مجله علوم گیاهان زراعی ایران
سال پنجاه و ششم شماره 1 (بهار 1404)

Water deficiency is an effective method to optimize water consumption, particularly in arid and semi-arid regions, making it a highly desirable approach for reducing water use. Additionally, growth regulators can serve as a supplementary strategy for plants under water deficiency conditions. This research evaluated the effects of yeast extract and 24-epibrasinolide under various irrigation conditions. It was conducted as a factorial split-plot experiment based on a randomized complete block design with three replications. The treatments included different irrigation intervals (8, 12, and 16 days), spraying of yeast extract (0 and 12 g/L), 24-epibrassinolide (0, 5, and 10 μM). During the 12 and 16-day irrigation periods, seed yield decreased by 21.80% and 25.61%, respectively, compared to the 8-day irrigation period. However, foliar spraying with 10 μM 24-epibrassinolide and yeast extract increased seed yield by 10.14% and 20.28%, respectively. Additionally, total chlorophyll content decreased by 15.71% and 47.54% during the 12 and 16-day irrigation periods compared to the 8 days. The application of 10 μM 24-epibrassinolide along with yeast extract increased chlorophyll content by 57.69%. In the 16-day irrigation cycle, the activities of ascorbate peroxidase and catalase enzymes increased by 314.63% and 194.73%, respectively, using 10 μM brassinolide and yeast extract. Additionally, the levels of proline, flavonoid, and malondialdehyde increased by 52.85%, 109.89%, and 96.33%, respectively, compared to the 8-day irrigation period. This research demonstrated that applying 12 g per liter of yeast extract combined with 10 μM brassinolide effectively increases seed yield and mitigates the impact of low irrigation in cowpeas

In order to determine the best planting date and time for hilling up operation in sugarcane, a split-plot experiment was conducted based on a randomized complete blocks design with three replications at the research farm of Khuzestan Sugarcane & by-Products Research and Training Institute, during the 2021-2022. Experimental treatments include the planting dates of August 11th, August 24th, September 6th and September 19th 2021 as the main plot and Hilling up operation at three levels (no Hilling up, Hilling up on November 11th and Hilling up on February 9th 2021) as the sub plot. The experiment was carried out in one year and on the plant cultivar CP69-1062. The results showed that the highest cane height (189 cm), number of millable canes (169,854 canes. ha-1) and the yield of sugarcane (94.78 tons.ha-1) were related to the planting date of August 20 th. Under Hilling up levels, cane yield of no Hilling up and Hilling up on November 11th (90.4 and 87.1 tons. ha-1, respectively), did not differ from each other and was higher than the Hilling up treatment on February 9th. Also, it was observed that the treatment of not Hilling up had the highest amount of complete cane (2138 kg.ha-1), chopper cane (1095 kg.ha-1), trash cane (512 kg.ha-1) and base cane (1662 kg.ha-1).

One of the critical stages in plant breeding programs is the genotype-by-environment interaction and the selection of high-yielding and stable genotypes. In this research, 20 pure rice lines were evaluated in a randomized complete block design with three replications over three years (2020, 2021 and 2022) at the Rice Research Institute of country (Rasht) for identification of high-yielding and stable genotypes. The analysis of variance of the main effects of year, genotype and genotype-by-year interaction showed significant differences at 1% probability level. The results of stability analysis using the GGE-biplot method showed that the first two components described a total of 97.43% of the variation in genotype and genotype-environment interaction, indicating the validity of the GGE-biplot method in explaining performance variations of genotypes. Based on the biplot polygon, lines 9, 19, 2, 6, 3 and 9 were identified as the most responsive lines. In the genotype-focused scaling diagram, line 9 was the closest to the genotype ideal line. The analysis of other characteristics of the studied lines revealed that lines 9, 10 and 13 exhibited shorter maturity time and plant height, along with a more moderate and desirable cooking quality compared to other lines. Therefore, these three lines are recommended for further experimentation to introduce a new variety

Cd stress, as one of the most significant abiotic stresses, negatively affects the growth and performance of maize. In this study, the diversity and relationship between yield and various agromorphological characteristics of maize lines in 95 genotypes were investigated using a RCBD with three replications under two conditions: non-stress and Cd stress, in a pot experiment conducted in an open area at the Agricultural Research Station of Jiroft during two cropping years. Under stress conditions, a cadmium chloride solution with a concentration of 30 mg.L−1 was applied at two stages of plant growth (at the six-leaf stage and the appearance of the first male flowers). In both conditions, the results revealed a positive and significant correlation between grain yield with grain number per main ear, 1000-grain weight, the grain number per row, and ear wood weight. In principal component analysis, the first nine and eight principal components were identified under both non-stress and stress conditions, explaining 79.26% and 76.42% of the total diversity of genotypes, respectively. In both conditions, the first component was identified as the phenology component, while the second and third components were recognized as the yield component, yield components, and the dimensional component, and plant type. The present study showed that yield traits, yield components, and phenological characteristics are key indicators for demonstrating the diversity and differentiation among different maize genotypes under Cd stress. This diversity can be utilized in maize breeding programs to enhance tolerance to Cd stress and achieve other breeding purposes such as earliness.

In order to investigate the effect of cold plasma on the seed germination and emergence of Black Cumin, an experiment was conducted in 2022 in the form of a completely randomized design with four replications on two ecotypes of Black Cumin, Dargaz and Yazd. The treatments include the control treatment (without cold plasma), cold plasma treatment based on gliding arc in 30s, 1, 2 and 3 minutes on Dargaz ecotype; and control treatment, radio frequency (RF) plasma treatments with power of: 50W in 5 minutes, 50W in 15 minutes and 100W in 5 minutes and cold plasma treatment based on Surface dielectric barrier discharge (SDBD) in 10, 15 and 20 seconds on Yazd ecotype. The results showed that in Dargaz ecotype, gliding arc treatment in 3 minutes with 67.5% and in Yazd ecotype, RF treatment with a power of 50W in 5 minutes with 68.5% achieved the highest germination percentage. In Dargaz ecotype, gliding arc treatment in 30s and in Yazd ecotype, SDBD treatment in 20s caused the maximum seedling length. In general, the results of this research showed that cold plasma improved the seed germination and morphological characteristics of Black Cumin seedlings in both ecotypes.

Increasing the application of chemical fertilizers and their high leaching rates leads to decreased consumption efficiency and environmental pollution. Therefore, soil nitrification inhibitors could enhance absorption efficiency and reduce the loss of urea fertilizer. intercropping is one of the strategies to increase biodiversity and improve production efficiency per unit area, Therefore, the intercropping of maize and forage sorghum was conducted in fields with different fertilizer and soil tillage systems in 2021-2022. The treatments included two tillage systems (conventional and no-tillage), three fertilizer types (control, urea, and urea + nitrapyrin). The cropping patterns were monoculture of forage maize and sorghum, and alternatives intercropping). The results showed that the highest plant height (268.83 cm), fresh forage weight (8.67 kg. m-2), and absorbed light (1135.32 MJ.m-2) were obtained in conventional tillage and urea + nitrapyrin treatment. The highest LER (1.14) and chlorophyll content (70.18%) were achieved in conventional tillage and urea + nitrapyrin treatment. In general, the results indicated that conventional tillage compared to no-tillage systems had higher performance in traits. This superiority is attributed to better root penetration and water infiltration. Application of nitrapyrin, combined with maintaining urea in the root zone, enhanced absorption and overall performance. Intercropping demonstrates superiority over monocropping, which could significantly contribute to reducing water consumption, especially considering sorghum's drought resistance.

To investigate the effects of different intercropping patterns of Persian clover and crimson clover under two planting densities on forage yield and quality, a two-year experiment (2020-2022) was conducted in Shahrekord using a factorial arrangement in a randomized complete block design with three replications. The experimental factors included five cropping systems with ratios of 0%-100%, 100%-0%, 75%-25%, 25%-75%, and 50%-50% and two planting densities (20 and 25 kg seed ha-1). The results showed that the highest dry matter digestibility (63.11%), dry matter intake (2.79%), total digestible nutrients (58.61%), ash (6.05%), water-soluble carbohydrates (6.68%), relative feed value (136.4%), net energy for lactation (1.43 Mcal kg-1), and plant height (67.79 cm) were obtained in the intercropping system of 50% Persian clover + 50% crimson clover with a planting density of 20 kg ha-1. The highest dry forage yield (6.60-ton ha-1) was obtained in the crimson clover monoculture with a planting density of 25 kg ha-1, whereas the maximum protein yield (0.85-ton ha-1) was obtained in the 25% Persian clover + 75% crimson clover cropping system with a planting density of 20 kg ha-1. Overall, to achieve both optimal forage yield and quality, the intercropping system of 50% Persian clover + 50% crimson clover with a planting density of 20 kg ha-1 is recommended.

Cold is one of the important environmental factors involved in the survival, growth and performance of crop plants. In this research, the traits related to cold tolerance were evaluated in the lines resulting from crossing Norstar (cold-tolerant) and Pishtaz (cold-sensitive) wheat (Triticum aestivum L.) in the vegetative stage (December, January and February) under field conditions. Norstar parent and lines L2 and L1 showed the highest LT50 degrees (-22, -20 and -18 ºC, respectively) in January. A decrease in cold tolerance was observed simultaneously with the beginning of the reproductive phase in February in all genotypes. Damage indices such as H2O2 and MDA were lower in winter lines than in spring lines. The content of H2O2 in the Norstar parent and lines L1 and L2 was low during cold acclimation periods, but increased with the transition from the vegetative stage to the reproductive stage. The high level of MDA in February, especially in spring genotypes, indicated the presence of oxidative stress and MDA. The activity of acetyl coenzyme A carboxylase and Δ12 desaturase genes increased with the continuation of the cold acclimation period, so that the highest increases were observed in winter lines and in January. Therefore, the genotypes with vernalization requirement by adjusting the traits related to cold tolerance in the vegetative stage have higher tolerance to cold stress.