Term
|
Definition
| A form of incomplete dominance. The heterozygoute is at a midpoint between the homozygotes. Example: the Waxy gene in maize. |
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Term
|
Definition
| When two genes produce the same effect, but effects are additive if both are present. The difference between two homozygotes. |
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Term
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Definition
| A component of genetic variance. Variation passed intect from parent to progeny. Variation in breeding value. |
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Term
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Definition
| A type of apomixis. The embryo develops from cells in tissues outside the embryo sac: ovule, nucellus, or integument cells. Most require pseudogamy for seed set. Fertilization occurs, but the nucellar embryo has a faster growth rate than the zygotic embryo. Polyembryonic seeds are produced. The endosperm is generated by fertilization. |
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Term
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Definition
| Different versions of a gene at the same locus. |
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Term
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Definition
| The frequency of a certain allele in a population. |
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Term
|
Definition
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Term
|
Definition
| The male reproductive organ of flowers. Contains the microsporangia. Each species has a different number of anthers, but the number is constant to each species. |
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Term
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Definition
| Cells in the embryo sac. Three are at the chalazal end of the embryo sac. |
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Term
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Definition
| A form of asexual reproduction. Production of seeds from somatic cells of the maternal parent. For some plants, psuedogamy is necessary to induce apomixis. Progeny is genetically identical to the mother. Example: citrus, bluegrass. Four types of apomixis: adventitious embryony, apospory, mitotic diplospory, and meiotic diplospory. |
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Term
|
Definition
| A type of apomixis. An embryo sac develops from cells that differentiated from the nucellus after formation of the megasporocyte. The embryo sac is diploid, so it grows faster than the haploid embryo sacs (not delayed by meiosis). The endosperm is formed by pollination from pseudogamy. |
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Term
|
Definition
| A method of artificial hybridization in wheat. The male spike is placed inside the glycine bag, kept in a drinking straw filled with water. |
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Term
| Artificial hybridization in Brassicas |
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Definition
| Wind is a more important pollinator than insects. Flowers are indeterminate, and the stigma is receptive 3 days before and 3 days after the flower opens. Pollen can be stored for 4 - 5 weeks. |
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Term
| Artificial hybridization in carrots |
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Definition
| The flowers are protandrous: pollen is shed before stigmas are receptive. The plants are fastened below the flowers and placed in a cage with flies that pollinate the flowers. |
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Term
| Artificial hybridization in soybeans |
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Definition
| Flowers are typically self-pollinated. Natural cross-pollination is about 1% from insect vectors. The flower has 5 petals: the standard, two wing petals, and two keel petals. |
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Term
| Artificial hybridization in wheat |
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Definition
| Two methods: Go-Go method and Approach method. |
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Term
|
Definition
Vegetative reproducction
Reproduction through plant parts other than the seed. Includes: bulb, corm, tuber, rhizome, stolon, micropropagation, and somatic embryogenesis. Apomixis, parthenogenesis, and artificial means such as cutting, grafting, layering, and tissue culture are also forms of asexual reproduction. |
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Term
|
Definition
|
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Term
|
Definition
| There are long spikes, awns, on the lema of wheat or barley. |
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Term
|
Definition
Apical cell
One of the cells formed in the first division of the zygote. It divides to form the embryo. |
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Term
|
Definition
| One of the cells formed in the first division of the zygote. In dicots it divides to form the suspensor. In monocots it does not divide, and forms the terminal cell of the suspensor. |
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Term
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Definition
| Rice with a good flavour, controlled by a genet. But no-one created the gene! Can you patent it? |
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Term
|
Definition
| The first stage in microgametogenesis. The microspore has cytoplasmic division, producing a generative cell and a tube cell. Most pollen is released in this stage. |
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Term
| Both self- and cross-pollination |
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Definition
| Some species have both self- and cross-pollination, with about 50% of each. Example: cotton, pigeon pea. |
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Term
|
Definition
| Highly self-incompatible. Self-pollinated seed is produced with difficulty. |
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Term
|
Definition
| Highly self-incompatible. Self-pollinated seed is produced with difficulty. |
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Term
|
Definition
| Self-fertile. 80% of seed is from self-pollination. This number is smaller when insect pollinators are abundant. |
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Term
|
Definition
| Self-fertile. 80% of seed is from self-pollination. This number is smaller when insect pollinators are abundant. |
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Term
|
Definition
|
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Term
|
Definition
| The value of an individual as judged by the mean value of the progeny. |
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Term
|
Definition
Genotypic variation / Phenotypic variation
An estimate of heritability. Measures the proportion of total variance that is genetic. Found using selfed progeny and progeny-parent regression heritability estimates. |
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Term
|
Definition
| A form of asexual reproduction. A large bud with a small stem at the lower end; buds in the axils of fleshy, scale-like leaves permit the bulb to be divided for asexual reproduction. Example: onion, garlic, tulips, lilies. |
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Term
| Cellular endosperm development |
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Definition
| The endosperm divides normally with cytokinesis; there is no free nuclear stage. |
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Term
|
Definition
| The origin of a cultivated species. Has wild species in addition to landraces. High level of genetic diversity. |
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Term
|
Definition
| The end of the embryo sac opposite from the micropylar end. The antipodal cells are on this end. |
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Term
|
Definition
| A device that promotes out-crossing. Flowers are open at anthesis. |
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Term
|
Definition
| A test of goodness of fit. The smaller the value, the more likely the hypothesis is correct. |
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Term
|
Definition
Plural: chiasmata
The point where two homologous, non-sister chromatids exchange genetic material during crossing over. |
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Term
|
Definition
| One of the places in the plant cell where DNA is kept. Chloroplast DNA is inherited maternally in most angiosperms, from both parents in some angiosperms, and paternally in a few angiosperms and most gymnosperms. |
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Term
|
Definition
| A condensed strand of DNA. |
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Term
|
Definition
| A device that promotes self-pollination. Flowers are closed at anthesis. Example: soybean, barley, wheat, oats. |
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Term
|
Definition
| A chemical that doubles the number of chromosomes. |
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Term
|
Definition
| When two non-allelic genes are required to produce a single effect. |
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Term
|
Definition
Duplicate recessive
A type of epistasis
aa is epistatic to B and b
bb is epistatic to A and a
Produces 9:7 ratios |
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Term
|
Definition
| When the heterozygote shows the same phenotype as one of the homozygotes. |
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Term
|
Definition
| Has all four floral organs: sepals, petals, stamens, and pistils. |
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Term
|
Definition
| A form of asexual reproduction. Resembles a bulb in size and form, but has different internal structure. Leaves are thin and small. Roots develop from the lower surface of the stem. Example: crocus, gladiolus. |
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Term
|
Definition
Allogamy
Have devices to promote outcrossing: chasmogamy, dioecious flowers, monoecious flowers, pin and thrum flowers, protandry, protogyny, protective film over the stigma, self-incompatibility, and male sterility. Often perennial. May also have asexual modes of reproduction. Individuals are heterozygous at many loci. Reduced performance when self-pollinated; inbreeding depression due to deleterious alleles in the population. Wild populations are heterogenous. Cultivated varieties are either heterogeneous or homogenous.
Natural self-pollination rates: 0% - 5%
Examples: corn, alfalfa, carrot, onion, rye, sunflower |
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Term
|
Definition
| A source of diversity from meiosis. Formation of a chasma and exchange of genetic material between chromosomes. Results in recombinant chromosomes. Genotype frequencies are unusual. |
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Term
|
Definition
| DNA in the mitochondria or chloroplast. Circular DNA, distinct from nuclear DNA. Usually inherited uniparentally. |
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Term
| Cytoplasmic male sterility |
|
Definition
| Male sterility controlled by the cytplasm, with many influences from nuclear genes, inhibiting normal development of anthers. |
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Term
|
Definition
| A soybean variety resistant to Frogeye leaf spot. |
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Term
|
Definition
A device that promotes out-crossing in imperfect flowers. Male and female reproductive parts are on separate plants.
Example: date plum, papaya, asparagus, hemp, hops |
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Term
|
Definition
| Two chromosome sets, one from each parent. Chromosomes are in homologous pairs. May be homozygous or heterzygous. |
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Term
|
Definition
| A long, double-helix molecule with 2 complementary strands with opposite polarity. |
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Term
|
Definition
| The dominance of alleles determines the phenotype of an organism. |
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Term
|
Definition
| Genetic variance that results from allelic interactions within loci. |
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Term
|
Definition
A type of epistasis.
A is epsitatic to B and b
Produces a 12:3:1 ratio |
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Term
|
Definition
| Unique to angiosperms. The egg cell is fertilized by a sperm cell, resulting in a diploid zygote. The polar nuclei are ferilized by the second sperm, resulting in the endosperm. |
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Term
|
Definition
| When either of two genes produce a similar effect. |
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Term
|
Definition
A type of epistasis
A is epistatic to B and b
B is epistatic to A and b
Prouces a 15:1 ratio |
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Term
|
Definition
Triticum turgidum
2n = 4x = 28 AABB
One of the parents of triticale. |
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Term
|
Definition
| A cell in the embryo sac. At the micropylar end. It is fertilized by a sperm cell to produce the zygote. |
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Term
|
Definition
| A diploid component of a seed. Develops from the axial cell of the zygote. In dicots it has four stages of development: globular, heart, late heart, and torpedo stage. |
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Term
|
Definition
Megagametophyte
Formed from the megapore in megagametogenesis. IT consists of seven cells and eight haploid nuclei: one egg, two polar nuclei (in one cell), two synergids, and three antipodal nuclei. Some species have more or less than the usual eight nuclei. It is surrounded by integuments, with the micropyle at one end. The micropylar end is near the micropyle, and the chalazal end is opposite from teh micropyle. |
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Term
|
Definition
| Forms from fusion of a sperm and the polar nuclei. Usually triploid, but can be 2n through to 15n. It draws nutrients from adjacent tissues. It either has nuclear development or cellular development. In monocots and endospermic dicots (such as castor beans0, the endosperm is generally no used until germination). In non-endospermic dicots, the endosperm reserve is depleted and reorganized into bulky, nutrient-rich cotyledons during seed development. |
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Term
|
Definition
| Expression of a gene at one locus affects the phenotypic expression at another locus. Incldues recessive epistasis, dominant epistasis, suppression, complementation, and duplication. |
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Term
|
Definition
| Genetic variation created by interactions between loic. Interactions are not passed intact from parent to progeny. Difficult to select for. |
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Term
|
Definition
| Variance due to the environment. Due to the inability to treat all genes equally. |
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Term
| Essentials of Plant Breeding |
|
Definition
|
|
Term
|
Definition
| A disease in soybeans caused by a fungus in hot humid soybean regions such as Brazil, China, Nigeria, and southern US. Causes yield losses 10 - 50%. Resistance is controlled by one or two genes. Susceptible plants have large, spreading, fertile lesions. Resistatn plants have no lesions, and small sterile flecks. |
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Term
|
Definition
A type of progeny-parent regression
b = narrow-sense heritability |
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|
Term
| Gametophytic self-incompatibility |
|
Definition
| Self-incompatibility where the genotype of the haploid gametes determines the compatibility reaction. If the allele in the pollen matches one in the female plant, then fertilization fails. |
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Term
|
Definition
| A stretch of DNA that transcribes a functional RNA or enables transcription of a protein. |
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Term
|
Definition
| A source of genetic diversity. Accessions are categorized by geographical source and phenotypic traits. Canada's main gene bank used to be in Ottawa, but was moved to Saskatoon in 1988. |
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Term
|
Definition
| One of the cells formed in the binucleate stage of microgametogenesis. It divides to form two sperm cells in the trinucleate stage. |
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Term
|
Definition
| The change in mean of a population from one generation cycle of selection. |
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Term
|
Definition
| Male sterility manifested through action of nuclear genes, inhibiting normal development of anthers. |
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Term
|
Definition
| The variation due to genetic differences among plants. Consists of additive, dominance, and epistatic variance. |
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Term
|
Definition
| The study of genes through their variation, or the study of inheritance. |
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Term
|
Definition
| The entire genetic information of an organism. |
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|
Term
| Genotype by environment (G x E) variance |
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Definition
| Variance due to genotypes responding differently to different environments. Reduces the association between genotypic and phenotype values. May cause selections from one environment to perform poorly in another environment. Minimized by using many environments and many replications. |
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Term
|
Definition
| The frequency of a certain genotype in a population. |
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Term
| Germplasm Resource Information Network (GRIN) |
|
Definition
| A source of information on accessions in gene banks. You can order accessions for free from the Canada gene bank. |
|
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Term
|
Definition
| The first stage of embryo development. The embryo is sphere shaped. |
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Term
|
Definition
| A method of artificial hybridization in wheat. The male spike is shaken inside the opening bag containing the female spike. The bag is then resealed. |
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Term
|
Definition
A type of progeny-parent regression.
2b = narrow-sense heritability |
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|
Term
| Hardy-Weinberg Equilibrium |
|
Definition
| Described by G.H. Hardy and W. Weinberg in 1908. Frequencies of alleles and genotypes stay constant if the population is large, randomly mating, absent of mutations, absent of selection, absent of migration. |
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Term
|
Definition
| The second stage of embryo development. Three major regions of mitotic activity: two on either side of the top of the embryo, and one near the suspensor. These develop into the cotyledons and radicle. |
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Term
|
Definition
| The proportion of the phenotypic variation that is due to genotype. Estimates of heritability can be used to predict selection gain. Includes broad sense and narrow sense estimates. |
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Term
|
Definition
| Having different alleles on two homologous chromosomes. |
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Term
|
Definition
| The lema of barley or wheat has a "hood" over it. |
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Term
|
Definition
| Chromosomes in a diploid organism which carry the same gene loci. May be homozygous or heterozygous. |
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Term
|
Definition
| Having the same allele on both homologous chromosomes. |
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Term
|
Definition
| A mutation in alfalfa causing increased activity of invertase, leading to starch build-up in the leaf. It is transmitted paternally more than it is transmitted maternally; this established that in Medicago species plastids are inherited paternally. It is studied using Restriction Fragment Length Polymorphism. |
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Term
|
Definition
| When the heterozygote is better than either homozygote. |
|
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Term
|
Definition
| Includes additive, partial, and over-dominance. |
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Term
|
Definition
| Lacks one or more floral organs: sepals, petals, stamens, or pistils. |
|
|
Term
| Independent assortment of chromosomes |
|
Definition
| A source of diversity from meiosis. Different chromosomes are independently separated from one another during gamete formation. |
|
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Term
|
Definition
| When one gene inhibits the effect of another gene at another locus. |
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Term
|
Definition
| Surround the embryo sac. Has a small opening at one end, the micropyle. After fertilization, develops into the testa. |
|
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Term
|
Definition
| A protein that exports sucrose from the cell. In high leaf starch alfalfa mutants it has increased activity, resulting in starch build-up in the leaf. |
|
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Term
|
Definition
| A petal in soybean flowers. There are two keel petals. |
|
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Term
|
Definition
| A cultivated form that evolved from a wild population, which is endemic to an area with origins going back 100s of years, well adapted to the environment, a mixture of types. |
|
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Term
|
Definition
| The third stage of embryo development. Elongation of regions of mitotic activity, defining cotyledons. |
|
|
Term
| Law of Independent Assortment |
|
Definition
| Alleles at a locus segregate independently from alleles at another locus, when gametes are formed. |
|
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Term
|
Definition
| Alleles of a gene separate randomly when gametes are formed. |
|
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Term
|
Definition
| A soybean vareity susceptible to most races of Frogeye leaf spot. |
|
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Term
|
Definition
| Genes are on the same chromosome. Produces unusual segregation ratios. |
|
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Term
|
Definition
| The location of a gene on a chromosome. |
|
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Term
|
Definition
| A device that promotes out-crossing. Includes genetic and cytoplasmic male sterility. |
|
|
Term
|
Definition
| When one gene hides the effect of another gene at another locus, when both are present. |
|
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Term
|
Definition
| A measure of central tendency, used when studying quantitative traits in populations. |
|
|
Term
|
Definition
| The megaspore undergoes division to form seven cells and eight nuclei that form the embryo sac. |
|
|
Term
|
Definition
| A haploid cell formed via meiosis of the megasporocyte. Arranged in a tetrad cluster or linear arrangement. Four are produced per megasporocyte, but three degenerate. |
|
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Term
|
Definition
Megaspore mother cell
Undergoes meiosis to form four megasporogenesis to form four megaspores. |
|
|
Term
|
Definition
| The megasporocyte undergoes meiosis to form four megaspores within the nucellus. |
|
|
Term
|
Definition
| Diploid cells divide to produce haploid cells. It produces diversity from independent assortment of chromosomes, and from crossing-over. Halves the number of chromosomes during production of sex cells. There is independent segregation of genes. |
|
|
Term
|
Definition
| A type of apomixis. The megasporocyte differentiates from the nucellus, but has a failure in meiosis I, resulting in a diploid megaspore. Development of an embryo from parthenogenesis; pollination is not required. |
|
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Term
|
Definition
| Development of pollen grains from microspores. Includes the binucleate and trinucleate stages. |
|
|
Term
|
Definition
| A form of asexual reproduction. |
|
|
Term
|
Definition
| The end of the embryo sac near the micropyle. The egg and synergids are on this side. |
|
|
Term
|
Definition
| A small hole in the integuments on the micropylar end of the embryo sac. The pollen tube enters through this opening. |
|
|
Term
|
Definition
Pollen sacs
Microsporogenesis occurs here. |
|
|
Term
|
Definition
| A haploid cell formed via meiosis of the microsporocyte in microsporogenesis. |
|
|
Term
|
Definition
Microspore mother cell
Undergoes meiosis in microsporogenesis, forming 4 microspores. |
|
|
Term
|
Definition
| The microsporocyte undergoes mieosis to form 4 microspores within the microsporangia of the anther. |
|
|
Term
|
Definition
| One of the places in the plant cell where DNA is kept. Mitochondrial DNA is inherited maternally. |
|
|
Term
|
Definition
| Diploid cells divide to produce diploid cells. Chromosomes are partitioned into daughter cells during somatic division. |
|
|
Term
|
Definition
| A type of apomixis. The megasporocyte is inhibited from entering meiosis. The embryo sac is diploid, but is identical in structure to the haploid embryo sac. The embryo is formed from parthenogenesis; pollination is not necessary. The endosperm is also produced by parthenogenesis, but in some cases pseudogamy is required form the endosperm. |
|
|
Term
|
Definition
| When one gene inhibits the effect of another gene at another locus. |
|
|
Term
|
Definition
| A device that promotes out-crossing in imperfect flowers. Male and female reproductive parts are on separate flowers on the same plant. Example: maize |
|
|
Term
|
Definition
| Genes or chromosomes changing from one allele to another. |
|
|
Term
| Narrow sense heritability |
|
Definition
| An estimate of heritability. The proportion of variance that is additive. The proportion which can be selected for. Found using full-sib and half-sib progeny-parent regression method. |
|
|
Term
|
Definition
| Megasporogenesis occurs here. Devlops into the perisperm in some species. |
|
|
Term
| Nuclear endosperm development |
|
Definition
| The endosperm undergoes several free nuclear divisions prior to cell wall formation. |
|
|
Term
|
Definition
| One of the places in the plant cell where DNA is kept. Nuclear DNA is inherited maternally and paternally. |
|
|
Term
|
Definition
| A type of incomplete dominance. The homozygote is greater than either heterozygote. |
|
|
Term
|
Definition
| A form of asexual reproduction. An embryo develops without fertilization, resulting in haploid progeny. No pollination is necessary. |
|
|
Term
|
Definition
| A type of incomplete dominance. The homozygote is between both homozygoutes, but is not at the midpoint. |
|
|
Term
|
Definition
| A soybean variety that is resistant to Frogeye leaf spot. |
|
|
Term
|
Definition
| Develops from the nucellus in some species. Assumes the role of the endosperm. Diploid, derived from the mother plant. Example: coffee. |
|
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Term
|
Definition
| Determined by the dominance of alleles in an organism. |
|
|
Term
|
Definition
| Genetic variance + Environmental variance + G x E interaction |
|
|
Term
|
Definition
| A soybean variety resistant to Frogeye leaf spot. |
|
|
Term
|
Definition
| A device that promotes out-crossing in imperfect flowers. Example: primula. |
|
|
Term
|
Definition
| Found in the nucleus, mitochondria, and chloroplasts. |
|
|
Term
|
Definition
| When a single gene may have more than one effect. |
|
|
Term
|
Definition
| A component of the embryo sac. Two nuclei in one cell. Near the centre of the embryo sac. It is fertilzied by a sperm cell to form the endosperm. |
|
|
Term
|
Definition
Microgametophyte
Formed from microspores in microgametogenesis. |
|
|
Term
|
Definition
| Pollen grains are transferred into the stigma by a variety of vectors: insects, animals, wind. Many species enter trinucleate stage at this point, producing two sperm cells. The pollen grain absorbs water and nutrients from the stigma surface, and the pollen tube emerges and grows through the stigma and style to the embryo sac, and enters the ovule through the micropyle. It penetrates a synergid, and deposits sperm cells. |
|
|
Term
|
Definition
| Seeds with more than one embryo. Created in adventitious embryony; there are a number of nucellar embryos in different stages, with or without a zygotic embryo. |
|
|
Term
|
Definition
| Originate as autopolyploids or allopolyploids. |
|
|
Term
|
Definition
| A group of interbreeding individuals that exist together in time and space. Distribution is measure with mean and variance. |
|
|
Term
|
Definition
| Creates genetics that you cannot get directly. There are seveal processes before getting the final product. Breeding with landraces or wild species transfers unwanted traits, which are removed in pre-breeding. |
|
|
Term
|
Definition
| A variety of dry bean Johannsen used in his experiments. Continuous breeding had no result because it was a pure-line. |
|
|
Term
| Progeny-parent regression |
|
Definition
| Calculating the regression coefficient of a line of parental vs. progeny phenotype. A higher number means a higher heritability. There are three types: selfed progeny, full-sib progeny, and half-sib progeny. |
|
|
Term
|
Definition
| Learning the genotype of a plant by growing and observing characteristics of its progeny. |
|
|
Term
|
Definition
| A device that promotes out-crossing. Stamens develop before pistils. |
|
|
Term
| Protective film over the stigma |
|
Definition
| A device that promotes out-crossing in perfect flowers. |
|
|
Term
|
Definition
| The product of genes. Transcribed based on the sequence of RNA strands. |
|
|
Term
|
Definition
| A device that promotes out-crossing. Stamens develop after pistils. |
|
|
Term
|
Definition
| When pollination and pollen tube development is necessary to induce apomixis. |
|
|
Term
|
Definition
| The progeny of a single plant, self-fertilized over many generations. All plants are homozygous and homogenous. |
|
|
Term
|
Definition
| Postulated by Wilhelm Johannsen in 1903. Continuous inbreeding leads to homozygosity. Variation within pure lines is caused by the environment only. Selection within a pure line is ineffective; all plants are genetically identical. |
|
|
Term
|
Definition
| Controlled by a few loci. Expression is not influenced by the environment. Phenotypes can be divided into discrete classes. Studied by analyzing the phenotypic ratios and inheritance patterns. Can show complete or incomplete dominance, and epistasis. Example: awned vs. hooded wheat and barley. |
|
|
Term
|
Definition
| Controlled by many loci. Expression is influenced by the environment. Phenotypes overlap and/or display continuous variation. Genotype cannot be determined from phenotype. Studied using measures of central tendency in populations. When environmental variation is eliminated, it can appear qualitative; Mendelian segregation patterns are followed. Example: yield in wheat. |
|
|
Term
|
Definition
A type of epistasis
aa is epistatic to B
Produces a 9:3:4 ratio |
|
|
Term
|
Definition
| Sometimes a different genotype is produced from different combinations of the sexes of the parents. Example: A female x B male vs. B female x A male, produce different phenotypes in the offspring. Indicates that genes are on mitochondrial or chloroplast DNA. Studied with Restriction Fragment Length Polymorphism. Example: high leaf starch mutation. |
|
|
Term
|
Definition
| Gene trait combinations that are a result of crossing-over. |
|
|
Term
| Regression coefficient (b) |
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Definition
| The slope of the line made in a progeny-parent regression method for estimating heritability. |
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Term
| Response to selection (R) |
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Definition
ckh2Ve
k is standardized selection differential
c is the parental control factor
To improve R, you can increase selection intensity, variability, or heritability (reduce errors in measurement of phenotype). |
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Term
| Restriction Fragment Length Polymorphism (RFLP) |
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Definition
| A marker used to follow transmission of plastids. Used to study high leaf starch mutation in alfalfa. |
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Term
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Definition
| A form of asexual reproduction. An underground horizontal stem that shoots and roots at nodes. It can be mistaken for a root when it grows underground. Example: bamboo, sugarcane, banana. |
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Term
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Definition
| A single-stranded molecule. Translated from genes. Can enable transcription of a protein. |
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Term
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Definition
2n = 2x = 14 RR
One of the parents of triticale. |
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Term
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Definition
| Triploid watermelon are sterile and produce no seeds. A diloid watermelon is treated with colchicine to produce a tetraploid watermelon, which is then backcrossed with diploid watermelon to create triploid progeny. |
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Term
| Selection differential (S) |
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Definition
| The mean phenotypic value of all the individuals selected as a derivation from the population mean. |
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Term
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Definition
| The proportion of the population which the breeder discards. |
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Term
| Self-incompatibility (SI) |
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Definition
| A device that promotes out-crossing. The inability of a plant to produce a zygote by self-pollination. Several mechanisms: pollen fails to germinate on the stigma, pollen tube is inhibited, pollen tube is insufficient length or strength, or the male gamete fails to unite with the egg cell. Can be gemetophytic or sporophytic. |
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Term
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Definition
Autogamy
Have devices to promote self-pollination: cleistogamy, staminal sheaths. Often annual species. Individuals are homozygous at many loci; there is no inbreeding depression. Wild populations are heterogeneous. Cultivated varieties are homogeneous - all individuals have the same genotype. Inheritance follows the Pure Line Theory.
Natural cross-pollination rates: 0% - 5%
Examples: barley, common bean, chickpea |
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Term
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Definition
A type of progeny-parent regression
b = broad-sense heritability |
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Term
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Definition
| Fusion of male and female gametes, regardless of whether they originate from one or more flowers or plants. Includes cross- and self-pollinating species. Each group has devices to promote their mode of reproduction. |
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Term
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Definition
| Two cells that arise from the generative cell of a pollen grain in trinucleate stage. One fertilizes the egg cell, forming the zygote. The other fertilizes the polar nuclei, forming the endosperm. |
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Term
| Sporophytic self-incompatibility |
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Definition
| Self-incompatibility where the genotype of the male parent determines the compatibility reaction. If either allele in the male parent matches one in the female parent, fertilzation fails, regardless of the genotype of the pollen grain. The genotype of the male parent is marked on the exine. |
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Term
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Definition
| A form of asexual reproduction. An embryo forms, and balanced hormones are used to produce a plant. Fertilization does not occur. |
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Term
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Definition
| A device that promotes self-pollination. The stamens are joined, surrounding the pistil. The pistil grows through the pollen, causing self-pollination. Example: cotton. |
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Term
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Definition
| A petal of a soybean flower. There is one standard petal. |
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Term
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Definition
| The floral organ which receives pollen. |
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Term
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Definition
Runners
A form of asexual reproduction. An above-ground horizontal stem. Example: strawberry, creeping bentgrass, Bermuda grass. |
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Term
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Definition
A type of epistasis.
A is epistatic to B and b
bb is espistatic to A and a
Produces a 13:3:0 ratio |
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Term
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Definition
| In dicots it is formed from the basal cell. In monocots it is formed from the axial cell, but its terminal cell is formed from the basal cell. Synthesizes growth factors and transports nutrients to the embryo. Can be unicellular, multicellular, large, small, filamentous, columnar, spherical, or irregular in shape. |
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Term
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Definition
| Cells in the embryo sac. There are two at the micropylar end. The pollen tube penetrates a synergid and disintigrates after fertilization. |
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Term
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Definition
| Formed from the basal cell in monocots. Becomes part of the suspensor, which is derived from the axial cell. |
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Term
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Definition
| Crossing a plant with a homozygous recessive individual to identify its genotype. |
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Term
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Definition
Seed coat
Develop from integuments. Diploid, derived from the mother plant. |
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Term
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Definition
| The fourthe stage of embryo development. Further elongation results in a bend in the region of the hypocotyl. |
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Term
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Definition
| The formation of a protein based on the sequence of an RNA strand. |
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Term
| Transgressive segregation |
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Definition
| When progeny fall outside of the range of the parents. |
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Term
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Definition
| The second stage in microgametogenesis. In most species it occurs when the pollen grain lands on the stigma. In others, it occurs before pollen is released. The generative cell undergoes division, forming two sperm cells. |
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Term
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Definition
| The first man-made crop. A cross between durum wheat (4n = 28 = AABB) and rye (2n = 12 = RR), creating a sterile 3n = 21 = ABR individual. Colchicine was used to double the chromosomes, producing 6n = 42 = AABBRR triticale. |
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Term
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Definition
Vegetative cell
One of the cells formed in the binucleate stage of microgametogenesis. Helps the sperm cells reach the egg. |
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Term
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Definition
| A form of asexual reproduction. A swollen, modified stem that acts as an underground storage organ. Example: potato, Jerusalem artichoke, yam. |
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Term
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Definition
| A measure of distribution. Used in studying quantitative traits in populations. |
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Term
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Definition
| A gene in maize that shows additive dominance. |
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Term
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Definition
| Has genes transgressed in from GP2 and GP3. It has 21 pairs of chromosomes. |
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Term
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Definition
| Postulated the Pure Line Theory in 1903. Used Princess dry beans in his experiments. |
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Term
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Definition
| A petal in soybean flowers. There are two wing petals. |
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Term
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Definition
| A diploid cell formed from fusion of the egg and a sperm. It develops into the embryo of the seed. The first division in the zygote forms the axial and basal cells. |
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