KNMAIZE–A Model to Investigate the Dynamics of Kernel Set in Maize

Abstract

Core Ideas The dynamics of kernel set in maize was modeled at the individual kernel level.Kernels survived when enough assimilate was available to meet their needs.The model captures the dynamics of ear size, plant growth rate, and kernel growth. The adjustment of kernels plant−1 to the assimilate supply is an important component of the yield production process in maize (Zea mays L.). A simulation model (KNMAIZE) was developed to better understand this process at the individual kernel level. Kernel survival was determined by comparing the assimilate supply (calculated from solar radiation) partitioned to reproductive growth during the initial stages of kernel development with the kernel assimilate requirement (based on published kernel growth curves) on a daily basis. When model parameters were optimized by maintaining the ratio of the sink (total kernel growth rate) and the source (total assimilate supply) equal to 1.0 during the linear phase of kernel growth, the model accurately mimicked the effect of plant growth rate, individual kernel growth rate, and ear size on kernels plant−1. The model also mimicked the plant density‐kernels m−2 relationship. Short‐term (3 or 5 d) variation in plant growth rate influenced kernels plant−1 11 to 15 d after the beginning of kernel growth. Modeling kernel number at the individual kernel level makes it possible to capture important aspects of the dynamics of kernel set that will lead to better predictions of kernel number and a clearer understanding of the elements of maize productivity in the field.