Horticulture 2061 FINAL Exam

Geophyte (definition)

plants that survive as specialized underground storage organs

Primary functions of geophytes

*storage of food, nutrients, and water

*survival during adverse Enviromental conditions

Geophyte Type Examples

*bulbs

*corms

*tubers

*tuberous roots

*rhizomes

*pseudobulbs

Geophyte Characteristics

*herbaceous perennials

*shoots die down at the end of the growing season

*dormant, fleshy organs bear buds for new shoots

Geophyte Adaptions

*withstand adverse growing conditions

*never physociologally dormant

*act as "bioprocesses" sensing and responding to the environment

1. warm-cold cycle (temp zones)

2. wet-dry cycle (tropical and sub tropical regions)

*clonal regeneration

*use of both sexual and asexual systems

Bulbs (definition)

*bulbs: specialized underground organ consisting of a short, usually vertical stem axis (basal plate) bearing at its apex a growing point or a flower primordial enclosed by a thick, scale-like leaves

*mostly produced by monocotyledonous plants

-> the usual plant structure is modified for storage and reproduction

-> sorrel is the one dicot genus that produces bulbs

Classification of Bulbs

*hardiness

-hardy, semi-hardy, or tender

*time of flowering

*structure

-tunicate (laminate)

-scaly (non-tunicate)

Structure of a Typical Bulb

*outer scales: fleshy, contain reserve food materials

*inner scales: more leaf-like, less storage function

*Central Structure: vegetative meristem or unexpanded flowering shoot

Bulb Propagation

*Most bulbs naturally multiply by bulblets that form as offsets from the basal plate.

*Bulblet: a miniature bulb that forms in the axil of a bulb scale and provides a method of vegetative propagation.

Types of Bulbs: Tunicate (Laminate)

•Dry, membranous outer bulb scales are called the "tunic"

-Provides protection from drying and mechanical injury

•Fleshy inner scales

-Food storage

•The fleshy scales are in continuous, concentric layers, or lamina, so that the structure is more or less solid.

•Produced in onion and garlic (Allium), daffodil (Narcissus), tulip (Tulipa) and many genera in the family Amaryllidaceae.

Tunicate Bulb/Structure

1. flower bud or vegetative meristem (center middle)

2. tunic at top

3. fleshy scales (middle)

4. basal plate (stem)

Types of Bulbs: Non-tunicate (Scaly)

•No tunic

•Scales are separate and attached to the basal plate

•Easily damaged and must be handled more carefully than the tunicate bulbs

•Must be kept continuously moist because they are injured by drying

•Contractile roots

•Represented by lily (Lilium) and Fritillaria

Structure of Non-tunicate Bulbs

1. current season's growth

2. leafy scales

3. flowering shoot of the mother bulb from current season

4. new daughter seals for next season

4. growing point f the daughter bulb that will produce best season's flower

Root System

•Geophytes can have fibrous and contractile roots.

•Fibrous: formed as adventitious roots; they absorb water and nutrients and normally function for only one growing season.

•By shrinking and expanding, contractile roots pull the bulb to the proper soil depth.

Droppers

•Certain geophytes used a modified stem called a dropper

•A new bulb that forms at the end of a stolon

•Helps to move the bulb down to its proper depth where a new bulb is formed

•Produced by tulips, trout lilies, seedling bulbs

Bulb Life Cycle

1.Reproductive phase

•Spring

•Bulb forms flower primordia (shoot)

•Flower shoot will emerge, bloom, produce seed

2.Vegetative phase

•New leaves emerge

•New offsets form and

A.The old bulb decays (tulips)

B.The old bulb remains (daffodil)

Storage Conditions

•Store bulbs in a cool, dry place to prevent premature sprouting

•First allow them to dry in an area with good air circulation to remove excess moisture

•Temperature range for storing most bulbs is between 40°F (4°C) and 50°F (10°C)

•Avoid areas with extreme temperature fluctuations or high humidity

•Containers that allow for air circulation, such as mesh bags, paper bags, or boxes with ventilation holes

•Regularly check the bulbs for signs of rot or dehydration

Propagation of Bulbs

1.Normal offsets

2.Underground stem bulbets

3.Aerial stem bulbets

Tunicate Bulbs: Propagate by Twin Scales: Structure

1. tunic (outer bulb scale) -top

2. main lateral bublets -bottom, center, top

3. basal plate -bottom, center, middle

4. adventurous roots -bottom, center, bottom

5. lateral bublets next to main ones

6. bulb scales

7. foliage leaves

8. flower bud

How to Propagate via Twin-Scaling

1. Cut bulb into sections each of which contain two scale sections and a portion of the basal plate

2. Optional: fungicide

3. Place bulb pieces in plastic bags with moistened perlite or vermiculite (14 perlite: 1 water)

4. Close bag tightly and place in a dark place at room temperature for 7 weeks

Twin Scaling

In twin scaling, two scales and a portion of the basal plate are cut from the bulb. The new bulblets, form between the pair of scales in 1-2 months

How to Propagate via Scaling

• Same as twin-scaling, except:

• Break off scales individually

• Scales do not need to contain part of the basal plate

• After bulbets develop, they may need at least 8 weeks of chilling at 35-40 degrees F

Propagation of Bulbs by Scoring & Scooping

•Wound basal plate and promote adventitious bulbetformation

Steps:

1. Score or scoop basal plate

2. Callused cut side down in dry sand

3. Incubate in dark, high humidity

4. Planted in ground in fall

5. Leaves produced following spring

6. Flower after 4-5 years

Bulb Cuttings

Steps:

1. A mature bulb is cut into a series of 8 to 10 vertical sections, each containing a part of the basal plate.

2. These sections are further divided by sliding a knife between each third or fourth pair of concentric scale rings and cutting through the basal plate.

3. Each of these fractions makes a bulb cutting, and consists of a piece of basal plate and segments of 3 or 4 scales.

Plants that respond to this method of propagation include Cobra lily (Chasmanthe), amaryllis, spider lily (Lycoris), and hyacinth.

Leaf Cuttings

Steps

1. Leaves are taken when they are well developed and green.

2. An entire leaf cut from the top of the bulb may in turn be cut into two or three pieces.

3. Each section is placed in a rooting medium with the basal end several inches below the surface.

4. Within 3 to 4 weeks, small bulblets form on the base of the leaf, roots develop, and the bulblets are planted in soil

Leaf cuttings are successful for blood lily, grape hyacinth, hyacinth, pineapple lily (Eucomis), and cape cowslip (Lachenalia).

Propagation by Tissue Culture

Tissue culture propagation of crinum lily by scaling

(a) Mother bulb and single offset daughter bulblet (arrow) take longer to propagate with only a few offsets produced. (b) Tri-scales with attached basal plate and elongating bulblets. (c) New bulblets will be divided, subcultured and multiplied via tissue culture.

Other Geophytes: Corm

•Corm: the swollen base of a stem axis enclosed by a dry, scale-like tunic. It has

•Contractile roots

•A solid stem structure with distinct nodes and internodes

•Tunic to protect against injury and water loss

•The bulk of corm consists of storage tissue composed of parenchyma cells.

•At the apex of the corm is a terminal shoot that will develop into the leaves and the flowering shoot.

•Examples: Gladiola and crocus, and food crops like taro (Colocasia).

Bulb vs. Corm

Bulb

-Leaf, stem, AND flower tissue

-Nodes & internodes NOT distinct

-Scales

Corm

-Stem tissue only

-Distinct nodes & internodes

-Solid, no scales

Structure of a Corm

*current season's developing corm above

*roots around it

*nodes below as well as tunic

*lateral bud on surface

*roots below aswell

Corm Growth Patterns

The growth pattern in corms has the current season's corms developing above the previous season's corm that shrivels as the storage materials are used for new growth.

Corm Life Cycle

1. Vegetative

◦New roots

◦Leaves

2. Reproductive

◦Floral initiation

◦New corm forms above old corm

◦Old corm shrivels and disintegrates

◦Offsets & cormels form

Corm Propagation

1. Sexual (seeds)

2. New corms

3. Cormels

◦Miniature corms that develop between the old and the new corms

4. Corm division

◦Large corms

◦Each section must contain a bud

5. Tissue culture

Other Geophytes: Tuber

•A tuber is a special kind of swollen, modified stem with nodes and internodes

•Functions as a storage structure as well as an organ of vegetative propagation

•"Tuberous stem"

•A tuber is highly nutritious and composed of enlarged parenchyma-type cells

Tuber Examples

Jerusalem artichoke, Irish potato, Caladium

Tuber Diversity

Potato is not the only tuber-bearing edible crop. (a) Olluco (Ullucustuberosus), (b and c) Oca (Oxalis tuberosa), and (d) Mashua(Tropaeolum tuberosum) are popular tuber crops in South America.

Tuber Growth Patterns

• Potato (Solanum tuberosum) serves as a good example of a tuber-producing plant

• The potato tuber is a storage structure that is produced in one growing season, remains dormant during the winter, and then functions to regenerate new shoots the following spring.

• After a new seasonal cycle begins, the shoots utilize the stored food in the old tuber, which then disintegrates

• As the main shoot develops, adventitious roots are initiated at its base, and lateral buds grow out horizontally into the soil to produce elongated, etiolated stems (stolons)

Tubers of potato (Solanum tuberosum) showing their development from (a) white stolons arising from stem tissue; roots are darker, thinner; the tuber is attached to the stolon at the tuber's morphological basal (proximal) end. (b) Tuberization (tuber formation) is characterized by the hook "gancho" at the subapical portion of the stolon and subsequent tuber enlargement.

•Tuberization: the biological process that leads to tuber formation

•This process is associated with

•Short or intermediate daylengths

•Reduced temperatures (particularly at night)

•High light intensity

•Low mineral content

•Increased cytokinins and inhibitors (ABA)

•and reduction in gibberellin levels in the plant

•Continued tuber enlargement is dependent on a continuing adequate supply of photosynthates

Tuber Propagation: Division

•Most common propagation method for tuber-producing plants

•Tubers are cut into sections, usually two buds per piece.

-"Seed" potato

•Seed potato: horticultural term applied to potato tubers when used for propagation

Tuber Propagation: Tubercles

•Aerial tubers (tubercles) produced in the axils of the leaves

•These tubercles are removed in the fall, stored over winter, and planted in the spring.

•Uncommon

•Begonia evansiana, the cinnamon vine (Dioscorea batatas), and wild yam (Dioscorea sp.)

Other Geophytes: Tuberous Roots

•Tuberous roots are thickened underground structures for food storage that are modified roots.

*Tuberous rooted plants have a fleshy, enlarged root that acts as a storage organ.

Tuberous Root Examples

Dahlia, Cassava, Sweet potato

Tuberous Root Growth Pattern

•Tuberous roots are biennial

•Tuberous roots are produced in one season

•Shoot die back in the fall à dormancy

•The following spring, buds from the crown produce new shoots, which utilize the food materials from the old root during their initial growth.

•The old root then disintegrates

•New tuberous roots are produced, which maintain the plant through the following dormant period

•Photoperiod is the dominant controlling factor of tuberization

•Short-day conditions

Tuberous Root Propagation: Crown Division

The usual method for propagating tuberous roots is by dividing the crown so that each section bears a shoot bud

(a) Dormant plants are lifted from the field and soil is removed by washing. (b) Plants are divided by cutting through the crown so that each division has (c) a section of the crown bearing several buds. (d) A high-grade division has four or more buds (eyes).

Tuberous Root Propagation: Adventitious Shoots

•The fleshy roots of a few species of plants have the capacity to produce adventitious shoots if subjected to the proper conditions.

-"Slips"

•Adventitious roots develop from the base of these adventitious shoots. After the slips are well rooted, they are pulled from the parent plant and transplanted into the field

Other Geophytes: Rhizomes

•A rhizome is a modified stem structure in which the main axis of the plant grows horizontally at or just below the ground surface.

•It is distinguished from a stolon because it also tends to be modified as a storage organ

Rhizome Examples

•Bamboo

•Sugarcane

•Banana

•Grasses

•Iris (some)

•Lily of the valley

•Low bush blueberry

•Ferns

Rhizome Growth Patterns

•There are two general types of rhizomes based on their stem growth patterns:

1.A leptomorph rhizome has

•Monopodial, indeterminate growth pattern

•Continuous growth in length from the terminal apex and from lateral branch rhizomes.

•This type does not produce a clump but spreads extensively over an area.

•Examples: Japanese spurge (Pachysandra), most bamboos, and a number ofgrasses.

2.A pachymorph rhizome has

•Sympodial, determinate growth pattern where

•The apical node terminates in a flowering stem.

•Subsequent growth continues from a lateral bud

•Plants with this growth pattern tend to form slow-growing clumps radiating from the initial plant.

•Examples: Solomon's seal (Polygonatum), Iris, and ginger (Zingiber).

Rhizome Propagation: Division

•Cut into pieces containing at least one bud

•Pip: section of rhizome with roots and terminal bud (leaf or flower).

Rhizome Propagation

•Propagation of (a and b) leptomorph rhizomes of lily-of-the-valley (Convallaria) and (c-e) pachymorph rhizomes of Iris by rhizome cutting.

•

•These are cut into sections containing adventitious roots and new shoots that develop from the nodes of the rhizome.

•

•Iris is divided in the summer and the leaves trimmed and sold as a "fan."

Other Geophytes: Pseudobulbs

•A pseudobulb is a specialized storage structure produced by many orchid species, consisting of an enlarged, fleshy section of the stem made up of one to several nodes.

•"false bulb"

*Pseudobulbs facilitate survival of orchids during adverse environmental conditions and can also be divided and used as propagules.

Propagation of Pseudobulbs

•Offshoots

•Division

-Performed during dormancy

-Must contain four to five pseudobulbs in the new section

•Back bulbs

•Do not have foliage

-Removed from plant, placed in rooting medium, new shoots develop

-Green bulbs

•Pseudobulbs with leaves treated with IBA

Micropropagation: Asexual/Vegetative

•An asexual propagation method in which plants are manipulated on a cellular level, causing them to duplicate themselves repeatedly and rapidly.

•Propagating plants using a small piece of tissue

•"Tissue culture"

•Different parts of the plant can be used

•Performed under aseptic conditions

Why?

•Can quickly grow many plants from very little plant material

Micropropagation: History (1839-1922)

•1838: Schleiden and Schwan— "Cell theory" and totipotency

•1902: Haberlandt— attempted in vitro growth of plant cells using hydroponic nutrient solution, sucrose and asparagine. Cells only lived 20 days

•1922: first organ cultures developed, adding yeast extracts

Micropropagation: History (1934-1939)

•1934: P.R. White—Developed new growth medium

•Also containing amino acids, vitamins

•1939: Gautheret, White, and Nobecourt—independently used the newly isolated growth hormone, auxin

•Cell culture establishment

•Constant regeneration and proliferation

•Carrot and tobacco cells

Micropropagation: History (1946-1962)

•1946: Ball—First entire plant via tissue culture

•1948: Skoog and colleagues—understood relationship between Cytokinin and Auxin

•1962: Murashige and Skoog—First standardized artificial growth medium

Relationship of Cytokinin: Auxin Ratio

low auxin/high cytokinin = shoots

moderate/imbalanced auxin/cytokinin = callus

high auxin/low cytokinin = roots

Terminology: Growth Medium

•substance containing nutrients and hormones used for plant growth.

Terminology: Explant

•any part of a plant taken out and grown in a test tube or In vitro, under aseptic conditions in special nutrient media.

Terminology: Totipotency

•the plants have a capacity to generate a whole plant from any explant.

Labor and Equipment Costs

•Disadvantage—high costs

•Must have trained technicians

•Aseptic techniques

•Clean rooms

•Specialized tools

-Laminar flow hood

•Requires carefully prepared growing medium

Genetic Diversity

•Cloned plants decrease genetic diversity

•All clones have same benefits

•All clones have same disadvantages

Environmental Requirements

1. Explant

•Removed from parent plant

•Placed in similar environment

2. Require

•Light

•Nutrition

•Hormones

•Moisture

•Appropriate temperature

•Aseptic environment

Maintaining an Aseptic Environment

•Laminar flow hood

•Test tubes and petri dishes

•Artificial light supply

•Growth medium

•Isopropyl alcohol solution (70%)

•Bleach solution (10%)

•Forceps, scalpel, plastic tape

Micropropagation: Growth Media

•Nutrients

•Growth regulators

•Water

•Sterile

•Liquid or gel

•Grow and sustain explant in vitro

Types of Micropropagation: Seed Culture

•Seeds may be cultured in vitro to generate seedlings or plants. It is the best method for raising the sterile seedling.

Types of Micropropagation: Embryo Culture

•Embryo culture is the sterile isolation and growth of an immature or mature embryo in invitro with the goal of obtaining a viable plant.

•In some plants seed dormancy may be due to chemical inhibitors or mechanical resistance, structures covering the embryo. Excision of embryos and culturing them in nutrient media help in developing viable seedlings

Types of Micropropagation: Meristem Culture

•The apical meristem of shoots can be cultured to get the virus-free plants.

•The size of explant may vary from 1.0-5.0 mm long meristem tip

• Often used to produce virus-free bananas

•Rapid multiplication of strawberries, chrysanthemum, African violets

Types of Micropropagation: Callus Culture

•Callus: un-organized dedifferentiated mass of cells arising from any kind of explant under in vitro cultural conditions.

•The cells in callus are parenchymatous in nature but may or may not be homogenous mass of cells.

•After callus induction it can be sub-cultured regularly with appropriate new medium for growth and maintenance.

•Carrot, potato, tobacco

Types of Micropropagation: Anther/Pollen Culture

•This technique involves culturing anthers to produce haploid plants, which have only one set of chromosomes.

•First established by Guha and Maheswari (1964, 1966) in Datura.

•Haploid plants are valuable for genetic research because they simplify the study of gene expression and inheritance

•Treatments can create diploid plants that are genetically uniform.

•Commercial breeding of tobacco since 1967

Stages of Propagation

•Success of micropropagation is largely due to separating different developmental aspects of culture into stages, each of which is manipulated by media modification and environmental control. These include:

•Stage 0: Selection and Cultivation of Stock Plants

•Stage 1: Initiation or Establishment

•Stage 2: Multiplication

•Stage 3: Rooting

•Stage 4: Acclimatization

Stage 0: Selection and Cultivation of Stock Plants

•Meticulous cultivation of stock plants

•Ensure disease free

•No insects

•Stage 0 limits and prevents contamination

Stage 1: Initiation or Establishment

•Aseptic environment

•Explant must be sterilized

•Explant transferred to in vitro culture

•Explant material sources

-Single cells from plants

-Small pieces of plant tissues

-Apical meristem

Stage 2: Multiplication

•This stage focuses on the multiplication and shoot growth of the plantlets

•Explants transferred to multiplication medium

•Must prevent contamination

•Medium composition

-Gel containing vitamins, sugars, and a plant growth regulator

Plantlets

Plantlets ready for transfer to stage 3 when

•Shoots and leaves present

•Rich in green pigment

•Do not have any roots

Stage 3: Rooting

•Plantlets transferred to rooting medium which contains

-Nutrients

-Growth regulators

-Sterile

•Roots develop below medium surface

•Root presence indicates transplant readiness

•Time required varies weeks to months

Stage 4: Acclimatization

•Acclimatization: the gradual exposure of plants to different environmental conditions; also known as hardening-off.

•Plantlets transferred to a sterile potting medium

•Acclimatization occurs

•Roots washed to remove stage 3 medium

•Rooted plantlets need to be acclimatized before they can resume growth outdoors or in the greenhouse.

Phase Potential

Thin-layer explants of epidermal tissue showing organ initiation potential relative to location on the mother plant where the explant was taken.

Micropropagation: Supply and Demand

•Micropropagated materials are costly

•Plant must be in demand

•Must be desired in large quantities

Plants Commonly Micropropagated

•Orchids: Due to their commercial value and difficulty in traditional propagation

•Bananas: To produce disease-free and genetically uniform plants

•Potatoes: For rapid multiplication and disease-free stock

•Strawberries: To ensure uniformity and high yield

•African violets: Popular among hobbyists for their ease of propagation

•Spider plants: Often used in educational settings for beginners

Tissue Culture Today

•Commercial micropropagation began in the United States in 1965 with orchid production.

•In the last quarter of the 20th century, commercial micropropagation emerged as an important method for propagating horticultural plants.

•The global market per annum for tissue-cultured products is estimated at 15 billion dollars

•The U.S. has approximately 100 tissue culture labs producing more than 120 million plants per year

•Within the last two decades, production has shifted with more and more micropropagated plants being imported into the United States because of the lower labor costs in outside countries.

•In the U.S., more than 80% of current production is for ornamental crops, while in developing countries the focus is on food, fiber, forestry, and medicinal crops.

Advantages of Micropropagation

•Uniformity of clones

•Ability to grow large numbers

•Produce plants when usually not compatible or difficult to propagate

•Vast quantities of clones from one plant

•Ability to produce pest-free plants

•Aid in conservation and replication of rare or endangered plants

Disadvantages of Micropropagation

•Requires expensive and sophisticated facilities, trained personnel, & specialize techniques.

•High labor costs.

•A high-volume distribution system, or adequate storage facilities to stockpile products, is required.

•Pathogen contamination or insect infestation can cause high losses in a short time.

•Variability and production of off-type individuals can be a risk.

•Decrease this risk by careful roguing, field testing and continuing research

•More companies fail for economic reasons than because of an inability to produce micropropagated plants.

What is bioengineering?

•The artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms

•AKA genetic engineering

GMOs

•Organism whose genome has been engineered in the laboratory in order to favor the expression of desired physiological traits or the generation of desired biological products

Gene-edited vs Transgenic

•Both are genetically modified

•Gene-edited uses or changes host DNA sequencing

•Transgenic is taking foreign DNA and introducing it

Bioengineering Methods

•Gene cloning/ Transformation

•Agrobacterium-Mediated Transformation

•Gene Gun (Particle Bombardment)

•CRISPR-Cas9 Gene Editing

•RNA Interference

Gene cloning/Transformation

•Goal: Isolate and copy a gene of interest.

•Process:

-The gene is identified in a donor organism.

-It's cut out using restriction enzymes.

-It's inserted into a plasmid (a circular piece of DNA).

-The plasmid is introduced into a host bacterium which replicates it, producing many copies.

Transformation

•Once cloned, the gene must be inserted into the target organism.

Bt Crops

•Plants given ability to produce Bt toxins

Rainbow Papaya

•Resistance to Papaya Ringspot Virus, saved Hawaii's industry

Roundup Ready Crops

•Resistant crops to glyphosate

Agrobacterium-Mediated Transformation

How it works:

•Agrobacterium tumefaciens is a soil bacterium that naturally transfers DNA into plant cells, causing crown gall disease.

•Scientists exploit this system by:

-Removing the disease-causing genes from the Ti plasmid.

-Inserting the gene of interest in their place.

-Infecting plant tissue and with the modified bacterium.

-The bacterium transfers the desired gene into the plant's genome.

-The transformed cells are selected and regenerated into whole plants using tissue culture.

Advantages:

•Highly efficient in many plant species.

•Precise integration of DNA.

Amflora Potato

•Produces pure amylopectin starch, ideal for industrial uses like paper and textiles

Flavr Savr Tomato

•First genetically modified food crop to be commercialized (approved in 1994)

Gene Gun

How it works:

•Microscopic gold or tungsten particles are coated with the desired DNA.

•These are shot at high velocity into plant cells or tissues using a burst of helium gas.

•Some DNA makes it into the nucleus and integrates into the plant's genome.

•Transformed cells are selected and regenerated.

Advantages:

•Can be used on a wide range of plants.

•Doesn't rely on biological vectors like bacteria.

Limitations:

•DNA may integrate randomly.

•Can cause damage to tissues or multiple insertions (less precise than Agrobacterium).

Golden Rice

•Biofortified with pro-vitamin A (β-carotene)

Starlink Corn

•Insect resistance using a variant of the Bt toxin

Waxy Corn

•Produces 100% amylopectin starch ideal for food processing, adhesives, and textile manufacturing

CRISPR-Cas9 Gene Editing

How it works:

•CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats.

•Cas9 is an enzyme that acts like molecular scissors.

•A guide RNA (gRNA) is designed to match a specific DNA sequence.

•Cas9 + gRNA complex binds to the target sequence in the genome.

•Cas9 cuts the DNA at that location.

•The cell tries to repair the break:

-Non-Homologous End Joining (NHEJ): An error-prone process that may knock out a gene.

-Homology-Directed Repair (HDR): A more precise repair process, especially if a DNA template is provided to insert new genes.

CRISPR Tomato: Sanatech Seed

•Increased GABA content, a compound linked to stress reduction and lower blood pressure

CRISPR Lettuce (in research)

•Improved shelf life, reduced browning or bolting delay (early flowering in warm temps)

CRISPR Rice (in trials)

•Traits

-Disease resistance: Edited OsSWEET genes to block bacterial blight infection.

-Nutrient improvement: Edited OsNAS genes for higher iron/zinc content

-Drought and salinity tolerance: Knockouts of negative stress regulators