SEX INFLUENCE ON RECOMBINATION FREQUENCY IN SECALE-CEREALE L

The variation in recombination frequency (rf) is important to plant br eeders since their major objective is to obtain favorable recombinants of linked genes. One source of variation in rf is sex. Sex difference s for recombination frequencies were studied in four of the seven chro mosomes of Secale cereale L. cv 'Ailes' using isozyme and storage prot ein loci and were determined on the basis of reciprocal crosses betwee n heterozygous plants of cv. 'Ailes' and homozygous plants of the inbr ed line 'Riodeva'. The differences were found to be strongly segment-s pecific. fn some cases the level of crossing-over in male and female m eiosis was about the same (between Pgm1 and Ndh1 loci on chromosome ar m 4RS). However, for most of the chromosome segments in 1R, 3RL and 6R L the male rf was significantly higher than the female rf. Different h ypotheses about the mechanisms of plant sex differences for recombinat ion are discussed.