EFFECT OF GENOTYPE AND SEED SIZE ON EARLY VEGETATIVE GROWTH OF SHEEPSBURNET

Emergence and early vegetative growth of sheep's burnet (Sanguisorba m inor ssp. muricata) were investigated in a glasshouse in autumn. Lucer ne (Medicago sativa cv. Rere) was included for comparison. One accessi on of sheep's burnet from the United States (Oregon), which is the mai n line available commercially in New Zealand, and another collected fr om plants growing at an early trial site in New Zealand (Cockayne), we re 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 s eed 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 f or large seed are recommended. Seedlings of the Oregon line frequently had greater vegetative growth than those of the Cockayne line with ch aracter estimates for the Oregon line being 1.1 (root length) to 4.3 ( stem dry weight) times those for Cockayne material. Use of germplasm s ourced from Oregon is recommended.