Path analysis of the productive traits in Sorghum species

Abstract

This research studied the phenotypic correlation coefficients between three Sorghum species, namely forage sorghum S. bicolor Moench. (c. NS-Dzin), Sudan grass S. sudanense L. (c. Zora) and interspecies hybrid S. bicolor x S. sudanense (c. Siloking). The analyses were performed on plant material samples taken from the first cutting, when plants were in the beginning phase of tasseling. The following morphologic traits were studied: plant height, number of leaves per plant, stem leaf weight and mean stem weight. Additionally, their direct and indirect effect on dependent variable green biomass yield was analyzed, for which path coefficients were calculated. This method enables more quality and full insight into relations existing among the studied traits, more precise establishment of cause-effect connections among them, as well as to separate direct from indirect effects of any particular trait on dependent variable, being biomass yield in this case. The analysis of phenotypic coefficients revealed differences in direct and indirect effect of certain traits on dependent variable. Sudan grass had the highest stem (2.281 m) and most leaves per plant (7.917). Forage sorghum had the largest leaf weight per plant (49.05 g), while interspecies hybrid had the highest mean stem weight (80.798 g). Variations of these morphologic traits among species were found to be significant and very significant. Morphologic traits - stem height and weight significantly affected sorghum green biomass yield. Leaf number and leaf portion in total biomass were negatively correlated with yield. Cultivars differed significantly regarding morphologic and productive traits. Sudan grass had the lowest green biomass yield, while forage sorghum and interspecies hybrid had significant yield increase.