Why male sterility is more important in self pollinated plants compared to cross pollinated in breeding programme?

Male sterility, the inability of plants to produce functional pollen, is often more important in self-pollinated plants compared to cross-pollinated plants in breeding programs for several reasons:

Ease of Hybrid Seed Production: In self-pollinated crops, achieving hybrid vigor (heterosis) typically requires the production of hybrid seeds through controlled crosses between genetically distinct parental lines. Male sterility facilitates hybrid seed production by preventing self-pollination and ensuring the purity of hybrid seeds.

Prevention of Self-Fertilization: Self-pollinated plants have mechanisms to prevent self-fertilization, such as physical barriers or self-incompatibility systems. However, these mechanisms are not always 100% effective, and self-pollination can still occur. Male sterility provides an additional safeguard against self-fertilization by eliminating the production of viable pollen.

Maintenance of Genetic Purity: Male-sterile lines serve as female parents in hybrid seed production, ensuring that the resulting hybrid seeds contain only the desired genetic combination from the male and female parents. This maintains genetic purity and uniformity in hybrid progeny, which is essential for commercial seed production and crop improvement programs.

Efficiency and Cost-Effectiveness: Using male sterility for hybrid seed production in self-pollinated crops can be more efficient and cost-effective compared to hand emasculation or other manual methods of pollen removal. Male-sterile lines eliminate the need for labor-intensive emasculation procedures and reduce the risk of human error in hybrid seed production.

Synchronization of Flowering: Male sterility allows breeders to synchronize flowering between male-sterile and pollen-parent lines, ensuring optimal timing for controlled pollination and hybrid seed production. This synchronization improves the efficiency of hybridization and facilitates the production of high-quality hybrid seeds.

Exploitation of Heterosis: Heterosis, or hybrid vigor, is often more pronounced in self-pollinated crops due to the accumulation of favorable alleles through repeated selfing. Male sterility enables the exploitation of heterosis by facilitating controlled crosses between genetically diverse parental lines and enhancing the performance of hybrid progeny.

Overall, male sterility is a valuable trait in self-pollinated crops breeding programs, as it enhances the efficiency, reliability, and cost-effectiveness of hybrid seed production, while also allowing breeders to exploit heterosis and maintain genetic purity in hybrid progeny.