جستجوی مقالات مرتبط با کلیدواژه "گیاهان صنعتی" در نشریات گروه "منابع طبیعی"

Tobacco is one of the important agricultural, industrial, and commercial plants that plays an important role in the economies of producer and consumer countries. Broomrape is an absolute parasitic plant that is attached to the roots of many important crops such as tomato, sunflower, cucumber, and tobacco. due to its lack of chlorophyll, it absorbs water and nutrients from the host plant and then reduces the growth and yield of the host plants. In the process of crop breeding, knowledge of relationships between traits is important for indirect selection of traits that are not easily measurable or that have low heritability. So far, few studies have been conducted to investigate the relationship between yield and yield components of tobacco under broomrape stress conditions. The aim of this study was to investigate the relationship between morphological traits and leaf yield (dry weight of leaf) and to determine the important traits effective in increasing the leaf yield of tobacco under normal and broomrape stress conditions.

In order to determine the most important traits affecting tobacco yield, 92 oriental tobacco genotypes were studied in a completely randomized block design with three replications in the presence and absence of broomrape during two years in the Urmia tobacco research center. The leaves of tobacco genotypes were harvested during industrial ripening and sun -cured. Characteristics such as plant height (cm), day to flowering (day), number of leaves, leaf area (square centimeters), fresh weight of leaf (g), dry weight of leaf (g), fresh weight of root (g), dry weight of root (g), and fresh and dry weight of shoot (g) were measured under normal and stressful conditions. Genotypic correlation coefficients were calculated among traits using Restricted (or residual, or reduced) maximum likelihood in SAS software. The stepwise multiple regressions were performed to identify traits affecting the leaf yield under normal and broomrape stress conditions. By path analysis based on genotypic correlation coefficients, the direct and indirect effects of traits affecting leaf yield were calculated. By path analysis based on genotypic correlation coefficients, the direct and indirect effects of traits affecting leaf yield were calculated.

Based on step-wise regression analysis, under the absence of broomrape conditions, fresh weight of leaf and leaf area were explained, and in the presence of broomrape conditions, fresh weight of leaf explained 80 and 73% of leaf yield variation, respectively. Based on path analysis, in both conditions, the fresh weight of the leaf showed the highest direct effect on leaf yield. In regression analysis for fresh weight of leaf in the absence of broomrape, aerial part fresh weight and in the presence of broomrape, aerial part fresh weight, leaf area, day to flowering, and plant height explained 61 and 72 % of fresh weight of leaf variation, respectively. In path analysis for fresh weight of leaf, in both the presence and absence of broomrape conditions, aerial part fresh weight showed the highest direct effect on fresh weight of leaf.

By comparing the results of step-wise regression and path analysis between two normal and broomrape stress conditions, it was observed that fresh weight of leaf is one of the traits that was effective on tobacco leaf yield in both conditions. In both conditions, the fresh weight of the leaf had a high and positive direct effect on leaf yield and explained a high percentage of changes in leaf yield, which shows the importance of this trait in the selection of high-yielding oriental tobacco genotypes. Of course, under normal conditions, the direct effect of the fresh weight of the leaf on tobacco leaf yield was greater than in the broomrape stress conditions. Therefore, the fresh weight of the leaf is introduced as the most important factor in both normal and broomrape stress conditions for increasing oriental tobacco leaf yield in breeding programs.

Cotton (Gossypium hirsutum L.) is one of the oldest agricultural crops, cultivated in over 100 countries with a total production of approximately 25 Mt. This plant's oil, protein, and seed cotton are used in human and animal nutrition, and as the best coating raw material for spinning mills, respectively. Cotton, following sugarcane (Saccharum officinarum) and sugar beet (Beta vulgaris), is Iran's third largest industrial crop and first oil crop. Appropriate agronomic practices, such as plant density and fertilizer management, have a substantial impact on crop development and final yield. Adjusting the distance between cotton rows has been a technique used to increase yield. Typically, cotton is planted in rows separated by 70 to 100 cm. Ultra narrow row (UNR) cotton production has been proposed as a cost-effective method for increasing yields and decreasing production expenses. The fertilizer needs of UNR cotton are not well-established, and the lint yield of UNR cotton relative to that of conventional-row (CR) cotton has been variable. This research aimed to determine the optimal nutrition systems for UNR and CR cotton production. This research was conducted on a private farm in Rudab (Khorasan Razavi province), 60 km from Sabzevar at a latitude of 36° 13',  longitude of 57° 44', and an elevation of 990 m above sea level, during 2019 and 2020. The experimental design consisted of a split plot arrangement of treatments with three replicates in a completely randomized complete block design. The type of fertilizer, which included chemical, organic, chemical+organic, and control (without fertilizer), was regarded as the main plot, while the planting method, which included conventional and ultra-row spacing cultivation, was regarded as the sub plot. Each plot consisted of four 50 cm (UNR) or 25 cm (CR) rows with a length of 4 m and a 20 cm plant spacing. Utilizing a pneumatic seeder and Varamin cultivar, sowing was performed. Before planting, a physicochemical analysis of the experimental soil was conducted. In accordance with the recommendation of the soil test, a uniform dose of phosphorus (150 kg ha-1) in the form of Triple Super Phosphate was applied at the time of sowing as part of the chemical treatment. The recommended amount of N (250 kg ha-1) was applied as urea. One-third of the N was applied at the time of sowing, and the remaining two-thirds were applied in two equal splits at the first and second weedings (50 and 80 days after sowing, respectively). In organic treatment, the rate of poultry manure application was 3000 kg ha-1. In the chemical+organic treatment, each organic and chemical fertilizer was applied at a rate of 50%. At the time of harvest, five plants were randomly selected from the middle rows of each plot and their final height, number of branches, and number of bolls per plant were measured. In order to determine the weight of bolls, 10 bolls were selected at random from the harvested plants and their average weight was determined. The seed cotton yield was harvested at one stage after approximately 90 percent of the bolls had opened. The lint and seeds were separated and weighed separately from the seed cotton. The lint percentage was calculated by dividing the lint weight by the seed cotton weight. The collected data on various parameters were statistically analyzed using SAS (Version 9.4), and the least significant difference (LSD) test at a 5% probability level was used to compare the treatment means. Chemical and organic treatment increased the number of lateral branches (48.7 percent), number of bolls per plant (88.9 percent), and boll weight (131 percent) compared to the control, while organic fertilizer treatment increased lint percentage (42.3 percent). In all nutrition systems, conventional cultivation produced more bolls per plant than ultra-row spacing, and integrated treatment and conventional cultivation produced the greatest number of bolls per plant. In ultra-row spacing and integrated nutrition systems, seed cotton yield was increased by 18.5% over conventional and organic fertilizer and cultivation, and lint yield was increased by 9.28% over conventional cultivation. Overall, the results of this experiment demonstrated that it is possible to produce a satisfactory seed cotton yield by substituting 50 percent of the chemical fertilizers in an integrated system with 50 percent less organic fertilizer and by utilizing ultra-row spacing.