Genome Size and Seed Mass Analyses in Cicer arietinum (Chickpea) and Wild Cicer Species

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  • 1 Department of Crop Sciences, University of Illinois, 360 E R Madigan Laboratory, 1201 West Gregory Drive, Urbana, IL 61801

The genome size of cultivated Cicer arietinum and 12 wild Cicer sp. including seven annual and five perennial species were analyzed using flow cytometry. A significant 2C genome size variation was observed among the Cicer sp. The 2C genome size ranged from 1.00 pg in wild species, Cicer judaicum, to 1.76 pg in cultivated species, C. arietinum. The wild perennial species all had a genome size of ≈1.6 pg. Most if not all of this genome size variation occurred among wild annual species. A significant positive correlation between 2C genome size and seed mass was observed among 12 wild Cicer sp. at α = 0.05. However, artificial selection appears to decrease nucleotype effects in cultivated C. arietinum, which resulted in no correlation between seed mass and genome size at α = 0.05.

Abstract

The genome size of cultivated Cicer arietinum and 12 wild Cicer sp. including seven annual and five perennial species were analyzed using flow cytometry. A significant 2C genome size variation was observed among the Cicer sp. The 2C genome size ranged from 1.00 pg in wild species, Cicer judaicum, to 1.76 pg in cultivated species, C. arietinum. The wild perennial species all had a genome size of ≈1.6 pg. Most if not all of this genome size variation occurred among wild annual species. A significant positive correlation between 2C genome size and seed mass was observed among 12 wild Cicer sp. at α = 0.05. However, artificial selection appears to decrease nucleotype effects in cultivated C. arietinum, which resulted in no correlation between seed mass and genome size at α = 0.05.

The genus Cicer belongs to family Leguminoseae, subfamily Papilionaceae, tribe Cicereae, and is well known for the cultivated taxon, C. arietinum or chickpea. Cicer arietinum is the second most widely grown annual legume crop in the world, and has been mainly cultivated in the Indian subcontinent, West Asia, North Africa, America, and Australia (Singh et al., 2008). Besides the cultivated species, this genus is known to have 43 wild species including 8 annual and 35 perennial species (Singh et al., 2008, 2014; van der Maesen, 1987). The wild Cicer sp. are commonly found in West Asia and North Africa covering Turkey in the north to Ethiopia in the south, and Pakistan in the east to Morocco in the west (Singh et al., 2008). The wild annual species such as Cicer reticulatum, Cicer echinospermum, Cicer pinnatifidum, C. judaicum, Cicer bijugum, and Cicer cuneatum are being used in breeding programs to expand chickpea genetic diversity (Ladizinsky and Adler, 1976; Pundir and Mengesha, 1995; Pundir and van der Maesen, 1983; Singh and Ocampo, 1993; van der Maesen, 1980).

Knowledge of genetic relationships between the cultivated C. arietinum and its wild relatives plays an important role in assessing the origin of C. arietinum and in using its close relatives to facilitate the transfer of agonomically useful traits into cultivated species (Singh et al., 2008). Karyotype studies in these Cicer sp. have been well documented (Galasso et al., 1996; Ladizinsky and Adler, 1976; Ohri and Pal, 1991) and showed that annual and perennial species consistently have the same chromosome number 2n = 16, with base chromosome number of 8 (Ladizinsky and Adler, 1976; Singh and Jauhar, 2005). Also, studies have reported nuclear DNA contents of annual Cicer sp. (Table 1) (Arumuganathan and Earle, 1991; Galasso et al., 1996; Ohri and Pal, 1991; Ruperao et al., 2014). Despite the constant chromosome number, the amount of DNA in the species has been reported to range from 1.53 to 3.57 pg per 2C nucleus (Arumuganathan and Earle, 1991; Galasso et al., 1996; Ohri and Pal, 1991; Ruperao et al., 2014). Although this could be due to intrachromosomal DNA variation, a concomitant chromosome size variation was not observed by the previous study (Ladizinsky and Adler, 1976). This leads to speculation that there may be errors in reporting genome size variation in the genus Cicer. Giving credence to this hypothesis is that two different 2C genome sizes have been reported in C. arietinum. Ohri and Pal (1991) and Galasso et al. (1996) obtained 3.57 and 3.29 pg for 2C genome sizes of C. arietinum, respectively, whereas Arumuganathan and Earle (1991) and Ruperao et al. (2014) reported 1.53 and 1.77 pg, respectively. Given these discrepancies in the literature, it would be prudent to confirm which, if any, of these estimates is more accurate. Such estimates are critical when correlating genome size variation with phenotypic variation.

Table 1.

Chromosome number, plant type, and genome size of Cicer sp. obtained in previous studies. The superscript lower case alphabet indicates the references.

Table 1.

The variation in genome size influences numerous cellular parameters such as chromosome size, nuclear volume, and cellular volume (Bennett, 1987; Grant, 1987), which has been called nucleotype effects (Bennett, 1972). The nucleotype effects can cause variation in phenotypic traits such as seed mass, and many previous studies have investigated the nucleotype effects on seed size and mass (Beaulieu et al., 2007; Bennett, 1987; Benor et al., 2010; Biradar et al., 1994; Chung et al., 1998; Knight and Ackerly, 2002). Most of the previous studies have indicated a positive relationship between genome size and seed mass within species and across species from the same genus and family (Benor et al., 2010; Biradar et al., 1994; Chung et al., 1998; Knight and Ackerly, 2002). However, in some cases, triangular (Bennett, 1987) and quadratic types of relationship between genome size and seed size (Beaulieu et al., 2007) were revealed in 1222 angiosperm species including, Alluium and Vicia, with species with large genomes tending to have large seed mass, whereas species with small genome sizes having either large or small seed mass. However, the correlation between genome size and seed mass may be disrupted by years of selective breeding/artificial selection. According to previous studies (Doebley et al., 2006; Zhao et al., 2015), during the domestication of crops, the nucleotide diversity associated with the selected trait in crops is expected to be lower than that of the wild crops, due to strong selective cultivars over many years of generations. A similar result has been observed in cultivated C. arietinum. Seeds of C. arietinum can be phenotypically classified into two seed types: desi (small angular and dark colored) and kabuli (large owl-shaped cream colored) (Choudhary et al., 2012; van der Maesen, 1972). The desi types are mostly distributed in the Indian subcontinent, whereas the kabuli types are grown in the Mediterranean regions. Despite geographic divergence and phenotype differences, no significant difference in DNA content between the two seed types of C. arietinum were observed by Ohri and Pal (1991). However, until the issues of genome size estimates in C. arietinum are resolved, the reported nonassociation between genome size and seed type can be questioned. It is also important to examine the relationship between genome size and seed mass across wild Cicer sp. for developing an understanding of nucleotype effects with regard to artificial and natural selection in Cicer sp.

In this study, we used flow cytometry to analyze nuclear DNA content of 13 Cicer sp. to provide valuable new genomic information for both genomic analysis and plant breeding strategies for cultivated plant improvement. Seed type and mass of Cicer sp. were investigated, and then the relationship between genome size and seed type/mass was examined within groups of cultivated C. arietinum and wild Cicer sp.

Materials and Methods

Plant material.

Seeds of cultivated C. arietinum and 12 wild Cicer sp. (Table 2) were obtained from the National Plant Germplasm Resource Laboratory/USDA, ARS, National Genetic Resource Program (Beltsville, MD) (Table 2). The genotypes included 15 accessions for cultivated C. arietinum including PI 193782, PI 193767, PI 359817, PI 360659, PI 451607, PI 360662, PI 360663, PI 374079, PI 374090, PI 420908, PI 426190, PI 426551, PI 458870, W6 3125, and W6 32898 and 12 wild species consisting of 1 accession for each C. bijugum (PI 458552), Cicer canariense (PI 557453), Cicer chorassanicum (PI 458553), C. echinospermum (PI 599041), C. judaicum (PI 458559), Cicer multijugum (PI 599085), Cicer nuristanicum (PI 604497), Cicer pugens (W6 14191), and Cicer yamashitae (PI 540657) and 2 accessions for each C. pinnatifidum (PI 458555 and PI 458556), C. reticulatum (PI 599052 and 36, PI 599050), Cicer songaricum (PI 599053 and PI 599074). The seeds were grown in potting soil under 24 h light at 26 °C. About 2–12 plants per Cicer accession were used for analysis of 2C genome size. Due to low germination rate, only one plant for C. canariense (PI 557453) was used for analysis of 2C genome size.

Table 2.

Species accession, 2C genome size (mean ± sd), seed mass per 10 seeds (mean ± sd), seed type, and geographic origin of the Cicer accessions used in this study. Two different seed sizes were observed in desi (small and big) and kabuli (medium and large).

Table 2.

Analysis of genome size.

To determine 2C genome size, flow cytometric analysis was performed using the protocol described by Kim et al. (2010). Fresh stem tissues (≈5 cm2 of each) from Cicer sp. and an internal standard were cochopped, and placed in 10 mL of extraction buffer and 200 µL of 25% Triton X. The extraction buffer consisted of 13% hexylene glycol, 10 mm Tris-HCl (pH 8.0), and 10 mm MgCl2. The use of the internal standard provides a relative measure of the 2C genome size of the sample. Maize was used as an internal standard because the 2C genome size of maize does not overlap with the targeted genome size of Cicer sp. The 2C genome size of maize (VT3 subpopulations) was calibrated at 5.15 pg using sorghum (Pioneer hybrid 84G62) with 1.74 pg/2C nuclei (Rayburn et al., 2009). For each sample, the tissue was homogenized using a tissue grinder for 10 s at 4500 gn, and the samples were filtered through a 50-µm filter (Partec, GmbH, Münster, Germany) into a test tube. After centrifuging for 15 min at 11,000 gn at 4 °C, the supernatant was removed, and the nuclei were suspended in 300 µL of PI stain (3% w/v polyethylene glycol (PEG) 6000, 5 µg·mL−1 of PI, 180 units/mL RNase, 0.1% Triton X-100 in 4 mm citrate buffer). The solution was transferred to a 1.5-mL tube and incubated in a water bath for 20 min at 37 °C. PI salt stain (3% w/v PEG 6000, 5 µg·mL−1 of PI, and 0.1% Triton X-100 in 400 mm NaCl) was added, and the tube was cooled to 4 °C for at least 1 h.

A BD LSR II flow cytometer (BD Biosciences, San Jose, CA) was used to analyze the stained nuclei. The excitation wavelength was set at 488 nm. The emission filter was a 695/40 nm-filter. At least 30,000 nuclei per sample were screened. The nuclei were gated on the basis of fluorescence integral vs. pulse width to exclude the doublets. The total 2C genome size reported in this study is the amount of nuclear DNA in somatic G1 nuclei of each plant.

Seed analysis.

Seed photographs were taken using a color camera (DP22; Olympus, Shinjuku, Tokyo, Japan) through a zoom stereo microscope (S2-CTV; Olympus). The seed mass of three replicates of 10 seeds per Cicer accession were measured.

Statistical analysis.

All statistical analyses were carried out using SAS 9.3 (SAS institute Inc., Cary, NY). General linear model analysis was conducted and Fisher’s protected least significant difference test was run to determine the significant difference (α = 0.05) among all Cicer accessions in 2C genome size and seed mass. The relationship between means of genome size and seed mass plotted on raw-scaled axes (Niklas, 1994), which was carried out separately on accessions of the cultivated species (C. arietinum) and on accessions of wild Cicer sp. Bivariate trait relationships were analyzed by fitting a linear regression trend line using the least squares fit method (Herkimer, 1986). The linear relationship is expressed as Y = α + β X, where Y and X stand for means of variables of seed mass and genome size, respectively, and α and β represent the intercept on the Y axis and the regression coefficient, respectively. F statistics were used for testing the null hypothesis that the regression coefficients are all equal to zero (α = 0.05).

Results and Discussion

A significant difference in the average of 2C genome size was observed among Cicer sp. ranging from 1.00 (C. judaicum) to 1.76 pg (C. arietinum) (P < 0.0001) (Table 1; Fig. 1). Compared with perennial Cicer sp., a larger range of 2C genome size was observed among the annual Cicer sp. (Tables 1 and 2). Similar results have been observed by Ohri and Pal (1991) who reported a significant difference in 2C genome size among six annual Cicer sp. However, there are some discrepancies between the previous data and ours; in previous 2C genome size estimations (Table 1) (Galasso et al., 1996; Ohri and Pal, 1991), the results obtained were in most cases larger than observed in our study (Table 2). Some noticeable differences in the data on 2C genome size were also observed in C. arietinum, C. bijugum, C. echinospermum, C. judacicum, C. pinnatifidum, and C. reticulatum. In these cases, previous estimations differed from ours by up to 80%. Unlike the previous estimation, done by Ohri and Pal (1991) and Galasso et al. (1996), the 2C genome size of C. arietinum observed by Arumuganathan and Earle (1991) and Ruperao et al. (2014) is similar to our results (Table 2). In addition, the draft whole genome sequence of C. arietinum has been reported to be ≈738 Mb, which converts to a 2C genome size of ≈1.5 pg (Varshney et al., 2013). Given these genome size results, a reassessment of the genome size for wild species was addressed.

Fig. 1.
Fig. 1.

Flow histograms of Cicer sp. somatic nuclei stained with PI. The bar represents the nuclei used to calculate the mean fluorescence of each peak. (A) G1 somatic nuclei of Cicer arietinum. (B) G1 somatic nuclei of Cicer bijugum. (C) G1 somatic nuclei of Cicer judaicum.

Citation: HortScience horts 50, 12; 10.21273/HORTSCI.50.12.1751

The 2C genome size for C. arietinum, C. bijugum, C. echinospermum, C. judacicum, C. pinnatifidum, and C. reticulatum were observed around 1.7, 1.31, 1.63, 1.00, 1.38, and 1.65 pg, respectively (Table 2). In addition, the 2C genome sizes for other seven wild Cicer sp. including five perennial (C. canariense, C. multijugum, C. nuristanicum, C. pugens, and C. songaricum) and two annual species (C. echinospermum and C. yamashitae) were around 1.66, 1.64, 1.63, 1.58, 1.6, 1.63, and 1.13 pg, respectively (Table 2). Both in cultivated and wild Cicer sp., the genome size estimates were in agreement with lower genome sizes of C. arietinum. In addition, the chromosome size data of Ohri and Pal (1991) is more consistent with the genome sizes obtained in this study. Whether this is due to differences in technologies between flow cytometry and Feulgen DNA microdensitometry, internal standard species, technical issues, or other unknown factors could not be addressed. Given the three previous studies agree with the lower genome size of C. arietinum (Arumuganathan and Earle, 1991; Ruperao et al., 2014; Varshney et al., 2013), the association of seed characteristics with genome size was reevaluated.

Seed phenotypes such as size, color, shape, and seedcoating varied within C. arietinum and among Cicer sp. (Fig. 2). Within C. arietinum, the two distinctive seed types, such as desi and kabuli, were distributed widely over geographic regions (Table 2). Two different seed sizes were found in desi types (Fig. 2). The range of seed mass for the bigger size of the desi type was 2.3–2.5 g, whereas the range of seed mass for the smaller size was 1.25–1.5 g/10 seeds (Table 2; Fig. 2). The seed size of the kabuli seed type also varied. According to Moreno and Cubero (1978) and Choudhary et al. (2012), the kabuli seeds used in this study can be classified into medium seeded (range 3.3–3.94 g/10 seeds) and large seeded (4.15 g/10 seeds) (Table 2). Seed phenotypes also varied among the wild species. Seed of wild perennial species are mostly round, triangular; shaped, and darker colored, but various seed sizes were found; higher seed phenotypic variations occurred within wild annual Cicer sp. (Fig. 2). Seed of C. reticulatum, which is well known as the wild progenitor of C. arietinum (Ahmad et al., 1987), has a mix of characteristics of desi (angular seed shape) and kabuli (cream color). Cicer bijugum has dark reddish colored hairy seedcoat, whereas C. echinospermum has a short yellowish colored hairy seedcoat (Fig. 3). Overall, the seed sizes of wild species were smaller than the two seed types of C. arietinum (Table 2), which reflects lower seed weights in wild species (Table 2).

Fig. 2.
Fig. 2.

The seed pictures of Cicer sp. Two different seed types are shown in Cicer arietinum: desi (PI 360659 and PI 360663) and kabuli (PI 458870). The size of bar is 1 cm.

Citation: HortScience horts 50, 12; 10.21273/HORTSCI.50.12.1751

Fig. 3.
Fig. 3.

The relationship between means of seed mass and means of genome size across 12 wild Cicer sp. (seed mass = 0.8157, genome size = 0.6533, R2 = 0.3528, P = 0.0196).

Citation: HortScience horts 50, 12; 10.21273/HORTSCI.50.12.1751

The relationship between 2C genome size and seed mass was investigated within groups of the cultivated Cicer sp. (C. arietinum) and 12 wild Cicer sp. Because the cultivated species have been subjected to many years of artificial selection by plant breeders, the relationship between 2C genome size and seed mass of cultivated and wild Cicer sp. was considered separately. We found no correlation between 2C genome size and seed type within 13 lines of C. arietinum including the two seed types, desi and kabuli (seed mass = 11.436, genome size = 17.187, R2 = 0.107, P = 0.233). The range of the 2C genome size within C. arietinum was between 1.66 and 1.76 pg (Table 2). The seed types having both highest and lowest genome sizes were desi (Table 2). This result is also supported by Ohri and Pal (1991) who reported that no significant difference in DNA content was observed between desi and kabuli cultivars of C. arietinum, despite using the inflated genome size. However, a significant linear relationship was found between 2C genome size and seed mass among 12 wild Cicer sp. (seed mass = 0.8157, genome size = 0.6533, R2 = 0.3528, P = 0.0196) (Fig. 3). For example, C. judaicum had the lowest genome size and also had lower seed mass. This strong positive relationship between genome size and seed mass in plants has also been observed in many previous studies (Bennett, 1972; Grime et al., 1997; Knight and Ackerly, 2002; Thompson, 1990). As genome size increases, the cell size within seed organs may get bigger, resulting in increase in seed mass (Beaulieu et al., 2008). Artificial selection appears to have disrupted the natural selection between genome size and seed mass in cultivated C. arietinum.

In conclusion, the 2C genome size estimations in this study confirm the previously reported findings, showing that the 1.5 (Arumuganathan and Earle, 1991) and 1.7 pg (Ruperao et al., 2014) are the more accurate 2C genome sizes of C. arietinum, and that other estimated genome sizes of 3.29 and 3.57 pg (Galasso et al.,1996; Ohri and Pal 1991) were likely an overestimation. In addition, the genome sizes for wild Cicer sp. estimated in this study were lower than the previous 2C genome sizes estimated in Ohri and Pal (1991) and Galasso et al. (1996). Significant differences in genome size were observed among 13 Cicer sp. The 2C genome size ranged from 1.00 pg in wild species, C. judaicum, to 1.76 pg in cultivated species, C. arietinum. Compared with perennial Cicer sp., the 2C genome size more varied within annual Cicer sp.. Nucleotype effects appear to result in phenotypic variation across wild Cicer sp., but not across cultivated C. arietinum. No correlation between genome size and seed size was observed within C. arietinum, but a strong positive relationship between genome size and seed size was observed among 12 wild Cicer sp. By understanding the role of nucleotype and seed size, the potential exists to develop novel breeding schemes for C. arietinum improvement.

Literature Cited

  • Ahmad, F., Slinkard, A.E. & Scoles, G.J. 1987 Karyotypic analysis of annual Cicer L. species Genet. Soc. Canada Bul. 18 130

  • Arumuganathan, K. & Earle, E.D. 1991 Nuclear DNA content of some important plant species Plant Mol. Biol. Rpt. 9 208 218

  • Beaulieu, J.M., Leitch, I.J., Patel, S., Pendharkar, A. & Knight, C.A. 2008 Genome size is a strong predictor of cell size and stomatal density in angiosperms New Phytol. 179 975 986

    • Search Google Scholar
    • Export Citation
  • Beaulieu, J.M., Moles, A.T., Leitch, I.J., Bennett, M.D., Dickie, J.B. & Knight, C.A. 2007 Correlated evolution of genome size and seed mass New Phytol. 173 422 437

    • Search Google Scholar
    • Export Citation
  • Bennett, M.D. 1972 Nuclear DNA content and minimum generation time in herbaceous plants Proc. R. Soc. Lond. B Biol. Sci. 181 109 135

  • Bennett, M.D. 1987 Variation in genomic form in plants and its ecological implications New Phytol. 106 177 200

  • Benor, S., Blattner, F.R., Demissew, S. & Hammer, K. 2010 Collection and ethnobotanical investigation of Corchorus species in Ethiopia: Potential leafy vegetables for dry regions Genet. Resources Crop Evol. 57 293 306

    • Search Google Scholar
    • Export Citation
  • Biradar, D.P., Bullock, D.G. & Rayburn, A.L. 1994 Nuclear DNA amount, growth, and yield parameters in maize Theor. Appl. Genet. 88 557 560

  • Choudhary, S., Jagmeet, K., Chhuneja, P., Sandhu, J.S., Singh, S.J. & Sirari, A. 2012 Assessment of genetic diversity in kabuli chickpea (Cicer arietinum L.) genotypes in relation to seed size using SSR markers J. Food Legume 26 1–2 96 99

    • Search Google Scholar
    • Export Citation
  • Chung, J., Lee, J.H., Arumuganathan, K., Graef, G.L. & Specht, J.E. 1998 Relationships between nuclear DNA content and seed and leaf size in soybean Theor. Appl. Genet. 96 1064 1068

    • Search Google Scholar
    • Export Citation
  • Doebley, J.F., Gaut, B.S. & Smith, B.D. 2006 The molecular genetics of crop domestication Cell 127 1309 1321

  • Galasso, I., Frediani, M., Maggiani, M., Cremonini, R. & Pgnone, D. 1996 Chromatin characterization by banding techniques, in situ hybridization, and nuclear DNA content in Cicer L.(Leguminosae) Genome 39 258 265

    • Search Google Scholar
    • Export Citation
  • Grant, W.F. 1987 Genome differentiation in higher plants, p. 9–32. In: K.M. Urbanska (ed.). Differentiation patterns in higher plants. Academic Press, London, England

  • Grime, J.P., Thompson, K., Hunt, R., Hodgson, J.G., Cornelissen, J.H.C., Rorison, I.H.G.A.F. 1997 Integrated screening validates primary axes of specialization in plants. Oikos 79:259–281

  • Herkimer, A.G. 1986 Understanding hospital financial management. 2nd ed. Aspen Publication, Rockville, MD. p. 133–136

  • Kim, S., Rayburn, A.L. & Lee, D.K. 2010 Genome size and chromosome analyses in prairie cordgrass Crop Sci. 50 2277 2282

  • Knight, C.A. & Ackerly, D.D. 2002 Variation in nuclear DNA content across environmental gradients: A quantile regression analysis Ecol. Lett. 5 66 76

    • Search Google Scholar
    • Export Citation
  • Ladizinsky, G. & Adler, A. 1976 Genetic relationships among the annual species of Cicer L Theor. Appl. Genet. 48 197 203

  • Moreno, M. & Cubero, J.I. 1978 Variation in Cicer arietinum Euphytica 27 465 485

  • Niklas, K.J. 1994 Plant allometry: The scaling of form and process. Chicago University Press, Chicago, IL

  • Ohri, D. & Pal, M. 1991 The origin of chickpea (Cicer arietinum L.): Karyotype and nuclear DNA amount Heredity 66 367 372

  • Pundir, R.P.S. & Mengesha, M.H. 1995 Cross compatibility between chickpea and its wild relative, Cicer echinospermum Davis Euphytica 83 241 245

  • Pundir, R.P.S. & van der Maesen, L.J.G. 1983 Interspecific hybridization in Cicer Int. Chickpea Nwsl. 8 4 5

  • Rayburn, A.L., Crawford, J., Rayburn, C.M. & Juvik, J.A. 2009 Genome size in three Mischanthus species Plant Mol. Biol. Rptr. 27 184 188

  • Ruperao, R., Chan, C.K., Azam, S., Karafiátová, M., Hayashi, S., Cížková, J., Saxena, R.K., Simková, H., Song, C., Vrána, J., Chitikineni, A., Visendi, P., Gaur, P.M., Millán, T., Singh, K.B., Taran, B., Wang, J., Batley, J., Doležel, J., Varshney, R.K. & Edwards, D. 2014 A chromosomal genomics approach to assess and validate the desi and kabuli chickpea genome assemblies J. Plant Biotechnol. 12 778 786

    • Search Google Scholar
    • Export Citation
  • Singh, M., Bisht, I.S., Dutta, M., Kumar, K., Basandrai, A.K., Kaur, L., Sirari, A., Khan, Z., Rizivi, A.H., Sarker, A. & Bansal, K.C. 2014 Characterization and evaluation of wild annual Cicer species for agro-morphological traits and major biotic stresses under Northwestern Indian conditions Crop Sci. 54 229 239

    • Search Google Scholar
    • Export Citation
  • Singh, R.J. & Jauhar, P.P. 2005 Genetic resources, chromosome engineering, and crop improvement: Grain legumes, Vol. 1. Technology and Engineering CRC press, Boca Raton, FL

  • Singh, K.B. & Ocampo, B. 1993 Interspecific hybridization in annual Cicer species J. Genet. Breed. 47 199 204

  • Singh, R., Sharma, P., Varshney, R.K., Sharma, S.K. & Singh, N.K. 2008 Chickpea improvement: Role of wild species and genetic markers Biotechnol. Genet. Eng. Rev. 25 267 314

    • Search Google Scholar
    • Export Citation
  • Thompson, K. 1990 Genome size, seed size and germination temperature in herbaceous angiosperms Evol. Trends Plants 4 113 116

  • van der Maesen, L.J.G. 1972 Cicer L., a monograph of the genus: With special reference to the chickpea (Cicer arietinum L.), its ecology and cultivation. Mededelingen Landbouwhogeschool (Communications Agricultural University), Wageningen, Netherlands, Thesis p. 310–342

  • van der Maesen, L.J.G. 1980 Growing wild chickpeas Intl. Chickpea Nwsl. 2 3 4

  • van der Maesen, L.J.G. 1987 Origin, history, and taxonomy of chickpea, p. 11–34. In: M.C. Saxena and K.B. Singh (eds.). The chickpea. CAB International Publications, Wallingford, UK

  • Varshney, R.K., Song, C., Saxena, R.K., Azam, S., Yu, S., Sharpe, A.G., Cannon, S., Baek, J., Rosen, B.D., Tar’an, B., Millan, T., Zhang, X., Ramsay, L.D., Iwata, A., Wang, Y., Nelson, W., Farmer, A.D., Gaur, P.M., Soderlund, C., Penmetsa, R.V., Xu, C., Bharti, A.K., He, W., Winter, P., Zhao, S., Hane, J.K., Carrasquilla-Garcia, N., Condie, J.A., Upadhyaya, H.D., Luo, M.C., Thudi, M., Gowda, C.L., Singh, N.P., Lichtenzveig, J., Gali, K.K., Rubio, J., Nadarajan, N., Dolezel, J., Bansal, K.C., Xu, X., Edwards, D., Zhang, G., Kahl, G., Gil, J., Singh, K.B., Datta, S.K., Jackson, S.A., Wang, J. & Cook, D.R. 2013 Draft genome sequence of chickpea (Cicer arietinum) provides a resource for trait improvement Nature Biotechnol. 31 240 246

    • Search Google Scholar
    • Export Citation
  • Zhao, S., Zheng, F., He, W., Wu, H., Pan, S. & Lam, H.M. 2015 Impacts of nucleotide fixation during soybean domestication and improvement BMC Plant Biol. 15 81

    • Search Google Scholar
    • Export Citation

Contributor Notes

This material is based on work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch project under ILLU-802-952.

We thank the USDA, ARS, National Genetic Resources Program-National Germplasm Resources Laboratory in Beltsville, MD for providing the seed material used for this study.

Corresponding author. E-mail: arayburn@illinois.edu.

  • View in gallery

    Flow histograms of Cicer sp. somatic nuclei stained with PI. The bar represents the nuclei used to calculate the mean fluorescence of each peak. (A) G1 somatic nuclei of Cicer arietinum. (B) G1 somatic nuclei of Cicer bijugum. (C) G1 somatic nuclei of Cicer judaicum.

  • View in gallery

    The seed pictures of Cicer sp. Two different seed types are shown in Cicer arietinum: desi (PI 360659 and PI 360663) and kabuli (PI 458870). The size of bar is 1 cm.

  • View in gallery

    The relationship between means of seed mass and means of genome size across 12 wild Cicer sp. (seed mass = 0.8157, genome size = 0.6533, R2 = 0.3528, P = 0.0196).

  • Ahmad, F., Slinkard, A.E. & Scoles, G.J. 1987 Karyotypic analysis of annual Cicer L. species Genet. Soc. Canada Bul. 18 130

  • Arumuganathan, K. & Earle, E.D. 1991 Nuclear DNA content of some important plant species Plant Mol. Biol. Rpt. 9 208 218

  • Beaulieu, J.M., Leitch, I.J., Patel, S., Pendharkar, A. & Knight, C.A. 2008 Genome size is a strong predictor of cell size and stomatal density in angiosperms New Phytol. 179 975 986

    • Search Google Scholar
    • Export Citation
  • Beaulieu, J.M., Moles, A.T., Leitch, I.J., Bennett, M.D., Dickie, J.B. & Knight, C.A. 2007 Correlated evolution of genome size and seed mass New Phytol. 173 422 437

    • Search Google Scholar
    • Export Citation
  • Bennett, M.D. 1972 Nuclear DNA content and minimum generation time in herbaceous plants Proc. R. Soc. Lond. B Biol. Sci. 181 109 135

  • Bennett, M.D. 1987 Variation in genomic form in plants and its ecological implications New Phytol. 106 177 200

  • Benor, S., Blattner, F.R., Demissew, S. & Hammer, K. 2010 Collection and ethnobotanical investigation of Corchorus species in Ethiopia: Potential leafy vegetables for dry regions Genet. Resources Crop Evol. 57 293 306

    • Search Google Scholar
    • Export Citation
  • Biradar, D.P., Bullock, D.G. & Rayburn, A.L. 1994 Nuclear DNA amount, growth, and yield parameters in maize Theor. Appl. Genet. 88 557 560

  • Choudhary, S., Jagmeet, K., Chhuneja, P., Sandhu, J.S., Singh, S.J. & Sirari, A. 2012 Assessment of genetic diversity in kabuli chickpea (Cicer arietinum L.) genotypes in relation to seed size using SSR markers J. Food Legume 26 1–2 96 99

    • Search Google Scholar
    • Export Citation
  • Chung, J., Lee, J.H., Arumuganathan, K., Graef, G.L. & Specht, J.E. 1998 Relationships between nuclear DNA content and seed and leaf size in soybean Theor. Appl. Genet. 96 1064 1068

    • Search Google Scholar
    • Export Citation
  • Doebley, J.F., Gaut, B.S. & Smith, B.D. 2006 The molecular genetics of crop domestication Cell 127 1309 1321

  • Galasso, I., Frediani, M., Maggiani, M., Cremonini, R. & Pgnone, D. 1996 Chromatin characterization by banding techniques, in situ hybridization, and nuclear DNA content in Cicer L.(Leguminosae) Genome 39 258 265

    • Search Google Scholar
    • Export Citation
  • Grant, W.F. 1987 Genome differentiation in higher plants, p. 9–32. In: K.M. Urbanska (ed.). Differentiation patterns in higher plants. Academic Press, London, England

  • Grime, J.P., Thompson, K., Hunt, R., Hodgson, J.G., Cornelissen, J.H.C., Rorison, I.H.G.A.F. 1997 Integrated screening validates primary axes of specialization in plants. Oikos 79:259–281

  • Herkimer, A.G. 1986 Understanding hospital financial management. 2nd ed. Aspen Publication, Rockville, MD. p. 133–136

  • Kim, S., Rayburn, A.L. & Lee, D.K. 2010 Genome size and chromosome analyses in prairie cordgrass Crop Sci. 50 2277 2282

  • Knight, C.A. & Ackerly, D.D. 2002 Variation in nuclear DNA content across environmental gradients: A quantile regression analysis Ecol. Lett. 5 66 76

    • Search Google Scholar
    • Export Citation
  • Ladizinsky, G. & Adler, A. 1976 Genetic relationships among the annual species of Cicer L Theor. Appl. Genet. 48 197 203

  • Moreno, M. & Cubero, J.I. 1978 Variation in Cicer arietinum Euphytica 27 465 485

  • Niklas, K.J. 1994 Plant allometry: The scaling of form and process. Chicago University Press, Chicago, IL

  • Ohri, D. & Pal, M. 1991 The origin of chickpea (Cicer arietinum L.): Karyotype and nuclear DNA amount Heredity 66 367 372

  • Pundir, R.P.S. & Mengesha, M.H. 1995 Cross compatibility between chickpea and its wild relative, Cicer echinospermum Davis Euphytica 83 241 245

  • Pundir, R.P.S. & van der Maesen, L.J.G. 1983 Interspecific hybridization in Cicer Int. Chickpea Nwsl. 8 4 5

  • Rayburn, A.L., Crawford, J., Rayburn, C.M. & Juvik, J.A. 2009 Genome size in three Mischanthus species Plant Mol. Biol. Rptr. 27 184 188

  • Ruperao, R., Chan, C.K., Azam, S., Karafiátová, M., Hayashi, S., Cížková, J., Saxena, R.K., Simková, H., Song, C., Vrána, J., Chitikineni, A., Visendi, P., Gaur, P.M., Millán, T., Singh, K.B., Taran, B., Wang, J., Batley, J., Doležel, J., Varshney, R.K. & Edwards, D. 2014 A chromosomal genomics approach to assess and validate the desi and kabuli chickpea genome assemblies J. Plant Biotechnol. 12 778 786

    • Search Google Scholar
    • Export Citation
  • Singh, M., Bisht, I.S., Dutta, M., Kumar, K., Basandrai, A.K., Kaur, L., Sirari, A., Khan, Z., Rizivi, A.H., Sarker, A. & Bansal, K.C. 2014 Characterization and evaluation of wild annual Cicer species for agro-morphological traits and major biotic stresses under Northwestern Indian conditions Crop Sci. 54 229 239

    • Search Google Scholar
    • Export Citation
  • Singh, R.J. & Jauhar, P.P. 2005 Genetic resources, chromosome engineering, and crop improvement: Grain legumes, Vol. 1. Technology and Engineering CRC press, Boca Raton, FL

  • Singh, K.B. & Ocampo, B. 1993 Interspecific hybridization in annual Cicer species J. Genet. Breed. 47 199 204

  • Singh, R., Sharma, P., Varshney, R.K., Sharma, S.K. & Singh, N.K. 2008 Chickpea improvement: Role of wild species and genetic markers Biotechnol. Genet. Eng. Rev. 25 267 314

    • Search Google Scholar
    • Export Citation
  • Thompson, K. 1990 Genome size, seed size and germination temperature in herbaceous angiosperms Evol. Trends Plants 4 113 116

  • van der Maesen, L.J.G. 1972 Cicer L., a monograph of the genus: With special reference to the chickpea (Cicer arietinum L.), its ecology and cultivation. Mededelingen Landbouwhogeschool (Communications Agricultural University), Wageningen, Netherlands, Thesis p. 310–342

  • van der Maesen, L.J.G. 1980 Growing wild chickpeas Intl. Chickpea Nwsl. 2 3 4

  • van der Maesen, L.J.G. 1987 Origin, history, and taxonomy of chickpea, p. 11–34. In: M.C. Saxena and K.B. Singh (eds.). The chickpea. CAB International Publications, Wallingford, UK

  • Varshney, R.K., Song, C., Saxena, R.K., Azam, S., Yu, S., Sharpe, A.G., Cannon, S., Baek, J., Rosen, B.D., Tar’an, B., Millan, T., Zhang, X., Ramsay, L.D., Iwata, A., Wang, Y., Nelson, W., Farmer, A.D., Gaur, P.M., Soderlund, C., Penmetsa, R.V., Xu, C., Bharti, A.K., He, W., Winter, P., Zhao, S., Hane, J.K., Carrasquilla-Garcia, N., Condie, J.A., Upadhyaya, H.D., Luo, M.C., Thudi, M., Gowda, C.L., Singh, N.P., Lichtenzveig, J., Gali, K.K., Rubio, J., Nadarajan, N., Dolezel, J., Bansal, K.C., Xu, X., Edwards, D., Zhang, G., Kahl, G., Gil, J., Singh, K.B., Datta, S.K., Jackson, S.A., Wang, J. & Cook, D.R. 2013 Draft genome sequence of chickpea (Cicer arietinum) provides a resource for trait improvement Nature Biotechnol. 31 240 246

    • Search Google Scholar
    • Export Citation
  • Zhao, S., Zheng, F., He, W., Wu, H., Pan, S. & Lam, H.M. 2015 Impacts of nucleotide fixation during soybean domestication and improvement BMC Plant Biol. 15 81

    • Search Google Scholar
    • Export Citation
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