Relationships between Plant Architecture Traits and Cotton Yield within the Plant Height Range of 80–120 cm Desired for Mechanical Harvesting in the Yellow River Valley of China.

Mechanical harvesting has become inevitable for cotton production in China due to the rising labor cost in the country. It usually requires a moderate plant height and compact plant architecture. Correlation and stepwise regression were employed to analyze databases of our 24 field experiments between 2010 and 2017 in Hebei Province. The purpose is to identify the relationships between plant architecture traits and seed cotton yield within natural plant height range (58.6–163.2 cm) or preferred plant height range (80–120 cm) for mechanical harvesting in the Yellow River Valley of China, and define some important factors affecting seed cotton yield. Under natural plant height range across all experiments, there was a significantly negative correlation (r = −0.452) between plant height and yield. On limited plant height range desired for mechanical harvesting, the degree of this negative correlation decreased to r = −0.366. The correlation of plant height with seed cotton yield varied greatly with year, cultivar, plant density and mepiquat chloride (MC) application. Moreover, stepwise regression analysis picked internode length of the 1st (generally including 1st–7th mainstem node from bottom), 2nd (8th–12th node) and 4th (above 17th node) mainstem section and the length of lower fruiting branch (LFB) as significant factors influencing seed cotton yield under plant height range of 80–120 cm. The results have implications for precise control of cotton plant architecture preferred for mechanized harvesting in China. [ABSTRACT FROM AUTHOR]