Distribution of chromosome numbers in BC2 and BC1F1 progenies derived from Triticum aestivum × Psathyrostachys huashanica

Abstract

In this study, 596 plants of the BC 2 BC 2 ((F 1 × CS) × CS, (F 1 × CSph2b) × CSph2b and (F 1 × J-11) × J-11) and BC 1 F 1 ((F 1 × CS) selfed, (F 1 × CSph2b) selfed and (F 1 × J-11) selfed) which derived from the F 1 hybrid be- tween CSph2b and P. huashanica were observed for analyzing the distribution of chromosome numbers. The chromosome numbers of the populations of BC 2 and BC 1 F 1 varied from 2n = 42 to 52, and plants with 2n = 45 accounted for the highest frequency (19.6%). The distribution of chromosome numbers in all combinations didn't fi t to normal distribution, indicating that the distribution of chromosome numbers was affected by some genetic factors. There were different main ranges of chromosome numbers and reduced chromosome numbers per a hundred of plants in BC 2 accessions and in BC 1 F 1 accessions. These results indicated that the distribution of chromosome numbers was affected by the genotype of the backcross parents. The effect of CSph2b higher than CS and J-11, and the effects of CS and J-11 were similar in BC 2 accessions. However, the effi ciency of J-11 was higher than CS in BC 1 F 1 accessions. And chromosome eliminated more rapidly by backcrossing than self- ing, and selfi ng may be facilitate to the screening of partial amphiploids and the recombinant between wheat and P. huashanica chromosomes.