Shahram Nazari; maryam hossieni; Mehrzad Allahgholipour
Abstract
In order to investigate the effect of seed priming (pretreatment) and coating on seedling characteristics, root morphology and phenological stages of rice, a two-year experiment has been conducted in the Rice Research Institute of Iran (Rasht) between 2020 and 2021. The experiment is performed as a factorial ...
Read More
In order to investigate the effect of seed priming (pretreatment) and coating on seedling characteristics, root morphology and phenological stages of rice, a two-year experiment has been conducted in the Rice Research Institute of Iran (Rasht) between 2020 and 2021. The experiment is performed as a factorial in a randomized complete block design with three replications. Experimental factors include two rice cultivars (Hashemi and Gohar) and the seed pretreatment of rice cultivars in seven levels, including (1) priming with calcium chloride (-1.25 MPa in 24 hours), (2) priming with potassium chloride (1.25 MPa in 24 hours), (3) priming with zinc sulfate (concentration of 0.5 mM in 12 hours), (4) hydro-priming (48 hours) + coating the seeds with calcium chloride, (5) hydro-priming (48 hours) + coating with potassium chloride, (6) hydro-priming (48 hours) + coating with zinc sulfate, and (7) hydro-priming (48 hours as control). The results show that the highest percentage and germination rate has been observed with 99.5% and 0.23 seeds per day under seed priming with potassium chloride in the Gohar cultivar, respectively. The lowest time required to achieve 90% emergence has belonged to Hasehmi and Gohar cultivars through priming with potassium chloride and calcium chloride. The highest root length (with 24.6 cm) has been observed in priming with potassium chloride in the Gohar cultivar. The highest root dry weight in Hashemi and the Gohar cultivars has been 2.14 and 4.9 g, respectively, in priming with potassium chloride. The results also show that the maximum root volume and area are obtained with 43 cm3 and 155.28 cm2 in priming with potassium chloride in Gohar cultivar, respectively. The least time required to achieve maximum tillering, 50% flowering, and physiological maturation takes place in priming treatment with calcium chloride and potassium chloride. Seed priming with potassium chloride and coating with calcium chloride have increased grain yield by 22% and 13%, respectively, compared to the control. The highest biological yield is observed in potassium chloride priming and coating with calcium chloride treatments with 5552 and 5414 kg. ha-1 in Gohar cultivar, respectively. In general, rice seed priming with calcium chloride and potassium chloride promoted plant yield by improving seedling characteristics, root system, and phenological stages.
Shahram Nazari; maryam hossieni; Sajjad Rahimi-Moghaddam; Mohammad Mohammadi
Abstract
In order to determine the phenological differences of some improved rice cultivars in Iran for applying in crop simulation models, an experiment has been conducted in the research farm of the Rice Research Institute of Iran (Rasht) in 2020 as a randomized complete block with three replications. The experimental ...
Read More
In order to determine the phenological differences of some improved rice cultivars in Iran for applying in crop simulation models, an experiment has been conducted in the research farm of the Rice Research Institute of Iran (Rasht) in 2020 as a randomized complete block with three replications. The experimental treatment consist of six rice cultivars (Rash, Anam, Gohar, SA1, SA6 and M7). Results show that the highest development rate can be observed in development rate in juvenile phase and grain filling phase in Anam cultivar. The minimum and maximum time required to start emergence with 3 and 6 days are in Anam and Gohar cultivars, respectively. The maximum time required to achieve maximum flowering and physiological maturity is obtained with 71 and 103 days in Gohar cultivar. The highest flowering period with 19 and 20 days is obtained in late maturing Rash and Gohar cultivars, respectively. The highest growth degree days (GDD) in beginning of grain filling to maturity stage is observed with 401 GDD for M7 cultivar. The highest growth-day for pre-flowering with 1208 GDD belongs to Gohar cultivar. The highest harvest index is obtained with 50.91% in Gohar cultivar. The results also show that the single grain weight under ideal growing conditions with 0.030 g is observed in Gohar and M7 cultivars. The highest plant height belongs to cultivar M7 with 150 cm and the highest total nitrogen uptake is observed in the plant at maturity of Anam cultivar. Overall, the estimated genetic coefficients in different models differ between cultivars and the coefficients vary in the range defined in the model for different groups of maturity. To accurately calculate the genetic coefficients, it is suggested that this experiment should be repeated over several years and in different ecosystems under rice cultivation.