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Abstract Background Chickpea is a key pulse crop grown in the spring in dryland regions. The cold resistance potential of chickpeas allows for the development of genotypes with varying sowing dates to take advantage of autumn and winter rainfall, particularly in dryland regions. In this study, we assessed grain yield, plant height, 100-seed weight, days to maturity, and days to flowering of 17 chickpea genotypes in five autumn-sown dryland regions from 2019 to 2021. Additionally, the response of selected chickpea genotypes to cold stress was examined at temperatures of -4 °C, 4 °C, and 22 °C by analyzing biochemical enzymes. Results Mixed linear model of ANOVA revealed a significant genotype × environment interaction for all traits measured, indicating varying reactions of genotypes across test environments. This study reported low estimates of broad-sense heritability for days to flowering (0.34), days to maturity (0.13), and grain yield (0.08). Plant height and seed weight exhibited the highest heritability, with genotypic selection accuracies of 0.73 and 0.92, respectively. Moreover, partial least square regression highlighted the impactful role of rainfall during all months except of October, November, and February on grain yield and its interaction with environments in autumn-planted chickpeas. Among the genotypes studied, G9, G10, and G17 emerged as superior based on stability parameters and grain yield. In particular, genotype G9 stood out as a promising genotype for dryland regions, considering both MTSI and genotype by yield*trait aproaches. The cold assay indicated that − 4 °C is crucial for distinguishing between susceptible and resistant genotypes. The results showed the important role of the enzymes CAT and GPX in contributing to the cold tolerance of genotype G9 in autumn-sown chickpeas. Conclusions Significant G×E for agro-morphological traits of chickpea shows prerequisite for multi-trial analysis. Chickpea`s direct root system cause that monthly rainfall during plant establishment has no critical role in its yield interaction with dryland environment. Considering the importance of agro-morphological traits and their direct and indirect effects on grain yield, the utilization of multiple-trait stability approches is propose. Evaluation of chickpea germplasm reaction against cold stress is necessary for autumn-sowing. Finally, autumn sowing of genotype FLIP 10–128 C in dryland conditions can led to significant crop performance.

IntroductionChickpea is the third most important grain legume and its seeds contain protein that is an important energy source for human. Drought diminishes crop yields and carries the potential to result in total crop failure. However, chickpeas are renowned for their superior drought tolerance compared to many other cool-season legumes. Given that water availability is the primary constraint on growth in arid conditions, optimal yields and crop production occur when plants efficiently absorb the limited soil moisture available. This feature will only be achieved through the compatibility mechanisms associated with the root system. Chickpea have a direct and deep root system that helps the plant absorb moisture from the lower layers of the soil. Therefore it has led to the prosperity of its cultivation in rainfed areas. Water absorption by the plant depends on the size of the root, its activity and distribution in the soil. Therefore, it seems that the understanding of plant root traits is necessary to further understand the mechanisms of drought resistance. In general, few studies have been done on the diversity of legume roots. Therefore, this research was carried out with the aim of investigating the diversity of root morphological traits of chickpea lines in order to use these traits to select drought-tolerant chickpea lines. Materials and MethodsThe plant materials of this experiment included 39 chickpea lines of Icarda origin, which were taken from the Kurdistan Research Center. The experiment was conducted as a completely randomized design with four replications in the research greenhouse of Ilam University. Seeds were implanted in PVC tubes with a diameter of 10 cm and a length of 60 cm. A drip irrigation system was designed in such a way that an emitter was located inside each tube. With this method, the test tubes were in favorable conditions. In the greenhouse the temperature was under control and had a temperature of 25 degrees Celsius and an average humidity of 70% and the plants used natural light without any additional light. After 35 days of seed germination traits were measured. For this purpose, first the aerial parts of the plant were separated by scissors. After separating the roots from the PVC tubes, they were placed in ethanol with a concentration of 98% and after being transferred to the laboratory, they were stored in the refrigerator, then the traits were measured. Variance analysis of traits and average comparison of data was done with Duncans multi-range test using SAS software version 9.1. Results and DiscussionAll the measured traits had a good variation range among the studied chickpea lines that these results are consistent with previous studies. None of the lines showed superiority for all root traits. Line FLIP07-20C having the longest root length, can benefit from the water available in a larger volume of the soil profile. In the examination of rooting depth in grain legumes, such as chickpeas, it was observed that root length remains relatively stable across a broad spectrum of soil moisture levels. Root length is considered a crucial parameter in plant growth, as researchers posit that the length of roots per unit of soil volume is the most effective characteristic for assessing water and nutrient absorption by plants. In our current investigation, a significant disparity was noted between the highest and lowest root volumes. Root volume stands out as one of the plant's key attributes for absorbing water and nutrients. In this research, line FLIP 82-150C had the highest and line FLIP97-706C had the lowest specific root length. The specific root length is one of the important traits in showing the efficiency of the root in absorbing water and resistance to drought. When faced with drought stress, the plant assigns more dry matter to the root system in order to increase the absorption ability of the roots; as a result, there are changes in the morphological characteristics of the roots, such as an increase in the specific length of the root. The highest root density was observed in line FLIP09-149C. root density is a trait that is affected by root weight and volume. In the condition of drought stress, the decrease in root volume caused an increase in root density and at the end of the growth period, the decrease in root dry weight was more than the decrease in its volume, which ultimately led to a decrease in root density. Studies have indicated that as humidity decreases and soil depth increases, there is a notable decrease in root density. Overall, the findings from this research offer foundational insights for advancing efforts to enhance root characteristics, thereby mitigating drought and enhancing the resilience of chickpea varieties to drought stress. ConclusionsThe results showed that Line FLIP07-20C had the highest root length, root length density and root water content compared to other lines, but none of the lines were superior in terms of all root traits. The obtained information about the characteristics of the roots of the studied lines can be used to improve drought-resistant chickpea lines.

IntroductionChickpea is one of the most important pulses in the world and it plays a key role in feeding of people in Iran. Iran is one of the original centers of chickpea. This plant has a significant genetic diversity and has favorable conditions for breeding and introducing new cultivars in Iran. According to FAO reports (2014), the average grain yield of chickpea in Iran with a cultivated area of 565 thousand hectares and an average yield of 557 kg per hectare is very low compared to the average of the major countries producing chickpeas. In order to solve this problem, identification of the initial variety of lines and cultivars to start the program is of particular importance. In fact, three factors of heredity, high diversity and severity of selection are effective factors in increasing the response to selection. In this regard, there are various methods for estimating genetic variation in plant species, one of the most important of these methods is multivariate analysis. It is necessary to use these methods for the classification of germplasm and the analysis of the genetic relationships existing between the modifying materials. Among the various methods of multivariate analysis, the principal component analysis, factor analysis, cluster analysis and decomposition function analysis are among the most important of these methods. In fact, one of the important goals of an outbreak is to select the best genotypes. In order to achieve this goal, the studied population should have a significant variation in terms of the characteristics studied, which knowledge of this diversity requires evaluation of the germplasm. Materials and MethodsThis study included 20 chickpea (Cicer arietinum L.) promising lines were planted in a randomized complete block design with three replications in 2013 growing season. To evaluate the diversity of lines based on important agro-morphological traits and to achieve the desired goals, various statistical methods including principal component analysis, factor analysis, cluster analysis and decomposition function analysis were used. Genotypic coefficient of variance (GCV) and phenotype coefficient of variance (PCV) using genotype variance and phenotype variance, respectively, were calculated. All calculations and statistical analyzes such as component analysis, cluster analysis, and decomposition function analysis were performed using SPSS and Minitab software. Results and DiscussionThe lowest and the highest coefficient of genotypic changes were related to day physiology (2.66%) and 100-seed weight (49.76%). The results showed that the three main first components explained 76% of the total variance of the traits totally. The first and second components were named as "component of grain yield increase" and "vegetative growth component". The results of factor analysis were consistent with the results of the principal component analysis. In order to cluster the studied lines and for their grouping based on the studied traits, Ward method and Pearson’s square distance matrix were used. According to the cluster analysis, the genotypes were located in three distinct groups, so that the second and third clusters had the highest genetic distance and they were recognized as “yield clusters" and "vegetative growth cluster", respectively. Therefore, crossing between the two above mentioned-groups, will result to high artificial diversity in the future generations. According to the cluster analysis, the lines were divided into three separate clusters. Discriminant function analysis confirmed the cluster grouping completely. In a study, nineteen chickpea lines and five genotypes of wild chickpea (Cicer veticulatum) were classified into three distinct groups using cluster analysis, so that wild-type genotypes in one group and two lines of cropping lines were grouped separately from other lines. Ganjali et al, (2009), applied the multivariate bi-plot analysis to evaluate the variation in chickpea germplasm for drought resistance. ConclusionThere was a remarkable genetic diversity for the current germplasm, therefore existence a high level of genetic diversity and a remarkable GVC for the trait of 100-seed weight indicating that this trait can be used as a suitable character for yield improvement in the germplasm and under this experiment conditions. Finally, selection for high levels of biomass, pod number per plant and seed number per plant, and a low amount of main branches number, will increase the grain yield in the future breeding program.

IntroductionPulses play an important role in human nutrition. Among the pulses, chickpea (Cicer arietinum L.) is the valuable food in terms of carbohydrates and protein. Chickpea with more than 8 million tons per year ranks third crop in the world. It is planting in 48 countries with more than 12.11 million hectares. The aim of any breeding program working for unpredictable and rainfed environments is to develop varieties with high and stable yields. Breeders take advantage of the selection for several traits to achieve maximum economic yield. The selection of genotypes based on indices using yield components was used by breeders for a long time. Breeders were believed that obtaining a linear function of traits or selection index could lead the selection of genotypes with better genetic values but including economic weights in this function have been expressed by many researchers. Simultaneous selection using characteristics with important and heritable economic values is more effective. Crop yield is a function of multiple interrelated variables and cannot be defined only by a single-variable equation. One of the most effective method is boundary lines that was introduced by Feiziasl et al, (2003 and 2010) for the first time to determine the optimum levels of plant (dryland wheat) characteristics and yield stability analysis. In this paper, “Boundary Lines” and averaging methods and PCA are used to determine optimum levels for some traits of dryland chickpea in cold areas, Iran. Materials and MethodsMore than 8000 data for each trait were collected from national and international trials conducted in Dryland Agricultural Research Institute (DARI) experimental stations in Maragheh, Kurdestan, Zanjan, Uromieh and Ardabil from 1996- 2016. The traits were days to flowering, days to physiological maturity, grain filling period, plant height, 100 seed weight and grain yield. The Excel software was used to develop a scatter diagram showing therelationship between each trait with grain yield in each location. Two methods were used to determine the optimum value for a given trait. One is based on the boundary lines method where the maximum grain yield and the optimum value for the trait considered coincide with the crossing point of the two boundary lines. “Boundary Lines” method was used to determine the maximum limit for each trait. The scatter diagram is surrounded by two regression lines, one on the left and the other on the right called boundary lines. Then Maximum yield was obtained at the intersection of both boundary lines. The other approach, called averaging method, is based on subdividing the data into two groups: high and low yielding groups. Results and DiscussionThe boundary lines method determined the optimum levels for days to flowering, days to physiological maturity, grain filling duration, plant height and 100 seed weight which were 56.2 days for spring and 89.2 days for autumn, 89.4 days for spring and 120.8 days for autumn, 33.1 days, 29.8 centimeters and 34.0 grams, respectively. By averaging of high yielding group method, optimum values for days to flowering, days to physiological maturity, duration grain filling duration, plant height and 100 seed weight characteristics were 75.6 days, 108.8 days, 37.7 days, 30.2 centimeters, and 26.0 grams, respectively. The optimum values for plant height and 100 seed weight were almost the same in both methods while for other traits optimum levels were so different. ­Principle component analysis (PCA) show that, the most important traits to select high yielding chickpea varieties were days to flowering, days to physiological maturity, and plant height. These methods could help breeders to determine the range of optimum value for traits determining the adaptation of genotypes to a given environment. Boundary lines method is more reliable to determine of characteristic’s optimum levels in comparison with the averaging method. ConclusionIt can be concluded that, determining the optimum levels of some dryland chickpea characteristics were closely equivalent in boundary lines and averaging methods while, for some characteristics, the estimated optimum levels by these methods were so different. Because boundary lines method is considered the data distribution process and gap data in databank, therefore, its estimations for the optimum levels of the characteristics are more accurate and reliable than the averaging of the high yielding group.

Chickpea (Cicer arietinum L.) is commonly grown under dryland conditions during spring on soils that conserve moisture from the preceding season, in Iran. Seeding rate can have a major impact on production of chickpea. A field trial was carried out at Gerizeh Agricultural Research Station of Kurdistan (35°16’N 47°1’E), west of Iran during 2015-16 cropping season. The trial was carried out in a factorial experiment based on randomized complete block design (RCBD) with three replications. The factor "A" was plant densities, consisting of 15, 25, 35, and 45 plants m-2 and factor "B" was chickpea varieties (Kaka, Pirouz, ILC 482, and Samin). The effect of chickpea varieties and interaction between plant densities and varieties were significant on all measured parameters, except on number of seed per pod, plant height and height of first pod. Also, the effects of plant densities on seed yield, 100 seed weight, leaf chlorophyll index, protein content, plant height, and number of branch per plant were also significant. Results showed that an increase in plant density resulted in significantly higher seed yield per hectare. The mean yields indicated the sensitivity of "Samin" cultivar to high plant population, while it was, suitabilie to cultivar "ILC482" (45 plants m2). "Kaka" and "Pirouz" produce near optimum yields at medium plant densities (25 and 35 plants m-2). Mean yield comparison of cultivar × palnt density showed that cultivars "Pirouz", "ILC482" and "Samin" did not differ significantly in protein content but "Kaka" significantly produced higher protein content the three cultivars. Correlation coefficient for seed yield, number of pods/plant, seed weight, number of branch/ plant and plant height were positive and significant, while for seed yield, and height of first pod were negative and significant. According to the results of the this study Samin, with its large seed size and other desirable characteristics and plant population of 35 plants m-2 can be recommended for planting in Sanandaj and similar climatic areas.

Root structure modification can improve important agronomic traits including yield, drought tolerance and nutrient deficiency resistance. The aim of the present study was to investigate the diversity of root traits and to find simple sequence repeat (SSR) markers linked to root traits in chickpea (Cicer arietinum L.). This research was performed using 39 diverse accessions of chickpea. The results showed that there is significant variation in root traits among chickpea genotypes. A total of 26 alleles were detected 26 polymorphic bands were produced by 10 SSR markers in the eight linkage groups (LG). The results indicated that there is substantial variability present in chickpea germplasm for root traits. By analyzing the population structure, four subpopulations were identified. PsAS2, AF016458, 16549 and 19075 SSR markers on LG1, LG3, LG2 and LG1 linkage group respectively were associated with root traits. The research findings provide valuable information for improving root traits for chickpea breeders.

Ascochyta blight caused by Ascochyta rabiei (Pass.) Lab. (Telomorph: Didymella rabiei) (Kov.) is one of the most important fungal diseases in chickpea worldwide. Knowledge about pathogen aggressiveness and identification resistance sources to different pathotypes is very useful for proper decisions in breeding programs. In this study, virulence of 32 A. rabiei isolates from different part of Iran were analyzed on seven chickpea differentials and grouped into six races based on 0–9 rating scale and susceptibility/resistant pattern of chickpea differentials. The least and most frequent races were race V and race I, respectively. Race V and VI showed highly virulence on most of differential, while race I showed least aggressiveness. Resistance pattern of 165 chickpea genotypes also were tested against six different A. rabiei races. ANOVA analysis showed high significant difference for isolate, chickpea genotypes and their interactions. Overall chickpea × isolate (race) interactions, 259 resistance responses (disease severity ≤ 4) were identified. Resistance spectra of chickpea genotypes showed more resistance rate to race I (49.70%) and race III (35.15%), while there were no resistance genotypes to race VI. Cluster analysis based on disease severity rate, grouped chickpea genotypes into four distinct clusters. Interactions between isolates or races used in this study, showed the lack of a genotype with complete resistance. Our finding for virulence pattern of A. rabiei and newly identified resistance sources could be considerably important for integration of ascochyta blight resistance genes into chickpea breeding programs and proper decision in future for germplasm conservation and diseases management.

Ascochyta blight (caused by Ascochyta rabiei) is an important disease of chickpea. Mating type distribution, genetic diversity and population structure A. rabiei isolates from western Iran, using specific matting type primers, and ISSR and SSR molecular markers. Two mating types were identified, with the 57% of isolates belonging to MAT1-1. Ten ISSR markers produced 78 polymorphic bands with an average polymorphism information content (PIC) value of 0.33. Seven SSR markers showed high allelic variation (four to seven alleles) with the average PIC value of 0.61. The generated dendrogram using neighbor joining approach with ISSR and SSR marker data grouped isolates in three clusters. Combined dendrogram and model-based population structure analysis divided the isolates into two distinct populations. No significant correlation was found between geographical origins of isolates and their genetic diversity patterns, although the isolates from North Kermanshah and Kurdistan were closely grouped, and most of isolates from Lorestan and Kermanshah were clustered in a separate group. This relative spatial correlation between geographical locations and A. rabiei grouping indicated high genetic diversity within populations and no significant gene flow between distinctly geographical regions. This suggests the nece0ssity of continuous monitoring of A. rabiei populations in order to design effective chickpea breeding strategies to control the disease.

Structure of alpha lattice designs makes removing the effects of incomplete blocks from residual effect of plots, and maximizes precision of comparison between genotypes at the same incomplete block. This investigation was conducted to study the international chickpea germplasm, for finding desirable lines regarding seed yield and other traits. Two trials including CIEN-LA-2010 and CIEN-S-2010 carried out at Saral station of Kurdistan province during 2009-2010 cropping season. CIEN-LA and CIEN-S were sown at normal time, early March and as 9×5 alpha lattice designs with two replications. Considering property of each trial, data recording was done and statistical analyses were performed. According to analysis of variance, there were significant differences between genotypes across two trials. The average standard error of difference between genotypes was used to calculate relative efficiency of alpha lattice design. These results revealed that, alpha lattice had more efficiency over traditional randomized complete block design in both experiments, and ranks of entries were changed in trials. In CIEN-LA and CIEN-S, lines FLIP 05-55C and FLIP 06-159C ranked first for seed yield, respectively. It is necessary to have a more precise look to the best entries of these trials at the next studies.