468 



The journal ot Heredity 



shown by the in\estigations of Tscher- 

 mak, Jesenko and others, these hyl)ri(ls 

 are generally sterile, which is explained 

 b>- the irregular di\ision of cells in the 

 pollen. The stamens are insiifhcienlK- 

 filled with jiollen, are ccnered with thick 

 films and in the absence of the neces- 

 sar\' turgor generalK' do not dehisce. 

 The fjollen is amorphous, for the most 

 part, bill fre(|tiently there can be 

 found some pollen with well defined 

 nuclei and firmer granulation. Like 

 Jesenko, we did not succeed in o])tain- 

 ing self-pollination in Inbrids. There 

 were 220 isolated heads which did not 

 yield a single seed. 



Still, during a period of three \ears 

 about 1200 seeds were obtained from 

 these hybrids. The number of heads 

 with seed varied in different years from 

 five to ten per cent of the total number 

 of heads, there being generalb' not 

 more than one seed to a head, rarely 

 two or three. The seeds are of the 

 wheat t\pe, but occasionally some- 

 what elongated, approaching the shape 

 of rye. 



Here arises the c}uestion: If self- 

 pollination in hybrids (Fi) is iiupossi- 

 ble, how were the seeds obtained by 

 Rimpati, C'armen — and at our station? 

 Dr. Jesenko explains the derivation of 

 the seeds as being due to the crossing 

 of the hybrids with rye and wheat, the 

 possibility of which he proved by 

 experiment, in a test made at our 

 station in 1919 with 970 flowers 

 pollinated by wheat, we succeeded in 

 obtaining five seeds; 1012 flowers pol- 

 linated by ne gaAe one seed. In 

 1920, on pollinating 870 flowers with 

 r>'e, not a single seed was obtained; 

 while 220 isolated heads al.so failed 

 entirely to >ield seed. So far e\ery- 

 thing goes Xo prove that seeds are 

 obtained in first-generation (Fi)wheat- 

 r>'e Inbrids only when their flowers 

 are jjollinated, preferal)ly by wheat, 

 or sometimes b\- r\e pollen. But on 

 account of certain cotisiderations, we 

 believe this matter has not been 

 sufficiently cleared up. 



I shall now consider the hybrids of 

 the second generation, (".ermi nation 

 of the seeds is about 70 to 80 per cent ; 

 the shoots are coloured or not co!f>ured 



with anthocyanin; albino plants were 

 noticed in the progeny of only one 

 plant. The winter form of the hybrid 

 f)lants \aries considerably — from a 

 rosette with stalks pressed to the 

 ground, to an upright bush with non- 

 spreading stalks; not infrequenth' the 

 plants ha\e narrow needle-pointed 

 lea\es, like those found on certain wild 

 grassses. But these forms usually per- 

 ish in the autumn. 



The plants vary greatU* in the 

 length and width of the leaf blade, 

 exceeding b\' far the parental types of 

 leaves in these respects. The meas- 

 urements of the stomata is interesting, 

 riie nimibers of stomata obser\ed 

 til rough the microscope, and their 

 lueasurements in microns, are as fol- 

 lows: in wheat 77 with an average 

 length of 52.8 microns; in rye 78, 

 a\erage length 46.5 microns, in Fi 

 hybrids 96, average length 47 microns. 

 The maximum number of stomata of 

 the Fi hybrids was 1 10 (maximum num- 

 ber in wheat 104) with a maximum 

 length of 73.6 microns, (the maximum 

 noted in wheat is 63.0). 



The first year (Fi) seeds were sown in 

 the field and only about 20 per cent of 

 the plants wx^re placed in the green- 

 house for the winter, but even under 

 these conditions onh' 60 or 80 per 

 cent sur\i\ed. Subjected to a de- 

 tailed botanical anaKsis 209 plants 

 ga\e the following results: two typical 

 rye plants with apparent inclination to 

 self-pollination, seeds l)eing formed even 

 under the parchment packet enclos- 

 ing the head; 87 plants clearK- of the 

 Irilicum t\pe, btit in these fre(iuentK- 

 were noted se\eral minor morphologi- 

 cal features of r\e, such as the shoots 

 colored with anthoc\'anin, lengthening 

 of the flowering glumes, tender awns, 

 carina on the flowering ghnues, etc., 

 whereas the forms corresponding to 

 the parent forms were luissing. Twelve 

 plants were entireh- new forms with 

 long heads, with a large number ol 

 spikclets and narrow elongated flower- 

 ing glumes. In these plants the rye 

 features were |)re(lominant. but the 

 empt\- glumes were man\-ner\ed, and 

 the seed typical of wheat. I'inalK', 

 102 plants were placed b>- us in the 



