The Effects of Planting Date and Plant Density on Phenological Characteristics, Quantitative Yield, Quality, and Yield Components of Guar (Cyamopsis tetragonoloba L.) in Rafsanjan

In order to evaluate the effects of planting date and plant density on phenology, seed yield, and essential oil quality of Guar, an experiment has been conducted during 2018-2019 and 2019-2020 growing seasons. It is a split plot layout based on a randomized complete block design with three replications. Different planting dates are considered as the main factor, including September 5th to February 5th as monthly. Three plant densities are considered as sub-factor (20, 40, and 60 plants in a square meter). The required growing degree- day (GDD) from sowing to physiological maturity ranges between 1802.3 and 2347.9 °d on different planting dates. The highest GDD from sowing to physiological maturity is observed on May 5th. The highest seed yield (3780 kg / ha) and galactomannan yield (1050 kg / ha), 100- seed weight (3.5 g), and oil percentage (17.9%) belong to May 5th + 40 plants per m2. by delaying planting time, 100- seed weight causes oil percentage to drop and the seed yield (40%), galactomannan (68%) and the oil percentage (15%) are observed in September.  Therefore, it seems that the best time and density for planting Alyssum is May 5th with a density of 40 plants per m2.