Interspecific and intergeneric hybrids in herbage grasses - VI.Lolium italicum A.br. intercrossed with otherlolium types
The results previously reported for crosses betweenLolium italicum andL. perenne are summarized and some new data are added. These two species can interbreed freely to produce fertile progeny.
The results previously reported for crosses betweenL. italicum and wind-pollinating annual types are also summarized.
No effective barrier against free interbreeding was found in the above crosses, although the seed-germination results for crosses betweenL. italicum andL. rigidum Gaud. are lower than in intraspecific crosses.
The results for crosses betweenL. italicum and the three self-pollinating annual speciesL. loliaceum, L. remotum andL. temulentum are parallel with one another in type but different in detail.
In all three cases whenL. italicum was used as the pollen parent, stimulation of the ovaries occurred, the caryopses being well developed in length, but with the exception of one doubtful case in the cross withL. loliaceum none of the seeds germinated.
WhenL. italicum was employed as the pistillate parent, seed-setting varied from an average of 25 % withL. temulentum to 60% withL. loliaceum.
In none of the crosses were the caryopses up to normal length forL. italicum, and withL. remotum they were particularly small.
Seed germination was exceptionally high withL. loliaceum as the pollen parent surprisingly high considering the poor caryopses withL. remotum as the pollen parent and moderately high withL. temulentum as the pollen parent.
The results of intercrossingL. italicum with the three self-pollinating annual species therefore differ strikingly according to the direction in which the crosses are made.
They also differ from those obtained whenL. italicum is intercrossed with other wind-pollinating species and types.
The results for further breeding show that theF1 plants from crosses with the self-pollinatingLolium species were highly sterile.
A comparison of the results obtained by usingL. rigidum andL. italicum with the self-pollinating annualLolium species strongly supports the suggestion that althoughL. rigidum andL. italicum intercross readily, they are yet constitutionally different from one another.
I wish to thank Mr A. R. Beddows, M.Sc., for assistance in the breeding work described and his general interest in the work as it proceeded; to technical assistants and others who from time to time assisted with the emasculation work; to Prof. E. T. Jones, M.Sc., the present Director of the Welsh Plant Breeding Station, for providing access to the records and facilities for the write-up; and to the Agricultural Research Council for providing financial facilities and clerical assistance.
Volume 100, 2021
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