PISTACHIO POLLINATION AND MALE TREE MANAGEMENT BEN THOMAS Ben - - PowerPoint PPT Presentation

PISTACHIO POLLINATION AND MALE TREE MANAGEMENT

BEN THOMAS Ben Thomas Consulting

PISTACHIO FLOWERS

FEMALE MALE

Slide 2

PISTACHIO FLOWERS

• The pistachio tree is dioecious

– Means ‘two houses’ – Male (staminate) flowers are borne on

• ne tree and female (pistillate) flowers
• n another
• A group of flowers is called a

panicle and flowers are formed on a rachis

• There can be hundreds of flowers

per panicle but set is very low

• Capable of parthenocarpy where the

fruit grows but there is no viable embryo

Slide 3

POLLINATION & FRUIT SET

• STAGE 1 : Pollination
• Pollen released from staminate flowers on male trees.
• Carried by wind to stigmas of pistillate flowers on female trees
• STAGE 2 : Pollen tube growth
• Pollen grain on stigma germinates to form a pollen tube.
• Pollen tube carrying male germ cells grows through stigma and style

tissue to the ovule.

• STAGE 3 : Fertilisation
• Fusion of male and female germ cells in the ovule.

Slide 4

PISTILLATE FLOWER ANATOMY - WALNUT

Slide 5

PISTACHIO POLLINATION & ORCHARD DESIGN

• Pistachio is wind pollinated

– Male trees are interspersed through the orchard, usually in a regular pattern. – Initial plantings in Australia had 7-11% male trees but given the amount of pollen produced, more recent plantings use 4% male trees – Additional male trees can be planted in border rows but solid male tree rows are usually not needed. – Pistachio pollen can travel long distances

Erdogan et al. (1998)

Slide 6

PLANTING DESIGNS

• Traditional planting designs

M F F M F F F F F F F F F F F F F F M F F M F F F F F F F F F F F F F F

Male tree every 3rd tree, every 3rd row 1 male tree for 8 female trees 11.1% male trees

M F F M F F F F F F F F F F F F F F F F F F F F F F F F F F M F F M F F F F F F F F F F F F F F F F F F F F F F F F F F

Male tree every 5th tree, every 3rd row 1 male tree for 14 female trees 6.7% male trees

Slide 7

PLANTING DESIGNS

• Modern planting design

Male tree every 5th tree, every 5th row 1 male tree for 24 female trees 4% male trees

M F F F F M F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F M F F F F M F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F

Slide 8

PISTACHIO POLLINATION & ORCHARD DESIGN

• Pistachio is wind pollinated

– Male trees are interspersed through the orchard, usually in a regular pattern. – Initial plantings in Australia had 7-11% male trees but given the amount of pollen produced, more recent plantings use 4% male trees – Additional male trees can be planted in border rows but solid male tree rows are usually not needed.

• Sirora can have different stages of female flowers on the same

branch

– Bloom overlap is critical – Males with different flowering times are used to ensure there is pollen being released to cover the flowering times of Sirora – 3 males commonly used in Australia – ‘Green’ flowers early season – ‘Blue’ flowers mid season – ‘Red’ flowers late season

Slide 9

SIRORA FLOWERING

Slide 10

BLANKS

• Blank nuts result when there is fruit set and ovary growth but the

embryo fails to grow

• Blanking during nut set – PARTHENOCARPY

– Pollination occurs but fertilisation fails – Stimulus of pollination and/or pollen tube growth induces fruit set but the lack of fertilisation means that no embryo is formed so there is no kernel to fill the shell resulting in a blank – Boron nutrition. Low boron limits pollen germination and pollen tube growth

• Blanking during nut fill

– Blanks can develop during nut fill when the fertilised embryos fail to grow – Cause unknown but tree carbohydrate reserves suspected – Blanking is also sensitive to insufficient irrigation

Slide 11

BLANKS

Slide 12

MALE TREE MANAGEMENT

• Male trees can be big!

Slide 13

MALE TREE MANAGEMENT

• Shading and crowding neighbouring female trees

Slide 14

MALE TREE MANAGEMENT

• Pruning male trees

Slide 15