Seed Sources and Nursery Management Practices

Seed Sources and Nursery Management Practices

Standard nursery management aims at the most rapid production of healthy and quality planting materials. The success depends on the kind of materials and management practices to be employed. This module explains the various recommended practices in raising seedlings in the nurseries.

Nursery management practices cover:

  • Sourcing, collection and selection of seeds for propagation
  • Handling of seeds to hasten germination
  • Management practices of germination beds
  • Techniques of sowing the seeds in the germination beds
  • Pricking out and transplanting
  • Weed and pest control.

Learning objectives

By the end of this module, the participants should be able to:

  • Identify the source of seeds, selection and collection
  • Undertake hastening, germination and storage of seed
  • Perform the standard practices of preparing a germination bed and germination medium
  • Demonstrate the proper method of sowing seeds in the germination bed
  • Perform the pricking out and transplanting following best practices.

Seed sourcing, collection and selection for rootstocks production

Identification of seed sourcing, collection and selection is crucial in achieving healthy and uniform-sized seedlings. For fruit rootstocks, optimum yield cannot be attained even with a favourable environment if the rootstocks used are not well adapted to environmental conditions.

The concept of proper selection is based on the following principles:

  • A parent tree with desired qualities is capable of producing offspring with similar performance
  • The performance of the seedlings may be predicted based on the performance of the parent materials.

Seed collection and sowing

  • Always collect seeds from plus trees or phenotypically superior trees.
  • A chart should be prepared in each nursery indicating the seed collection period of local or preferred tree species along with the location of such plus trees. Seedlings developed from poor or abnormal trees will never produce good trees.
  • After collection, seeds should be processed carefully otherwise they may become damaged and lose viability.
  • Each species requires different processing after seed collection, i.e., seeds with pulp are processed differently compared to the pods, drupes and capsules.
  • Most of the seeds have short viability; therefore, sowing should be done immediately after collection and processing.

A simple method of determining moisture content

  • Fill one quarter of the jar with salt and then add the seed sample.
  • Close the lid tightly and shake the jar well.
  • Allow the seeds to settle for about 10 minutes.

If damp salt sticks on the sides of the jar, then the seeds are too moist for storage (moisture is above 13-15 per cent). On the other hand, if the jar is still dry and no salt is stuck on its sides then the seeds have less than 13 per cent moisture content and thus can be stored safely.

Viability test using floating method

  • Fill a jar about three-quarter way with water
  • Pour seeds into the water-filled jar
  • Seed separation takes place: some will float while others will sink
  • Sinkers are viable while floaters are not
Seed pre-treatment 1

In this trial you will try several types of seed pre-treatment of mango seeds to understand the advantage of pre-treatment.

Materials
– Local mango seeds
– 2 buckets of water
– Secateurs

Procedure
– Prepare three small seedbeds.
– Divide the 60 mango seeds into three groups of 20
– Put 20 mango seeds in a net, place it in a bucket of water and put a big stone on top of it so that they do not float. Leave the seeds in water for 24 hours.
– Cut off a small section of the mango seed end of another 20 seeds, put them in a net and place them in another bucket of water. Put a big stone on top so that they do not float. Leave them in water for 24 hours.
– Sow each group of seeds separately in the three different seedbeds. Check everyday and water the seedbeds when dry.
– When the seeds start germinating, record the date and number of germinated seeds in each bed as shown in table 1.

Questions for discussion

  • How many seedlings germinated in each seedbed?
  • How many days did it take for the seed to start germinating in each bed?
  • How long did take for germination to end in each seedbed?
  • Apart from the time of germination, is there any difference in the characteristics of the seedlings?
  • What were the advantages and disadvantages of the different pre-treatments?
Seed pre-treatment 2

In this trial you will test several types of seed pre-treatments in several species to understand the appropriate pre-treatment for each tree species.

Materials
Seeds of some tree species e.g. Grevillea robusta, which the farmers would like to plant.

Procedure
– Prepare two small seedbeds.
– Divide the 200 Grevillea seeds into two groups of 100 seeds each.
– Put one group of seeds in a net, place them in a water bucket and put a big stone on top to prevent them from floating. Leave for 24 hours.
– Sow the two groups of seeds in two different seedbeds. Check everyday and water the seedbed when it is dry.
– When germination starts, record the date and number of germinating seeds in each seedbed.

Questions for discussion

  • How many seedlings germinated in each seedbed?
  • How many days did it take for the seeds to start germinating in each bed?
  • How long did it take for germination to end in each seedbed?
  • Apart from the time of germination, is there any difference in the characteristics of the seedlings?
  • What were the advantages and disadvantages of the different pre-treatments?
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