Genetics Department, Research School of Biological Sciences, The Australian National University, Canberra, Australia.
Theor Appl Genet. 1979 May;55(3-4):139-44. doi: 10.1007/BF00295440.
Interspecific crosses of Hordeum brachyantherum (2n = 28) and H. depressum (2n = 28) with H. bulbosum (2n = 14 or 28) and H. vulgare (2n = 14 or 28) were made. Crosses between brachyantherum and diploid bulbosum resulted in dihaploids (2n = 14) of brachyantherum and hybrids (2n = 21), whilst the crosses of brachyantherum by tetraploid bulbosum or vulgare gave hybrid progeny. Similarly, crosses between H. depressum and diploid bulbosum resulted in dihaploids (2n = 14) of depressum and hybrids (2n = 21), whereas depressum by tetraploid bulbosum or vulgare invariably produced hybrids.Cytological observations on 12 day old embryos obtained from these crosses revealed chromosome variability down to 14 in crosses with diploid bulbosum indicating thereby that chromosome elimination leads to haploid formation. Embryonic cells from the brachyantherum by diploid vulgare cross also exhibited a certain degree of chromosomal instability as micronuclei.The results indicate that the ratio of parental genomes in the zygote determines whether haploids or hybrids will be produced in crosses of brachyantherum or depressum with bulbosum. Furthermore, brachyantherum appears to be more efficient in eliminating bulbosum chromosomes in comparison with depressum.
将短颖野大麦（2n=28）和垂穗披碱草（2n=28）与中间偃麦草（2n=14 或 28）和普通小麦（2n=14 或 28）进行种间杂交。短颖野大麦与二倍体中间偃麦草杂交产生短颖野大麦的单倍体（2n=14）和杂种（2n=21），而四倍体中间偃麦草或普通小麦与短颖野大麦杂交产生杂种后代。同样，垂穗披碱草与二倍体中间偃麦草杂交产生垂穗披碱草的单倍体（2n=14）和杂种（2n=21），而四倍体中间偃麦草或普通小麦与垂穗披碱草杂交总是产生杂种。对这些杂交产生的 12 天龄胚胎进行细胞学观察发现，与二倍体中间偃麦草的杂交中染色体多样性下降到 14，表明染色体消除导致单倍体形成。来自短颖野大麦与二倍体普通小麦杂交的胚胎细胞也表现出一定程度的染色体不稳定性，出现微核。结果表明，合子中亲本基因组的比例决定了短颖野大麦或垂穗披碱草与中间偃麦草杂交是产生单倍体还是杂种。此外，与垂穗披碱草相比，短颖野大麦似乎更有效地消除中间偃麦草的染色体。
