Clustering Different Greenhouse Pepper Varieties Based on Some Morphological and Fruit Yield

10.30486/roce.2018.545278

Abstract

Abstract
 
Pepper is one of most important vegetables in the world. Pepper has important role in world vegetablecommerce and the worth of its export and import is very high. Selection of better plants is inseparableparts of breeding programs and need a variable population. So assessment of genetic variation is the firststep of breeding programs/ For this purpose, genetic variation of 22 different varieties of greenhousepepper was assayed for days to flowering and fruiting, plant height, peduncle length, single fruit weight, fruit yield and fruit length. Descriptive results showed that there was high variation between varieties forearliness, fruit yield and fruit number. Cluster analysis could group varieties into 5 groups that showedthe highest difference for single fruit weight, fruit yield and plant height. Late ripening varieties showedlow yield, however varieties with high fruit yield showed high fruit number. Therefore, fruit number had more effect on fruit yield in contrast to single fruit weight. Over all varieties in different groups could usein breeding programs with different aims.
 
Keywords: Cluster analysis, Pepper, Fruit weight

Keywords


       
   

                 Research on Crop Ecophysiology                                  Vol.13/1, Issue 1 (2018), Pages: 1 - 6  

 

 

 
 

Original Research

 
 

 

 

 

Clustering Different Greenhouse Pepper Varieties Based on Some Morphological and Fruit Yield

 

Maryam Golabadi1,2*, Abdol-Reza Eghtedari1,2, Hamed Gholami2, Mojtaba Mahdavi2

1. Department of Agronomy and Plant Breeding, Islamic Azad University, Isfahan (Khorasgan) Branch, Isfahan, Iran

2. Plant Improvement and Seed Production Research Center, Isfahan, Iran.

 

* Corresponding author email: golabadim@gmail.com

Received: 7 December 2017                                           Accepted: 18 January 2018

 

Abstract

 

Pepper is one of most important vegetables in the world. Pepper has important role in world vegetablecommerce and the worth of its export and import is very high. Selection of better plants is inseparableparts of breeding programs and need a variable population. So assessment of genetic variation is the firststep of breeding programs/ For this purpose, genetic variation of 22 different varieties of greenhousepepper was assayed for days to flowering and fruiting, plant height, peduncle length, single fruit weight, fruit yield and fruit length. Descriptive results showed that there was high variation between varieties forearliness, fruit yield and fruit number. Cluster analysis could group varieties into 5 groups that showedthe highest difference for single fruit weight, fruit yield and plant height. Late ripening varieties showedlow yield, however varieties with high fruit yield showed high fruit number. Therefore, fruit number had more effect on fruit yield in contrast to single fruit weight. Over all varieties in different groups could usein breeding programs with different aims.

 

Keywords: Cluster analysis, Pepper, Fruit weight

 

Introduction

 

Pepper (Capsicum annuum L.) is the world’s most important vegetable after tomato and used as fresh, dried or processed products, as spices or condiments (Crosby, 2008). Pepper has important role in world vegetable commerce, and the worth of its export and import (fresh or dried fruit) is very high. The horticultural and biochemical characteristics are important breeding objective in pepper (Daskalov and Poulos, 1994). Fruit yield, single fruit weight and fruit number per plant are the most important traits in pepper breeding programs. The color type and intensity, fruit uniformity, fruit flavor and quality, fruit shape, size and pericarp thickness and shelf life are also known as other important traits for goals of pepper improvement (Bosland, 1993; Pruthi, 2003). The other objectives of pepper genetic breeding are characteristics such as abiotic stresses (drought, salinity, flooding …) (Singh, 2007). Fruit characters such as fruit color also are important in deletion abnormal plants as selection criteria (Rakita and McCormack, 2005).

Germplasm can be used for plant improvement and also used for determination of phylogenetic relationship and biological and biochemical aspects in pepper (Kang and kole, 2013). Pepper breeders are interested in improving new high fruit yield varieties with other desirable traits. Estimates of the genetic diversity of these traits can assist the design of breeding programs for new varieties. The use of reliable multivariate statistical algorithms such as cluster analysis is an important strategy for classification of germplasm and analysis of genetic relationships among breeding materials (Mohammadi & Prasanna, 2003). Ravindran et al. (1997) reported that forty-four cultivars and seven wild black pepper (Piper nigrum) accessions (51 Operational Taxonomic Units) based on 22 characters grouped in 11 clusters. Among these, four groups had one cultivar, four had two cultivars, one had four cultivars, one had seven cultivars and one had 28 cultivars each. Therefore, the objective of this study was to classify different pepper varieties based on variable characteristics and to introduce them for breeding goals.

 

Material and methods

 

This research was carried in agricultural research greenhouse of Islamic Azad University of Isfahan (Khorasgan) Branch during 2015-2016 crop seasons. The seeds of 22 greenhouse pepper cultivars (listed in table 1) were obtained from agricultural inputs sales centers for this trial. The nursery was watered thoroughly seed germination to facilitate seedling establishment.

Manures and fertilizers were applied as per recommended dose to the roots to enhance active root formation and shoot growth. Before sowing cultural practices such as mold board plowing to a 25 cm depth, disking, and land leveling were also applied.

Seeds were sown on November, 2015 in separate plots. The seedling emerged 8-13 days after sowing. Frothy five days old seedlings were transplanted in lines 0.9 – 1.1 m apart and 0.6-0.7 m between plants, two stem per plant. From all of cultivars, eight plants per three replications were cultivated (Occhiuto et al., 2014). Water was applied to the crops using a drip irrigation system. All nutrients were used in combination with irrigation water (fertirrigation according to the needs of the plants at different stages of growth. Pests in the greenhouse included white flies and trips were controlled using appropriate pesticides. Data recording on single plant were carried out according to International Plant Genetic Resources institute (IPGRI) descriptor (IPGRI, 1995). The variable traits included fruit length (cm), plant height (cm), days to flowering, days to fruiting, single plant yield (g) and single fruit weight (g) and peduncle length (cm), were measured.   

During growth stages, mean daily and nightly temperatures of greenhouse were 27.5 and 18.5 ° C respectively as well as mean relative humidity was %60. The heating and cooling system were hot air and evaporation types respectively in greenhouse.

 

 

      

 

Results and discussion

 

The various evaluated characteristics in cultivars including fruit length (cm), plant height (cm), days to flowering, days to fruiting, single plant yield (g) and single fruit weight (g) are shown in Table 1.

Some descriptive statistical parameters of the studied traits for all cultivars are also given in Table 2. This results showed that Ca-301 and Ca-302 were the earliest and latest flowering varieties respectively. Ca-301 took the shortest period to fruiting, while Car-48 was the late among the varieties. The highest plant yield was observed in Ca-3010 and the lowest value of this trait was found in Car-48 (Table 1). Ca-3010 had the highest fruit yield, however some characteristics such as fruit length and single fruit weight was not high, which suggested the high fruit yield in this cultivar may considerably due to the high value of fruit number per plant. On the other hand, Car-48 had the lowest fruit yield, also had the highest value of days to flowering and fruiting, thus this variety scored as the late maturing cultivar with the shortest fruiting duration. The highest mean value of fruit weight was recorded by Oli-4 and the minimum by Ca-nas (Table 1). The highest plant height was obtained by Oli-4 and the least plant height was recorded by Ca-301. A-270 and Oli-4 had the highest and the lowest value of peduncle length, respectively. In the case of fruit length, Ca-302 had the highest and Ca.Cs had the lowest amount of this trait. Results of descriptive analysis (Table 2) indicated that single fruit weight followed by days to fruiting had the highest rate of standard deviation. This gives us an opportunity to use these quantitative traits to create useful subsets of diverse cultivars for further characterization and breeding works on commercial and agronomic importance traits.

Cluster analysis is very useful in revealing complex relationships among diverse genotypes in a more simplified manner and it is also effective inindicating genetic matters with useful traits belonging to different clusters for breeding goals (Se-Jong et al., 2012). The 22 pepper varieties were grouped in to five groups with 5, 3, 8, 3 and 3 genotypes, respectively (Figure 1). Comparing cluster means with studied traits revealed considerable variation among different clusters. In this analysis, the first group had five varieties (Table 3). Fruiting occurred later in these cultivars compared to others. They had the highest single fruit weight and fruit length, while fruit yield had the lowest amount in this group. This negative relation might be due to lower number of fruit which is caused by shorter fruiting duration. Nkansah et al. (2017) reported a highly significant negative relationship between fruit yield (tons/ha) and fruit length of sweet pepper.

 

 

 

 

 

 

 

 

Table 1. Values of evaluated traits in studied pepper varieties

Num.

Variety

Days to flowering

Days to fruiting

Plant  height (cm)

 

Peduncle length (cm)

Single fruit weight (gr)

Plant yield

(gr)

Fruit length

(cm)

1

A-270

96

150

137.75

4.89

219.62

1610.53

10.01

2

A-140

98

128

100

4.04

144.35

1610.1

9.34

3

CA-cs

76

114

94.5

3.6

131.03

1895.07

8.89

4

Ca-301

74

96

85.67

3.77

128.18

1673.05

9.02

5

C-3010

98

128

94

3.56

151.06

3625.47

9.2

6

Ca-302

107

129

95

3.84

134.5

3342.3

12.13

7

Ca-310

76

114

97.67

3.3

129.65

1664.2

8.89

8

Ca-nas

98

133

92.5

3.77

127.39

3105.98

11.36

9

Cam-1

84

116

110

3.04

135.66

1474.57

10.69

10

Car-35

76

106

100

4.01

147.52

2096.34

9.96

11

Car-48

107

166

87.5

3.42

132.43

1102.16

9.54

12

Exc13

92

125

116.67

4.42

150.92

1775.96

10.35

13

Exp10

79

129

139.5

3.72

204.13

1735.07

10.71

14

Exp4

84

145

125.5

4.56

217.65

1305.9

11.36

15

Fi-67

84

130

143

4.57

192.18

1350.43

10.84

16

Insp-39

96

156

103

4.75

229.39

1284.6

11.95

17

King

84

116

116.67

3.74

132.29

1909.39

9.17

18

Non50137

79

140

130.4

3.75

202.73

1452.9

9.24

19

Oli-4

90

140

159

3.03

234.38

1552.75

9.36

20

Pel-7

79

99

101.5

3.81

153.38

2265.16

9.59

21

Pi-5

101

157

105.75

4.57

214.27

1157.03

10.56

22

Wiz-44

79

115

111.33

3.22

141.73

1940.08

9.34

 

Considering these results, it can be stated that earlier cultivars had longer period for fruiting compared to others, so their fruit yield also increased. In contrast, the average value of cultivars in fourth cluster for fruit yield was higher than the total means of all varieties. However, genotypes in this group were in the lowest rate with respect to plant height, so the increasing in fruit yield, may be due to a higher number of fruit which might, in turn, be due to a lower internode length in these cultivars. This cluster consisted of Ca-302, Ca-3010- and Ca-nas. The third cluster had the highest number of genotypes having a high value of plant fruit weight after cluster 4. Fruit weight in these two groups had significant difference. Overall, the results of this research showed that the evaluated cultivars had the enough diversity for using in further pepper breeding programs. 

 

 

Table 2. Some descriptive parameters of studied varieties

Traits

Mean

Range

Standard deviation

Minimum

Maximum

Days to flowering

88.04

33

0.59

74

107

Days to fruiting

128.73

70

8.71

96

166

Plant  height (cm)

111.22

73.33

0.07

85.67

159

Peduncle length (cm)

3.88

1.86

0.54

3.03

4.89

Single fruit weight (g)

166.11

106.99

38.86

127.39

234.38

Plant yield(g)

1860.41

2523.31

9.36

1102.16

3625.47

Fuit length(cm)

10.06

3.24

1.00

8.89

12.13

 

 

Figure 1.Cluster diagram of 22 pepper cultivars based on evaluated traits using ward method (the number of varieties are based on table 1)

 

Table 3. Mean comparison between groups based on cluster analysis in primary parents

Mean comparison of each clusters

Mean of Square

Traits

Group 5

Group 4

Group 3

Group 2

Group 1

82.68 b

101 a

78.5 b

99a

92.2 a

441.36**

Days to flowering

109.5 b

130 a

136.3 a

139.67 a

147.6 a

1318.95**

Days to fruiting

142.97 a

93.83 b

102.17 b

101.39 b

123 a

1392.41**

Plant height

3.5 b

3.72 b

3.56 b

3.96 b

4.67 a

1.11**

Pedicle length

213.75 a

137.65 b

137.43 b

142.57 b

214.62 a

7311.98**

Single fruit weight

1580.2 bc

3357.9 a

1864.7 b

1496.1 bc

1341.7 c

2176687**

Fruit yield per plant

9.77 ab

10.89 a

9.44 b

9.74 ab

10.94 a

2.41**

Fruit length

Means followed by the same letter was not significantly different at 0.05 level using LSD test.

**: F-test significant at P<0.01

 

 

 

References

 

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