Soybeans Flashcards
Planting a lower maturity group south of its adaption zone will result in what?
The plant to flower earlier in the season.
Soybeans flower based upon what factor
Photoperiod or Day Length
Planting a higher maturity group north of its adaption zone will result in what?
The plant will flower earlier in the season.
Define growth stage VE
- Cotyledons have emerged
Define growth stage VC
- Unifoliate leaves have unrolled
- First node
Define growth stage V1
- One unrolled trifoliate leaf
- Two nodes
Define growth stage V2 and subsequent vegetative stages
- Two unrolled trifoliate leaves (opposite)
- Nodules have been established
- Three nodes (plant growth stage +1)
Nodulation occurs on the roots of soybeans; what is nodulation?
Nodulation is the effect of a mutalistic relationship between legumes and rhizobium bacteria (Bradyrhizobium japonicum).
This relationship provides the bacteria sugars and then plant usable nitrogen.
This process is inhibited by the presence of NO3
How fast do soybean plants progress between growth stages?
VC-V5: Every 5-7 days
V5-R5: Every 3-5 days
Define growth stage R1
Beginning Flowering
- On open flower at any node
- Rapid root growth
Define growth stage R2
Full Flowering
- An open flower at one of the uppermost nodes
Define growth stage R3
Beginning Pod
- Pod 3/16in long at one of the four uppermost nodes
- 60-75% of flowers abort and never contribute to yield
Define growth stage R4
Full Pod
- Pod is 3/4in long at one of the four uppermost nodes
- Pod number is determined at this stage
- Start of critical yield determination period
Define growth stage R5
Beginning Pod
- Seed 1/8” long in pod at one of the four uppermost nodes
- Large demand for water and nutrients
- DM accumulation will stop between R5 and R6
Define growth stage R6
Full Seed
- Pod contains a green seed that fills the pod cavity at one of the four uppermost nodes
