F. C. Miles 203 



barely possible that there might be 12 green plants without the 

 occurrence of any golden ones. But there is also the possibility that 

 the single grain which gave rise to the F^ plant was accidentally either 

 self-pollinated (the cross was green % x golden ^) or crossed by a 

 grain of pollen from a green plant. Seed from seven of the F^ ears 

 gave 230 green plants and 67 golden plants. This is a ratio of 3-4 : 1 

 instead of the expected 3 : 1 ratio, but since nearly all of the plants 

 were grown in the greenhouse under rather crowded conditions not all 

 of the golden individuals may have been identified. 



A cross of an F^ plant with one of the golden plants yielded some 

 interesting results. The resulting ear had 195 grains which lacked 

 aleurone colour, and 36 grains which had black aleurone. When seed 

 lacking aleurone colour was planted there resulted 15 green plants and 

 15 golden ones, just as is expected when an F^ plant is crossed with the 

 recessive parent, but the seed having black aleurone gave eight plants, 

 all of which were green. It would be interesting to note whether or 

 not there is any coupling between the factors concerned in the develop- 

 ment of green in the leaves and the various factors involved in the 

 formation of aleurone colour. 



Several of the golden plants were self-pollinated, but only three 

 small ears resulted as this type of plant rarely produces ears. The 

 three ears produced progenies of 4, 20, and 21 plants, respectively, and 

 all 45 plants were of the golden type. This, together with the various 

 other tests herein reported, indicates rather clearly that a simple 

 Mendelian recessive is being dealt with. 



The cross between ordinary green plants and striped plants of the 

 race known as Zea japonica (PL VIII, figs. 8«, Hb) is affording interesting 

 study. The first generation is green, and when self-pollinated yields 

 a second generation consisting of both green plants and striped' plants 

 similar to the japonica parent. The results thus far obtained indicate 

 that the percentage of striped segregates in a progeny depends, to some 

 extent at least, upon whether or not aleurone colour is developed in 

 the grains planted. In the original cross part of the grains lacked 

 aleurone colour, and part of them had dark aleurone. These were 

 separated and F^ plants were grown from each lot. 



In the second generation the family which developed no aleurone 

 colour in the grains consisted of 94 green plants and 30 striped ones, 



' At first the striped segregates, as well as the individuals of Zea japonica, cannot 

 be distinguished from green plants, but about five to eight weeks after planting the new 

 leaves begin to show the prominent longitudinal stripes. 



