Inheritance of Plant Traits Exam

Allele: Different forms of a gene (e.g., A for dominant, a for recessive).
Homozygous: Having two identical alleles for a gene (e.g., AA or aa).
Heterozygous: Having two different alleles for a gene (e.g., Aa).
Dominant allele: An allele that masks the effect of a recessive allele in a heterozygous individual.
Recessive allele: An allele whose effect is masked by a dominant allele in a heterozygous individual.
Genotype: The genetic makeup of an organism (e.g., AA, Aa, aa).
Phenotype: The physical expression of a genotype (e.g., stem pubescence).
Monohybrid cross: A cross between individuals that differ in one trait (e.g., stem pubescence).
Dihybrid cross: A cross between individuals that differ in two traits (e.g., fruit color and rind pattern).
Punnett square: A diagram used to predict the genotype and phenotype ratios of offspring.
Chi-square test: A statistical test to compare observed and expected phenotypic ratios.

Pureline cultivar: A cultivar with homogeneous and homozygous seeds, developed through repeated selfing.
F1 hybrid: The first-generation offspring from a cross between two homozygous lines, typically heterozygous and homogeneous.
Heirloom cultivar: A traditional, open-pollinated cultivar that has been passed down through generations.
Open-pollinated variety (OPV): A cultivar maintained by natural pollination, often heterogeneous.
Clone: A genetically identical copy of a plant, produced through vegetative propagation.
Dioccious: Plant species with separate male and female plants (e.g., spinach).
Monoccious: Plant species with both male and female flowers on the same plant (e.g., corn).
Dichogamy: A mechanism where male and female reproductive parts mature at different times to prevent self-fertilization.
Heterozygosity: The presence of different alleles at a gene locus.
Homozygosity: The presence of identical alleles at a gene locus.

Chloroplast inheritance: Typically maternal in most plants, meaning chloroplasts are inherited from the mother.
Mitochondrial inheritance: Also typically maternal in most plants.
Polyploidy: The condition of having more than two sets of chromosomes.
- Autoploid: A polyploid derived from the duplication of chromosomes within the same species.
- Alloploid: A polyploid derived from hybridization between different species.
Tetraploid: An organism with four sets of chromosomes (4x).
Hexaploid: An organism with six sets of chromosomes (6x).
Base number (x): The number of chromosomes in a basic set (e.g., x=6 for a tetraploid with 24 chromosomes).

Agrobacterium-mediated transformation: A method of introducing foreign DNA into a plant using the bacterium Agrobacterium tumefaciens.
GMO (Genetically Modified Organism): An organism whose genetic material has been altered using biotechnology.
Horizontal disease resistance: A low-level resistance to many pathogen races, often controlled by multiple genes.
Vertical disease resistance: A high-level resistance to specific pathogen races, often controlled by a single gene.
Eukaryotic translation initiation factor 4E (eIF4E): A host gene that provides resistance to certain viruses, such as papaya ring spot virus (PRSV-W).
Nucleotide-binding site–leucine-rich repeats (NBS–LRR): A class of disease resistance genes in plants.

Self-pollination: The transfer of pollen from the anther to the stigma of the same flower or plant.
Cross-pollination: The transfer of pollen from the anther of one plant to the stigma of another plant.
Unisexuality: A condition where a plant has either male or female flowers (dioccy).
Dichogamy: A temporal separation of male and female flower maturation to prevent self-fertilization.
Heterosis (hybrid vigor): The phenomenon where hybrid offspring exhibit superior traits compared to their parents.

Haploid (n): A cell or organism with one set of chromosomes (e.g., gametes).
Diploid (2n): A cell or organism with two sets of chromosomes (e.g., somatic cells).
Triploid (3n): A cell or organism with three sets of chromosomes.
Tetraploid (4n): A cell or organism with four sets of chromosomes.
Hexaploid (6n): A cell or organism with six sets of chromosomes.

Horizontal resistance: Broad-spectrum resistance to many pathogen races, often quantitative.
Vertical resistance: Specific resistance to certain pathogen races, often qualitative.
PRSV-W (Papaya Ring Spot Virus - Watermelon strain): A virus that infects watermelon, with resistance provided by the eIF4E gene.
First GMO crop: The Flavr Savr tomato, approved for human consumption in the USA.

Seed saving: The practice of collecting and storing seeds for future planting.
Heterogeneous seed: Seed that is genetically diverse.
Homogeneous seed: Seed that is genetically uniform.
Heterozygous seed: Seed with mixed alleles at a gene locus.
Homozygous seed: Seed with identical alleles at a gene locus.