PROGRESS IN FORAGE GRASS BREEDING

D. Reheul, A. Ghesquière
Many courses in plant breeding start with focusing on the first plant breeders: the farmers. It is said that farmers always have selected the best roots, ears or fruits to grow a further generation. Recently in history some smart people realised there was more money or intellectual satisfaction in breeding than in farming and that's how breeding was taken away from farming.

I've never heard nor read stories suggesting that farmers collected individual superb grass inflorescences. The reason is quite obvious : grass isn't cultivated as individuals, grassland even wasn't cultivated at all until recently. It consisted of many grass species growing together with other species. As a consequence tracing outstanding plants belonging to the best species was hardly possible. Moreover heading dates between and within species in such populations are very different which causes an uneven ripening of the seeds. In those days (no further away than 5 decades) grassland either was reseeded spontaneously by scattered seeds or by man using seeds collected on the hay floor.

Unlike most products of arable land grass is not an end product : it's a feed. Nobody really is interested in its productivity : what counts is animal performances. Even on the farm there is no good idea of the productivity of grassland since its yield is seldom measured. There is only a visible potential wealth of leaves, grazed by or fed to animals. And since the feed rations in many cases are completed with other feeds or concentrates, the influence of the grassland on the animal performances often is indefinite.

Almost all forage grasses are biannuals and perennials. It is well known that the evolution in grassland swards is quite dynamic. Spontaneous species are introgressing and the sown species may gradually disappear. As a consequence the performance of a pasture is the semi long run not always is a true reflection of the bred and sown varieties.

By the way no other agricultural crop in this part of the world is grown for its vegetative parts (the "source"). Agricultural crops are usually grown for their "sink" parts: roots, tubers, seeds.

Add to all these particularities the allogamous status of reproduction of most forage grasses and the high seed requirements to establish the crop and one may understand the rather low profile of the forage grass breeding.

The allogamous reproduction and the high seed requirements complicate the breeding work. The problem in outbreeders is not to create good genotypes but to fix the superb gene combinations. Unlike in many other crops there's today almost no activity in hybrid breeding in forage grasses. Reasons: if one happens to have inbreds, there's no reliable and economical system to hybridize the inbreds in a way to produce large quantities of hybrid seed. Fodder grass breeding is a costly activity and the return never has been as rewarding

Reheul, D. and Ghesquière, A. (1994). PROGRESS IN FORAGE GRASS BREEDING. Acta Hortic. 355, 135-142
DOI: 10.17660/ActaHortic.1994.355.13
https://doi.org/10.17660/ActaHortic.1994.355.13

Acta Horticulturae