Notes on Intensities in the Spectrum O II.

19 c sh Wx and 34 c sh wx kernels. Crossing-over between the loci of C, Sh and Wx occurred with a frequency equal to that found in normal material. When some of the colored, non-shrunken, non-waxy (C c, SE sh, Wx wx) and colorless, shrunken, waxy (c c, sh sh, wx wx) kernels were grown, it was found that crossing-over had occurred in the region between the locus of C and the deficiency. All of the plants were yellow-green whether they possessed the gene yg2 in the simplex (heterozygous for deficiency) or in the duplex condition (homozygous for the recessive). Counts of the pollen from the middle part of single anthers of plants heterozygous for the deficiency showed that there was no more abortion of pollen grains than is normal for maize. In one case 92 out of 1694 (5.4 per cent) were undeveloped. Pollen from one of the plants heterozygous for the deficiency and for the genes C, Sh and Wx was used in crosses to the multiple recessive stock the results agreeing with those obtained in the previous backcross (171 C :165 c). It was possible to self-pollinate only one individual heterozygous for the deficiency. Unfortunately, it was homozygous for recessive c, sh and wx. This makes necessary a cytological examination of the plants from the kernels obtained for the presence of the diminished knob in the homozygous condition before it can be known whether a homozygous deficiency is viable.