A BEACH YTIC VAKIATION IN MAIZE. 21 



ears were found with staminate spikes ranging from 15 cm. in 

 length to those with just a few scattered spikelets near the tip or 

 with only a disorganized area where spikelets failed to develop, 

 leaving a bent and deformed ear. The range of variation in the 

 Boone-brachytic hybrids is shown in Plates XV and XVI. 



The variation is one which is found frequently in maize in several 

 forms. The nature of its inheritance has not been reported, but 

 that it is heritable seems certain. 



While neither the Boone nor the brachytic parent plants produced 

 ears with staminate spikes, many plants of the first generation pro- 

 duced such ears. The exact ratio in the F 1 was 17 with staminate 

 tips to 63 normal. This is a very close approximation to a Men- 

 delian monohybrid ratio, where the variation is recessive to the 

 normal form of the ear. To secure such a ratio in an F 15 it may be 

 assumed that both parents were heterozygous for the character in- 

 volved. The same result would be obtained if normal ear form were 

 the result of two dominant independent factors with the brachytic 

 parent heterozygous for both of these factors and the Boone parent 

 homozygous for one dominant factor and heterozygous for the other. 

 On this latter hypothesis the progeny of the self-pollinated brachytic 

 parent would have 43.75 per cent of the plants bearing ears terminat- 

 ing in staminate spikes, while the self -pollinated Boone parent would 

 give 25 per cent of the progeny with such ears. 



Of the nine hand-pollinated ears obtained from brachytic plants, 

 six were the result of self-pollination, the other three representing 

 crosses between sister plants. Only one progeny grown from these 

 nine ears exhibited the staminate spike character. This progeny 

 was from a self-pollinated ear. Ears were produced by 36 plants, 20 

 of which had staminate spikes that ranged in length from 2 to 12 cm. 

 The average length was 6.55 ±0.52 cm. The percentage of plants 

 having staminate spikes (55.5±5.6) is very close to that for a 

 Mendelian dihybrid, where the character is the result of the com- 

 bination of two dominant factors and the parent plant is heterozy- 

 gous for both of them. As in all the second-generation progenies in 

 which this character reappeared it behaved as a recessive character, 

 the percentage of 55.5 may be considered a chance departure from 

 43.75. With the small number involved (only 36), the deviation of 

 11.75 per cent above the 43.75 is less than three times the probable 

 error. 



If the above explanation is correct, self -pollinated F 1 plants should 

 give the following progenies : One all normal, three with 25 per cent 

 of the plants with staminate spikes, two with 43.75 per cent of the 

 plants with staminate spikes, and two with all the plants with stami- 

 nate spikes. The last two, of course, would be recognized in the first 



