lo Jan., 1911-] Sterility in Fruit Trees. 



Varieties Affected. 



That certain kinds of fruit trees are prone to barrenness is well known, 

 in fact, this infertility or self-sterility although partially affecting many 

 kinds may, to a great extent, be looked upon as a varietal characteris-tic. 

 In Victoria, such kinds as Kieft'ers Hybrid and Winter Nelis pears. 

 Northern Spy apple, Coe's Golden Drop plum, and Early Purple Guigne 

 cherry are notable as very shy or, in some cases, non-bearers. This 

 has, unfortunately, been the experience of many growers in this and other 

 States — experience that has been made tedious by long years of patient 

 waiting for the trees to end their profitless, and commence their profitable, 

 career. They have, as a rule, remained either completely or almost barren, 

 despite the fact that they have, to use common parlance, been " white 

 over with blossom" year after year. There are exceptions where these 

 varieties have done well in the matter of fruiting and, on the other hand; 

 instances are not rare where trees, even of good bearing varieties, are 

 known to be duffers. It is, however, safe to say that contributing causes 

 may usually be found such as will be explained subsec]uently. 



Causes of Sterility. 



At first thought, this fact — that varieties may be self-sterile — looks 

 strange; but it would not so appear were we to study thoroughly the; 

 conditions governing the undesirable quality, for it is like all other effects 

 due to some specific cause or causes, which, if defined, open the way for 

 remedial treatment. Realizing this, the writer has made special observa- 

 tions during the present season in the Diamond Creek and Bacchus Marsh 

 districts of various factors essential to the fertilization of blossoms. 



The first and most important detail in connexion with this vital process 

 is perfection in the structural arrangement of the flower organs, for if there 

 be any imperfection here sterility or partial sterility is likely to be the 

 natural result. As a case in point, the writer found at Mr. A. C. Simon's 

 orchard, Bacchus Marsh, an apple tree — a seedling — which Mr. Simon 

 had planted fifteen years ago, but the tree had never fruited. Recently, 

 when visiting the orchard, the writer was asked the cause of barrenness 

 and upon examining the blossoms, the reason was very evident, for they 

 were foimd to be totally unisexual, with the pistils entirely missing, 

 'i'hus. through this imperfection, sterility was the natural result. Although, 

 m this singular case, the cause was so marked it was not so with the great 

 majority of the other trees examined. The blossoms of a large number 

 of trees of Kieffer's Hybrid pear, Coe's Golden Drop plum. Early Purple 

 Guigne cherry and others were examined carefully, but no imperfection 

 was found to exi.st ; in fact, the stigmas of a large percentage of the 

 blos.soms were found to be self -pollinated, despite which no setting took 

 })lace. 



It was quite singular, in some ( ases of sterile trcx-s, to observe how 

 ])lentiful was the sup|)ly of pollen even when the stigma was in a recep- 

 tive condition. With ref('reni'e to this aspect of the subject Inspectoi 

 Hammoiul. of Doticaster district, writes — " The result of a careful ex- 

 amination of the carpels, anthers, stamens, pistils, and stigmas of the 

 "shy" varit'ties was of a negative character, and up to the jiresent time 

 I cannot account for their infertility. An examination of the flowers of 

 the diftcrent kinds of trees which failed to .set their fruit did not disclose 

 any defect in the essential organs of reproduction." Inspector l'"arre!l 

 (Evelvn district) states — " I have not been able to detect any obstruction 



