The Journal of Heredity 



were very rye-like, especially with re- 

 spect to such characters as beards, cili- 

 ation and shape of the lemmas. They 

 were bearded in spite of the fact that all 

 the wheat parentswere beardless, but the 

 beards in some cases were much shorter 

 than those on rye. The lemmas were 

 all lanceolate in shape and possessed 

 distinct ciliate keels with the exception 

 of five plants in the cross with Hybrid 

 128 which showed a slight modification 

 in this character, as they were ciliate 

 only toward the tips. 



The fourth column of table 2 shows 

 that the average plant height of each 

 cross is intermediate to its parents. The 

 low extreme approximates wheat and 

 the upper extreme approximates rye 

 in height. The average head length of 

 the four F2 families analyzed is shorter 

 than rye but longer than the wheat 

 parent in each case. The heads of 

 family number 3912 averaged one and 

 one-half centimeters shorter than its 

 three sibs. Its shortest heads were but 

 little longer than the longest heads of 

 Hybrid 128. The striking contrast in 

 head length is shown in figure 17 which 

 represents a head of each of the parents 

 with two of the F2 segregates between. 

 This shows the rye (female) to be 

 nearly three times as long as the wheat 

 (male). The F2 types are intermediate 

 in length. The one to the right is 

 infected with Tilletia tritici. The 

 extremes in head length and fertility 

 are illustrated in figure 19. 



Ninety percent of the F2 plants of 

 Rosen X Jones Fife had purple straw 

 although the wheat and rye that went 

 into the cross both have white straw 

 with no indication of purpling in leaf- 

 sheath or internode. The appearance 

 of color evidently comes from the 

 unusual recombinations of rye and 

 wheat chromatin. This purpling of the 

 straw, especially in the upper internode 

 also appeared to a less degree among 

 the F2 plants of Rosen X Hybrid 128. 

 No purpling appeared in the Fo family 

 of Rosen X Jenkin. 



Number 3911 gave 46 percent of 

 plants with pubescent peduncles which 

 is lower than that found in the rye 

 parent but the percentage in all the 



other families was very similar to the 

 variation in Rosen. In the F2 families 

 of Rosen X Hybrid 128 a higher per- 

 centage of hollow culms was found than 

 in the rye parent. 



The plants in number 3914 not only 

 contained hollow culms up to the base 

 of the heads in more than one-half of 

 the plants, but the neck immediately 

 below the head was thicker and stififer 

 and more like that of wheat. None of 

 these segregations give a simple unit 

 character ratio but the variations show 

 a recombination of the characters of 

 wheat and rye with those of the female 

 parent predominating. 



FIRST GENERATION OF WHEAT-RYE 

 HYBRIDS 



Maternal dominance is shown again 

 in the wheat-rye hybrids. The general 

 appearance of the two Fi plants of 

 Turkey X Rosen was very much like 

 that of wheat, but they could be readily 

 distinguished as true Fi plants by the 

 high degree of sterility. One plant 

 produced 24 completely sterile heads 

 and 6 that were partly sterile, the 

 other produced 13 sterile and 10 partly 

 sterile heads. 



SECOND GENERATION OF WHEAT-RYE 

 HYBRIDS 



That the chromatin material was 

 disarranged when the recombination 

 took place is shown by the plant char- 

 acters in the Fo generation. Nine of the 

 15 plants were beardless although Tur- 

 key and Rosen are both bearded. The 

 wheat chromosome carrying the gene for 

 beards might have been eliminated in 

 the first hybrid seed. The rye gene for 

 beards recombining in the Fi genera- 

 tion would then produce beardless and 

 bearded plants in the Fo in the ratio 3:1. 

 This hypothesis could also be used to 

 explain the unusual results obtained by 

 Love and Craig. 



Hybridization under normal condi- 

 tions increases fertility but in this cross 

 only one plant showed normal fertility. 

 Two others were 50 percent sterile, two 

 75 percent, six from 90 to 98 percent 

 and three completely sterile. 



Fach of the characters, pubescent 

 peduncle and solid culm, seemed to be 



