GENETIC VARIATION OF SOME TRAITS OF SORGHUM UNDER POPULATION DENSITIES 1- FIELD TRAITS

Abstract

To estimate the extent of genetic variability of some sorghum characters under different plant population, a field experiment was carried out at the experimental field of Dept. of Field Crop science, Coll. of Agric. Univ. of Baghdad during fall 2011 and spring 2012 using three different populations 71.4, 95.2, and 143 thousands plants per ha.. The cultivars were Lelo improved and original. The experiments were factorial and laid out in completely randomized block design with four replicates. Several traits were studied in terms of plants’ performance and variations aspects, observations were recorded on ten plants in each treatment. The values of genetic, environmental variance, genetic and phenotypic coefficient variation, stability and the heritability of sorghum were calculated .The highest genetic variation environmental variation were 27.0, 12.18, 10.11, 6.40 and 5.15 for dates to maturity, number of functional leaves, total dry matters, leaf area index, crop growth rate, stalk dimension, respectively, while the lowest rates were 0.79, 0.89,2.0, 2.33 for stalk dimension, effective filling period, dates to flowering and plant height correspondingly. The highest heritability was for dates to maturity 96% and the lowest was stalk dimension 44%. The highest phenotypic stability was dates to maturity 96% for improved cultivar during fall season. The population density has significantly affected the entire studied traits in both seasons, the improved cultivar was superior in the whole traits under study apart from plant height, there was a significant interaction cultivars X population in fall season for the traits of dates to maturity, crop growth rate, number of functional leaves, and plant height, while the traits of dates to flowering, effective filling period, leaf area index, total dry matters, and stalk dimension were non significant. We conclude that some traits are more affected by environmental factors; therefore we recommend considering the total dry matters and crop growth rate as a criteria in measuring grains’ production ability of sorghum.