Interspecific and intergeneric hybrids in herbage grasses
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The paper is concerned with results obtained when wind-pollinating annualLolium types Were intercrossed with otherLolium species:L. italicum, L. perenne, L. loliaceum, L. remotum andL. temulentum.
Of these five other species, the first two are wind-pollinating and non-annual and the other three self-pollinating and annual.
The wind-pollinating annual types are considered in two groups:
Those classifiable asL. rigidum Gaud.
Those not classifiable asL. rigidum Gaud.
This distinction is not emphasized except in crosses withL. italicum andL. perenne.
The results obtained by intercrossing eitherL. italicum orL. perenne with plants of group 3 (b) (above) are of the same order as would be expected in intraspecific crosses.
The hybrid plants obtained under 5 (above) are fertile and interbreed freely with one another and with plants of the parental species.
Seed produced by intercrossing plants of group 3(a) (above) with eitherL. italicum orL. perenne have a lower germinating capacity than seed produced in intraspecific crosses, but established progeny are easily produced in both cases.
The hybrid plants produced under 7 (above) are fertile and again produce fertile progeny amongst themselves and with the parental species.
The slight barrier that may exist betweenL. rigidum Gaud. on the one hand andL. italicum andL. perenne on the other does not preclude free interbreeding between all the wind-pollinating types ofLolium.
The non-annual habit is nominally dominant in all cases, but its expression varies according to the perenniality of the non-annual parent.
Segregation for both annual and non-annual habit and for plant type occurs in F2 and in backcrosses, but the backcross causes a strong swing-over towards the pure species parental type.
A very strong interbreeding barrier exists between the wind-pollinating annualLolium types and the self-pollinating annualLolium species.
This is mainly shown in poor caryopsis development and almost complete failure of the seed to germinate.
KeywordsOvary Stimulation Intergeneric Hybrid Intraspecific Cross Pistillate Parent Backcross Family
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