1. Chap 2. Biology of Propagation
General Terminology
a. Genotype: the genetic make-up of an organism
b. Phenotype: the external appearance of an organism (usually the outcome of interaction between a genotype and environment)
c. Ploidy: Variation in the genomic number (x) of chromosomes
x =
n =
2n = “wholeness”
n = “halfness”

2. Variation in Euploidy (for Organisms with x=12)
Ploidy No. Chromosomes Somatic Gametic
Diploid 2x=24 2n= n=12=x
Tetraploid 4x=48 2n= n=24=2x
Hexaploid 6x= n= n=36=3x
Octoploid 8x= n= n=48=4x
Haploid 1x=12 2n= n= 6 (?)
Triploid 3x=36 2n= n=18 (?)
Pentaploid 5x=60 2n= n=30 (?)
Seedless watermelons are triploids

3. Reproductive Biology Cell Division Flowering and Anthesis
Somatic cell division (Mitosis)
Reproductive cell division (Meiosis)
Flowering and Anthesis
Megagametogenesis (EMC to Egg Cells)
Microgametogenesis (PMC to Pollen Grains)
Pollination and Fertilization
Pollen germination on stigma
Pollen tube growth through style tissue
Double fertilization

4. Mitosis 2N → 2N + 2N - Somatic Cell Division
Ends up with same number of chromosomes in divided cells
Divided cells are genetically identical to maternal cells
2N → 2N + 2N

5. Meiosis 2N → → N + N + N + N Reproductive cell division
Undergoes 2 separate divisions
Forms gametes
Divided cells have a half of the chromosome numbers
Ends up with genetic re- assortment by chromosomal translocation (cross-over)
2N → → N + N + N + N

6. An Example of Meiosis

7. Fertility in Polyploid (Euploidy) Plants
Somatic
Gametic
Fertility
Monoploid
2n=1x
n = ?
Very low
Diploid
2n=2x
n = x
High
Triploid
2n=3x
Tetraploid
2n=4x
n = 2x
Variable
Pentaploid
2n=5x
Hexaploid
2n=6x
n = 3x
Heptaploid
2n=7x
Octoploid
2n=8x
n = 4x
Nonaploid
2n=9x
Decaploid
2n=10x
n = 5x

8. Polyploidization
Use of Cholchicine to induce polyploids
Colchicine interferes with spindle fiber function during metaphase of meiosis

9. Production of Seedless Watermelon

10. Example of Ploidy Variation
Chromosome Number
Species
Ploidy
Somatic
(2n)
Gametic
(n)
Genomic
(x)
Spinach 2x 12 6
Corn 20 10
Potato 4x 48 24
Strawberry 8x 56 28 7

11. Polyploidy Terminology (continued)
Euploidy
Variation between chromosome sets
Aneuploidy
Variation within a chromosome set
Autoploidy
Multiplication of the complete set of genomes of a species
Alloploidy
Polyploid containing genetically different sets of chromosomes derived from 2 or more species

12. Aneuploidy Variation within a chromosome set
A diploid plant ( ) would contain the following chromosome numbers depending on aneuploidy conditions:
Aneuploidy
Somatic chromosome number 
Examples
 Trisomic
 2n + 1 (extra)
11  22  33  44  55 
 Monosomic 
 2n - 1 (deficient) _
 Double-trisomic
2n (2 extra)
11  22  33  44  555  66  777
4 of one chromosome
2n + 2 (2 extra)
11  22  33  44  5555  66  77

13. - One tube nucleus - Two sperm nuclei
Pollen Tetrad and Microgametophyte
  - One tube nucleus    - Two sperm nuclei 

14. Megagametophyte

15. Pollination and Fertilization, Angiosperms

16. Double Fertilization
A process of fertilization in which one male gamete (sperm nucleus, n) unites the egg nucleus (n) to form embryo (zygote, 2n) and the other sperm nucleus (n) unites polar nuclei (2n) to form endosperm (3n)

17. General Terminology (continued)
Homozygous-
b. Heterozygous- Having unlike alleles at one or more corresponding loci on homologous
c. Meiosis-
- Chromosome number is reduced to one half
- Results in formation of gametes
- Allows genetic recombination
d. Mitosis-
- Chromosome number same in daughter cells
- Results in somatic tissues genetically identical
- Allows clonal duplication

18. Fruit Flesh Color and Skin Texture Inheritance - Peach

20. Inheritance of Flower Color and Color Pattern Salpiglossis sinuata
RR or Rr Red flower color
rr Yellow flower color
DD or Dd Solid color pattern
dd Dilute color pattern

21. Gene Symbols
RR DD or R_R_
(red, solid)
RR dd or R_ dd
(red, dilute)
rr DD or rrD_
(yellow, solid)
rr dd
(yellow, dilute)

22. x P1 P2 F1 F2 9 Dilute Red (RRdd) Solid yellow (rrDD) Solid Red (RrDd)3
Solid yellow
(rrD-) 3
Dilute yellow
(rrdd) 1

23. 2. Nomenclature Family-Genus-Species-Variety-Form-Individual
Based on ICBN (International Code of Botanical Nomenclature)
a. Botanical Classification
Family-Genus-Species-Variety-Form-Individual
- Subspecies
- Clines-
- Ecotypes-
b. Cultivated Plants
Genus, species, cultivar
Cultivar = Cultivated variety (cv.)
Cultigen = Cultivated variety that has been naturalized
Examples:

24. 3. Kinds of Cultivars Cultivars made up of self-pollination of an F-1
a. Line- Self pollinated seed-propagated cultivar (homozygous)
- Inbred lines
- Synthetic lines (composite lines)
b. Hybrids (sexual)
F-1 hybrid- first generation progeny from a cross between 2 inbred lines (single cross)
c. F-2 Cultivars (sexual)
Cultivars made up of self-pollination of an F-1

25. 3. Kinds of Cultivars (continued)
d. Open Pollinated Cultivar
- Cultivar made up of seeds formed by open pollination
- Can be mixtures of hybrids, selfs)
- Inbred lines
- Synthetic lines (composite lines)
e. Clonal Cultivars
Clone-
Asexual propagation- cuttings, tubers, bulbs, grafts, rhizomes, cormels, stolon
f. Apomictic Seeds
Seed formed from maternal (ovule) tissues

26. 4. Requirements for New Cultivar a. Distinctive-
b. Uniform-
Homogeneous (but, can be heterozygous as in F1)
Homozygous (no segregation)
c. Stable-
d. Commercial-