Yield components of pearl millet and grain sorghum across environments in the central great plains

Location, year, and water supply influence the relationship between grain yield and yield components of pearl millet [Pennisetum glaucum (L.) R. Br] and grain sorghum [Sorghum bicolor (L.) Moench]. Field experiments were conducted in 2000 and 2001 on a silt loam soil in semiarid western Nebraska and on a silty clay loam soil in subhumid eastern Nebraska to determine how environment (location, year, water regime) influences number of panicles per square meter, kernel weight, and kernels per panicle in determining grain yield of pearl millet and grain sorghum. Grain yield components were examined by analysis of variance, correlation, and path analysis. Four water regimes were used: (i) no irrigation, (ii) single irrigation at boot stage, (iii) single irrigation at mid-grain fill, and (iv) multiple irrigations. Grain sorghum produced from 109 to 212 g m(-1) greater yield than pearl millet in all environments in western Nebraska and 52 to 150 g m(-1) greater yield in eastern Nebraska. Correlation and path analysis direct effects indicated that the number of kernels per panicle (R from 0.36-0.93; P from 0.21-0.45) and kernel weight (R from 0.46-0.89; P from 0.460.73) were associated with grain yield for both crops at both locations, but in the path analysis, kernel weight was more highly associated with grain yield for grain sorghum (P from 0.65-0.73) than the number of kernels per panicle (P from 0.21 and 0.32). Plant breeding and production research to increase pearl millet and grain sorghum yield should consider all yield components, but increased emphasis on kernel weight is merited for grain sorghum.