Improved pasture, forage and seed production technology through pod and leaf retention on annuals of the medicago genus (annual medics)

摘要

The present invention relates to improved cultivars, varieties, lines or plants of annual medics (Medicago genus) wherein the majority of seed pods, upon reaching maturity, remain attached to their respective pedicels (this being referred to as the "pod holding" trait). In particular, the present invention relates to improved cultivars, varieties, lines or plants of annual medics (Medicago genus), having a mutant form of the gene for pod shedding (ie for formation of an abscission layer between maturing seed pods and their respective pedicels), thereby resulting in the aforementioned "pod holding" trait. ??In a further aspect of the invention, seed from known cultivars or wild-type varieties of annual medics (Medicago genus) are subjected to treatment with a mutagenic agent, and improved cultivars, varieties, lines or plants having the aforementioned "pod holding" trait are isolated, eg by a selective breeding program. ??A yet further aspect of the invention relates to a method of transferring the "pod holding" trait from an annual medic having this trait to another annual medic of the genus Medicago by a process of controlled cross-breeding of the annual medic having the trait with said other annual medic and selection of progeny or descendants having the "pod holding" trait. In particular, the method can include the following steps: (i) cross-breeding the annual medic having the trait with said other annual medic, and collecting hybrid seed resulting from this cross-breeding; (ii) planting said hybrid seed and producing F1 hybrid (first generation) plants therefrom; (iii) allowing the F1 plants to self-pollinate and set seed; (iv) planting the seed from the F1 plants and producing F2 (second generation) plants therefrom; (v) assessing the F2 or any later generation of plants for said "pod holding" trait and selecting said F2 or later generation plants having this trait. ??A still further aspect of the invention relates to a method of obtaining plants having the "pod holding" trait from a population of annual medics of the genus Medicago. That population is derived by controlled or natural cross-breeding of annual medics, where one or more of the population parents carries one or more copies of the gene conferring the "pod holding" trait, and individual plants, progeny or descendants of the said population having the "pod holding" trait are selected. In particular, the method can include the following steps: (i) obtaining a population derived from controlled or natural cross-breeding of an annual medic where one or more parents of said population have the "pod holding" trait or are progeny or descendants of controlled or natural cross-breeding involving one or more parents having the "pod holding" trait; (ii) growing plants of the population; (iii) assessing plants of the population or plants grown from seed harvested from any descendant generation of the population for said "pod holding" trait and selecting plants having this trait. ??The progeny or descendants created by either of the aforesaid methods may also be selected for improved mature leaf retention, this being a trait directly associated with the "pod holding" trait. IMAGE