AGRI 32: Laboratory Exercise No. 4 PROPAGATION AND NURSERY MANAGEMENT

Plant Propagation

the intentional multiplication of a plant while preserving its unique characteristics (Hartmann et al., 2011).

Sexual propagation

- multiplication of plants using seeds
- offspring have characteristics which reflect the genetic contribution of its two parents
- practical method in mass producing a species

Polyembryony

development of more than one embryo in a single seed

utilizes a plant's various vegetative parts
(leaves, stems, roots) for reproduction
- no union of the male and female gametes

utilizes a plant's various vegetative parts (leaves, stems, roots) for reproduction
- no union of the male and female gametes

Apomixis

- asexual seed production
- embryo was formed from an unreduced egg or the nucellar tissues of the ovary of the mother
plant
- has bypassed the process of meiosis and fertilization, the resulting plant is a clone of the
mother plant

Obligate apomicts

species or individuals that
produce only apomictic embryos

Facultative apomicts

species or individuals that
produce both sexual and asexual embryos

Seed processing

extraction from the fruit or the
plant, cleaning and storing

Seed viability

the ability of the seed to
germinate and produce a normal seedling under favorable conditions

Seed dormancy

a physical or physiological
condition of viable seed that prevents germination even in the presence of otherwise favorable conditions.

Exogenous or coat-imposed dormancy

- seed coat physically serves as a barrier, inhibiting water imbibition and gas exchange; and restricts embryo enlargement
- to break exogenous dormancy, scarification may be done either physically, mechanically, or chemically

Endogenous or physiological dormancy

dormancy due to the presence of a chemical inhibitor (e.g., ABA) or embryo dormancy

Seed Storage

preservation of the initial viability of seeds from the time of collection until they are ready for sowing

Orthodox seeds

can be dried to low moisture content
- can be stored at low temperatures without losing viability, even for an extended period
- can be stored in hermetic (air-tight) containers together with desiccants to prolong storage
- e.g., rice, corn, field legumes (like mungbean), atis, balimbing, chico, guyabano, passionfruit,
tamarind

Recalcitrant seeds

- seeds that lose viability when their moisture content is below a critical value (usually in the
range of 12-30%)
- considered short-lived seeds and should be planted immediately after extraction
- e.g., mango, durian, rambutan, lanzones, mangosteen, santol, cacao, and jackfruit

Intermediate seeds

- seeds that can withstand drying to around 10- 12% MC
- can be stored successfully in hermetic containers
- seeds lose viability more rapidly at low temperatures (<10°C) than at warmer temperatures (12- 21°C)
- e.g., papaya, coffee, African oil palm, citrus

vernalization

subjecting seeds to cold treatment

Crop protection

pre-treated with fungicides to control fungal diseases that attack at the seedling stage

Separation

- using naturally detachable organs from the mother plant as planting materials
- applicable to plants having modified organs such as sucker (banana, abaca, pineapple), runner (strawberry, mint, black pepper), slip (pineapple), crown (pineapple), bulb (garlic; onion), corm (saffron, gabi, gladiolus), tuberous root (sweet potato), tuber (potato), rhizome (ginger, turmeric, banana), and plantlet

division

involves cutting the modified organ into
sections, with each piece having at least 2 buds
(nodes or "eyes"), where new shoots and roots will arise
- modified organs can be divided into "seeds" or "seed pieces."
- e.g., corms (or rhizomes) of banana and abaca, tubers of potato and yam, storage roots of sweet potato, and rhizome of ginger and turmeric

Cutting/ Cuttage

shoots and roots regenerate on a detached vegetative part to form a complete, separate plant.

Marcotting (Air layering)

involves rooting a shoot or branch while it is still attached to the mother plant and then later separating the rooted shoot /branch to become a new plant

Graftage

refers to the joining of two plant parts to have the parts united so they can continue to grow as one

Rootstock

the lower portion of the graft which develops into the root system of the grafted plant; provides the desirable root system

Scion

the upper portion which eventually becomes the shoot system of the plant having
good characteristics (early maturity, better fruit yield and quality, and better resistance to insect pests and diseases)

Budding

It is a form of grafting where the scion consists of a
single bud or a piece of the stem with a single
bud.

Plant tissue culture (Micropropagation)

the science of growing plant cells, tissues, or organs isolated from the mother plant in vitro on
a nutrient media under aseptic conditions

Developmental Stages in micropropagation key: ESRA

Nursery

managed site designed to grow
seedlings under favorable conditions until they are ready for transplanting into a permanent
place, either as an agricultural unit or as something sold to various consumers

Basic Nursery Operations, key: SSM GG IFP

light

the source of radiant energy needed by plants for photosynthesis; Germination, rooting of asexual materials, seedling growth, and shoot
multiplication of explants are affected directly and indirectly by light

water

essential for photosynthesis and nutrient transport within the plant; rate of transpiration
must be managed to prevent desiccation

- temperature

the success of germination
and rooting

gas exchange

important for cellular respiration
to produce energy (i.e., ATP) needed by plants for growth and maintenance

Characteristics of a good propagation media

- Must be firm and dense enough to hold the plant in place.
- Must be well-decomposed and stable.
- Must be easy to wet and able to retain enough moisture.
- Must be porous to drain excess water and prevent waterlogging.
- Must have high/good cation exchange capacity.
- Must be free from pests and disease.
- Must be readily available and practical