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Genetic diversity of spinach (Spinacia oleracea L.) landraces collected in Iran using some morphological traits

Authors:
  • Islamic Azad University, Isfahan (Khorasgan) Branch, Iran

Abstract and Figures

Spinach has become an important vegetable crop in most regions of the world and remarkable changes in production amounts have occurred in the past decades due to demand increase in many countries. Fifty-four spinach landraces collected from diverse geographical regions of Iran were evaluated for several qualitative and quantitative traits. Landraces indicated a high variability for measured morphologic characteristics regarding results of variance analysis and descriptive statistics. The first three factors of factors analysis explained 76.8% of variation of spinach landraces. The first extracted factor can be regarded as a leaf property vector; the extracted second factor could be named as yield vector and the third factor was female plants percent vector. The dendrogram of cluster analysis generated from genotypes distance matrices showed that in a distance linkage of 800, the 54 spinach landraces could be agglomerated into sixteen clusters. The number of clusters was verified by multivariate analysis of variance test through Wilks' Lambda statistics. Some spinach landraces such as G10 G13, G38 and G41 were individual cluster and were not similar to the other collected genotypes while some of the spinach landraces were similar to each other and grouped as one cluster such as cluster 9 (C9). The cluster C14 (landrace Karaj 2) was the most favorable genotype due to good performance for most measured quantitative traits. This landrace could be recommended for commercial release after complementary experiments. Also, landraces G1 (Arak) and G3 (Urmia) indicate good potential regarding the measured traits. These landraces could be used directly as commercial cultivars or introduced in spinach breeding programs.
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1 Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Maragheh, Maragheh, Iran
2 Department of Horticulture Science, Islamic Azad University, Khorasgan Branch, Isfahan, Iran
Acta agriculturae Slovenica, 103 - 1, marec 2014 str. 101 - 111
COBISS Code 1.01
DOI: 10.14720/aas.2014.103.1.11
Agrovoc descriptors: germplasm, genetic resources, spinacia oleracea, spinach, land varieties, biogeographic regions,
agroclimatic zones, biogeography, statistical methods, methods, genotypes, genetic distance
Agris category code: f30
Genetic diversity of spinach (Spinacia oleracea L.) landraces collected in Iran
using some morphological traits
Naser SABAGHNIA1, H.A. ASADI-GHARNEH2, Mohsen JANMOHAMMADI1
Received August 28, 2013; accepted October 16, 2013.
Delo je prispelo 28. avgusta 2013, sprejeto 16. oktobra 2013.
ABSTRACT
Spinach has become an important vegetable crop in most
regions of the world and remarkable changes in production
amounts have occurred in the past decades due to demand
increase in many countries. Fifty-four spinach landraces
collected from diverse geographical regions of Iran were
evaluated for several qualitative and quantitative traits.
Landraces indicated a high variability for measured
morphologic characteristics regarding results of variance
analysis and descriptive statistics. The first three factors of
factors analysis explained 76.8% of variation of spinach
landraces. The first extracted factor can be regarded as a leaf
property vector; the extracted second factor could be named as
yield vector and the third factor was female plants percent
vector. The dendrogram of cluster analysis generated from
genotypes distance matrices showed that in a distance linkage
of 800, the 54 spinach landraces could be agglomerated into
sixteen clusters. The number of clusters was verified by
multivariate analysis of variance test through Wilks' Lambda
statistics. Some spinach landraces such as G10 G13, G38 and
G41 were individual cluster and were not similar to the other
collected genotypes while some of the spinach landraces were
similar to each other and grouped as one cluster such as cluster
9 (C9). The cluster C14 (landrace Karaj 2) was the most
favorable genotype due to good performance for most
measured quantitative traits. This landrace could be
recommended for commercial release after complementary
experiments. Also, landraces G1 (Arak) and G3 (Urmia)
indicate good potential regarding the measured traits. These
landraces could be used directly as commercial cultivars or
introduced in spinach breeding programs.
Key words: germplasm, morphological variation, multivariate
analysis, spinach
IZVLEČEK
GENETSKA RAZNOLIKOST AKCESIJ ŠPINAČE
(Spinacia oleracea L.) ZBRANIH V IRANU, DOLOČENA
Z NEKATERIMI MORFOLOŠKIMI ZNAKI
Špinača je postala pomembna zelenjadnica v večjem delu
sveta in znaten porast njene pridelave se je pojavil zaradi vse
večjega povpraševanja v mnogih državah. 54 akcesij špinače,
nabranih v različnih delih Irana, je bilo ovrednotenih na
osnovi številnih kvalitativnih in kvantitativnih znakov.
Akcesije so pokazale veliko variabilnost v merjenih
morfoloških znakih glede na rezultate analize variance in
opisne statistike. Prvi trije faktorji faktorske analize so
pojasnili 76.8 % variabilnosti akcesij špinače. Prvi faktor od
teh je bil povezan z lastnostmi listov, drugi s pridelkom in
tretji z deležem ženskih rastlin. Dendrogram klasterske
analize, generiran na osnovi izračunanih distanc med genotipi
je pokazal, da lahko na osnovi distančne povezave 800, 54
akcesij špinače združimo v 16 skupin. Število skupin je bilo
potrjeno z multivariatno analizo variance s pomočjo Wilks'
Lambda statistke. Nekatere akcesije kot na primer G10 G13,
G38 in G41 so bile samostojne skupine in niso bile podobne
drugim zbranim genotipom, med tem ko so si bile druge
akcesije podobne in so se uvrstile v eno skupino, npr. skupino
9 (C9). Skupina C14 (akcesija Karaj 2) je bila najboljši
genotip glede na dobre vrednosti za večino merjenih
kvantitativnih znakov. To akcesijo bi lahko priporočili za
komercialno uporabo po dopolnih preizkusih. Tudi akcesiji G1
(Arak) in G3 (Urmia) kažeta dober potencial glede na merjene
znake. Ti akcesiji bi bili lahko neposredno uporabljeni kot
komercialni sorti ali vključeni v žlahtniteljski program
špinače.
Ključne besede: genski material, morfološka variabilnost,
multivariatna analiza, špinača
Naser SABAGHNIA et al.
Acta agriculturae Slovenica, 103 - 1, marec 2014
102
1 INTRODUCTION
Spinach (Spinacia oleracea L.) is an edible and
annual plant that grows rapidly and has the ability
to survive over moderate winter. It is versatile
which is used as a salad, a cooked vegetable or as a
component of many other cooked meat and
vegetable dishes (Sensoy et al., 2011). Leafy
vegetables are an important part in the human diet
and spinach is one of the dark green leafy
vegetables which contains high beta carotene and
folate, and is also a good source of vitamin C,
calcium, iron phosphorous, sodium and potassium
(Dicoteau, 2000; Avsar, 2011). Spinach as
dioecious specie with both male and female plants
is an herbaceous leafy vegetable in the family of
Amaranthaceae (Salk et al., 2008) and its leaves
are alternate, simple, from ovate to triangular-
based, with larger leaves at the base of the plant
and small leaves higher on the flowering stem
(Vural et al., 2000).
Today, China, the United States, Indonesia, Japan
and Turkey are among the largest commercial
producers of spinach (FAO, 2011). Iran is the one
of the spinach producers with about 105 thousand
tons per year based on FAO statistics. The average
yield of spinach in Iran is 2096 kg ha-1 while
world’s average yield is 2420 kg ha-1 (FAO, 2011).
Also, the average yield of spinach in China is 2768
kg ha-1, in the United States is 2360 kg ha-1,
Indonesia is 3424 kg ha-1, Japan is 12471 kg ha-1,
and Turkey is 9249 kg ha-1 (FAO, 2011). Spinach
is native to southwest Asia and commonly thought
to have originated in Iran (Nonnicke, 1989;
Swiader and Ware, 2002) and was first mentioned
by the Chinese as the herb of Persia. It was first
cultivated in North Africa, came to northern
Europe by way of Spain, documented in Germany
and then was a common garden vegetable by 1500
in England and France (Dicoteau, 2000; Swiader
and Ware, 2002)
Although, hybrids cultivars of spinach were
introduced in the 1950's and they have become the
major type of spinach cultivars (Morelock and
Correll, 2008), but Iranian farmers currently use
native spinach landraces, which have good
adaptability to different local conditions. The yield
performance of these landraces is very low
(typically about 2000 kg ha-1) compared with the
highest global yields (12471 kg ha-1, produced in
Japan; FAO 2011). Therefore, it is essential for
Iran to has had spinach breeding program for
increasing the genetic potential of yield as well as
other important traits. Since Iran is a centre of
genetic diversity of many cultivated plants,
including wheat, alfalfa, spinach and etc, it is
essential to conserve these important resources.
Most of the spinach accessions are landraces which
are highly adapted to specific environmental
conditions and are useful sources of genetic
variation (Asadi and Hasandokht, 2007). However,
utilization of the genetic potential of different
germplasms needs detailed knowledge about these
genetic collections (Morelock and Correll, 2008),
including characterization, evaluation and
classification.
Multivariate procedures are useful for
characterization, evaluation and classification of
germplasm collections when a large number of
accessions are to be assessed for several traits. The
usefulness of multivariate procedures for handling
morphological variation in plant genetic resources
has been proved in many crops; wheat (Damania et
al., 1996; Sorghum (Ayana and Bekele, 1999). The
generated information of multivariate procedures
can be useful for identifying different accessions
that have explained traits for crossing, for planning
efficient plant improvement program. Also, it is
possible to establish core collections for revealing
the structure of variation in plant genetic resources
and for investigating some aspects of crop
evolution (Perry and McIntosh, 1991; Ayana and
Bekele, 1999).
Some investigations have been performed in the
past on Iranian spinach germplasm collections, but
most of them studies are limited with either using
only univariate statistics or studying samples from
a limited geographical range (Benedictos, 1999;
Asadi and Hasandokht, 2007; Eftekhari et al.,
2010). The objective of this investigation was to
determine the structure of distribution of
morphological variation for 10 quantitative traits
and 9 qualitative traits in 54 accessions of native
Iranian spinach germplasm collections sampled
from a wide geographical range of Iran and
identify groups of accessions with similar
quantitative traits.
Genetic diversity of spinach (Spinacia oleracea L.) landraces collected in Iran using some morphological traits
Acta agriculturae Slovenica, 103 - 1, marec 2014 103
2 MATERIALS AND METHODS
2.1 Trial protocol
Fifty-four native Iranian spinach germplasm
collections were collected as seed in Iran, and then
evaluated in the field in a randomized complete
block design (RCBD) replicated four times. Each
spinach germplasm was collected as seed
multiplied by the farmers. The geographical
properties of the 54 sites of the collected spinach
landraces are given in Table 1. Field soil was
calcareous, loamy structure, low organic matter,
and low salt content. Also, it had poor nitrogen and
phosphorous and adequate potassium. Fertilization
was carried out by spreading 80 kg N ha-1 (half of
N at sowing stage and half of N at seedling
emergence). Sowing was done manually at the rate
of 50 kg seed ha-1. Each plot contained six 3 m
long rows with 25 cm between rows and plot size
was 4.5 m2. Control by hand weeding was carried
out twice when the weed density was high, in the
pre-flowering and post-flowering stages. The
harvested plot size was 2.5 m2 (four 2.5 m rows at
the center of each plot).
Several quantitative traits consist on leaf length
(LL), leaf width (LW), petiole length (PL), petiole
diameter (PD), leaf area (LA), leaf numbers in
flowering (LN), days to flowering (DF), female
plants percent (FP), fresh yield (FY) and dry yield
(DY) were measured. Also, various qualitative
traits consist on leaf texture (LT, 1=smooth,
2=slight crinkled, 3= crinkled), seed type (ST,
1=smooth, 2=prickly), stem anthocyanin (SA,
1=very low, 3=low, 5=intermediate, 7=high,
9=very high), petiole attitude (PA, 1=erect,
2=semi-spared, 3= spared), vegetative leaf shape
(VL, 1=elliptic, 2=broad elliptic, 3=circular,
4=ovate, 5=broad ovate, 6=triangular),
reproductive leaf shape (RL, 1=smooth, 2=pointy);
leaf edge (LE, 1=smooth, 2= rippler); leaf color
(LC, 1=yellow-green, 2=grey-green, 3=blue-
green); seed color (SC, 1=yellow-green, 2=grey-
green, 3=blue-green) were measured.
2.2 Statistical analysis
The datasets were first tested for normality by
Anderson and Darling normality test using
MINITAB version 16 (2010) statistical software.
Analysis of variance was performed to evaluate
differences among measured quantitative traits and
the accessions were compared by LSD (least
significant differences) criteria. The factor analysis
(Cattell, 1965), which consisted of the reduction of
a large number of correlated variables to a much
smaller number of groups of variables called
factors. After extraction, the matrix of factor
loading was submitted to a varimax orthogonal
rotation, as applied by Kaiser (1958). The array of
communality, the amount of variance of a variable
accounted by the common factors together, was
estimated by the highest correlation coefficient in
each array as suggested by Seiller and Stafford
(1985). The 54 spinach accessions were clustered
using the SPSS 16 (SPSS, 2008), which grouped
the accessions into different clusters. The measure
of dissimilarity was Euclidean distance and the
clustering method was un-weighted pair group
method using centroids or UPGMC (Sneath and
Sokal, 1973). The number of clusters was
determined using multivariate ANOVA via Wilks'
lambda statistics.
Naser SABAGHNIA et al.
Acta agriculturae Slovenica, 103 - 1, marec 2014
104
Table 1: Geographical properties of the 54 locations where spinach landraces are collected
No. Name Longitude Latitude Altitude
(meter) No. Name Longitude Latitude
Altitude
(meter)
1 Arak 49
ْ
41 َ
E 34 ْ 05 َ
N 1755 28 Qum 50 ْ
53 َ E 34 ْ 38 َ
N
930
2 Ardestan 52
ْ
22 َ
E 33 ْ 23 َ
N 1205 29 Gochan 58 ْ
30 َ E 37 ْ 06 َ
N
1240
3 Urmia 45
ْ
04 َ
E 37 ْ 33 َ
N 1340 30 Kashan 51 ْ
27 َ E 33 ْ 59 َ
N
950
4 Esfahan 1 52
ْ
02 َ
E 32 ْ 32 َ
N 1525 31 Karaj 1 50 ْ
97 َ E 35 ْ 82 َ
N
1300
5 Esfahan 2 51
ْ
35 َ E 33 ْ 10 َ
N 1570 32 Karaj 2 50 ْ
85 َ E 35 ْ 80 َ
N
1350
6 Bojnord 57
ْ
19 َ E 37 ْ 28 َ
N 1070 33 Karaj 3 50 ْ
87 َ E 35 ْ 86 َ
N
1230
7 Brojerd 48
ْ
45 َ E 33 ْ 53 َ
N 1580 34 Kerman 57 ْ
05 َ E 30 ْ 17 َ
N
1775
8 Beenab 46
ْ
05 َ E 37 ْ 53 َ
N 1290 35 Kermanshah 47 ْ
65 َ E 34 ْ 31 َ
N
1400
9 Birjand 59
ْ
21 َ E 32 ْ 87 َ
N 1491 36 Lahijan 1 50 ْ
14 َ E 37 ْ 26 َ
N
-11
10 Tabriz 46
ْ
18 َ E 38 ْ 04 َ
N 1366 37 Lahijan 2 50 ْ
11 َ E 37 ْ 16 َ
N
-10
11 Chamkahriz 51
ْ
18 َ E 32 ْ 18 َ
N 1685 38 Langrood 50 ْ
14 َ E 37 ْ 19 َ
N
-25
12 Khoramabad 48
ْ
21 َ E 33 ْ 29 َ
N 1200 39 Mako 44 ْ
55 َ E 39 ْ 28 َ
N
1182
13 Drood 48
ْ
70 َ E 33 ْ 40 َ
N 1326 40 Mobarake 51 ْ
30 َ E 32 ْ 21 َ
N
1900
14 Rahimabad 51
ْ
57 َ E 32 ْ 28 َ
N 1550 41 Maragheh 1 46 ْ
16 َ E 37 ْ 21 َ
N
1477
15 Rahnan 1 51
ْ
36 َ E 32 ْ 41 َ
N 1545 42 Maragheh 2 46 ْ
20 َ E 37 ْ 24 َ
N
1485
16 Rahnan 2 51
ْ
40 َ E 32 ْ 42 َ
N 1525 43 Mashahad 59 ْ
36 َ E 36 ْ 18 َ
N
979
17 Zabol 61
ْ
29 َ E 31 ْ 01 َ
N 475 44 Malekan 1 46 ْ
06 َ E 37 ْ 08 َ
N
1302
18 Zanjan 48
ْ
40 َ E 36 ْ 40 َ
N 1650 45 Malekan 2 46 ْ
09 َ E 37 ْ 03 َ
N
1291
19 Saveh 50
ْ
05 َ E 35 ْ 10 َ
N 998 46 Minandab 46 ْ
06 َ E 36 ْ 57 َ
N
1314
20 Salmas 44
ْ
76 َ E 36 ْ 19 َ
N 1398 47 Mianeh 47 ْ
72 َ E 37 ْ 41 َ
N
1100
21 Sanandaj 46
ْ
89 َ E 35 ْ 31 َ
N 1518 48 Hamadan 48 ْ
31 َ E 34 ْ 48 َ
N
1850
22 Sirjan 55
ْ
40 َ E 29 ْ 27 َ
N 1735 49 Varamin 1 51 ْ
39 َ E 35 ْ 19 َ
N
915
23 Shiraz 1 52
ْ
22 َ E 29 ْ 37 َ
N 1540 50 Varamin 2 51 ْ
38 َ E 35 ْ 11 َ
N
911
24 Shiraz 2 52
ْ
12 َ E 29 ْ 17 َ
N 1320 51 Varamin 3 51 ْ
28 َ E 35 ْ 19 َ
N
923
25 Shirvan 57
ْ
92 َ E 37 ْ 40 َ
N 1492 52 Varamin 4 51 ْ
38 َ E 35 ْ 23 َ
N
918
26 Salehabad 50
ْ
57 َ E 34 ْ 31 َ
N 970 53 Varamin 5 51 ْ
35 َ E 35 ْ 19 َ
N
905
27 Ajabsher 45
ْ
55 َ E 37 ْ 28 َ
N 1330 54 Yazd 54 ْ
21 َ E 31 ْ 53 َ
N
1215
3 RESULTS AND DISCUSSION
All of the quantitative dataset was normal
according to Anderson and Darling normality test,
and so no transformation was applied for traits
(data not shown). Some descriptive statistics
including minimum value, maximum value,
arithmetic mean and coefficient of variation (CV)
for all measured traits (variables) of 54 spinach
genotypes are presented in Table 2. For example,
the minimum amount of fresh yield was 5949.60
kg ha-1, the maximum amount of fresh yield was
44957.00 kg ha-1 and the average fresh yield of
studied genotypes was 22151.82 kg ha-1. The
maximum leaf length was 15.98 cm; the minimum
leaf length was 5.87 cm and the average leaf length
was 10.16 cm. The maximum, minimum and
average leaf numbers at flowering time were 24,
12 and 16.93, respectively. The maximum percent
of female plants was 84 %, the minimum percent
of female plants was 20 %, and the average percent
of female plants was 54.88 %. Such information
can be derived for the other traits from Table 2.
Regarding CV values which ranges from 6 (in days
to flowering) to 40 % (in fresh yield) in
quantitative traits and ranges from 32 (in leaf edge)
Genetic diversity of spinach (Spinacia oleracea L.) landraces collected in Iran using some morphological traits
Acta agriculturae Slovenica, 103 - 1, marec 2014 105
to 46 % (in vegetative leaf shape) in quantitative
traits, indicates remarkable variation among 54
spinach landraces (Table 2).
The results of factor analysis are given in Table 3.
When fitting the factor analysis model, the first
three factors explained 76.8 % of variation for
spinach landraces. The first factor extracted can be
regarded as a leaf property vector (Table 3). It has
high loadings for five traits as leaf length, leaf
width, petiole length, leaf area and leaf numbers in
flowering, which all of them were the related to
leaf characteristics. This factor accounted for
50.6 % of the total variation in spinach landraces
data set. The extracted second factor could be
named as yield vector and accounted for 15.4 % of
the total data variability. It has high loadings for
days to flowering, petiole diameter, fresh yield and
dry yield traits, which petiole diameter, fresh yield
and dry yield were the related to yield
performance. The third factor is a female plants
percent vector (Table 3) which shows this trait had
high loadings in this factor and accounted for 10.7
% of the total data variability. It seems that leaf
property vector as the most important factor and
yield vector are more influent characteristics
among nine measured quantitative traits.
Table 2: Descriptive statistics of the measured traits in 54 spinach landraces
Traits Max. Min. Average CV
Leaf length (cm) 15.98 5.87 10.16 0.17
Leaf width (cm) 10.50 2.61 6.31 0.24
Petiole length (cm) 13.3 4 8.40 0.22
Petiole diameter (mm) 14.6 6 10.62 0.15
Leaf area (cm2) 118.8 11.2 53.88 0.36
Leaf numbers in flowering 24 12 16.93 0.14
Days to flowering 183 137 162.36 0.06
Female plants percent 84 20 54.88 0.20
Fresh yield (kg ha-1) 44957.00 5949.60 22151.82 0.40
Dry yield (kg ha-1) 4286.90 526.00 2161.66 0.38
Leaf texture 3 1 1.74 0.43
Seed type 2 1 1.24 0.35
Stem anthocyanin content 9 1 1.52 0.46
Petiole attitude 3 1 1.85 0.37
Vegetative leaf shape 6 1 1.65 0.46
Reproductive leaf shape 2 1 2.31 0.44
Leaf edge 2 1 1.57 0.32
Leaf color 3 1 2.02 0.39
Seed color 3 1 2.39 0.45
LT, Leaf texture (1=smooth, 2=slight crinkled, 3= crinkled); Seed type (1=smooth, 2=prickly); SA, Stem
anthocyanin (1=very low, 3=low, 5=intermediate, 7=high, 9=very high); PA, Petiole attitude (1=erect, 2=semi-
spared, 3= spared); VL, Vegetative leaf shape (1=elliptic, 2=broad elliptic, 3=circular, 4=ovate, 5=broad ovate,
6=triangular); RL, Reproductive leaf shape (1=smooth, 2=Pointy); LE, Leaf edge (1=smooth, 2= Rippler); LC, Leaf
color (1=yellow-green, 2=grey-green, 3=blue-green); SC, Seed color (1=yellow-green, 2=grey-green, 3=blue-green).
Naser SABAGHNIA et al.
Acta agriculturae Slovenica, 103 - 1, marec 2014
106
Table 3: Factor components loadings of quantitative traits obtained from 54 spinach landraces.
F1 F2 F3
Leaf length (cm) 0.66 0.40 0.27
Leaf width (cm) 0.92 0.11 0.04
Petiole length (cm) 0.86 0.12 -0.08
Petiole diameter (mm) 0.21 0.78 0.10
Leaf area (cm2) 0.89 0.29 0.13
Leaf numbers in flowering 0.63 0.41 -0.11
Days to flowering 0.07 0.66 0.12
Female plants percent 0.04 0.03 0.97
Fresh yield (kg ha-1) 0.33
0.90 -0.08
Dry yield (kg ha-1) 0.27
0.92 -0.11
Eigen value 5.1 1.5 1.1
% Variance 50.6 15.4 10.7
% Cumulative variance 50.6 66.0 76.8
To better understand the relationships among the
quantitative traits of spinach landraces, the
relationships are graphically displayed in a plot of
factor 1 and factor 2 (Fig. 1). In this plot, the first
factor axis mainly distinguishes the methods of
leaf width from the other quantitative traits. The
second factor axis separates leaf length and petiole
length from the other remained quantitative traits
(Fig. 1). Therefore, regarding two factors’ loading
scores, nine measured quantitative traits could be
divided into three groups: leaf width as the first
group, leaf length and petiole length as the second
group, and petiole diameter, leaf area, leaf numbers
in flowering, days to flowering, female plants
percent, fresh yield and dry yield.
Cluster analysis is a tool for classifying objects
into groups. Agglomerative hierarchical clustering
methods use the elements of a proximity matrix to
generate a tree diagram or dendrogram. The
dendrogram generated from genotypes distance
matrices showed to clearly group them (Fig. 2). In
a distance linkage of 800, the examined 54 spinach
landraces could be agglomerated into sixteen
clusters. The number of clusters was verified by
multivariate analysis of variance test through
Wilks' Lambda statistics (data not shown). The
related spinach landraces of each sixteen clusters
and their qualitative traits are given in Table 4.
Some spinach landraces such as G10 G13, G38
and G41 were individual cluster and were not
similar to the other collected genotypes while some
of the spinach landraces were similar to each other
and grouped as one cluster such as cluster 9 (C9)
which consist on G17, G12, G23, G37, G28, G34,
G36, G40, and G48.
Genetic diversity of spinach (Spinacia oleracea L.) landraces collected in Iran using some morphological traits
Acta agriculturae Slovenica, 103 - 1, marec 2014 107
Figure 1: Plot of two first factor analysis of nine traits for the 54 spinach genotypes. LL, Leaf length (cm); LW, Leaf
width (cm); PL, Petiole length (cm); PD, Petiole diameter (mm); LA, Leaf area (cm2); LN, Leaf numbers in
flowering; DF, Days to flowering; FP, Female plants percent; FY, Fresh yield (kg ha-1); DY, Dry yield (kg ha-1).
Figure 2: Hierarchical cluster analysis of the 54 spinach genotypes based on Ward’s method using measured traits.
The mean and LSD (least significant differences)
values of the quantitative traits of sixteen clusters
are given in Table 5. The highest leaf length (LL)
was belong to cluster C7 (12.57 cm) and the lowest
LL was belong to cluster C2 (6.78 cm); and it is
clear that, there are good variations in length of
spinach landraces. According to the LSD values,
sixteen clusters could be divided to six distinct
groups based on leaf length. Larger leaves are
found at the base of the plant and small leaves are
found higher on the flowering stem (LeStrange et
al., 1999; Avsar, 2011). The cluster C14 had the
largest leaf width (8.18 cm) and the cluster C1 had
the smallest leaf width (3.76 cm). According to the
LSD values of leaf width, sixteen clusters could be
divided to five distinct groups. Both leaf length
and leaf width are important traits in spinach yield
performance (Asadi and Hasandokht, 2007). Due
Naser SABAGHNIA et al.
Acta agriculturae Slovenica, 103 - 1, marec 2014
108
to high variability of these two traits which is
observed in studied landraces, it is possible to
establish a breeding program to increase leaf yield
in spinach.
The longest petiole length (PL) was seen in the
cluster C11 (9.87 cm), while the shortest PL was
seen in the cluster C1 (5.51 cm). The LSD values
of petiole length divided the sixteen clusters into
three distinct groups. The long petiole length is
essential for machinery harvesting and genetic
improving for having long petiole length is one of
the breeding targets of spinach (Eftekhari et al.,
2010). Also, the relative length of petiole is a
commercial factor for the producing of spinach
canner. The most petiole diameter (PD) as 12.81
mm was observed in the cluster C15 and the low
PD as 7.5 mm was observed in the cluster C2
(Table 5). There are not any general correlations
among petiole length and petiole diameter, but
plants that produce the largest petioles also
produce in general the thickest (Pandey and
Kalloo, 1993; Avsar, 2011).
The largest leaf area (LA) was belong to cluster
C14 (76 cm2) and the smallest LA was belong to
cluster C1 (24.06 cm2). The largest size of leaf area
produces the longest leaf length both in absolute
length and relative to petiole length, and
conversely, the shortest petioles. This would seem
to show that the most of petiole length growth was
made relatively in early stages, when conditions
favorable for growth occurred; growth in leaf
length was more rapid than growth in petiole
length. The cluster C14 had the most leaf numbers
in flowering time (20 leaf) while the cluster C5 had
the lowest leaf numbers in flowering time (12.33
leaf). Harvest of spinach plants of marketable size
is depending on leaf number and it is correlated
with the length of growing period. Spinach is
mainly grown for fresh leaves and both the number
of leaves and leaf area determine yield
performance. However, a high variance was
observed for number of leaf in this study which
depicted a broad base of the studied landraces for
these traits. This maximizes the scope of selection
for these traits in the germplasm assayed. Also, the
different environmental conditions influences on
leaf numbers production and it seem that leaf
production per day to be highest under long-day
and moderate temperature conditions (Pandey and
Kalloo, 1993).
The early flowering cluster was C4 with 146.67
days to flowering and the late flowering clusters
were C7 and C8 with 171 days to flowering (Table
5). The higest percent of female plants (64.67%)
was seen in cluster C8 and the lowest percent of
female plants (46%) was seen in cluster C4. The
high fresh yielding landrace was cluster C16
(36429.50 kg ha-1) and the low fresh yielding
landrace was cluster C1 (7452.34 kg ha-1). The
LSD values of fresh yield divided the sixteen
clusters into nine distinct groups. Finally, the high
dry yielding landrace was cluster C15 (3405.66 kg
ha-1) and the low dry yielding landrace was cluster
C1 (727.97 kg ha-1). The LSD values of dry yield
divided the sixteen clusters into six distinct groups.
It seems that there are remarkable variation in both
fresh and dry yield of 54 spinach landraces and
these genotypes could be used for increasing yield
in future spinach improvement programs.
Regarding all quantitative traits, it seems that
cluster C14 which contain only landrace Karaj 2
was the most favorable genotype due to good
performance for most measured quantitative traits.
Its leaf texture was smooth and so could
accumulate low amounts of nitrate, and it had low
amounts of anthocyanin (Table 4). Petiole shapeof
landrace Karaj 2 is semi-spared and regarding the
long petiole length simply could be used for
machinery harvest. This landrace has many of
good characteristics for proper performance and
could be recommended for commercial release
after complementary experiments. The finding of
such good spinach landrace in this study at Iran as
its origin indicates the high potential of native
landraces in origin of plants.
After cluster C14, cluster C16 which consist on
landraces G1 (Arak) and G3 (Urmia) indicate good
potential regarding the measured traits. The leaf
texture of these landraces was moderate (slight
crinkled), and their anthocyanin content was
acceptable (low). The leaf color of both Arak and
Urmia landraces was grey-green which is suitable
for frizzing industries (Table 4). However, these
landraces could be used directly as commercial
cultivars or introduced in spinach breeding
programs due to high potential in most measured
qualitative and quantitative characteristics.
Clusters C12, C13 and C15 had good performances
for some important traits such as dry yield and are
useful sources of genetic variation for improving
Genetic diversity of spinach (Spinacia oleracea L.) landraces collected in Iran using some morphological traits
Acta agriculturae Slovenica, 103 - 1, marec 2014 109
yield performance in spinach. There were
landraces G8 (Beenab), G9 (Birjand), G11
(Chamkahriz), G14 (Rahimabad), G15 (Rahnan 1),
G16 (Rahnan 2), G22 (Sirjan), G50 (Varamin 2) in
these clusters which are collected from different
geographical regions of Iran. It seems that these
landraces were variable from other aspects which
are not measured in this study. Finally every one of
the 54 spinach landraces which is used in this
investigation maybe had at least one important trait
resource and could be enter to different spinach
breeding program based on the breeder target(s).
Spinach is a very important source of nutrients and
is dispersed throughout Iran as its origin and all
over the world. Plant materials of present
investigation were chosen because there are not
many studies on spinach especially on landraces. A
total of 54 spinach landraces were collected from
different geographical regions of Iran which
provided morphological data for the landraces. The
dendrogram of cluster analysis for the dataset
showed 16 groups. Multivariate PCA analysis of
morphological data was performed for 3
parameters and the analysis showed good
separation of the quantitative traits on the plot
based on first two PC. This investigation provided
suitable information that may be useful to plant
breeders who wish to find the most distinct spinach
landraces. For germplasm collections, the results of
present investigation may aid to conserve more
distinct accessions and to eliminate similar
accessions to preparing proper spinach gene-bank
in Iran. In future studies, a plant breeder may select
two distinct accessions and hybridize them to
create a new generation and to obtain one or more
new cultivars with favorable characteristics such as
resistance to biotic and abiotic stresses.
In conclusion, it was seen that characterization of
spinach landraces based on the morphological
traits was suitable to assess the genetic diversity
among collected spinach landraces. Results of this
investigation also can aid to define strategies for
further collection. Since our results show that the
pattern of observed variation is governed by
morphological traits, future germplasm collections
should aim to investigate genetic variation via
different molecular markers. Also, it is essential to
explore variation using more landraces which are
collected geographically and climatically from
different regions, instead of collecting extensively
within individual regions. However, a high
variability was observed for most measured traits
and obtaining more diverse collections especially
exotic germplasm is not needed for future breeding
in spinach.
Table 4: The genotypes of 16 clusters and their qualitative characteristics
Class Landraces LT ST SA PA VL RL LE LC SC
C1 G5, G20 2 1 5 2 4 1 1 2 2
C2 G38 1 1 1 3 6 2 2 2 3
C3 G41 3 1 7 2 3 1 1 3 3
C4 G10 3 1 3 1 2 1 2 3 1
C5 G13 1 1 1 2 5 1 2 2 2
C6 G53, G33, G26, G45, G43, G7 2 1 5, 7 2 2,3 1 2 3 3
C7 G24 2 1 7 2 1 1 1 3 3
C8 G4 1 1 9 2 2 1 2 1 2
C9 G37, G40, G36, G48, G28, G23,
G34, G17, G12 1 1
3,5,
9
1,
2 3 1,
2 2 2,
3 2
C10 G49, G44, G42, G51, G52, G54,
G35, G27, G47, G18, G19, G6 2 1,
2
1,
5
2,
3
1,
2 1 2 2 2,
3
C11 G29, G21, G46, G39, G30, G31,
G25, G2
1,
2 1 3,
7
1,
2 1 1,
2 2 1,
2 3
C12 G50, G11, G14, G9 2 2 1 2 1,3 1 2 2 2
C13 G22, G16, G8 1 1 5, 9 2 4 1 1 2 3
C14 G32 1 1 3 2 1 1 1 1 1
C15 G15 1 1 9 3 2 2 1 1 2
C16 G3, G1 2 2 3 2 1 1 1 2 1
LT, Leaf texture (1=smooth, 2=slight crinkled, 3= crinkled); Seed type (1=smooth, 2=prickly); SA, Stem
anthocyanin (1=very low, 3=low, 5=intermediate, 7=high, 9=very high); PA, Petiole attitude (1=erect, 2=semi-
spared, 3= spared); VL, Vegetative leaf shape (1=elliptic, 2=broad elliptic, 3=circular, 4=ovate, 5=broad ovate,
6=triangular); RL, Reproductive leaf shape (1=smooth, 2=pointy); LE, Leaf edge (1=smooth, 2= rippler); LC, Leaf
color (1=yellow-green, 2=grey-green, 3=blue-green); SC, Seed color (1=yellow-green, 2=grey-green, 3=blue-green).
Naser SABAGHNIA et al.
Acta agriculturae Slovenica, 103 - 1, marec 2014
110
Table 5: The quantitative characteristics of 16 clusters of spinach landraces
Class LL LW PL PD LA LN DF FP FY DY
C1 7.20 3.76 5.51 8.67 24.06 14.33 150.50 53.17 7452.34 727.97
C2 6.78 4.64 8.05 7.50 31.67 16.67 162.00 53.33 9158.45 973.10
C3 10.73 5.54 7.63 10.63 47.84 18.33 147.67 59.67 10787.81 1109.33
C4 8.89 4.94 7.13 10.43 38.59 14.00 146.67 46.00 15783.36 1534.02
C5 8.08 5.78 7.05 9.50 35.17 12.33 169.33 52.33 14811.47 1546.44
C6 10.01 5.66 7.95 10.07 47.75 15.83 152.72 54.50 13111.50 1365.14
C7 12.57 6.57 8.30 12.57 69.97 17.33 171.00 62.33 28633.95 2729.43
C8 12.50 6.08 8.77 12.77 68.93 18.00 171.00 64.67 27509.96 2669.30
C9 10.64 7.02 8.93 10.51 58.65 17.37 165.27 55.93 23377.59 2302.94
C10 9.98 6.24 8.20 10.37 52.58 16.58 160.94 53.71 20891.73 2057.99
C11 10.54 7.58 9.87 9.97 61.37 16.83 168.00 64.67 24355.39 2131.18
C12 10.45 6.86 9.51 11.67 58.17 19.33 170.33 48.78 33168.25 3240.43
C13 10.90 6.32 9.39 12.20 59.79 18.00 169.56 57.89 31702.52 3103.02
C14 10.63 8.18 9.79 11.81 76.00 20.00 166.00 46.33 35384.93 3167.40
C15 11.01 6.12 9.01 12.81 60.31 17.00 170.67 61.33 34545.36 3405.66
C16 10.88 7.05 7.83 12.29 68.36 19.50 170.17 54.50 36429.54 3291.19
LSD 0.88 0.86 1.03 0.79 11.00 1.34 5.56 7.05 3395.16 314.65
LL, Leaf length (cm); LW, Leaf width (cm); PL, Petiole length (cm); PD, Petiole diameter (mm); LA, Leaf area
(cm2); LN, Leaf numbers in flowering; DF, Days to flowering; FP, Female plants percent; FY, Fresh yield (kg ha-1);
DY, Dry yield (kg ha-1).
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In this study, 95 Turkish spinach (Spinacia oleracea L.) accessions were used for genetic diversity analysis by using the SRAP (Sequence Related Amplified Polymorphism) marker system and also 81 of the spinach accessions were used for morphological data analysis using data from the Centre for Genetic Resources, Wageningen University, The Netherlands. In the study, a total of 25 SRAP marker combinations were used and 19 of these were suitable for genetic analysis because they gave amplification and they were polymorphic. For the 19 SRAP markers, 123 bands were amplified and 67 were polymorphic. These polymorphic bands were used to construct a dendrogram for spinach cultivars and to determine the genetic distance. Dendrogram analysis was done UPGMA method which was calculated using DICE matrix. Genetic similarity ranged between 0.30 and 0.95. Group B had most related accessions, 0.77 similar, and Group A, C, and D had more distinct accessions, 0.60 similarities. For the morphological data PCA(Principal Component Analysis) was performed and no any apparent group was seen so high diversity was indicated by the 2D plot. All these results showed that the SRAP marker system was a suitable marker to determine genetic diversity, that Turkish spinach germplasm is diverse and that accessions should be preserved. Another importance of this results is that it is the first and only study that has been done with Turkish spinach germplasm.
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Chapter
Spinach, Spinacia oleracea L. (2n = 12), is an important leafy vegetable, of which the leaves and tender shoots are consumed fresh or processed. Spinach is native to central Asia, most probably Persia (Iran). Spinach (Spinacia oleracea L.) belongs to the family Chenopodiaceae. Spinach is annual for leaf production and biennial for seed production. It produces rosettes of fleshy leaves, which may be crinkled or smooth in the vegetative phase; later, the stem elongates and forms flower stalks during the reproductive phase, with narrow, pointed leaves. This chapter discusses the cytology and genetics of spinach. Spinacia oleracea L. contains 2n = 12 chromosomes. Sex expression in spinach is controlled by a single pair of sex chromosomes (XY). The main objectives of spinach improvement are high yield, good quality of green leaf, uniformity, and resistance to major diseases. Breeding methods applicable to the improvement of cross-fertilizing vegetable crops may also be applicable to spinach improvement. Population improvement methods such as recurrent selection, mass selection, and progeny testing are suitable for the development of new variation. The chapter discusses the objectives for breeding spinach and the breeding methods used in the breeding of this vegetable.