Effect of different harvest dates on growth characteristics and aloin content of aloe barbadensis miller

To investigate the effect of different harvest stages on growth characteristics of aloe vera (Aloe barbadensis Miller), an experimental was carried out at faculty of agriculture, Tarbiat Modares University in Tehran under greenhouse conditions during 2008 and 2009 years. The experimental design was a completely randomized design with 4 replications. The treatments were three harvest times including before flowering, early flowering and full flowering. Harvest time was arranged in 12, 16 and 18 months after planting. The results showed that the different harvest stages had significant effect on some growth characteristic of aloe vera. The lowest and highest leaf length were obtained at the before flowering and early flowering, respectively. Significant difference was observed between treatments in the weight and diameter of leaf, so that maximum of these traits were obtained in early flowering. Also, harvest at early and full flowering resulted in the highest fresh and dry weight of gel, respectively. However, some traits such as leaf thickness and gel weight to leaf ratio were not affected by treatments. The maximum of leaf number, gel dry weight, gel/leaf weight and powder yield were observed in full flowering. The highest of leaf aloin content was attained in before of flowering. In general, the best time for harvest is early flowering to obtain the economical yield of aloe vera.