Forbes produced more spring biomass than all other early flowering varieties over three years at five trial sites and maintained higher seed bank densities than all currently available cultivars two and three years after sowing. The advantage of its high hardseededness was evident in two trials that were cropped in the second year, whereby Forbes had higher seedling regeneration densities in the year after cropping and produced 96% more spring biomass than Dalkeith.
Origin
Forbes is a sister line to Tammin, derived from the same complex cross involving the variety Dalkeith, three naturalisd strains collected in WA and a wild plant collected in Sicily with RLEM seedling resistance. It was one of 18 early flowering breeding lines and 6 commercial varieties evaluated in trials in WA at Tammin and Katanning (2 trials) and at two sites in eastern Australia.
Varietal characters
Forbes flowers approximately 101 days from an early May sowing in Perth (Table 1). It has only trace levels of the oestrogenic compound, formononetin, and will not cause infertility problems in ewes. Forbes suffers markedly less RLEM cotyledon damage than other current early flowering varieties. Forbes is also considerably more hardseeded than Dalkeith, Geraldton, Izmir, Nungarin, Urana and Losa, resulting in greater persistence in crop rotations, but is less hardseeded than Tammin (Table 1). The timing of seed softening over the summer-autumn period indicates a more delayed hardseed breakdown for Forbes, suggesting it has a lower potential for seedling losses from false breaks than currently available cultivars (Figure 1).
| Variety | Flowering time | Formononetin | RLEM damage | Hardseededness |
|---|---|---|---|---|
|
| (days from sowing in Perth) | (% of dry matter) | (% cotyledon silvering) | (% hard seeds in May after 5 months on the soil surface) |
| Forbes | 101 | 0.0 | 6.0 | 32.7 |
| Tammin | 88 | 0.0 | 6.1 | 51.3 |
| Dalkeith | 96 | 0.0 | 39.2 | 16.3 |
| Geraldton | 88 | 1.1 | 40.8 | 20.3 |
| Izmir | 80 | 0.1 | 27.9 | 21.7 |
| Losa | 95 | 0.1 | 28.3 | 9.3 |
| Nungarin | 77 | 0.1 | 32.9 | 23.7 |
| Urana | 105 | 0.0 | 25.4 | 24.3 |
Field performance
Across all sites and seasons Forbes produced more total biomass than other early flowering varieties (Figure 2). Total biomass production for Forbes was similar to Tammin and was 12% more than Dalkeith, 47% more than Geraldton, 30% more than Nungarin, 18% more than Izmir and 16% more than both Losa and Urana.
The real advantage of the high hardseededness of Forbes was apparent in the Tammin and Katanning trials, which were cropped in the second year. Across both sites, Forbes retained 32% more seeds in the seed bank during the crop phase than Dalkeith, which resulted in 96% more spring biomass (Figure 3).
Figure 2 Total clover biomass across all sites and seasons of Forbes and other early flowering varieties, expressed as a percentage of cv. Dalkeith
The real advantage of the high hardseededness of Forbes was apparent in the Tammin and Katanning trials, which were cropped in the second year. Across both sites, Forbes retained 32% more seeds in the seed bank during the crop phase than Dalkeith, which resulted in 96% more spring biomass (Figure 3).
Figure 3 Spring biomass of Forbes and other early flowering cultivars, in the year following a year in crop at Tammin and Katanning, expressed as a percentage of cv. Dalkeith
Seed availability and PBR status
Seed of Forbes can be purchased through Seed Force agencies.
Forbes is protected under the Plant Breeders Rights Act 1994. Under the Act sale of Forbes seed can only be carried out by agreement with the licensee, Seed Force Pty Ltd. However, this does not restrict sale of produce, such as hay or silage, provided seed was legally purchased.
For seed sales information visit seedforce.com.au
