Effects of plant density on leaf area index, anthesis to silking interval, yield and yield components of maize inbreds and their sister-lines

Abstract

Yield of maize inbreds is often a limiting factor in hybrid seed production. Thus, the main aim was to evaluate the effect of plant density on leaf area index (LAI), anthesis to silking interval (ASI), grain yield and yield components of inbreds and their sister-lines at two locations over two growing seasons. Inbreds Bc 279 and Bc 64, and their corresponding sister-lines Bc 279026-22 and Bc 822-1064, respectively, were grown at 60,000 and 86,000 plants*ha-1. When compared to inbreds, grain yields improved for sister-lines by an average of 1188 kg*ha-1 (21%) for Bc 279026-22 and 4816 kg*ha-1 (141%) for Bc 822-1064 primarily due to more kernel rows per ear and kernels per ear row. This greater kernel number per ear and per plant was associated with larger LAI for Bc 279026-22, while Bc 822-1064 out-yielded inbred Bc 64 despite of similar LAI and ASI. Inbred Bc 64 and its sister-line Bc 822-1064 increased LAI similarly at higher plant density, but the former showed limited yield increment because of a large increase in barren plants. In contrast, inbred Bc 279 and its sister-line Bc 279026-22 responded similarly for grain yields and LAI across plant densities. A growing season × location × plant density interaction indicated various grain yield responses to plant densities under different environmental conditions. Higher plant density significantly improved grain yields for sister-lines and inbred Bc 279, but had limited advantage for inbred Bc 64; these genotype-specific responses could not be always explained by changes in LAI and ASI.

Keywords

• inbred
• leaf area index
• maize
• sister-line
• yield
• yield components