Hybrid Corn CH894945 Breeding via Male Sterility and Segmentation

The patent applies preliminary action by inducing male sterility in the female parent before pollination occurs. This is achieved through chemical treatments (such as applying sterility-inducing agents like triazole or herbicides) or physiological methods (such as temperature stress or nutrient deprivation) that prevent the male flowers from producing viable pollen before self-pollination can occur. This preliminary prevention ensures that only cross-pollination from desired male parents can fertilize the female plants, thereby maintaining genetic stability while improving hybrid seed production efficiency

The patent uses an intermediary substance or agent to control pollination. Chemical sterilants or physiological modifiers act as intermediaries between the male and female reproductive systems, blocking self-pollination while allowing controlled cross-pollination. For example, applying growth regulators or stress-induced sterility agents creates a controlled barrier that selectively prevents self-fertilization while permitting intended cross-fertilization, thus resolving the contradiction between maintaining genetic purity and enabling efficient hybrid production

The patent applies segmentation by dividing the breeding program into distinct modules, each targeting a specific desirable trait. Instead of attempting to combine multiple traits in a single complex cross, the breeding program is segmented into separate breeding lines, each optimized for one or few specific traits (such as disease resistance, yield, stress tolerance). These segmented lines are then systematically combined through controlled crosses, allowing complex multi-trait hybrids to be developed through a series of manageable, organized steps rather than a single overwhelming breeding operation

The patent employs universality by developing inbred parental lines that serve multiple functions. Each inbred line is bred to possess a specific set of desirable traits that can be consistently combined with other standardized lines. This creates a library of universal, pre-characterized parental lines that can be systematically crossed to produce hybrids with predictable combinations of traits, thereby reducing breeding program complexity while maintaining high agronomic quality through standardized, multi-functional parental stocks

The patent applies local quality by creating spatial and functional differentiation between sterile and fertile lines in the breeding program. Specifically, male-sterile female parent lines are planted in designated areas where they cannot self-pollinate, while male-fertile maintainer lines are planted in adjacent or separate areas to provide pollen. This local differentiation allows efficient hybrid seed production in the sterile line zones while using the fertile lines only for pollen donation and maintenance, thereby managing the complexity through localized functional zones rather than uniform program-wide management

The patent uses copying by creating duplicate sets of inbred lines with different fertility statuses. For each female parent line, a corresponding maintainer line (with normal fertility) is developed that carries the same nuclear genome but has fertile cytoplasm. This copying approach allows the sterile lines to be used efficiently for hybrid production while the copied fertile versions serve as maintainers to propagate the sterile lines and as pollen donors. This duplication strategy simplifies management by creating paired, functionally differentiated line sets that are easier to track and manage than single complex systems