Green Revolution participant Norman Borlaug
High-yielding varieties
The novel technological development of the Green Revolution was the production of novel wheat cultivars. Agronomists bred cultivars of corn, wheat, and rice that are the generally referred to as HYVs or "high-yielding varieties". HYVs have higher nitrogen-absorbing potential than other varieties. Since cereals that absorbed extra nitrogen would typically lodge, or fall over before harvest, semi-dwarfing genes were bred into their genomes. A Japanese dwarf wheat cultivar Norin 10 developed by Japanese agronomist Gonjiro Inazuka, which was sent to Orville Vogel at Washington State University by Cecil Salmon, was instrumental in developing Green Revolution wheat cultivars. IR8, the first widely implemented HYV rice to be developed by IRRI, was created through a cross between an Indonesian variety named "Peta" and a Chinese variety named "Dee-geo-woo-gen" In the 1960s, when a food crisis happened in Asia, the spread of HYV rice was aggravated intensely.Dr. Norman Borlaug, the "Father of the Green Revolution", bred rust-resistant cultivars which have strong and firm stems, preventing them from falling over under extreme weather at high levels of fertilization. CIMMYT (Centro Internacional de Mejoramiento de Maiz y Trigo – International Center for Maize and Wheat Improvements) conducted these breeding programs and helped spread high-yielding varieties in Mexico and countries in Asia like India and Pakistan. These programs led to the doubling of harvests in these countries.Plant scientists figured out several parameters related to the high yield and identified the related genes which control the plant height and tiller number. With advances in molecular genetics, the mutant genes responsible for Arabidopsis thaliana genes (GA 20-oxidase, ga1, ga1-3), wheat reduced-height genes (Rht)  and  a rice semidwarf gene (sd1) were cloned. These were identified as gibberellin biosynthesis genes or cellular signaling component genes. Stem growth in the mutant background is significantly reduced leading to the dwarf phenotype. Photosynthetic investment in the stem is reduced dramatically as the shorter plants are inherently more stable mechanically. Assimilates become redirected to grain production, amplifying in particular the effect of chemical fertilizers on commercial yield.HYVs significantly outperform traditional varieties in the presence of adequate irrigation, pesticides, and fertilizers. In the absence of these inputs, traditional varieties may outperform HYVs. Therefore, several authors have challenged the apparent superiority of HYVs not only compared to the traditional varieties alone, but by contrasting the monocultural system associated with HYVs with the polycultural system associated with traditional ones.