Genetical and cytological studies in the breeding of amphidiploid types between Triticum and Secale. : IV. Fertillty and germlnatlon in seeds of T.turgbdum (n=14) x S. cereale (n=7) F₂ and external characters and somatic chromosomes of F₃ progenie.

Abstract

1. In the present reseach were studied the fertility and germination of the seeds of F2 piants, and the external characters, fertility and somatic chromosomes of F₃ plants raised from T. turgidum (n=14) and S. cerea!e (n=7). 2. 17 individuals of 42 F₂ plants were fertile, 5 individuals of them having 2n=41 chromosomes and the remaining 12 individuals having 2n=42 chromosomes (Table 1). 3. The fertility for the number of spikelets of the F2 plants having 2n=41 chromosomes appears to vary from 0.54 to 20.88 percent, and that for the case of those having 2n=42 chr.omosomes from 3.0 to 50.56 percent. In other words, in the former case 92 grains of seed were obtained from 690 spikelets and in the latter 555 grains from 1725 spikelets, and the fertility for the number Of spikelets corresponds to 13. 33 and 32..12 percent respectively, the latter value being 2.4 times than the former one. 4. That the fertility is low as mentioned above seems due to the fact that these hybrids are intergeneric and that the generations they passed are very few. As a consequence, the hybrids show irregularity in meiosis, generally resulting poor fertile power in the gametes. 5. 76 of 92 grains of seed obtained from F₂ plants having 2n=41 chromosomes and 345 of 555 grains of seed obtained from those of having 2n =42 chromosomes were sown in pots and in the former case 30 F8 plants, in the latter one 137 of them were obtained, the percentage of the number of germinated plants fer the number of seed sown being 39. 5 and 39. 7 percent respectively.