280 Nebraska State Horticultural Society. 



considerablj' longer. The use of squashes and pumpkins would of 

 course necessitate the growing of a new supply each year. 



There is a second difficulty that is hard to get around, particularly" 

 where the student is to grow the plants rather than to depend upou 

 preserved specimens. This is that large numbers of individuals are 

 required in order that any adequate idea can be had of the possibilities 

 of hybridization. ' Where only a few individuals of any hybrid are 

 grown it is improbable that all or anything like all the possible com- 

 binations of parent characters will be secured; but even admitting the 

 probability of the presence of most of the possible forms, certainly no 

 accurate idea can be had from a few individuals of any numerical 

 relation which might exist between the various forms. Large num- 

 bers of plants cannot be grown during the winter when school is in 

 session without the use of considerable room in greenhouses. The 

 choice of comparatively small plants will of course reduce the difficulty 

 materially. If preserved specimens are used they also should not be 

 too bulky. This is the greatest drawback to the use of such plants as 

 squashes and pumpkins. 



How to Study Hybrids in the Laboratory. 



In case only one or two exercises are to be devoted to the study of 

 hybrids in a general laboratory course in horticulture, it will doubtless 

 be sufficient for the student, first, to note in a general way the rela- 

 tive amount of variation in the first and succeeding generations in 

 comparison with the variations shown by the parents; whether they 

 resemble one parent more than the other, or whether they are like one 

 parents in some respects and like the other in other respects; third, to 

 learn whether certain types seem to breed more nearly true than others. 

 "When more time is at the disposal of the student, as would be the case 

 iu a regular course of plant breeding, the work might be started much 

 as outlined above, but a more careful study should follow at once. 

 The student should be impressed at the start wtih the importance 

 of studying unit characters. He should take up a single character at 

 a time as, for instance, wartiness in squashes, stringiness in bean pods, 

 hairiness in poppies and the like, and study this one character in all 

 generations of the hybrid as well as in the parent races. He should 

 not only observe the variation in the development of this character 

 in the various individual plants, but he should note in case of alternate 

 inheritance the number of individuals that have the character and the 

 number in which it is wanting. In case of certain characters he 

 should make accurate measurements of all individuals as, for instance. 



