EFFECT OF GENOTYPE AND SEED SIZE ON EARLY VEGETATIVE GROWTH OF SHEEPS BURNET

Emergence and early vegetative growth of sheep's burnet (Sanguisorba minor ssp. muricata) were investigated in a glasshouse in autumn. Lucerne (Medicago sativa cv. Rere) was included for comparison. One accession of sheep's burnet from the United States (Oregon), which is the main line available commercially in New Zealand, and another collected from plants growing at an early trial site in New Zealand (Cockayne), were evaluated. Each seed lot was divided into small (< 2.0 mm), medium (2.0-2.8 mm), and large (> 2.8 mm) seed. All sheep's burnet treatments had similar final emergence (54%) which was higher than lucerne (35%). The mean proportion of sheep's burnet hypanthia (''seed'') producing two seedlings was 32%. Sheep's burnet took 4 days longer than lucerne to reach 50% seedling emergence. At 45 days after sowing, leaf area, shoot height, and root length and dry weight of seedlings from large seed were up to 3, 1.5, 1.6, and 3.1 times those from small/medium seed, respectively. Physical seed separation and/or a breeding programme for large seed are recommended. Seedlings of the Oregon line frequently had greater vegetative growth than those of the Cockayne line with character estimates for the Oregon line being 1.1 (root length) to 4.3 (stem dry weight) times those for Cockayne material. Use of germplasm sourced from Oregon is recommended.