Detailed chromosome measurements and karyotype asymmetry of some Vicia (Fabaceae) taxa from Turkey

ABSTRACT

This study examined the detailed chromosome measurements and karyotype asymmetries of seven taxa in the genus Vicia. The taxa are V. articulata, V. cassubica, V. villosa subsp. villosa in sect. Cracca, V. noeana var. noeana, V. sativa subsp. sativa, V. peregrina in sect. Vicia and V. caesarea in sect. Ervum. V. cassubica, V. noeana var. noeana, V. sativa subsp. sativa, V. caesarea have 2n = 12 chromosomes. V. articulata, V. villosa subsp. villosa, V. peregrina have 2n = 14 chromosomes in somatic cells. Total chromosome lengths range between 2.93–4.99 µm in V. articulata, 2.09–4.73 µm in V. cassubica, 1.86–3.36 µm in V. villosa subsp. villosa, 4.23–6.05 µm in V. noeana var. noeana, 2.07–3.72 µm in V. sativa subsp. sativa, 4.32–7.21 µm in V. peregrina and 2.39–5.78 µm in V. caesarea. The detailed chromosome measurements, relative lengths, centromeric indexes and karyotype asymmetries are also given. V. articulata is the most symmetrical karyotype, while V. villosa subsp. villosa is the most asymmetrical karyotype in intrachromosomal asymmetry including parameters of M_CA, AsK, TF, Syi, A1, and A. However, the asymmetrical karyotypes are different in interchromosomal asymmetries. While V. noeana var. noeana is the most symmetrical karyotype in CV_CL, Rec, and A2. V. caesarea is the most asymmetrical karyotype in only CV_CL and A2. Unlike all parameters, V. cassubica is the most asymmetrical karyotype in Rec value. The scatter diagrams are given between M_CA–CV_CL and Syi–Rec.

KEYWORDS:

• Vicia
• Fabaceae
• chromosome
• karyotype asymmetry

Introduction

The family Fabaceae (Leguminosae) is the third largest family of flowering plants and contains more than 700 genera and 19,000 species (Lewis et al. 2005; Kahraman et al. 2013). The family consists of two subfamilies (Papilionoideae and Mimosoideae) whose members are monophyletic and one subfamily (Caesalpinioideae) of which each member is paraphyletic. The largest subfamily Papilionoideae contains more than 13,800 species, including important food crops. The genus Astragalus L., Dalea L., Erythrina L., Lupinus L., Lathyrus L., Robinia L., Vicia L. and Onobrychis Mill. belong to this subfamily (Miller et al. 2011; Kahraman et al. 2013; Tanaomi et al. 2016).

The genus Vicia is placed in the tribe Fabeae in the subfamily Papilionoideae. It contains about 180–200 species, spread throughout the temperate regions of Europe, Asia, North and South America (Kupicha 1976; Jaaska 2005). The highest specific diversity of Vicia is found in Turkey and northwest Asia (Maxted and Hawkes 1997). In Maxted (1993), the subgenus Vicia has been divided into nine sections based on the phenetic basis. The sections are Atossa (Alef.) Asch. & Graebner, Microcarinae Maxted, Hypechusa (Alef.) Asch. & Graebner, Peregrinae Kupicha, Wiggersia (Alef.) Maxted, Vicia, Narbonensis (Radzhi) Maxted, Bithynicae (B. Fedtsch. ex Radzhi) Maxted and Faba (Mill.) Ledeb. (Kahraman et al. 2013).

The origin center of the subgenus Vicia is a restricted area in central northeast Mediterranean including Iraq, Iran, Turkey, Syria and the former Soviet Union (Kahraman et al. 2013). Vicia are represented by 66 species, 27 subspecies and 29 varieties in Turkey (Başbağ et al. 2013; Binzat et al. 2014).

The genus Vicia is widely used in the world and in our country. Many taxa are used in the food and feed industry because they are very rich in terms of nutritional value. The taxa are also used as feed plants in the agricultural area, grassland plants, green manure plants and used in the cultivation season in the fallow soil. In addition, some taxa are also grown as ornamental plants in parks and gardens. There are also taxa used as bioindicators to remove oil pollution, especially in the seas (Kahlaoui et al. 2009; Gedik et al. 2013; Başbağ et al. 2013; Büyükkartal et al. 2013; Kahraman et al. 2013; Binzat et al. 2014).

Different diploid chromosome number counts have been reported in the genus Vicia. In the genus, the most frequent chromosome numbers are 2n = 2x = 12 and 14. The number of somatic chromosomes of the taxa belonging to the genus Vicia varies from 2n = 6 to 2n = 42, e.g. 2n = 6, 10, 12, 14, 18, 22, 24, 26, 28 and 42 (Yefimov 1988; Şahin and Babaç 1990; Şahin et al. 1996; Meriç and Dane 1999; Bağcı and Şahin 2000; Rahiminejad et al. 2000; Tabur et al. 2001; Karadağ and Büyükburç 2003; Sevimay et al. 2005; Çeliktaş et al. 2006; Gianfranco et al. 2008; Namazi et al. 2008; Kahlaoui et al. 2009; Tabur et al. 2009; Arslan et al. 2012; Gedik et al. 2013).

Karyotype asymmetry is widely used in comparative cytotaxonomy. The symmetrical karyotypes are mainly derived from median and submedian chromosomes with approximately the same size, whereas the asymmetric karyotypes are mainly derived from subtelocentric and telocentric chromosomes. The asymmetry degrees may also increase depending on differences in relative sizes. In parallel, the karyotype heterogeneity also increases. Karyotype asymmetry consists of two parts as intrachromosomal asymmetry and interchromosomal asymmetry (Peruzzi and Eroglu 2013). The parameters of M_CA (Peruzzi and Eroglu 2013) and CV_CL (Paszko 2006) are perfectly suited to measure intrachromosomal asymmetry and interchromosomal asymmetry, respectively.

In the present study, three sections of the genus Vicia were investigated karyologically to determine the detailed chromosome measurements and to compare with earlier results. New information on the karyotype of the examined species growing in Turkey has been obtained by karyotype analysis, which might help a better understanding of their taxonomic treatment.

Materials and methods

Seeds of seven Vicia taxa were collected from central Anatolia in Turkey. These taxa are V. articulata, V. cassubica, V. villosa subsp. villosa in sect. Cracca; V. noeana var. noeana, V. sativa subsp. sativa, V. peregrina in sect. Vicia and V. caesarea in sect. Ervum. The localities of the taxa used in the study are given in Table 1.

Table 1. Localities and collector numbers of studied Vicia.

Taxa	Localities	Voucher
Vicia articulata	B4 Ankara: Ankara Forest Farm, 22.06.2010	O. Binzat 180
Vicia cassubica	B3 Eskişehir: Türkmen mountain, Forest Management Directorate, 1088 m, 27.6.2009	O. Binzat 55
Vicia villosa subsp. villosa	B3 Eskişehir Türkmen tepesi 1203 m, 16.06.2010	O. Binzat 151
Vicia noeana var. noeana	B6 Sivas: Divriği to Kangal, 1887m, 21.06.2010	O. Binzat 184
Vicia sativa subsp. sativa	B5 Sivas: Hafik, 1346 m, 22.06.2010	O. Binzat 204
Vicia peregrina	B5 Sivas: Hafik, 1579 m, 22.06.2010	O. Binzat 201
Vicia caesarea	B5 Nevşehir: Sarıkız plateou, 1802 m, 18.6.2010	O. Binzat 170

The seeds were germinated between wet filter papers in Petri dishes. The root tips were pretreated in α-bromonaphthalene for 16 h at 4°C, then fixed in absolute alcohol-acetic acid (3:1) for 24 h, and then kept in 70% ethanol at 4°C in the refrigerator. The root tips were hydrolyzed in 1 N HCl for 12 min at room temperature, then stained in aceto-orcein for 2 h at room temperature, and finally squashed in 45% acetic acid. The permanent slides were made by mounting in Depex (Esra et al. 2008, Martin et al. 2011, 2015). The observations of the mitotic plates were made using an Olympus BX-53 microscope (Olympus Corporation, Tokyo, Japan) and photographed with an Olympus DP72 digital camera.

Chromosome properties including long arm length (L), short arm length (S), total chromosome length (L + S), arm ratio (L/S), relative length (RL) and centromeric index (CI = S/[L + S] × 100) were measured using Software Image Analyses (Bs200ProP). The determination of centromeric position as median, submedian and/or subtelocentric followed Levan et al. (1964). The karyotype asymmetries were classified as the Stebbins classification (a quali-quantitative method), intrachromosomal asymmetry using M_CA, AsK, TF, Syi, A1 and A and interchromosomal asymmetry using CV_CL, Rec and A2 (for details see Paszko 2006; Eroğlu et al. 2013; Peruzzi and Eroglu 2013). Finally, asymmetry parameters were compared with Pearson correlation.

Results

The chromosomes of the genus Vicia are large enough and the centromere regions are quite evident. For this reason, chromosome types can be easily distinguished. The characteristics of mitotic metaphase chromosomes are given below according to the measurement data.

Sect. Cracca

Vicia articulata

The chromosome number of V. articulata is 2n = 14 (Figure 1(a)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 2.93, 4.99, 3.74 and 26.18 μm, respectively. The chromosome arm rates, centromeric index and relative length are 1.20–1.69, 37.27–46.84 and 11.18–19.08, respectively. The karyotype formula is 2n = 14 = 7m (Table 2). Figure 2(a) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 1A, 13.28 and 20.20, respectively.

Table 2. The measurement data of chromosome pairs of species of section Cracca.

Taxa	Pair	L + S (μm)	L (μm)	S (μm)	L/S	RL (%)	CI (%)	Type
	1	4.99	3.13	1.86	1.69	19.08	37.27	m
	2	4.45	2.69	1.76	1.53	16.99	39.55	m
	3	3.80	2.02	1.78	1.14	14.49	46.84	m
Vicia articulata	4	3.62	1.94	1.67	1.16	13.82	46.26	m
	5	3.42	1.93	1.49	1.29	13.05	43.57	m
	6	2.98	1.65	1.33	1.24	11.39	44.63	m
	7	2.93	1.60	1.33	1.20	11.18	45.39	m
	1	4.73	3.50	1.23	2.83	24.03	26.00	sm
	2	3.91	2.93	0.98	2.99	19.83	25.06	sm
Vicia cassubica	3	3.52	2.43	1.09	2.22	17.87	30.97	sm
	4	3.07	2.10	0.97	2.18	15.60	31.60	sm
	5	2.38	1.71	0.66	2.59	12.07	27.85	sm
	6	2.09	1.42	0.67	2.12	10.60	32.06	sm
	1	3.36	2.48	0.88	2.81	17.47	26.19	sm
	2	3.16	2.36	0.80	2.96	16.39	25.32	sm
Vicia villosa	3	2.99	2.22	0.77	2.87	15.52	25.75	sm
subsp. villosa	4	2.86	2.07	0.79	2.62	14.85	27.62	sm
	5	2.64	1.97	0.67	2.94	13.70	25.38	sm
	6	2.40	1.72	0.67	2.56	12.43	28.03	sm
	7	1.86	1.25	0.60	2.08	9.64	32.43	sm

Abbreviations: total chromosome length (L + S), long arm length (L), short arm length (S), arm ratio (L/S), relative length (RL), centromeric index (CI), median (m), submedian (sm).

Figure 1. Somatic metaphase chromosomes of Vicia taxa. (a) V. articulata; (b) V. cassubica; (c) V. villosa subsp. villosa; (d) V. noeana var. noeana; (e) V. sativa subsp. sativa; (f) V. peregrina; (g) V. caesarea.

Figure 2. Ideograms of Vicia taxa. (a) V. articulata; (b) V. cassubica; (c) V. villosa subsp. villosa; (d) V. noeana var. noeana; (e) V. sativa subsp. sativa; (f) V. peregrina; (g) V. caesarea.

Vicia cassubica

The chromosome number of V. cassubica is 2n = 12 (Figure 1(b)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 2.09, 4.73, 3.28 and 19.69 μm, respectively. The chromosome arm rates, centromeric index and relative length are 2.12–2.99, 25.06–32.06 and 10.60–24.03, respectively. The karyotype formula is 2n = 12 = 6sm (Table 2). Figure 2(b) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 4B, 42.15 and 30.00, respectively.

Vicia villosa subsp. villosa

The chromosome number of V. villosa subsp. villosa is 2n = 14 (Figure 1(c)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 1.86, 3.36, 2.75 and 19.25 μm, respectively. The chromosome arm rates, centromeric index and relative length are 2.08–2.96, 25.32–32.43 and 9.64–17.47, respectively. The karyotype formula is 2n = 14 = 7sm (Table 2). Figure 2(c)) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 4A, 45.51 and 18.55, respectively.

Sect. Vicia

Vicia noeana var. noeana

The chromosome number of V. noeana var. noeana is 2n = 12 (Figure 1(d)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 4.23, 6.05, 5.01 and 30.08 μm, respectively. The chromosome arm rates, centromeric index and relative length are 1.80–3.33, 23.06–35.70 and 14.07–20.12, respectively. The karyotype formula is 2n = 12 = 5sm + 1st (Table 3). The satellite is observed in the first chromosome pair. Figure 2(d) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 3A, 41.68 and 12.58, respectively.

Table 3. The measurement data of chromosome pairs of species of section Vicia.

Taxa	Pair	L + S (μm)	L (μm)	S (μm)	L/S	RL (%)	CI (%)	Type
	1	6.05	3.89	2.16	1.80	20.12	35.70	sm^sat
	2	5.33	3.62	1.71	2.12	17.72	32.08	sm
Vicia noeana	3	5.04	3.87	1.16	3.33	16.74	23.06	st
var. noeana	4	4.84	3.53	1.31	2.71	16.09	27.07	sm
	5	4.59	3.15	1.45	2.18	15.26	31.52	sm
	6	4.23	3.15	1.08	2.90	14.07	25.53	sm
	1	3.72	2.70	1.03	2.63	20.99	27.61	sm
	2	3.35	2.30	1.05	2.19	18.89	31.34	sm
Vicia sativa	3	3.11	2.37	0.75	3.17	17.55	24.04	st
subsp. sativa	4	2.76	1.86	0.90	2.07	15.52	32.61	sm
	5	2.73	1.81	0.92	1.98	15.40	33.70	sm
	6	2.07	1.46	0.60	2.42	11.65	29.13	sm
	1	7.21	4.59	2.62	1.75	19.29	36.34	sm
	2	5.65	4.11	1.54	2.67	15.12	27.26	sm
	3	5.41	3.66	1.75	2.09	14.47	32.35	sm
Vicia peregrina	4	5.11	3.85	1.25	3.07	13.66	24.51	st
	5	4.91	3.87	1.04	3.73	13.13	21.18	st
	6	4.77	3.48	1.30	2.68	12.77	27.20	sm
	7	4.32	3.24	1.08	2.98	11.56	25.00	sm

Abbreviations: total chromosome length (L + S), long arm length (L), short arm length (S), arm ratio (L/S), relative length (RL), centromeric index (CI), submedian (sm), subterminal (st).

Vicia sativa subsp. sativa

The chromosome number of V. sativa subsp. sativa is 2n = 12 (Figure 1(e)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 2.07, 3.72, 2.96 and 17.75 μm, respectively. The chromosome arm rates, centromeric index and relative length are 1.98–3.17, 24.04–33.70 and 11.65–20.99, respectively. The karyotype formula is 2n = 12 = 5sm + 1st (Table 3). Figure 2(e) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 3A, 40.52 and 19.56, respectively.

Vicia peregrina

The chromosome number of V. peregrina is 2n = 14 (Figure 1(f)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 4.32, 7.21, 5.34 and 37.38 μm, respectively. The chromosome arm rates, centromeric index and relative length are 1.75–3.73, 21.18–36.34 and 11.56–19.29, respectively. The karyotype formula is 2n = 14 = 5sm + 2st (Table 3). Figure 2(f) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 3A, 44.62 and 17.42, respectively.

Sect. Ervum

Vicia caesarea

The chromosome number of V. caesarea is 2n = 12 (Figure 1(g)). The smallest chromosome length, the largest chromosome length, the mean chromosome length and the total haploid length are 2.39, 5.78, 4.08 and 24.46 μm, respectively. The chromosome arm rates, centromeric index and relative length are 1.32–2.02, 33.05–43.01 and 9.78–23.64, respectively. The karyotype formula is 2n = 12 = 4m + 2sm (Table 4). Figure 2(g) shows the monoploid ideogram. The values of the Stebbins classification, intrachromosomal asymmetry (M_CA) and interchromosomal asymmetry (CV_CL) are 2B, 22.45 and 35.18, respectively.

Table 4. The measurement data of chromosome pairs of species of section Ervum.

Taxa	Pair	L + S (μm)	L (μm)	S (μm)	L/S	RL (%)	CI (%)	Type
	1	5.78	3.46	2.32	1.49	23.64	40.14	m
	2	5.34	3.41	1.93	1.76	21.82	36.14	sm
Vicia caesarea	3	4.90	2.87	2.03	1.42	20.03	41.43	m
	4	3.19	1.95	1.24	1.58	13.03	38.87	m
	5	2.86	1.63	1.23	1.32	11.71	43.01	m
	6	2.39	1.60	0.79	2.02	9.78	33.05	sm

Abbreviations: total chromosome length (L + S), long arm length (L), short arm length (S), arm ratio (L/S), relative length (RL), centromeric index (CI), median (m), submedian (sm).

Discussion

The detailed chromosome measurements and karyotype asymmetry are significant data for cytotaxonomy of plant. Wild and cultivated species are used because of their economic importance in family Fabaceae (Jha et al. 2017). Thus it is possible to make phylogenetic comparisons of ancient and new crops. Recently, synthetic polyploids are also used in chromosomal data of genus Vicia (Pavlíková et al. 2017). Phylogenetic and cytogenetic data may be useful for conservation of genetic diversity and future crop breeding methods.

In Tables 2–4, the chromosome numbers of V. cassubica, V. noeana var. noeana, V. sativa subsp. sativa and V. caesarea are shown as 2n = 12. It was reported that the chromosome numbers were 2n = 10 in V. sativa L. subsp. incisa (Bieb.) Arc.; 2n = 12 in V. cassubica, V. noeana, V. noeana var. noeana, V. noeana Boiss. & Reut. ex Boiss. var. megalodonta Rech. Fil., V. sativa, V. sativa subsp. sativa, Vicia sativa L. subsp. nigra (L.) Ehrh. and V. caesarea; 2n = 14 in V. noeana var. noeana, V. sativa subsp. nigra and V. sativa subsp. incisa (Yefimov 1988; Şahin and Babaç 1990; Şahin et al. 1996; Meriç and Dane 1999; Bağcı and Şahin 2000; Rahiminejad et al. 2000; Sevimay et al. 2005; Gianfranco et al. 2008; Namazi et al. 2008; Kahlaoui et al. 2009; Arslan et al. 2012; Gedik et al. 2013). In Çeliktaş et al. (2006), the chromosome number was 2n = 10 in wild V. sativa and 2n = 12 in cultured V. sativa. All reports include both similar and dissimilar results with our results.

In Tables 2 and 3, the chromosome numbers of V. articulata, V. villosa subsp. villosa and V. peregrina are shown as 2n = 14. It was reported that the chromosome numbers are 2n = 12 in V. peregrina; 2n = 14 in V. articulata, V. villosa, V. villosa Roth subsp. dasycarpa (Ten.) Stank. and V. peregrina (Rahiminejad et al. 2000; Tabur et al. 2001, 2009; Namazi et al. 2008; Kahlaoui et al. 2009). The reports include both similar and dissimilar results to our results. Also, Pavlíková et al. (2017) showed the 26 diploid (2n = 2x = 14), 25 natural tetraploid (2n = 4x = 28) and 27 synthetic tetraploid (2n = 4x = 28) in basic species V. cracca of sect. Cracca. They reported that the comparison of synthetic and natural polyploids provide understanding of the results of polyploidization and separate the effects of the duplication from evolution. Polyploidy originates by autopolyploidy (genome duplication of one species) and allopolyploidy (genome duplication with different species) and has played a major role in the speciation and evolution of higher plants (Demirci Kayıran and Özhatay 2017). The polyploidy rates increase with factors such as climate shifts, glaciations, high latitudes and high altitudes (Metzgar et al. 2016) In future studies, it is necessary to compare diploids and synthetic polyploids for all Vicia species.

The chromosome morphologies belonging to the studied taxa are different. Turkey is a very convenient area for genetic variations because of its location in different plant geographical regions which are Mediterranean, Euro-Siberian and Irano-Turanian. The genetic variations in Vicia in Turkey, which are clearly detectable, are in the chromosome morphologies and chromosome numbers. The haploid karyotype formulae are 7m in V. articulata, 6sm in V. cassubica, 7sm in V. villosa subsp. villosa, 5sm + 1st in V. noeana var. noeana, 5sm + 1st in V. sativa subsp. sativa, 5sm + 2st in V. peregrina and 4m + 2sm in V. caesarea. As an interesting note, sect. Cracca and Ervum only have median and submedian chromosomes, with no subtelocentric ones, and sect. Vicia only has submedian and subtelocentric chromosomes, with no median ones. A satellite was only observed in the first pair of chromosomes of V. noeana var. noeana. In literature, different chromosome formulae have been reported.

The karyotype formula of V. articulata was 1m + 2sm + 4st with satellite in the first and fourth chromosome pairs (Tabur et al. 2001). The karyotype formula of V. villosa subsp. villosa was 1m + 6sm with satellite in the seventh chromosome pair (Namazi et al. 2008). The karyotype formula of V. villosa subsp. darycarpa was 7sm with satellite in the sixth chromosome pair (Tabur et al. 2001). The karyotype formulae of V. noeana var. noeana were 6m (Karadağ and Büyükburç 2003), 3sm + 3st, 2sm + 4st, 6sm with satellite in the first chromosome pair (Gianfranco et al. 2008) and 1m + 3sm + 2st (Gedik et al. 2013). The satellite in the first chromosome pair is compatible with this study, but not the karyotype formula. The karyotype formula of V. noeana var. megalodonta was 5sm + 1st with satellites in the third and sixth chromosome pairs (Gedik et al. 2013). The karyotype formula is compatible with this study, but not the satellite. The karyotype formulae of V. sativa subsp. sativa were 1m + 5sa with satellites in the second and third chromosome pairs (Namazi et al. 2008) and 2sm + 3st + 1t (Gedik et al. 2013). The karyotype formulae of V. sativa subsp. nigra and V. sativa subsp. incisa were 1m + 1sm + 4a (Arslan et al. 2012) and 1sm + 6st (Meriç and Dane 1999), respectively. The karyotype formulae of V. peregrina were 1m + 3st + 3t and 1m + 4st + 2t with satellites in the first and third chromosome pairs (Gianfranco et al. 2008) and 7st with satellite in the third chromosome pair (Tabur et al. 2009). The karyotype formula of V. caesarea was 1m + 5sm (Şahin et al. 1996). Our results are different from all reports given above. It was reported that the differences in chromosome morphologies may contribute to the variation of the genera, sections and species (Altay et al. 2017).

The intrachromosomal asymmetry gradually increases with centromere shift from median point to terminal point. The values of AsK, TF, Syi, A1, A, and M_CA are parameters used in the calculation of intrachromosomal asymmetry. The interchromosomal asymmetry increases with more heterogeneity of chromosome sizes. Rec, A2 and CV_CL are parameters used in the calculation of intrachromosomal asymmetry (Peruzzi and Eroglu 2013).

In sect. Cracca, V. articulata is the most symmetrical karyotype, while V. villosa subsp. villosa is the most asymmetrical karyotype according to the M_CA, AsK, TF, Syi, A1, and A. Whereas V. villosa subsp. villosa is the most symmetrical karyotype, V. cassubica is the most asymmetrical karyotype in CV_CL, Rec, and A2 (Table 5).

Table 5. The asymmetry index values of Vicia taxa.

Taxa	AsK	TF	Syi	Rec	A1	A2	A	CVCL	MCA
V. articulata	57.14	42.86	75.00	74.95	0.23	0.20	0.13	20.20	13.28
V. cassubica	71.56	28.44	39.74	69.38	0.59	0.30	0.42	30.00	42.15
V. villosa subsp. villosa	73.09	26.91	36.82	81.84	0.62	0.19	0.46	18.55	45.51
V. noeana var. noeana	70.51	29.49	41.82	82.86	0.58	0.13	0.42	12.58	41.68
V. sativa subsp. sativa	70.42	29.58	42.00	79.31	0.57	0.20	0.41	19.56	40.52
V. peregrina	71.70	28.30	39.48	74.06	0.61	0.17	0.45	17.42	44.62
V. caesarea	61.00	39.00	63.94	70.53	0.36	0.35	0.22	35.18	22.45

In sect. Vicia, V. sativa subsp. sativa is the most symmetrical karyotype, while V. peregrina is the most asymmetrical karyotype according to the M_CA, AsK, TF, Syi, A1, and A. Whereas V. noeana var. noeana is the most symmetrical karyotype, V. sativa subsp. sativa is the most asymmetrical karyotype in CV_CL together with only A2. As a small difference from the other parameters, V. noeana var. noeana is the most symmetrical karyotype, while V. peregrina is the most asymmetrical karyotype in Rec value (Table 5).

In all sections, V. articulata is the most symmetrical karyotype, while V. villosa subsp. villosa is the most asymmetrical karyotype according to the M_CA, AsK, TF, Syi, A1, and A. However, the asymmetrical karyotypes are different in interchromosomal asymmetries. While V. noeana var. noeana is the most symmetrical karyotype in CV_CL, Rec, and A2. V. caesarea is the most asymmetrical karyotype in only CV_CL and A2. Unlike all parameters, V. cassubica is the most asymmetrical karyotype in Rec value (Table 5).

Intrachromosomal asymmetry follows the same trends as the taxa showing symmetrical and asymmetric karyotypes. In Table 6, the M_CA value showed perfect positive and negative correlations with AsK (r = 0.998), TF (r = − 0.998), Syi (r = − 0.998), A1 (r = 0.999) and A (r = 0.998) for intrachromosomal asymmetry. In interchromosomal asymmetry, it is the same as the taxa showing symmetrical and asymmetric karyotypes. In Table 6, while the CV_CL value showed the perfect positive correlation with A2 (r = 0.999), it showed weaker correlation with Rec (r = − 0.826).

Table 6. Pearson correlation for asymmetry indices.

	AsK	TF	Syi	Rec	A1	A2	A	CVCL	MCA
AsK	1
TF	−1.000*	1
Syi	−0.999*	0.999*	1
Rec	0.372	−0.372	−0.363	1
A1	0.996*	−0.996*	−0.999*	0.353	1
A2	−0.355	0.355	0.337	−0.804	−0.333	1
A	0.997*	−0.997*	−0.998*	0.386	0.998*	−0.380	1
CVCL	−0.371	0.371	0.353	−0.826	−0.348	0.999*	−0.394	1
MCA	0.998*	−0.998*	−0.998*	0.372	0.999*	−0.366	0.998*	−0.380	1

* Correlation is significant at the 0.05 level

The very weak negative correlations were determined in an interchromosomal asymmetry against an intrachromosomal asymmetry as M_CA–CV_CL (r = − 0.380), Syi–Rec (r = − 0.363) and A1–A2 (r = − 0.333) and (Table 6 and Figure 3). It was likely that the weak negative correlations are due to parameters of interchromosomal asymmetry. It was reported that a parameter of interchromosomal asymmetry gives reliable results with a parameter of intrachromosomal asymmetry (Peruzzi and Eroglu 2013). Figure 3 gives scatter diagrams of M_CA–CV_CL and Syi–Rec. The diagrams are like mirror images of each other. This is because the M_CA–CV_CL values increase with increasing asymmetry; conversely, Syi–Rec values decrease with increasing asymmetry (Eroğlu et al. 2013; Altay et al. 2017).

Figure 3. Scatter diagram between M_CA–CV_CL and Syi–Rec: Sect. of Cracca, Vicia and Ervum. (a) V. articulata; (b) V. cassubica; (c) V. villosa subsp. villosa; (d) V. noeana var. noeana; (e) V. sativa subsp. sativa; (f) V. peregrina; (g) V. caesarea.

In Figure 3, the sections of genus Vicia have different degrees of karyotype asymmetry: sect. Cracca with a balance between interchromosomal and intrachromosomal, sect. Vicia with higher intrachromosomal, sect. Ervum with higher interchromosomal. On the other hand, more chromosomal data will give more accurate results.

In this study, detailed chromosome measurements and karyotype asymmetry degrees are determined for V. articulata, V. cassubica, V. villosa subsp. villosa, V. noeana var. noeana, V. sativa subsp. sativa, V. peregrina and V. caesarea. The diploid chromosome numbers and basic chromosome numbers are 2n = 12, 14 and x = 6, 7. In many genera and genus Vicia, the basic chromosome numbers are x = 5, 6, 7 and the most common diploid numbers are 2n = 12, 14 (Gianfranco et al. 2008; Gedik et al. 2013; Tanaomi et al. 2016). All taxa have relatively large chromosomes, between 1.86 and 7.21 μm. The little variations were showed in size of the chromosomes. The karyotypes of V. articulata are quite symmetric, because it has completely median chromosomes. In all results, chromosomes vary from median to subterminal and karyotypes vary from symmetric to asymmetric. The variation of interspecific, intersection and intergeneric may increase with diversity in karyotype asymmetry degrees and karyotype formulae.

Disclosure statement

No potential conflict of interest was reported by the authors.