter 



pear. 



No. 2 shows a self-pollinated Bartlett pear. 



No. 3 shows seeds under a from cross-pollinated Bartlett 

 pears ; under b, seeds from self-pollinated pears. 



About three-fifths of the varieties of pears experimented 

 upon appear to have been wholly self-sterile, or were greatly 

 benefitted by cross-pollination. 



Even with those varieties capable of self-fecundation, 

 the pollen of another variety is prepotent (more powerful) ; 

 and unless the entrance of foreign pollen is prevented, the 

 greater number of fruits will be effected with it. 



As apples blossom soon after pears, a large amount of 

 work was done with them to ascertain the effects of self 

 and cross fertilization. He says : 



" In a general way the results were similar to those ob- 

 tained in the experiments with pears. The division of the 

 varieties into self-sterile and self-fertile sorts was not 

 nearly so well markt. . 



"Crossing gave decidedly better results in all cases than 

 self-pollination. The Baldwin, which was experimented 

 upon freely, may be cited as a variety that comes as near 

 being self- fertile as any, and yet even this is far from being 

 entirely so ; for in the best trees the percentage of fruit re- 

 sulting from self-pollination was not more than a fourth of 

 that which resulted from crossing. Some of the Baldwin 

 trees, in fact, seemed to be self-sterile, and all the varieties 

 occasionally set self-pollinated fruit." 



He does not seem inclined to place much confidence in 

 a strict classification, even of pears, as a variety may be 

 quite self-sterile in one section, as in the North, and yet be 

 quite self-fertile in the South or in some other season. 



Among the sorts of pears he found more or less com- 

 pletely self-sterile are the Bartlett, Anjou, Boussock, Clair- 

 geau Clapp's Favorite, Sheldon, Louisa Bonne de Jersey, 

 and other common varieties. Still less would it be possible 

 to classify apples. A variety may be self-fertile this year 

 and quite the reverse next year, or in one section of country 



and not in another. The weather at blooming-time is im- 

 portant. He says : 



" The weather during the blooming period exerts both 

 a direct and indirect influence on the setting of fruit. Even 

 when not injured by frosts, the blossoms are often chilled 

 by tlje cold to such an extent as to interfere with fecunda- 

 tion. Moderate cold renders the self-fertile trees self-ster- 

 ile, and severe cold renders them sterile to cross-pollination 

 as well. Warm and sunny weather at this time indirectly 

 aids the fertilization by favoring insects in their work of 

 cross-pollination. " 



The results of self-pollination in apples are very inter- 

 esting. Again I quote from his paper : "The apples re- 

 sulting from some of the experiments were collected and 

 studied, and the results were found to be parallel with those 

 obtained in the experiments with pears, the crosses being^ 

 larger, more highly colored, and better supplied with seed. 

 For example, the hand-crost Baldivin apples ivere highly col- 

 ored, ivell matured, and contained abundant seeds, while the 

 self-fertilized zverc only slightly colored, tvere but one-fourth 

 to two-thirds the regular size, and seedless. The crosses 

 were, in other words, like the better specimens of apples not 

 bagged from the same tree, and the self-fertilized fruits cor- 

 responded with the undersized, poorly-colored specimens 

 from the same trees." The italics are my own, for I wisht 

 to call attention to the inferior quality of apples produced 

 by self-pollination, rendering them of little value except for 

 cider or swine. 



Fig. 4 of my illustrations shows a Baldwin apple crost 

 by pollen of the yellow Bellflower, while No. 5 shows a large 

 specimen of Baldwin self-crost, and No. 6 a small specimen 

 of the same. The effects of cross-fertilization in increasing- 

 the size of fruits is an exceedingly interesting fact. 



Prof. Munson, of the Maine Experiment Station, has 

 found that the size of tomatoes may be quite dependent upon 

 the amount of pollen they receive while in bloom. One re- 

 ceiving a large amount may be four times as large as one 

 receiving only a small quantity. We have, doubtless, all 

 observed that a pea-pod that has set only one or two peas is 

 greatly dwarft in size. What the pod is to the pea, the skin 

 and pulp are to the apple-seeds. Facts prove, beyond the 

 shadow of a doubt, that the cross-pollination of apples does 

 affect not only the seed but the fruit also. 



Prof. Waite gave considerable attention to the quince, 

 but did not find so great a difference, and the fruits were as 

 perfect and as abundant where self-fertilized as when crost. 

 This is not as we should have expected, but we should be 

 satisfied with the truth. 



Prof. F. A. Waugh, of the Vermont Agricultural Col- 

 lege, has been at work along this same line in a careful 

 study of the numerous varieties of native and Japanese 

 plums, and has found them, almost without exception, self- 

 sterile here in the North. 



In concluding his paper Mr. Waite says : " The number 

 of insect visitors in any orchard determines to a great ex- 

 tent the amount of cross-pollination carried on. The pollen 

 of the pear and apple is not produced in sufficient quantity, 

 nor is it of the right consistency, to be carried by the wind; 

 and the pollination of these trees is, therefore, dependent 



upon the activity of insects If there is no apiary in the 



neighborhood, therefore, each large orchardist should keep 

 a number of colonies of bees. Honey-bees and other mem- 

 bers of the bee-family are the best workers in cross- 

 pollination." 



His advice to fruit-growers is to plant not more than 

 three or four rows of any one variety together, unless the 

 variety is known to be perfectly self-fertile, and be sure 

 there are enough bees in the neighborhood, or within two 

 or three miles, to visit properly the blossoms, and, when 

 possible, to favor the bees by planting in a sheltered situa- 

 tion, or by planting windbreaks. 



I must confess a keen enjoyment in again taking up the 

 study of this subject under the light that recent scientific 

 investigation by careful, painstaking, and unprejudiced ob- 

 servers has thrown upon it. We can now see why there was 

 such a variety of opinion on this subject in the symposium 

 referred to. We find that, while some varieties of both 

 apples and pears are, under favorable conditions, capable 

 of self-fertilization, yet a majority of the various varieties 

 of apples and pears are either wholly dependent upon insect 

 visits, or greatly.benefited by them, in setting and matur- 

 ing their fruits. 



Should any wish toOstudj' this^^ subject further, I would 

 refer them to a paper by M. B. Waite, Assistant Patholo- 

 gist, Division of Vegetable Physiology and Pathology, in 

 the Yearbook of the Department of Agriculture for 1898, 

 which I wish might be placed in^the hands of every fruit- 



