EAST: INTERCROSSES BETWEEN SELF-STERILE PLANTS 149 



38 28, 35, 39, 42, 43, 46 34. 37, 47 



39- 9. 44 18, 40, 42 



~~'io 22, 43, 44, 47, 49 6, 33, 46 



41 10, 37, 44. 48 33, 40, 46 



42 20, 44 39, 41, 45 



43 5, 27, 33, 38, 39, 40, 42, 44, 46, 51 



44 10, 14, 23, 34, 45 



45 18, 44, 48 46, 52 



46 10, 22, 37, 44, 51 52 



47 20,42, 44, 45, 46, 51, 52 38 



48 40, 41, 43, 46 10, 23, 24, 27, 34 



49 42, 44, 45 o, 9, 27, 34, 47 



50 18, 39, 51, 52 9, 27, 37 



51 9, 18, 23, 39, 45, 46, 50 8, 29 



52 10, 23, 29, 37, 51 3, 4, 6, 18, 41, 45, 46 



The numerous cross-matings made are shown in Table i. There 

 were 103 reciprocal matings. Of these 100 gave duplicate results, 39 

 pairs being fertile and 61 sterile. The three which did not check are: 



2 X 3, sterile, i pollination 1 , , r ^-i 



r •, 11- • I classed as fertile, 



3X2, fertile, i pollination J 



6 X 52, fertile, i pollination 1 , , ^ ., 

 , ^ ., ,,. • f classed as sterile, 



52 X 6, sterile, i pollination J 



37 X 21, fertile, i pollination 1 , , ^ ., 



., ... . > classed as sterile. 



21 X 37, sterile, i pollination J 



Since but one pollination was made in each of these cases we have 

 made our decision as to fertility or sterility by a consideration of the 

 ^circumstantial evidence. The behavior of these plants in other crosses 

 shows conclusively that 3 should be fertile with 2, 6 sterile with 52, 

 and 21 sterile with 37. They have been classed accordingly. That 

 this grouping is correct is further shown by the fact that the mating 

 3X2 (classed fertile) was made at the height of the flowering season, 

 while the matings 6 X 52 and 37 X 21 (classed sterile) were re- 

 spectively the last and next to the last matings made on those plants. 

 In spite of the fact that plants 0-39 are from cross N. alata X N. 

 forgetiana, and plants 40-52 are from cross N. forgetiana X N. alata, 

 they behave as one family in intercrosses. The entire population 

 can be grouped into 6 d asMs in a\ hicli there is interclass fertility, and 

 intraclass sterility. The following explanation may be necessary to 

 make it clear justnow Table II was obtained from Table I. Table I 

 shows all of the matings, but in the form given it is not easy to see at a 

 glance every combination in which a particular plant was used, both 

 as male and as female. It was necessary, therefore, to make a new 

 table, in which the pedigree numbers in the column at the left were 

 tabled as males, and the pedigree numbers in the columns headed 

 "Fertile matings" and "Sterile matings" were tabled as females. 



