فریدون عجم گرد

Low fruit and oil yield are the most important challenges of olive production in the southern and western regions of Iran. For identifying and selecting high-yielding olive cultivars adapted to the environmental conditions of these regions, this research was carried-out in Fars (Kazeroun), Khuzestan (Baghmalek), and Kermanshah (Reejab) provinces. For this purpose, in each province in 2013, an orchard was established with 10 olive cultivars, four trees of each cultivar, using randomized complete block design with three replications. The vegetative and reproductive traits were measured and estimated in 2022 and 2023. The 10 olive cultivars included: Mavi, Keup, Avan, Tokhm Kabki, Dosty, Shiraz, Dehghan, Dakal, Amygdalolia and Konservolia. The results showed that in Kazeroun cv. Keup had the highest fruit yield (22 kg tree-1) and oil yield (3 kg tree-1). In Baghmelek cv. Keup and cv. Konservolia had the highest fruit yield (30 and 25 kg tree-1, respectively), and oil yield (2.9 kg tree-1). In Reejab, cv. Shiraz, cv. Dakal, cv. Tokhm Kabki, cv. Keup and cv. Konservolia had the highest fruit yield, respectively. Also, oil content in fresh matter of the olive cultivars in Reejab was 1.5 to 2.2 percent higher than in Kazeroun and Baghmalek.

In some olive trees despite suitable vegetative growth and reproductive to maturity stage, fruits do not set and development do not occur, due mainly to lack of the adaptability. This research was conducted to determine the optimal time for topworking in olive trees using scions from two common cultivars in each of the six provinces including Fars, Khuzestan, Kermanshah, Lorestan, Ilam and Qazvin in Iran during 2021-2022. Results showed that optimal time for topworking in olive trees in Khuzestan was in the mid-October with cv. Conservolia scion, in Ilam in the second half of October with cv. Conservolia and cv. Diereh scions, in Lorestan in the first half of October with cv. Amygdalia scion, in Fars in the first half of October with cv. Consevolia scion, in Kermanshah in September with cv. Conservolia scion, in Qazvin on May 20th with cv. Conservolia scion.

In some olive trees despite suitable vegetative growth and reaching to maturity stage, fruits does not set and development do not occur, due mainly to lack of the adaptability (Hartman et al., 2017). Topworking has been practiced, for long-time, in some fruit trees such as pecan (Yates and Sparks, 1992) and walnut (Rezaee and Vahdati, 2008). Sometime in a region, a fruit tree variety is planted without assessment of its adaptability and quality properties. Therefore, its performance is not satisfactory and economically profitable. Therefore, changing the variety is necessary. In such a case, topworking-using scions from adapted and high yielding with desirable fruit and oil quality is a strategy to save farmer’s investments. It has been demonstrated that topworking in different olive varieties resulted in better vegetative growth and fruit yield. However, it differed with rootstock variety (Lion et al., 2020). In recent decades olive orchards in Khuzestan and Fras provinces in Iran has been established using olive varieties that are not well adapted and produce low yield with low quality (Ajamgard and Zeinanloo, 2013; Taslimpour, et al., 2016). To change the variety of olive orchard, olive producers should bear high costs. Therefore, topworking can help to graft scions from adapted high yield varieties on the rootstock of existing orchards. The main objective of this research was to determine the optimal time for topworking in olive trees in different regions of Iran, and to recommend the optimal time and suitable scion cultivars for each region. 

The experiments were carried out, during 2021 and 2022, as split-plot arrangements in completely randomized design with three replications. Grafting dates at five levels from Auguest 29th to November 28th (in Qazvin from May) were assigned to main plots, and olive cultivar at two levels (cv. Conservolia was common + one adapted cultivar in each location) were randomized in sub-plots. The grafting success rate and the scion growth were evaluated and recorded. Analysis of variance for data was performed using SAS 9.4 software. Duncan’s Multiple Range Test was employed for means comparsion at the 5% and 1% probability levels. 

The results showed that in Khuzestan province the mid-October was the optimal date for topworking of olive trees. Also cv. Conservolia’s scions had significantly (P ≤ 0.01) greater growth than cv. Avan scions. In Ilam province, the results showed that the maximum grafting success rate achieved in the second half of October with cv. Conservolia nd cv. Diereh scions. In Lorestan province, the grafting success rate, using scions of cv. Conservolia and cv. Amygdalolia were 88% and 80%, respectively, in the first half of October. In Fars province, the success of topworking in the first half of October was 80%, while the vegetative growth of cv. Conservolia’s scion was greater than cv. Amygdalolia. In Kermanshah province, the results showed that the grafting success rate of olive trees was significantly (P≤ 0.05) higher in September with cv. Consevolia scion. In Qazvin province, the results showed that the optimal date for topworking of olive trees was May 20th with grafting success rate of 75% and 94% for cv. Conservolia and cv. Zard, respectively. Hussain et al. (2021) reported that topworking in olive trees in Pakistan was more successful in June-July. Yates and Sparks (1992) and Rezaee and Vahdati (2008) also reported that topworking improved yield and quality of pecan and walnut, respectively.The highlight of the results of this research was determination of optimal time (optimal window) and suitable cultivars (scions) for topworking in olive trees in the six target regions in Iran. 

To select the high yielding and adapted pecan genotypes for Dezful climatic conditions in Iran, 50 seedling trees were evaluated in 2019-2021 in Dezful in southwest of Iran. The results showed that P200-7 and P200-8 genotypes had the largest and smallest nuts with 14.3 and 4.2 grams, respectively. P220-2-1 genotype had the highest and P200-9, and P220-2-5 genotypes had the lowest percentage of blank nuts. Kernel removal was easy in P200-1 and P200-10 genotypes, while it was very difficult in P200-3 and P200-31 genotypes. Fruit ripening time was the earliest in P200-1 and P220-2-5 genotypes and the latest in P200-23. P200-23, P220-1-1 and P200-9 genotypes had the highest yield index with 65, 49 and 39 g cm-2 of tree trunk, respectively. The results of evaluation for heat stress tolerance in pecan genotypes showed that 40 to 70% of the branches of all genotypes were damaged by hot temperatures in the summer of 2021 with 430 hours of temperatures above 45 oC, while the branches of P200- 23 genotype were not damaged. In addition, the results indicated that heat stress damage had significant correlation with yield index (r = 0.311*) and kernel color (r = 0.323*). There was highly significant (r = -0.597**) correlation between shell thickness and kernel removal. The relationship between mean fruit weight and nut length (r = 0.386**) and nut width (r = 0.440**) were also highly significant. Factor analysis showed that nut length, shell thickness, blank nuts percentage, nut weight, yield index and heat stress damage accounted for 67% of the total variance. Finally, P200-23 genotype with high yield index, golden bright kernel color and very high heat stress tolerance, and P220-1-1 genotype with high yield and low percentage of blank nuts were identified as promising genotypes for future supplemental research.

Investigation on adaptability of various olive cultivars in the Khuzestan climate conditions showed that most of the commercial cultivars in these regions were affected by the warm weather so that their yield and oil were strongly reduced. To obtain adapted olive cultivars with high yield and oil percentage, several studies were implemented at Safiabad Agricultural Research Center since 1998. Among genetic resources, a genotype, Avan, that had different oil accumulation process from other genotypes was identified. Preliminary evaluations showed that oil accumulation curve in Avan was double sigmoid and its oil content exceeded 20%, while the oil content in other local cultivars, such as Dezful and Zard, can rarely exceed 10%. For further evaluations, Avan plants were cultivated in Baghmalek, located in the east of Khuzestan province, in 2007. The results of experiments in Baghmalek also showed that the oil accumulation process of Avan had double sigmoid curve. The average yield of 6-years-old trees of Avan was 17 kg with 21% oil content in the fresh fruits. In contrast, the amount of oil content in Mavi (local olive cultivar in Baghmalek) was 10.5% and in Conservolia foreign cultivar this amount was less than 10%. Results of these studies showed that Avan is an adapted olive cultivar for subtropical regions with the ability to produce 5 to 7 tons of fruit and 1000 to 1200 kg of oil per hectare. Using Avan in subtropical regions of Iran such as east of Khuzestan, south of Fars and Kermanshah provinces and similar regions, can increase the yield of oil in olive orchards about 300-400 kgha-1. Avan is tolerant to biotic and abiotic stresses so that no signs of damage by pests and diseases as well as sunburn and drying on its branches have been observed so far.

Pecan is one of the most important nut fruits of subtropical regions that has very high commercial value. In this research, chilling and heating requirements of 16 pecan cultivars (GraTex, Peruque, Comanche 4M, 10J, Wichita 6J, Mohawk, Mahan, Stuart 2J, 3J, Stuart 4J, GraKing, Choctaw, Apache, 6M, Wichita 7J, and Comanche 5M) were carried out at the Saidabad Agricultural Research Center of Dezful during 2014–15. The Utah model and chilling treatments of cuttings were used to determine chilling requirement of cultivars. Heat requirements were determined by growth degree day (GDD) method.The experiment was a randomized design factorial with 16 cultivars and 11chilling treatments for 0, 150, 300, 450, 600, 750, 900, 1050.1200, 1500 and 1800 hours at 4°C±1 and three replications. To calculate the chilling requirement of pecan cultivars in natural conditions, meteorological data of Safiabad station were used. The results showed that chilling requirement was lower than 200­h for 'GraKing', 'Wichita 6J' and ‘Wichita 7J’ and higher than 800­h for 'Comanch 5M' and heat requirement were 416­GDD for 'Apache' and 625­GDD for 'Comanch 5M'. In all of cultivars, heat requirement varied inversely with chilling accumulation hours and they required at least 500­h with >18ºC heating for spring budbreak. Finally, results of this study showed that 'Wichita 6J', 'GraKing', ‘10J’ and ‘Apache’ were suitable for subtropical regions of Iran with 300­h chill units and 'Comanch 5M', ‘GraTex’ and ‘6M’ were suitable for regions with 400-600­h chill units.

The experiment was conducted in 2006 and 2007 to evaluate the efficacy of some herbicides against weeds in tuberose fields in Dezful, Iran. The experimental design was a completely randomized block with 14 treatments and three replications. Treatments included application of paraquat POST at 0.6 kg ai/ha, oxyfluorfen PRE at 0.48 kg ai/ha, ioxynil POST at 0.66 kg ai/ha, trifluralin PPI at 1 kg ai/ha 10 days before planting, trifluralin PPI at 1 kg ai/ha, EPTC PPI at 4 kg ai/ha, oxadiazon PRE at 0.36 kg ai/ha, alachlor PRE at 2.5 kg ai/ha, diuron PRE at 1.6 kg ai/ha, atrazine PRE at 1.2 kg ai/ha, atrazine PRE at 0.8 kg ai/ha one handweeding, 2,4-D haloxyfop-r–methyl POST one week after 2,4–D applicationat 1.44 0.08) kg ai/ha, weedy and weed free checks. In both the years of the experiments, compared to the weedy check, application of diuron and atrazine, with 100% and 97%, were the most effective treatments in reducing the total number of weeds, respectively. 2, 4 - D haloxyfop - r – methyl with 95% was the most effective treatment in reducing total dry weight of weeds. Compared with the weedy check, after weed free check application of atrazine one handweedingwith 5.87 ton/ha-1 was the most effective treatmentinincreasing spike yield. In2006 and 2007, application of ioxynil and atrazine one handweeding had the highest level of corm weight respectively. Considering the results of this experiment, application of each of atrazine PRE at 0.8 kg ai/ha one handweeding, oxyfluorfen PRE at 0.48 kg ai/ha, ioxynil POST at 0.66 kg ai/ha, atrazine PRE at 1.2 kg ai/ha or handweedings throughout the growing season of tuberose are recommended.

Considering the importance of grafted seedlings for the development of pecan orchards in subtropical regions of Iran, and in order to achieve a scientifically practical method of producing grafted pecan seedlings, this project was carried out in Safiabad Agricultural Research Center of Dezful during 2011-12. The project investigated three grafting methods including hot cable, hypocotyl and lateral. For each grafting method, scions of Gratex, Wichita, Choctaw, 10J and Graking pecan cultivars were grafted onto two-year old seedling rootstocks having a diameter of 1-1. 5 cm. Scions were grafted on seedling rootstocks using the hot cable grafting method in 5 times ranging from late October to mid-February and the hypocotyl and lateral grafting methods in five times ranging from early November to early March. The graft success was then investigated four weeks after grafting. The best grafting time was late-January to late-February using the hot cable grafting method and mid-February to late-March using the hypocotyl grafting method. Also, the highest percentage of grafted success was achieved by using Wichita scions (91. 7%), while «10J» had the lowest percentage. The Lateral grafting method was unsuccessful compared to the other two methods and percentages for different cultivars using this method were below 20%.

In order to assess the adaptability of olive cultivars in Northern Khuzestan، an experiment was conducted as a complete randomized block design with 21 cultivars in three replications. Study of flowering of cultivars showed that X-S and Doebli cultivars had 20% (lowest) and 100% (highest) complete flowers، respectively. Results of analysis of variance for quantitative traits showed that cultivar had a significant effect on all studied traits (P ≤ 0. 01). Results of combined analysis (2007-2009) also showed that the effect of year on fruit yield and oil yield/tree was significant (P ≤ 0. 05). Considering the yield and size of trees in different cultivars، the highest fruit yield was achieved in cultivars Conservalia (7549 kgha-1)، Mahzam Abu-Satl (6769 kgha-1)، Kronaieki (6239 kgha-1) and X-D (4022 kgha-1) respectively. Cultivar X-S had the highest and Valanolia had the lowest oil content /fresh weight (18. 1 and 3. 1%، respectively). Based on yield، oil content and size of trees، the highest oil yield /ha was achieved in Conservalia (723 kgha-1)، X-D (404 kgha-1)، Amigdafolia (396 kgha-1) and X-S (373 kgha-1) respectively. Based these results، Conservalia could be suggested as a double purpose cultivar in commercial olive orchards in Khuzestan due to its high yield and good conserving quality.

This investigation was carried out in Safiabad Agricultural Research Center (Dezful-Iran) for two years in order to introduce adapted pecan cultivars in subtropical regions of Iran. Gratex, Peruque, Comanche, 10J, Wichita, Mohawk, Mahan, Stuart, Graking, Choctaw, Apache, 6M and 3J cultivars were evaluated for some of their morphological and phenological characteristics. Among cultivars evaluated in this study, bud break was observed in Apache and Mohawk at mid-March and in 6M and Gratex at early April. Evaluation of flowering in these cultivars showed that Peruque was the only protandrous cultivar and all the other cultivars were protogynous. Pollination overlap was observed in Graking, Mohawk, Wichita and 3J cultivars just for 1-3 days while the other cultivars were completely dichogamous. Graking had the biggest and Apache had the smallest fruit among cultivars in this study. Gratex and Mahank had the highest and lowest percentage of kernel, respectively. Peeling was very easy in Choctaw, 10J and Gratex cultivars and very hard in M6 and Mohawk. Comanche and Stuart had the highest and lowest kernel oil content of 78% and 60%, respectively. Finally, five cultivars including Gratex, Graking, Wichita, 10J and Choctaw were recommended as superior cultivars while Peruque and Graking were recommended as pollinators for all the other cultivars in this study.