“Reproductive Control Systems and their applications in Plant Breeding” ( Seminar Synopsis)

 

UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE
DEPARTMENT OF GENETICS AND PLANT BREEDING
M.Sc. Seminar - GPB 582 (0+1)
“Reproductive Control Systems and their applications in Plant Breeding”

SYNOPSIS

Male sterility, one of the most reliable biological tools for genetic control of reproduction, boosts crop productivity in the face of rising food demand, shrinking arable land, and environmental limitations. It prevents self-pollination, facilitates hybrid seed production, and improves crop performance. Three main types of male sterility exist: Genetic Male Sterility (GMS), Cytoplasmic Male Sterility (CMS), and Cytoplasmic-genic Male Sterility (CGMS), each with unique applications and mechanisms.

Genetic Male Sterility (GMS) is controlled by nuclear genes and inherited in a Mendelian manner. It is effective but less stable due to environmental influences. Cytoplasmic Male Sterility (CMS) results from interactions between mitochondrial and nuclear genes and is maternally inherited. It offers stable expression across environments and is widely used in crops like maize, sorghum, and rice. CGMS combines CMS with fertility restorer genes (Rf), offering precise control over fertility restoration and enabling efficient hybrid seed production.

Reproductive control systems are integral in exploiting heterosis (hybrid vigor), ensuring cross-pollination, and increasing yield. The discovery of CMS systems in petunia (1954) marked a turning point, with further identification in crops like rice, maize, sunflower, and wheat. CMS-based hybrid systems require three lines: A-line (male-sterile), B-line (maintainer), and R-line (restorer).

Molecular markers are now used to identify sterility/fertility alleles, enhancing efficiency and precision. Tools like SSRs, SNPs, and QTL mapping assist in sterility gene identification and marker-assisted selection (MAS). CRISPR-based tools are also being developed for sterility gene editing.

Self-incompatibility (SI) is another reproductive barrier in plants that prevents self-fertilization and promotes cross-pollination. It is classified into sporophytic (SSI) and gametophytic (GSI) systems. SSI involves sporophyte-derived S-alleles, whereas GSI depends on the pollen genotype. Molecular studies have identified S-RNase and F-box genes as key players in GSI mechanisms.

These systems not only improve breeding efficiency and genetic diversity but also highlight the critical role of reproductive biology in advancing sustainable agriculture.

REFERENCES:

1. HAJARAHU, C., ADIMOOLAM, A., BISHET, N. AND SINGH, N. P., 2016, Cytoplasmic male sterility (CMS) in hybrid rice. Int. J. Theor. Appl. Sci., 8(1): 96-101.

2. RAO, K. K., DEVI, K. L. AND ARUNDHATI, A., 1990, Applications of genetic male sterility in plant breeding. Indian Farming, 18(10):1225.

3. WANG, X., HUANG, L., ZHANG, M. AND HU, F., 2021, Confirmation of a Gametophytic Self-Incompatibility in Oryza longistaminata. Front. Plant Sci., 12:1635.