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-Džin), 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.

Predmet istraživanja ove studije su fenotipski koeficijenti korelacije tri vrste roda Sorghum, i to krmni sirak S. bicolor Moench. (genotip NS-Džin), sudanska trava S. sudanense L. (genotip Zora) i interspecies hibrid S. bicolor x S. sudanense (genotip Siloking). Analize su urađene na uzorcima biljnog materijala iz prvog otkosa kada su biljke bile u početku faze metličenja. Proučavane su sledeće morfološke osobine: visina biljke, broj listova po biljci, masa listova na stablu i prosečna masa stabla i analiziran je njihov direktan i indirektan uticaj na zavisno promenljivu prinos zelene biomase za koju su izračunati path koeficijenti. Ovom metodom moguće je kvalitetnije i potpunije sagledati odnose koji postoje između proučavanih osobina, preciznije ustanoviti uzročno-posledične veze između njih i razdvojiti direktne i indirektne efekte jedne osobine na zavisno promenjivu osobinu, u ovom slučaju prinos biomase. Analizom fenotipskih koeficijenata uočavaju se razlike u direktnom i indirektnom delovanju nekih pokazatelja na zavisno promenljivu. Najveću vrednost visine stabla imala je sudanska trava (2.281 m), kao i broj listova po biljci (7.917). Najveća masa listova po biljci bila je u krmnog sirka (49.05 g), a najveću prosečnu masu stabla imale su biljke interspecies hibrida (80.798 g). Variranja ovih morfoloških pokazatelja po vrstama bila su signifikantna i vrlo signifikantna. Morfološke osobine, visina i masa stabla značajno su uticali na prinos zelene biomase sirkova. Broj listova, kao i njihov udeo u ukupnoj biomasi ispoljio je negativan uticaj na prinos. Genotipovi su se po morfološkim i proizvodnim osobinama značajno razlikovali. Najmanji prinos zelene biomase imala je sudanska trava. Značajno povećanje prinosa bilo je u genotipova krmnog sirka i interspecijes hibrida.