PERSONAL EQUATION IN BREEDING EXPERIMENTS. 54 ' 



-I.VII-.MENT OF PROBLEMS AND PLAN OF INVESTIGATION. 

 The problems with which this work is concerned may be 

 .-ummarily stated as follo\\ - : 



1. To what extent is the personal equation of the observer a 

 lificant factor in the Mendelian ratios described for simple 

 riments with cross-bred maize? In other word-, h>\v closely 



Mould the different individuals of a group of competent biological 

 ob-ervers agree in their classification ami count of the same V 

 in. nrrial from a maize cross involving -uch rclati'.ely -imple and 

 e.i-il\ judged unit characters as color ot" endo-perm, or chemico 

 phy-ical character of endosperm (starchy r swe< 



2. I )oes somatic "intermediateness" in mai/e imply garnet ic 

 "intermediateness"? In other word-, do F_. kernel* \\hich are 

 inn rmediute snmatically give rise to any diffen-nt -on of progeny 

 \vheii pi. uitcd than do kernels which belo, \\\ and indubi- 

 i.iliU n> one or another of the well-defined :>imcti(- d '">\ \ .'. 

 If ihe\ are true "blends" in the (ialtoniaii . the\ \\ould 



ainly be expected so to do. If, ho\\ever, they merely re; 

 sent a phenomenon essentially like the incomplete <>r p.mial 

 (somatic) dominance so frequently oh>-r\ei| in Mendelian work, 

 it would be expected that their progeny would dill'er in im essen- 

 tial particular from that obtained from ~ni,uii .i!l\ nun-inter- 

 mediate kernels having the same gametic c<m-titution. 



To test these questions the following plan wa- di \ i-ed : I'mir 

 .ii- ln-.iring p2 kernels were taken quite at random from a lot 

 ot about two bushels of such ears, which in turn was a random 

 -ample of a whole crop which included a much larger number of 

 bu-liels. Each of these four ears was given an arbitrary number 

 and was separately shelled, great care bein- taken to see that 

 im kernel* were lost. All the kernels from each ear were pre- 

 . i -d t' Aether in a bag (or box). The -hell in- was done in t h-- 

 \\riter\ laboratory in the presence ol -e\eral \\orker-. so thai 

 there can be no question whatsoever, that all of the kernel- in 

 each one of the four parcels originally a< \\ upon the -ame ear. 



Three of the ears so dealt \\ith No uid 101 \\eienormal 



in everj re-pect. Kar No. 11 was -li^htl\- abnormal in the 

 re-pert that a fungus had attacked -ome of the urain-. ^i\in^ 

 them a -li.uht pinki>h tinge in addition to their o\\ n propi-r 



