What is transgenic male sterility?
Transgenic male sterility is controlled by foreign nuclear genes. In this system two types of transgenes, viz., barnase and barstar are used. The gene barnase causes male sterility and the gene barstar restores the fertility. Both these genes have been utilized from the bacterium Bacillus amyloliquefaciens.
What is Gametophytic male sterility?
Cytoplasmic male sterility (CMS) has now been identified in over 150 plant species. Male sterility is more prevalent than female sterility. This could be because the male sporophyte and gametophyte are less protected from the environment than the ovule and embryo sac.
What are the types of male sterility in plants?
Phenotypic Male Sterility (Morphological) Structural or Staminal Male Sterility. Pollen Male Sterility. Functional Male Sterility.
What causes male plant sterility?
In plants, male sterility can be caused either by mitochondrial genes with coupled nuclear genes or by nuclear genes alone; the resulting conditions are known as cytoplasmic male sterility (CMS) and genic male sterility (GMS), respectively.
Which male sterility is mostly used in cultivated crops?
Of the three types of male sterility mentioned, pollen sterility is by far the most common and the only one that has played a major role in plant breeding and hybrid seed production.
What is CGMS in plant breeding?
This is a case of cytoplasmic male sterility where dominant nuclear gene restores fertility. This system is utilized for the production of hybrids in onion, maize and many other crops.
What is Sporophytic self-incompatibility?
Sporophytic self-incompatibility (SSI) is a self-pollen recognition system that enforces outcrossing in plants. Recognition in SSI systems is typically controlled by a complex locus (S-locus) with separate genes that determine pollen and stigma specificity.
What is male sterility explain various types of male sterility?
Male sterility is defined as an absence or non-function of pollen grain in plant or incapability of plants to produce or release functional pollen grains. The use of male sterility in hybrid seed production has a great importance as it eliminate the process of mechanical emasculation.
Which type of male sterility is used for asexually propagated crops?
Cytoplasmic genetic male sterility is widely used for hybrid seed production of both seed propagated species and vegetative propagated species. It is used commercially to produce hybrid seed in maize, cotton, rice, sunflower, etc. Functional male sterility.
Which gene is responsible for male sterility?
In the mitochondrial genome of Chinsurah Boro II, a chimeric gene called orf79, located downstream of e atp6, which encodes a cytotoxic peptide, was confirmed to be responsible for the gametophytic male sterility of CMS-BT rice by transgenic experiments (Iwabuchi et al., 1993; Akagi et al., 1994; Wang et al., 2006b).
What are the three types of male sterility?
- Genetic Male Sterility: The pollen sterility, which is caused by nuclear genes, is termed as genic or genetic male sterility.
- Cytoplasmic Male Sterility: The pollen sterility which is controlled by cytoplasmic genes is known as cytoplasmic male sterility (CMS).
- Cytoplasmic Genetic Male Sterility:
How many types of male sterility are there?
There are three basic types of male sterility, viz.: There are two other types, viz., chemical induced male sterility, and transgenic male sterility. Almost all crop plants possess male sterility if investigated property.
What is difference between gametophytic and sporophytic incompatibility?
The key difference between gametophytic and sporophytic self incompatibility is that in gametophytic self-incompatibility system, pollen phenotype is determined by its gametophytic haploid genotype while in sporophytic self-incompatibility, pollen phenotype is determined by the diploid genotype of the plant.
What is Heteromorphic incompatibility?
(a) Heteromorphic system: In this type of incompatibility same species produce more than one morphological type of flowers. For example relative length of styles and stamens in flowers of same species. Distyly and tristyly (Fig. 2.37) has been reported in Primula and Evening primrose respectively.
What is sporophytic incompatibility?
What is gametophytic incompatibility?
angiosperm reproduction A second type, gametophytic self-incompatibility, involves the inability of the gametes from the same parent plant to fuse and form a zygote or, if the zygote forms, then it fails to develop. These systems force outcrossing and maintain a wide genetic diversity.
What is the difference between homomorphic and Heteromorphic self incompatibility?
Self-incompatibility (SI) systems in flowering plants are either homomorphic, with many different incompatibility types (Figure 1a) whose flowers are indistinguishable, or heteromorphic, with only two or three incompatibility types that also have different positions of flower parts (often called heterostyled plants).
What is the difference between gametophytic and sporophytic incompatibility?