Meiotic behaviour, chromosome stability and genetic analysis of the preferential transmission of 1B-1R, 1A-1R and 1R(1D) chromosomes in intervarietal hybrids of wheat.

摘要

The meiotic behaviour and relative transmission of segregant chromosomes was studied in the progeny of the F1 hybrids formed between a normal common wheat cv. Pane 247 and lines which contained single or double wheat-rye translocations 1AL-1RS, 1BL-1RS and/or the substitution 1R(1D). Chromosome stability was evaluated in the F2 progenies by the analysis of different markers: C-bands, LMW- and HMW-glutenins, gliadins and secalins coded for by genes Glu-A1, Glu-B1, Glu-D1, Glu-R1, Glu-A3, Glu-B3, Gli-A1, Gli-B1 and Gli-R1, located on either the short or long arm of the chromosomes of homoeologous group 1. Direct analysis of chromosome constitution and the chi2 test, used in the genetic analysis of genes located in each chromosome arm, indicated thatobserved frequencies were significantly different from the expected Mendelian values in hybrids with only one translocation. The segregation patterns were biased in favour of the transmission of normal 1A over 1AL-1RS, normal 1B over 1BL-1RS, arm 1DL over 1RL and arm 1RS over 1DS. However, the same genes segregated in a Mendelian fashion in other hybrids with normal constitutions for these chromosomes or which showed double structural heterozygous constitution. The different response to the selection of different chromosomes or chromosome arms may be the product of an integrated contribution of meiotic behaviour plus differences in the vigour of male gametes carrying a normal chromosome compared to those carrying rye chromatin. However, it might alsobe due to differences in viability once male and female gametes combine.