Presentation on theme: "Plant Reproduction System"— Presentation transcript:
1 Plant Reproduction System PLANT BREEDING AGR 3204Plant Reproduction System
2 Plant Reproduction System The reproduction mechanism of a particular plant species or the way it reproduces determinesits genetic characteristicsthe breeding approach.
3 1. Sexual ReproductionUsing sex organs to form next generation / to produce seeds.
4 1. Sexual reproduction (cont.) Important steps:Production of gametes (gametogenesis)Pollination – Transfer of pollen from anther (male organ) to the stigma (female organ).Fertilization – The union of male and female gametes to produce new genotypes.
9 POLLINATIONTransfer of pollen from anther (male organ) to the stigma (female organ).Two kinds of pollination,Self pollinationCross pollination
10 Self PollinationTransfer of pollen from anther to stigma of the same flower / plant
11 Self pollination Natural mechanisms that encourages self pollination: CleistogamyPollination happens when flower is still closed.Example: Rice
12 Self Pollination (cont.) Stigma protected by antherAnthesis and pollination occur instantaneously once the flower blooms.Many pollen are produced, covering the stigma, hence preventing pollination by pollen from outside.Example: lime, tomato and chilliChilli flower
13 Self pollination (cont.) 3. Stigma and anther protected by other parts of flower.Male (stamen) and female (pistil) organs covered by keel, i.e. two fused petals.Example: Leguminosae family, sub-family Papilionoideae.
14 Cross PollinationTransfer of pollen from anther to stigma of flower of different plant.
15 Cross Pollination(cont.) Natural mechanisms to promote cross pollination:DieociousMale and female flowers are formed on different plants.Have male and female plants.Example: Papaya, salakMale salak flowerFemale salak flower
16 Cross Pollination(cont.) 2. MonoeciousMale and female flowers are in separate positions on the same plant but mature at slightly different times.Example: Oil palm, corn and rubber.
17 Cross Pollination(cont.) 3. DichogamyAnther and stigma from hemaphrodite flower or flower of monoecious plant mature at different times.ProtogyneStigma (female flower) matures before anther (male flower).Example: Potato, cassava and cashew.Protogyne: Potato flower
18 Cross Pollination(cont.) 3. Dichogamy (cont.)ProtandryAnther (male flower) matures before stigma (female flower).Example: Starfruit and rubber.Protandry: Starfruit flower
19 Cross Pollination(cont.) 4. Self-incompatibilityPollens are unable to fertilize ovule (female gamete) of the same flower/plant due to genetic factor (self incompatibility gene)Example: Potato, passion fruit and starfruit.
20 Cross pollination(cont.) In some species, there are more than one mechanism to promote cross pollination:Rubber and corn: monoecious and protandry.Potato, Sweet potato: Self- incompatibility and protogyneStarfruit & passion fruit: Self- incompatibility and protandry
21 Methods to determine modes of pollination 1. Identify flower formation system.2. Isolate plants.No fruit/seed cross pollinatedFruit set/seed set self pollinated and possibly cross pollinated3. Selfing.To observe the effects of inbreeding.Present cross pollinated.Absent / minimal self pollinated.
22 2. Asexual ReproductionDoes not involve sex or union of male and female gametes.Mechanisms:-Vegetative reproductionApomixis
23 Vegetative Reproduction Stem/branch/root cuttings e.g. cassavaGrafting e.g. rubber, rambutan & durianRhizome e.g. tumeric & gingerStolon e.g. grassTuber e.g. potato & sweet potatoTiller e.g. pineapple , sugarcane & banana
24 apomixisFormation of seeds without union of gametes, i.e. fertilization.
25 Apomixis (cont.)Apogamy – Embryo formation from synergids or antipodals
26 Apomixis (cont.)Apospory Embryo develops from somatic cell such as nucellus and integument.Diplospory Embryo develops from megasporocyte.Adventitious embryo Embryo develops directly from nucellus and integument cells without involving embryo sac cells.Parthenogenesis Embryo develops from unfertilized eggs.