432 EXPERIMENT STATIOX RECORD. 



In general, no matter which variety was used as the female parent, there 

 was no immediate" visible effect of the male parent in tlie endosperm of crosses 

 between the flint and floury maize. The Fi generation plants produced ears 

 in which there was a clear segregation of corneous and floury seeds in a 1 : 1 

 ratio. This ratio was unaffected whether the Fi ears were pollinated with 

 pollen from either the pure flint or the pure floury parent. Seventy-six Fz ears 

 produced from a self-fertilized Fi ear of the floury-flint cross, gave a ratio of 

 1 pure flint ear, 2 hybrid ears, and 1 pure floury ear. The flint and the floury 

 ears bred true in later generations. A total of 69 self-fertilized ears showing 

 segregation gave a ratio of 8,803 corneous §eeds to 8,562 floury seeds. 



There seemed to be a close agreement between the results of the cross be- 

 tween the floury and Leaming dent and those for the cross between the floury 

 and flint. It was, however, more diflicult to classify the seeds in the former 

 cross as in the Leaming dent corneous starch is produced only on the sides of 

 the seed, the cap and the immediate vicinity of the embryo being filled with 

 soft starch. This difference in type of starch produced is evidently one factor, 

 yet since Fs families showed variations in the amount of corneous starch pro- 

 duced, there must be several minor factors which modify its development 

 " There is good evidence that at least some of these minor factors are factors 

 which have a direct effect on totally different tissues. For example, the size 

 and shape of the seed, which is at least partly controlled by the type of peri- 

 carp (a maternal character), has considerable influence upon the appearance 

 of the starch. To put the matter roughly, in plants which fundamentally have 

 the same zygotic possibilities as regards the type of starch in the endosperm, 

 the amount of soft starch actually developed is directly proportional to the size 

 of the seed." 



The pollen of White Rice popcorn apparently had no effect on the character 

 of the endosperm of the floury type. This is in agreement with the resiilts of 

 the crosses floury X flint and floury X dent. The F, ears showed the results 

 of segregation, although in this case there was a range of variation from the 

 floury to the corneous type. Seeds of this Fi generation (Fi seeds) produced 

 a population of ears ranging from the pure corneous to the pure floury type. 

 One uniformly floury ear bred true in Fa and F, for the floury habit ; three ears 

 with purely corneous seeds also bred true. Two Fi ears gave as variable an F» 

 progeny as had been found in Fs. the ratio in this case being approximately 1 

 pure corneous ear to 6.2 intermediates and definite hybrids to O.S pure floury 

 ears. Other F; ears gave a 1 : 2 : 1 ratio in Fs. Several self- fertilized intf-rmetli- 

 ate F2 ears bred comparatively uniformly, giving a progeny which contained 

 more corneous starch than the floury parent but less than the "SAhite Rice pop- 

 corn parent, i 



In the cross between the White Rice and Pearl popcorn " the F, penerati<»n 

 was of intermediate habit, there being some projection of the seeds at the point 

 of attachment of the silk. Four selfod Fi ears furnished Fj generations. The 

 progeny of these ears was variable, the seeds of some cars being as completely 

 pointed as the White Rice pop parent, the seeds of others nonpointeil like the 

 Pearl pop pnrent, while the greater number were of various intermediate tyix's. 

 Of a total progeny of 263 individuals, 24 ears were classed as pure pointed like 

 the White Rice parent. ... A number of F2 ears were self-pollinated, but none 

 happened to be obtained which could be classed as typically pointed. One ear 

 having seeds but slightly pointed (possibly nonpointed) was gi-own in Fs. The 

 21 ears produced were like the parent ear, showing only slight projections on 

 the seeds at the tip of the ear." 



In the cross between the White Rice pop (No. 64) and Leaming dent corns 

 (No. 6) " the Fi generation was intermediate as regards the pointed condition. 



