Interrelationship of vegetative characters in black saxaul (Haloxylon aphyllum)

Abstract

Black saxaul (Haloxylon aphyllum) is one of the best options for rehabilitating drought affected desert lands. The species is remarkably adapted to the central dry environment ofIran and a major source of raising pasture productivity of the areas. Progenies of 25 randomly selected black saxaul trees from four populations of the species were studied in a randomized complete block design with three replications. Path analysis was used to study interrelationship of four vegetative characters, plant height, crown diameter, number of lateral branches, and collar diameter. There were substantial differences of the vegetative characters observed between the studied progeny families, implying enough variability to be used in the correlation coefficient estimating and partitioning. Correlation coefficient values varied from 0.202 to 0.935, all statistically significant for all combinations of the studied characters. Path analysis revealed that among the independent characters, crown diameter had the strongest direct effect (0.725) on plant height. Lateral branch numbers showed the lowest and trivial negative direct effect (-0.025) on the dependent variable. Collar diameter showed the strongest positive total indirect effect (0.673) on plant height. It can be summarized that direct and indirect effects of crown diameter and collar diameter mainly positively affect plant height respectively. <br /><br />