334-5 Sample Size For Estimating Components Of Variance In Maize Experiments In a Tropical Rainforest Ecology.

See more from this Division: ASA Section: Climatology & Modeling
See more from this Session: General Model Applications In Field Research: II

Wednesday, November 6, 2013: 9:05 AM
Tampa Convention Center, Room 37 and 38

Morakinyo A.B. Fakorede1, Abimbola Oluwaranti2, Abidemi Talabi2 and Olufemi Awosanmi2, (1)Department of Crop Production & Protection, Obafemi Awolowo University, Ile-Ife, Nigeria
(2)Obafemi Awolowo University, ILE-IFE, Nigeria
Abstract:
Sample size determination is the act of choosing the number of observations to include in a statistical sample of empirical studies in which the goal is to have sufficient statistical power for making inferences about a population from the sample. The objective of the study reported herein was to determine the optimum sample size (N) for estimating components of variance in maize (Zea mays L.) yield trials conducted in a tropical rainforest location in Sw Nigeria. In a field study involving 100 maize varieties (G), divided into sample sizes of 10, 20,........, 100 with three replications at two locations (L) in each of two years (Y), data obtained for grain yield were subjected to analysis of variance to obtain variances (𝜎2) and coefficients of variation (CV). Most variance components were relatively overestimated when N<50. Estimates of 𝜎g2, 𝜎gy2, 𝜎gl2, 𝜎gyl2 , and 𝜎e2 showed negative quadratic response as N increased (R2= 0.61 to 0.97), stabilizing at about N=60-70. Contrarily, 𝜎yl2 increased linearly as N increased (R2= 0.92) while CV had a positive curvilinear response to N, reaching a peak of about 46% at N=70 (R2= 0.94). It was concluded that relatively large sample sizes are needed for maize studies from which variance components are to be estimated.

See more from this Division: ASA Section: Climatology & Modeling
See more from this Session: General Model Applications In Field Research: II