Wightman Wells Garner and Harry Ardell Allard is known for their discoveries of

Wightman Wells Garner and Harry Ardell Allard were known for their discoveries on Photoperiodism. Photoperiodism is the response of an organism to the length of the night or a dark period. In 1920, they reported that the length of daylight that was critical for plant growth and development but later it was discovered that the length of the night was the controlling factor for growth and development in plants