Seed Rate

Seed Rate

1. 800 ears/m2

   • Approx 3 tillers per plant
     • Affects no of ears per plant
     • Spring plant population = 266
       • established plants = 296
         • 10% loss over winter
         • rate = 350seeds/m2
           • 15% loss prior to establishment
         • less plants/m2 means more shoots/plant
           • HGCA 2000
       • HGCA recommended populations
         • Sept - 62
         • Oct - 90
         • Nov - 142
         • Actual population is irrelevant
           • Plant will grow to componsate
             • hence no yield effect
         • Minimum - no safety margin
           • Every plant lost directly affects yield

2. As SR increases...

   • ...Yield increases
   • ...TGW increases, then decreases
     • Hence quality effect if too high
   • ...HFN decreases and then increases
   • ...grain protein decreases
   • ...percentage of disease increases
     • as more seeds
   • No specific weight relationship
   • Gooding et al 2002

3. Yield decreases linearly with date after 21st Sept

   • Green & Ivins 1985

4. Date of sowing

   • later date requires higher optimum no of plants/m2
     • Spink et al 2000