نشریه زراعت دیم ایران
سال نهم شماره 1 (بهار و تابستان 1399)

In this study, the methods of genotype × trait (GT) and genotype by yield× trait biplot (GYT) were used to identify interrelationships between different traits and the best wheat genotypes selection based on multiple traits. During the 2017-2018 cropping season, fifteen cultivars/ promising lines along with a durum wheat cultivar, Zahab, were tested on field’s farms at two sites, Delfan and Khorramabad (Imanabad region). The results of ANOVA for the evaluated traits showed significant differences among genotypes for plant height, day to heading and maturity, grain yield and harvest index. According to the mean grain yield of the genotypes at both experimental sites, the maximum grain yield was obtained for Varan, Sadra, Ivan and Azar2/Sabalan/… genotypes with mean grain yield of 3374, 3207.5, 3054 and 2866.5 kg/ha, respectively. Based on GT-Biplot polygon, Varan and Sadra cultivars were displayed high GY, SSM, TKW and PH at two experimental sites. The vector view of GT biplot showed high correlation between grain yield with 1000-kernel weight, plant height and harvest index at experimental sites. Based on results of GYT biplot, Varan and Sadra cultivars were the best genotypes in combining grain yield with all traits evaluated. The high correlations between combinations of 1000-kernel weight and plant height with grain yield were observed, suggesting the importance of these traits in combining with grain yield to increase genotypes productivity.

Sufficient nutrition on crop is one of the most important factors for improving wheat grain yield and quality. To evaluate the effect of Nitrogen (urea) by different foliar application treatments and top dressing fertilizer on yield and yield components of wheat, a strip split plot design based on RCBD with three replicates was conducted under rainfed and supplemental irrigation conditions during two cropping seasons 2016-17 and 2017-18. Experimental treatments were: A: control (without application of N), foliar application of urea during booting, booting + grain filling and grain filling stages in main plot, B: different wheat cultivars including in sub plots, C: top dressing fertilizer including application and non-application (control) in strip factor were considered. Based on combined-ANOVA, the effect of year under rainfed condition was significant for grain yield, biological yield, number of grain per spike, number of spike/m2, harvest index and spike length. Application of N as top dressing fertilizer had significant effect on all studied traits in both rainfed and supplemental irrigation conditions. Also, foliar application of N in the all three stages increased BY, GY, 1000-grain weight, NGPS and SL. In terms of GY under rainfed conditions, Paraw cultivar had the most grain yield and yield components with the highest biological yield. Under supplemental irrigation condition, Baran cultivar had the highest grain yield, while Azar-2 produced the lowest gain yield in both rainfed and supplemental irrigation conditions.

In order to identification and survey of weed species in rainfed wheat fields of Maragheh, sampling was done in 50 fields followed a "W" pattern by 20 quadrats 0.25 m2 for each field during the wheat tillering to stem elongation stages in spring 2018. Ranking of weeds were done with relative dominant index. Data on weeds and environmental factors of all fields were analyzed through redundancy analysis (RDA) and weed species distribution and their relationships with environmental factors displayed in ordination diagrams. Overall, 81 weeds species belonging to 20 plant families were identified in these fields. The sunflower, grasses, and mustard families with 14, 13, and 11 weed species, respectively were dominant plant families in these fields. Cow soapwort (Vaccaria grandiflora), Russian knapweed (Acroptilon repens), sticky willy (Galium aparine), and false carrot (Turgenia latifolia) with 30.45, 29.51, 26.49, and 25.30, respectively were dominant weed species. Among observed weeds, 61.73% were annual and 38.27% were perennial. Also, 83.95% of weeds were dicotyledonous and 16.05% of them were monocotyledonous. RDA was done with frequency of 60 frequent weed species (observed in more than 3 fields) and sampling sites latitude, longitude, and elevation using CANOCO (Version 4.5). RDA results showed that site latitude and then elevation had maximum effect on weed species distribution. The first and second RDA axes described 77.9% of variations in weeds distribution affected by surveyed environmental factors. Cow soapwort and Russian knapweed had maximum presence in fields with highest elevation, but Iranian knapweed (Centaurea depressa) was observed in fields with minimum elevation.

Growing season is the part of a year with suitable temperature and sufficient moisture for crop normal growth. Whit recognizing the growing period in the region and crop water requirement can adopt appropriate management to better compromise crop with climate limitations in rainfed agriculture. In the research, the length of growing period in Abhar area using linear interpolation and climatic data was investigated. Besides that, crop water requirement, potential yield, and yield reduction in heavy, medium, and light soil texture for rainfed winter wheat and spring barley were studied using FAO method and long-term synoptic information. Results showed that the length of growing period in terms of moisture was estimated 179 days that its beginning and ending were 1st November and 28th April, respectively. But, considering air temperature and crop critical temperature, from beginning of December to end of February was not involved in the growing period. Therefore, the length of the growing period was declined to 89 days. The humid period was calculated 38 days that its begging and ending were 9th December and 15th January, respectively. Efficient rainfall, crop water requirement, and crop irrigation requirement during winter wheat growing cycle were 89, 611.2, and 522.4 and during spring barley growing cycle were 41.8, 390.3, and 348.5 mm, respectively. Generally, the average, minimum and maximum final yields were estimated for wheat by 1.26, 0.50 and 1.90 Mg ha-1 and for barley by 0.48, 0.18 and 0.80 Mg ha-1, respectively. To mitigate the negative consequences of the shortness of region growing period and its incomplete overlapping with crop growth cycle, measures such as optimum rainwater harvest, sowing in time, improving water use efficiency, selecting drought-resistant or short-season cultivars, and using conservation tillage practices to maintain water are suggested to reach sustainability in rainfed crop production.

In order to investigate the effects of different levels of tillage and nitrogen fertilizer on wheat yield in rotation with chickpea and introduce best economic treatment, a split plot experiment based on  randomized complete block design with 3 replicates during 4 years were conducted. tillage methods (minimum tillage and no tillage) were located in main plots and different nitrogen fertilizer application (without nitrogen application, 30, 45 and 60 kg/ha pure nitrogen) was located in sub plots. The results showed that tillage treatment did not have a significant effect on grain yield. The effect of tillage treatment on soil moisture was significant and in without tillage, soil moisture was higher than low tillage. The results of the economic evaluation showed that no tillage treatment with 60 kg/ha of pure nitrogen fertilizer with The ratio of the difference in the present value of the interest to the difference in the present value of the expenses, equivalent 43.6 was recognized as the best financial treatment. In the treatment without tillage and 45 kg/ha of pure nitrogen this ratio was 41.2 and was ranked second. Finally, due to the importance of designing cultivation systems and with respect to environmental principles and ecosystem services and in order to increase the sustainability and productivity of production and production of healthy and high quality products, without tillage treatment and consumption of 45 kg/ha Nitrogen (T0N45) as the most economical treatment in areas Cold rain is recommended.

This study was performed for the evaluation of the effect of Azotobacter and nitrogen levels on morphological traits, plant nitrogen uptake rate, seed oil and yield and nitrogen use efficiency of six safflower (Carthamus tinctorius L.) genotypes under rainfed conditions, as a factorial experiment based on a randomized complete block design with three replications, during 2015-2016 and 2016-2017 growing seasons. Experimental factors were seed inoculation with Azotobacter and urea chemical fertilizer application (Non-inoculated with Azotobacter and urea as control, seed inoculation with Azotobacter, inoculation with Azotobacter + 50% N and inoculation with Azotobacter + 100% N) and six genotypes of safflower (312-S6-692, PI-401478, PI-253895, PI-306974, padide and sina). The combined analysis of variance for two years showed that the main effects of fertilizer and genotype had significant effect on all of the traits. The interaction of nitrogen × genotype was significant on root volume, leaf are index, number of lateral branches, grain nitrogen, straw nitrogen and total nitrogen uptake. Result showed that inoculation with aztobacter + 50% use of nitrogen had higher nitrogen use efficiency than aztobacter + 100% use of nitrogen. However, there was no significant difference in the grain yield between those fertilizer treatments. Sina with the highest values of grain yield (1203 kg.ha-1) and nitrogen use efficiency (17.49 kg.kg) was considered as superior variety. Therefore, with the aim of reducing environmental pollution by excessive use of N chemical fertilizer, application of Azotobacter is suitable for safflower production under daryland conditions.