﻿i 9 i6] CURRENT LITERATURE 537 



therefore, is 1:4:2:2:1:2:1:2:1. The analysis was carried out on a com- 

 mendably large scale and gave the following approach to expectation : 



It is clear that the results of this analysis will account for the discrepancies in 

 the results of other investigators, since the short awned individuals may be 

 classed on one basis with the awned, or on another basis with the awnless, 

 and would naturally be classed either with the awnless, or as a distinct 

 intermediate class, if a strictly awnless wheat had not been used in the cross- 



ids. — By this term De Vries" designates those F t 

 hybrid progenies in which a portion of the individuals resemble the one parent, 

 and the remainder resemble the other parent, a type of behavior which is not 



between 0. Lamarckiana and O. Lamarckiana mut. nanella. The percentage 

 of nanella among the F r offspring of this cross can be modified by the condi- 

 tions under which the mother plant is grown, from nearly o per cent to nearly 

 100 per cent. When the Lamarckiana mother was grown as an annual, the 

 average percentage of nanella was 22; and when the Lamarckiana was grown 

 as a biennial, the average number of nanella among the offspring reached 65 

 per cent . Corresponding with this result there is also a much higher percentage 

 of nanella from capsules developed early in the season, when the mother is in 

 most vigorous condition, than from capsules produced later in the season when 

 vegetative vigor is declining. For example, on 3 different biennial- Lamarckiana 

 plants used in these extensive crosses, capsules developing July 12-23 yielded 

 73-88 per cent of nanella, those produced between July 24 and August 4 yielded 

 61-67 P er cent nanella, and between August 5 and 16 the capsules produced 

 48-57 per cent nanella. 



Another experiment showed that the time of transplanting has a marked 

 influence on the percentage of nanella offspring, those reset on April 15 yield- 

 ing 50 per cent, while plants of the same culture set out on May 15 produced 

 only 29 per cent nanella. In this case the Lamarckiana mothers were grown 

 as annuals. Further experiments showed that keeping the plants well watered 

 also resulted in an increase in the percentage of nanella plants among the F x 

 progeny.— Geo. H. Shull. 



468. 1915- 



