Genetic Variability and Relative Importance of Nine Phenological and Physiological Characters Studied in Spring Wheat (Triticum aestivum L.)

Experiment was designed to establish a more defi nitive relationship of phenological and physiological traits with yield in wheat using twenty fi ve spring wheat genotypes. Because many of these traits are interrelated, correlation coeffi cient, path analysis and principal component analysis were used to expose these relationships more clearly. Experiment was conducted at the Wheat Research Center, Bangladesh Agricultural Research Institute, Gazipur during the Rabi season of 2009-10. Th e analysis of variances showed highly signifi cant variations among the genotypes for all the traits studied. Th e results revealed that moderate to high heritability along with moderate genetic advances for ground coverage, biomass, grain fi lling duration and grain fi lling rate off er chances of expected response to selection. Th e association of phenological traits with grain yield suggests selecting the genotypes with early maturity and relatively long grain fi lling duration for the development of high yielding wheat cultivars. Signifi cant negative correlation of physiological maturity and canopy temperature with biomass, grain fi lling rate and grain yield revealed that early maturing genotypes having high biomass can change their physiology to suit with variable environments to attain a high grain yield. Path analysis confi rmed physiological maturity, grain fi lling duration and grain fi lling rate as major contributing characters for improvement of wheat grain yield through their direct eff ects. Th e rest of the traits contributed indirectly either via grain fi lling duration or grain fi lling rate. Th e latent vectors obtained from principal component analysis also identifi ed grain fi lling attributes, biomass and physiological maturity as major contributors to the diff erentiation of studied genotypes. Screening of wheat genotypes on the basis of these traits may be more fruitful and may have long lasting eff ect to supplement empirical breeding approach.