Experience in Use Alpha Lattice Design in Pakistan

Abstract

The agricultural field experiments play an important role for selection and screening of varieties. In Pakistan, these experiments are usually conducted in randomized complete block design (RCBD). It is very difficult to maintain the homogeneity condition when number of varieties exceeds eight or ten in a block. Due to this reason, in scientifically advance countries, RCBD are criticized for large field experiments for large number of varieties and varietal trials are conducted using generalized lattice design called Alpha designs. Nine maize varietal trials were conducted at Maize and Millet Research Institute (MMRI), Yousafwala (Sahiwal, Pakistan) during the year 2004-07 using alpha design. Data from each trial was analyzed using Alpha Lattice and RCBD and the efficiency was calculated using Yates [30] method. The average calculated efficiency was 114% in favour of Alpha Lattice. The detailed examination suggested that alpha lattice design is more effective. Ranking of genotypes in all trials were performed using both designs and differences were observed in ranks. Since the changeover to alpha lattice design did not require major inputs or changes in present field layout except changes in the randomization plan and decreasing the size of block therefore use of alpha lattice design for varietal trials in Pakistan in different crops like maize, wheat, rice etc., is strongly recommended.