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

The meiotic behaviour and relative transmission of segregant chromosomes wa s studied in the progeny of the Fl hybrids formed between a normal common w heat and lines which contained single or double wheat-rye translocations 1A L-1RS, 1BL-1RS and/or the substitution 1R(1D). Chromosome stability was eva luated in the F-2 progenies by the analysis of different markers: C-bands, LMW- and HMW-glutenins, gliadins and secalins coded for by genes GluA1, Glu B1, GluD1, GluR1, GluA3, GluB3, GliA1, GliB1 and GliR1, located on either t he short or long arm of the chromosomes of homoeologous group 1. Direct ana lysis of chromosome constitution and the chi(2) test, used in the genetic a nalysis of genes located in each chromosome arm, indicated that observed fr equencies were significantly different from the expected Mendelian values i n hybrids with only one translocation. The segregation patterns were biased in favour of the transmission of normal 1A over 1AL-1RS, normal 1B over 1B L-1RS, arm 1DL over 1RL and arm 1RS over 1DS. However, the same genes segre gated in a Mendelian fashion in other hybrids with normal constitutions for these chromosomes or which showed double structural heterozygous constitut ion. The different response to the selection of different chromosomes or ch romosome arms may be the product of an integrated contribution of meiotic b ehaviour plus differences in the vigour of male gametes carrying a normal c hromosome compared to those carrying rye chromatin. However, it might also be due to differences in viability once male and female gametes combine. (( C) Inra/Elsevier, Paris.).