| Accordingly, plant No. 1 and No. 2 are considered to have the same chromosome
constitution which is quintuply monosomic for A-genome chromosomes, nullisomic for
another chromosome of the same genome and disomic for all other chromosomes of common
wheat. Plant No. 3 should be considered as the aneuploid which is sextuply monosomic for
A-genome chromosomes, nullisomic for another chromosome of the same genome, trisomic
for a chromosome of B- or D-genome and disomic for all other chromosomes. Some morphological characteristics at maturity are shown in Table 3. In Plant No. 1 and No. 2 all spikes were pollinated with normal disomic pollen. Rather large number of seeds set in these plants shows that they had enough function in fertilization in their female organs. On the other hand all spikes of Plant No. 3 were self-pollinated. Its smaller number of seeds obtained is attributable to poor function of male gamete in consideration with the score of 36.6 per cent of stainable pollen in this plant. The 35-chromosome plants obtained in the present experiment are considered to be originated from occasional fertilization of pollen which has unusual chromosome constitution resulted from pairing failure of homologous chromosomes or non-disjunction in meiosis of nullisomics used in the cross. Literature Cited MOCHIZUKI, A. and S. SHIGENAGA 1964. Extraction of B genome from hexaploid wheat Sci Rep. Hyogo Univ. Agric., Ser. Agric. Biol. 6(2) : 49-52. SHIGENAGA, S. 1968a. Studies on the hypoaneuploids of common wheat. I. Double monosomics and triple monosomics. Jap. J. Genet. 43: 109-119. SHIGENAGA, S. 1968b. Studies on the hypoaneuploids of common wheat. II. Quadruple monosomics and quintuple monosomics. Jap. J. Genet. 43 : 203-210. SHIGENAGA, S. 1976. Studies on the hypoaneuploids of common wheat. III. Production of sextuple monosomics. Canad. J. Genet. Cytol. 18: 255-261. |
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