Characteristics of normal and abnormal seedlings
There are some basic characteristics of normal and abnormal seedlings, which are given below.
Characteristics of Normal Seedling:
- High Vigor Normal Seedling (HVNS)
- Low Vigor Normal Seedling (LVNS)
a. High Vigor Normal Seedling (HVNS):
- A healthy–developed root and shoot system, including primary taproot.
- A well–developed intact epicotyl and hypocotyl without any damage to the conducting tissue.
- Presence of healthy cotyledons.
- Presence of primary and secondary roots.
- Presence of healthy primary leaves.
- Presence of healthy growing point.
b. Low Vigor Normal Seedling:
- Slightly smaller cotyledons and primary leaves.
- Slightly narrow and weak stem having all other parts.
- Roots of poor growth.
Characteristics of Abnormal Seedling:
- Seedling with no or damaged cotyledon.
- Seedling with constriction.
- Seedling with splits, cracks, or lesions is neither superficial nor limited in a particular area.
- Seedling with damaged primary leaves and apical bud.
- Seedling with weak and unbalanced development of the essential structures.
- Injurious hypocotyls and epicotyls.
- Very poor root system.
Causes of abnormal seedlings
- Age immatured seed.
- Unfavorable storage condition of the seed.
- Essential structure becomes missing.
- Disease infection.
- Mechanical injury – caused by harvesting, threshing, cleaning, and transport purposes.
- Insect injury – caused in field or storage time. It may be externally or internally.
- Chemical treatment – different types of chemical use, such as 2,4 – D Furadan.