88 



FLORIDA STATE HORTICULTURAL SOQETY 



It must be noted that in effecting cross- 

 pollination insects must fly back and forth 

 repeatedly between trees of reciprocating 

 varieties. If individual bees or other in- 

 sects confine their visits to the flowers of 

 one tree or to trees of one variety the 

 interplanting will be of no special advan- 

 tage. Possibly the quality of the nectar 

 produced by various varieties may influ- 

 ence the activities of bees. There may be 

 such differences in the flavor and odor of 

 nectar produced by certain varieties that 

 individual bees may refuse to fly back and 

 forth l)etween them and collect nectar 

 from both. 



The whole matter of the behavior of 

 bees and other insects in the pollination 

 of avocados and especially in extended 

 plantings of them deserves a very careful 

 study. Insect behavior is without doubt 

 one of the deciding factors as to the re- 

 sults obtained in interplanting. 



3. When pollinations are made at the 

 proper time and in the proper way fruit 

 does not necessarily start to develop. In 

 numerous fruit crops, apples, pears, plums, 

 cherries, etc., certain pollinations are not 

 compatible in fertilization and hence do 

 not lead to the setting of fruit. Usually 

 it is self-compatibility that is not effective 

 and this limits or entirely restricts self- 

 and cross-pollinations as fully as does the 

 flower behavior in avocados. 



Sometimes cross-pollinations between 

 varieties of the same fruit also fail and 

 so differences in affinities of fertilization 

 may e.xist between avocado varieties. 

 Certain results in FKnida have led some 

 of the growers of avocados in the state 

 to consider it possible that interplanting 

 \\\' t Indian and Guatamalan varieties is 



especially productive of good yields. In 

 California, many controlled cross-pollina- 

 tions were made between varieties in the 

 hope of obtaining some evidence on this 

 matter of affinities in fertilization. Most 

 of these pollinations were made during 

 the months when there was much irreg- 

 ular and offstride blooming and the per- 

 centages of "sets" were too low to be re- 

 liable in judging the matter. 



In Florida, no fruit developed 

 to either self- or close-pollinations artifi- 

 cially made during 1924. From hundreds 

 of flowers artificially self- and close-pol- 

 linized during February and March 1925 

 only three close-pollinations w^ere hold- 

 ing March 28, while eight fruits were 

 holding from the cross-pollinations made 

 prior to March 17. Between March 17 

 and 28, 562 flowers were cross-pollinized 

 in 35 different ways, using 13 different 

 varieties of flowers and 14 different kinds 

 of pollen, from which some interesting 

 data may be obtained. 



Undoubtedly certain varieties will cross- 

 fertilize more readily than others even 

 when there are equally good chances for 

 cross-pollination. It would be well worth 

 while to determine this by appropriate 

 experimental tests. 



It is to be recognized that at the present 

 time there is no rule of thumb for the 

 interplanting of avocados which will guar- 

 antee uncjualified success. In respect to the 

 behavior of flowers, alone one can have 

 no hesitancy in advising interplanting for 

 every variety and of making the choice 

 of various i)airs of varieties which will 

 provide the chances for greatly increased 

 pollinations. Any interplanting on this 

 ba'^is is better than none at all! 



