Analysis of Complete and Incomplete Block Designs

This study was conducted with the overall purpose of comparing the performance of commonly used incomplete block designs over that of the classical RCBD. Among the incomplete block designs, Lattice design and alpha lattice designs were employed. The comparison was statistically done mainly based on mean square errors and their corresponding CVs for each design. For this purpose, three datasets obtained from SARI were analyzed using CRD, RCBD, lattice and alpha lattice designs. The results of the soybean variety trial data containing 8 treatments having two factors with 3 replications at five different locations were used to assess the performance of RCBD over CRD. The result showed that 31, 3, 53, and 13% precision increased with RCBD over CRD for four sites namely, Hawassa, Areka, Gofa and Bonga, respectively. The CV for CRD is 25.9, 19.2, 7.3 and 12.9% for the four sites above, respectively. While that of RCBD is 22.6, 18.8, 5.9 and 12.3% respectively. This again confirms that RCBD is more efficient than CRD under those tested sites. The implication of the insignificant block effect is there is no need of block for this site.