Ploidy level is one of important factors for plant breeders; therefore models that can predict it are very practical. To estimate of ploidy levels in some species, hybrids and cultivars of Rosa, dimensions of over 500 pollens include pollen length, width and area measured at ABRII. The calculations were carried out in several stages. First, Ploidy levels were regressed with pollen dimensions, after that, pollen area was regressed with pollen length and width. Finally the best models from previous step were tested to estimate of pollen level. In the present study, although a highly positive correlation (r2 ≥0.80, except for 2x) was obtained between pollen length and pollen area, but to predict of ploidy level, the correlation between it and pollen demotions was very weak (r2 ≥0.24). Results of test the best models (with highest r2 and lowest SES) for estimating of ploidy level, despite could be used, but because of the strong correlation among them, were not reliable. تفاصيل المقالة

Water scarcity is an important obstacle to the development and expansion of the urban landscape in the arid and semi-arid regions of the world. Nowadays, organic and artificial materials can be used to reduce water consumption without impairing the quality and quantity of urban landscape. In order to study the effect of mulch type on reducing irrigation interval for a popular seasonal plant in the Middle East, African marigold, an experiment was carried out in Mashhad, Iran during 2016-2017 in which two treatments were applied including mulch type (typical soil as control, palm fiber mulch, plastic mulch, and superabsorbent) and irrigation intervals (3, 6 and 9 days). Some morphological, biological, physiological and biochemical traits were evaluated. Results indicated that the superabsorbent could significantly increase most recorded traits. The palm fiber mulch also improved plant height, flower number, and dry shoot weight. In most traits, the 3-day irrigation interval indicated a significant increase versus the 6- and 9-day intervals, but plant height, flower number, and photosynthetic rate did not differ significantly between the 3-day and 9-day irrigation intervals. The findings show that superabsorbent and at the next level, palm fiber mulch with 9-day irrigation intervals can be suggested for African marigold in the arid and semi-arid climates. تفاصيل المقالة

Estimating urban trees growth, especially tree height is very important in urban landscape management. The aim of the study was to predict of tree height base on tree diameter. To achieve this goal, 921 trees from five species were measured in five areas of Mashhad city in 2014. The evaluated trees were ash tree (Fraxinus species), plane tree (Platanus hybrida), white mulberry (Morus alba), ailanthus tree (Ailanthus altissima) and false acacia tree (Robinia pseudoacacia). Regression analysis of tree height versus tree diameter revealed several models (linear, logarithmic, exponential and power) that could be used for estimating the tree height of these five species. The logarithmic, power and exponential functions provided a good fit to the data on tree height against tree diameter for ash tree (R2 = 0.9 and RMSE = 0.74), ailanthus tree (R2 = 0.92 and RMSE = 0.44) and plane tree (R2 = 0.72 and RMSE = 0.72), respectively. تفاصيل المقالة