GENETIC REPEATABILITY, PHENOTYPIC AND GENOTYPIC COEFFICIENT OF VARIABILITY OFWHITE MAIZE (Zea mays L.) POPULATIONS

A plant breeder’s success in executing any breeding program depends greatly in the presence and amount of genetic variation including the genetic repeatability of the traits of interest. Fifteen white maize populations available at the Institute of Plant Breeding (IPB), University of the Philippines Los Baños (UPLB) were grown and evaluated at the Central Mindanao University (CMU) and UPLB on July and December 2011 respectively, to assess the genetic repeatability and the estimates of genetic coefficient. Different maize characters such as yield, days to anthesis , days to silking, plant and ear height, stand count, number of ears, ear length, ear diameter and shelling percentage were studied. The results revealed that in terms of repeatability, yield (31%), plant height (34.88), ear height (41.84%), and shelling percentage (35.54%) obtained moderate values while the rest of the traits indicated low values. Estimates of phenotypic coefficient of variation (PCV) exhibited moderate values for yield, stand count and number of ears while low values were indicated by all of the traits for genotypic coefficient of variation (GCV). Low magnitude of GCV as well as moderate genetic repeatability for the traits being investigated suggests that these parameters were under the control of environmental effects.