Selection of superior genotypes of Haloxylon aphyllum (Minkw.) L. by multivariate statistical methods

Haloxylon species are adaptable plants that have had satisfactorily results in sand fixation programs. To investigate the genetic potential of progeny of the superior Haloxylon aphyllum genotypes, an experiment with 19 genotypes was performed using a randomized complete block design with three replications at Hossein Abad sand dune stabilization station, Qom, Iran in 2013,. During five years, various morphological traits were evaluated. Combined analysis of variance over years for all traits showed that there was a significant difference between many of  traits among genotypes in all years. Tree height, main trunk diameter and crown diameter showed a positive and significant correlation with each other in all years. Height in the fifth year showed a positive and significant correlation with the height and diameter of the main trunk in the preceding years. The first five factors resulting from principal component analysis with specific values higher than one were entered into factor analysis as the main factors. The first to fifth factors were identified as "crown diameter", "height", "survival and seedling survival", "pest and disease damage " and "powdery mildew infection", respectively. Based on the mean comparison of the four groups obtained from cluster analysis, the groups showed significant differences in all the traits at p < 0.01 or p£0.05. The genotypes in cluster2 were superior to other groups in terms of height, main trunk diameter and crown diameter in all years. This group included genotypes of primary origins of Yazd 4 and Semnan 3, 5 and 6.