Crops ›› 2025, Vol. 41 ›› Issue (6): 73-82.doi: 10.16035/j.issn.1001-7283.2025.06.010

Previous Articles     Next Articles

Genetic Diversity Analysis and Disease Resistance Evaluation of 100 Pepper Germplasm Resources

Yang Shuo(), Ma Xiaojuan, Zheng Xuan, Hou Yi, Ye Lin(), Cheng Guoxin()   

  1. College of Enology and Horticulture, Ningxia University, Yinchuan 750021, Ningxia, China
  • Received:2024-06-20 Revised:2024-07-10 Online:2025-12-15 Published:2025-12-12

RichHTML

3

PDF (PC)

110

Abstract:

To screen superior core germplasm resources, a comprehensive evaluation was conducted on 100 pepper germplasm resources using multivariate statistical methods, combining phenotypic trait measurement with disease resistance molecular marker detection. The results indicated that the coefficients of variation for the 14 phenotypic traits ranged from 9.66% to 58.42%, and the genetic diversity indices varied between 0.56 and 2.03. Principal component analysis revealed that the eigenvalues of the first four principal components were all greater than 1, with a cumulative contribution rate of 73.326%. Based on the comprehensive ranking of principal component scores, the top three germplasm accessions were identified as Deluoba, 21-584 and Jinka No.36. Cluster analysis grouped the tested materials into three clusters at an euclidean distance of 0.15. Disease resistance molecular identification showed that 12 materials contained two disease resistance genes, six materials contained three, and three materials contained four. By integrating the molecular identification of disease resistance with phenotypic trait analysis, four high-quality germplasm accessions (Fangxing No.9, Deluoba, 21-878 and Jinka No.36) with top four comprehensive phenotypic scores were selected and more than two resistance genes were identified. This provides valuable germplasm resources for breeding superior and disease- resistant pepper varieties.

Key words: Pepper, Germplasm resource, Genetic diversity, Disease resistance marker, Cluster analysis

Table 1

Test materials"

编号
Number		 代号
Code		 类型
Type		 名称
Name		 编号
Number		 代号
Code		 类型
Type		 名称
Name		 编号
Number		 代号
Code		 类型
Type		 名称
Name
1 22-1799 朝天椒 15g 35 21-1277 长椒 新辣十三 69 21-2042 长椒 娇龙206
2 22-1802 长椒 11g 36 21-1076 长椒 红光 70 21-1274 线椒 镇辣36号
3 20-905 长椒 金富175 37 20-392 线椒 黑线至尊 71 22-1805 长椒 22-1805
4 22-1617 长椒 22-1617 38 22-1825 长椒 21-587 72 22-1734 长椒 22-1734
5 21-1275 长椒 辣天下50号 39 22-15 长椒 辛香A2 73 22-1695 长椒 金鼎21
6 23-186 长椒 13.1g 40 22-702 长椒 22-702 74 21-393 长椒 长盛
7 20-62 长椒 巨峰1号 41 21-390 长椒 精品加长2313 75 22-1373 长椒 21-1594
8 23-289 长椒 绿天丹 42 21-204 长椒 凯莱 76 21-1077 长椒 娇龙7号
9 22-1798 长椒 24g 43 20-1335 长椒 20-1335 77 19-203 长椒 巨丰长冠
10 22-697 长椒 22-697 44 22-1730 长椒 22-1730 78 18-177 长椒 娇艳2号
11 21-206 长椒 祥陇124 45 22-1223 长椒 22-1223 79 22-1205 长椒 22-1205
12 21-1855 长椒 泰斗2号 46 21-50 灯笼椒 20-169 80 19-232 长椒 极光
13 22-1731 长椒 9.5g 47 19-204 朝天椒 世农朝天椒 81 22-1924 长椒 改良娇龙12号
14 21-1696 长椒 21-1696 48 21-297 灯笼椒 金卡 82 19-456 长椒 娇龙12号
15 21-395 长椒 欧育长剑 49 20-113 线椒 娇美1号 83 21-1862 长椒 娇艳10号
16 22-1641 长椒 22-1641 50 20-1334 长椒 20-1334 84 22-14 螺丝椒 螺线1号
17 19-347 朝天椒 果然好朝天椒 51 21-1559 长椒 娇龙19号 85 22-1640 长椒 22-1640
18 21-1276 长椒 月丰801 52 23-11 长椒 23-11 86 21-584 灯笼椒 21-584
19 22-1732 长椒 4.5g 53 21-352 长椒 21-352 87 21-298 灯笼椒 金卡36号
20 21-1515 长椒 21-1515 54 22-1801 长椒 13g 88 19-1002 长椒 19-1002
21 21-392 长椒 长成 55 20-114 线椒 娇美2号 89 20-352 线椒 娇美3号
22 22-1797 长椒 22-1797 56 20-1858 长椒 娇美4号 90 22-1827 长椒 21-603
23 21-391 长椒 精品2313 57 22-1211 长椒 22-1211 91 22-1764 长椒 21-1689
24 22-1697 灯笼椒 方兴9号 58 22-1010 长椒 科罗旺21 92 22-992 长椒 22-992
25 22-1765 长椒 21-399 59 21-394 长椒 金椒王 93 22-993 长椒 22-993
26 21-296 线椒 卡洛尔8号 60 23-92 长椒 21-878 94 21-1512 长椒 21-1512
27 21-1103 长椒 平园1号 61 22-79 长椒 娇艳8号 95 20-63 长椒 超级椒王
28 21-400 长椒 20-580 62 22-1212 长椒 22-1212 96 22-694 长椒 巨峰3号
29 21-387 长椒 德罗巴 63 23-183 长椒 5.8g 97 20-151 长椒 长冠1号
30 22-1800 长椒 22-1800 64 21-1711 长椒 21-1711 98 22-1520 长椒 21-1055
31 21-205 长椒 辣宝89 65 23-288 长椒 冬椒6 99 22-1819 长椒 22-1819
32 22-1618 长椒 22-1618 66 22-535 线椒 22-535 100 19-1357 长椒 巨峰2号
33 23-182 长椒 8.1g 67 21-2041 长椒 改良娇龙7号
34 21-1278 长椒 润线9号 68 22-1009 长椒 公牛巨椒王

Table 2

Molecular marker primers"

标记
Marker		 上游引物（5'-3'）
Forward primer		 下游引物（5'-3'）
Reverse primer		 退火温度
Annealing temperature (℃)
YB2 CTTTTGGTCTTTTCTCCCCC AAATCGGCTTGGAATGACGTA 58
YB3 TCCTCGTCATACCAAAAGCC CCAAGCAACAAGAGAAAGGG 58
YB4 TTGATGAGATGGGAAGTAAA CACCAACAATAATAGAACTACA 58
YB5 TCCCAAGTCAAGGGCAAGGATA GGGGAATGGGGGATTTCATACA 58
YB6 CCAAGATCAACTCTTACGCTATCA ACAGGTGAAAATCCCTCAAGAA 58
CA2 TGTGTGTGTGTAAATCTCCAA ACGGCATGTAAATAAAGTTCA 58

Table 3

Analysis of the diversity of quantitative traits in pepper germplasm resources"

性状
Trait		 最小值
Minimum		 最大值
Maximum		 平均值
Mean		 标准差
SD		 变异系数
CV (%)		 遗传多样性指数
H'
叶长Leaf length (cm) 8.32 18.86 13.43 1.95 14.48 2.02
叶宽Leaf width (cm) 4.12 10.32 6.63 1.21 18.27 1.98
株高Plant height (cm) 47.80 142.40 93.49 15.53 16.61 1.99
茎粗Stem diameter (mm) 11.48 17.86 14.64 1.42 9.66 2.02
单株果实数量Number of fruits per plant 0.00 50.40 16.44 8.24 50.11 2.00
单果重量Single fruit weight (g) 3.09 130.86 46.31 22.82 49.27 1.93
果肉厚度Flesh thickness (mm) 1.03 5.31 2.25 0.75 33.25 1.78
果实长Fruit length (mm) 5.62 26.80 17.71 4.56 25.74 1.89
果实宽Fruit width (mm) 9.06 72.40 30.25 12.51 41.37 1.74
果梗洼大小Fruit stem depression size (mm) 4.65 23.19 12.18 3.40 27.91 1.89
可滴定酸含量Titrable acid content (kg/cm2) 0.42 3.75 1.65 0.64 38.50 2.01
果实硬度Fruit hardness 0.88 5.37 2.34 0.82 34.95 1.91
维生素C含量Vitamin C content 0.01 0.15 0.03 0.02 58.42 0.56
可溶性固形物含量Soluble solids content (%) 1.60 12.75 5.65 2.19 38.74 2.03

Table 4

Correlation analysis of 14 major agronomic traits of pepper germplasm resources"

性状Trait A B C D E F G H I J K L M N
A 1.000
B 0.862** 1.000
C -0.023 -0.055 1.000
D 0.591** 0.593** 0.201* 1.000
E -0.104 -0.224* 0.387** 0.094 1.000
F 0.550** 0.667** -0.298** 0.359** -0.448** 1.000
G 0.403** 0.532** -0.457** 0.162 -0.435** 0.870** 1.000
H 0.015 0.021 0.548** 0.134 0.283** -0.105 -0.379** 1.000
I 0.404** 0.557** -0.419** 0.334** -0.530** 0.809** 0.795** -0.351** 1.000
J 0.511** 0.620** -0.349** 0.330** -0.451** 0.931** 0.836** -0.152 0.821** 1.000
K -0.237* -0.314** 0.174 -0.177 0.264** -0.265** -0.241* 0.114 -0.140 -0.250* 1.000
L -0.278** -0.355** -0.259** -0.308** 0.098 -0.158 0.054 -0.584** -0.022 -0.147 0.171 1.000
M 0.089 0.068 -0.184 0.202* -0.167 0.241* 0.249* -0.264** 0.225* 0.263** -0.158 0.143 1.000
N -0.265** -0.341** 0.020 -0.133 0.217* -0.300** -0.158 -0.056 -0.160 -0.258** 0.271** 0.161 -0.001 1.000

Table 5

Principal component analysis of pepper germplasm resources"

性状Trait 主成分1 PC1 主成分2 PC2 主成分3 PC3 主成分4 PC4
叶长Leaf length 0.297 0.275 0.026 0.330
叶宽Leaf width 0.348 0.259 -0.011 0.185
株高Plant height -0.168 0.432 0.098 0.044
茎粗Stem diameter 0.198 0.359 0.108 0.441
单株果实数量Number of fruits per plant -0.236 0.217 0.332 0.331
单果重量Single fruit weight 0.403 -0.001 0.092 -0.109
果肉厚度Flesh thickness 0.371 -0.185 0.138 -0.040
果实长Fruit length -0.105 0.474 -0.017 -0.364
果实宽Fruit width 0.375 -0.137 0.198 -0.062
果梗洼大小Fruit stem depression size 0.396 -0.034 0.118 -0.129
可滴定酸含量Titrable acid content -0.166 -0.032 0.565 -0.091
果实硬度Fruit hardness -0.082 -0.436 0.167 0.408
维生素C含量Vitamin C content -0.045 -0.084 -0.548 0.410
可溶性固形物含量Soluble solids content -0.156 -0.128 0.374 0.206
特征值Eigenvalue 5.310 2.567 1.296 1.092
贡献率Contribution rate (%) 37.932 18.338 9.255 7.801
累计贡献率Cumulative contribution rate (%) 37.932 56.270 65.525 73.326

Table 6

Comprehensive scores and ranking of the top ten pepper germplasm resources"

编号
Number		 F1 F2 F3 F4 F值
F-value		 排名
Ranking
29 6.19 -1.54 1.60 1.48 3.18 1
87 7.16 -3.47 1.70 0.38 3.09 2
86 6.77 -2.67 -0.28 2.26 3.04 3
28 4.52 -2.64 1.09 0.98 1.92 4
24 4.41 -2.17 0.90 0.60 1.92 5
60 2.53 1.04 0.17 -0.24 1.57 6
46 4.54 -3.35 0.76 -0.73 1.53 7
90 1.71 2.30 -0.60 1.12 1.50 8
42 2.39 1.49 -0.93 -0.24 1.46 9
20 1.18 2.61 0.33 0.58 1.37 10

Fig.1

Cluster analysis of agronomic characteristics of pepper germplasm resources"

Fig.2

Molecular marker-based identification of disease resistance genes CA2, YB2, YB3, YB4, YB5, and YB6 M: marker."

Table 7

Disease resistance identification results of 100 pepper materials"

编号Number CA2 YB2 YB3 YB4 YB5 YB6 编号Number CA2 YB2 YB3 YB4 YB5 YB6
1 0 2 1 1 0 2 51 1 1 1 0 2 0
2 1 2 1 1 1 1 52 0 0 1 1 0 1
3 1 0 0 0 1 0 53 1 2 1 1 1 1
4 1 0 0 1 1 0 54 1 2 1 0 1 1
5 1 0 1 0 0 2 55 1 2 1 1 1 0
6 1 0 1 1 0 0 56 1 0 1 0 1 0
7 1 0 1 0 1 2 57 1 1 1 1 1 1
8 1 0 1 0 1 1 58 1 0 2 1 1 1
9 0 0 1 0 0 0 59 1 1 1 1 1 2
10 0 0 2 1 0 1 60 2 0 1 1 2 1
11 0 0 1 0 0 1 61 0 0 1 1 1 2
12 0 0 1 0 0 2 62 1 1 1 1 1 0
13 1 2 0 1 1 1 63 1 2 1 0 1 0
14 1 2 1 0 1 2 64 0 2 2 1 0 0
15 1 1 1 1 1 1 65 1 1 1 0 1 1
16 0 0 1 1 0 1 66 1 1 0 1 1 1
17 0 0 0 0 0 1 67 1 1 1 1 1 1
18 0 2 0 0 1 1 68 1 1 1 0 1 1
19 1 0 0 0 1 0 69 1 1 0 1 1 2
20 2 1 1 0 1 0 70 2 1 1 1 2 2
21 1 0 2 1 1 1 71 2 2 0 1 2 1
22 1 2 1 1 1 0 72 2 0 1 1 1 1
23 1 2 0 0 1 0 73 1 1 1 1 1 1
24 2 0 1 1 2 2 74 1 1 1 0 1 1
25 2 1 2 1 1 1 75 1 2 1 1 1 1
26 2 2 1 1 2 2 76 1 2 1 1 1 0
27 1 0 2 1 1 1 77 1 1 1 2 1 1
28 1 0 2 1 1 1 78 1 2 1 1 1 1
29 2 1 1 1 2 1 79 1 2 0 0 1 1
30 1 1 1 1 1 2 80 1 2 0 1 1 2
31 2 1 2 1 2 1 81 1 2 0 1 1 1
32 1 2 2 0 1 1 82 1 1 1 1 1 0
33 1 0 1 1 1 0 83 1 1 1 1 1 0
34 2 1 1 1 2 2 84 1 0 0 0 1 1
35 1 1 0 1 2 0 85 0 0 1 1 0 1
36 1 1 0 1 1 1 86 0 2 1 1 0 1
37 1 1 1 1 1 1 87 2 0 1 1 2 1
38 1 1 1 1 1 1 88 0 1 1 0 0 0
39 1 2 1 0 2 1 89 2 1 1 1 2 0
40 1 2 2 1 2 2 90 1 2 1 1 1 0
41 1 1 1 1 2 0 91 1 0 0 1 1 0
42 1 2 0 1 1 1 92 0 0 1 1 0 0
43 1 1 1 1 1 1 93 1 1 1 1 1 0
44 1 0 1 1 1 2 94 1 1 1 1 1 1
45 0 2 0 0 1 2 95 1 2 0 1 1 1
46 0 1 1 1 2 0 96 1 0 0 0 0 0
47 2 2 0 1 2 0 97 1 0 1 0 1 0
48 2 2 1 2 2 1 98 1 0 1 0 1 0
49 1 1 1 1 2 0 99 0 1 1 0 2 0
50 0 1 2 1 1 1 100 1 0 1 0 1 2
[1] 洪成, 赵建荣, 程春园, 等. 辣椒种质资源农艺性状综合评价. 中国蔬菜, 2024(7):33-41.
[2] 陈学军, 周坤华, 宗洪霞, 等. 中国灌木辣椒种质遗传多样性的SRAP和SSR分析. 西北植物学报, 2012, 32(11):2201-2205.
[3] 朱珍花, 濮丹, 杨洋, 等. 干制辣椒种质资源表型性状遗传多样性分析. 北方园艺, 2024(6):1-8.
[4] 袁娟伟, 贾利, 唐菁, 等. 275份辣椒种质资源表型性状的遗传多样性分析. 安徽农业大学学报, 2024, 51(2):244-255.
[5] 刘林娅, 黄亚成, 杨那, 等. 81份辣椒种质资源表型性状的遗传多样性分析. 热带作物学报, 2023, 44(4):706-715.
doi: 10.3969/j.issn.1000-2561.2023.04.006
[6] 杨娟, 王雯, 沈火林. 辣椒恢复基因SSR标记定位及分子标记辅助选择育种. 中国瓜菜, 2010, 23(5):1-5.
[7] 郭广君, 朱雪梅, 潘宝贵, 等. 利用InDel分子标记辅助选育辣椒抗黄瓜花叶病毒病种质. 江苏农业学报, 2021, 37(5):1251-1261.
[8] 于海龙, 靳远, 周黛媛, 等. 内蒙古地区辣椒种质资源抗病性鉴定与评价. 中国蔬菜, 2023(11):69-79.
[9] 许向阳, 赵爽, 何梦曦, 等. 128份番茄种质资源主要农艺性状鉴定及抗病性评价. 东北农业大学学报, 2022, 53(5):32-41.
[10] 张锐, 尚伟, 韦新宇, 等. 辣椒疫病的发生及疫病抗性连锁标记适用性评价. 分子植物育种, 2022, 20(10):3285-3293.
[11] 桂敏, 龙洪进, 钟秋月, 等. 引进辣椒种质资源果实性状的多元统计分析. 西南农业学报, 2014, 27(2):772-776.
[12] 李锡香, 张宝玺. 辣椒种质资源描述规范和数据标准. 北京: 中国农业出版社, 2006.
[13] Puchooa D. A simple, rapid and efficient method for the extraction of genomic DNA from lychee (Litchi chinensis Sonn.). African Journal of Biotechnology, 2004, 3(4):253-255.
doi: 10.5897/AJB
[14] 李江博, 叶盛, 常国斌, 等. 213份海岛棉种质资源的遗传多样性分析. 植物遗传资源学报, 2024, 25(11):1857-1874.
[15] 韩娅楠, 行文妍, 史艳艳, 等. 加工型辣椒种质资源遗传多样性分析. 山东农业科学, 2024, 56(1):34-42.
[16] 孔子雯, 田如霞, 苗如意, 等. 60份螺丝椒种质资源农艺性状的遗传多样性分析. 中国农业科技导报, 2024, 26(3):40-47.
[17] 李宁, 王飞, 姚明华, 等. 国内外辣椒种质资源表型性状多样性及相关性分析. 辣椒杂志, 2015, 13(1):8-13.
[18] 步洪凤, 张忠武, 邓正春, 等. 26个辣椒品种主要农艺性状分析与测评. 热带作物学报, 2019, 40(7):1290-1296
doi: 10.3969/j.issn.1000-2561.2019.07.007
[19] 王丹丹, 师建华, 李燕, 等. 基于主成分与聚类分析的辣椒主要农艺性状评价. 中国瓜菜, 2021, 34(2):47-53.
[20] 张国儒, 唐亚萍, 杨涛, 等. 272份辣椒资源的农艺性状分析. 新疆农业科学, 2021, 58(12):2300-2311.
doi: 10.6048/j.issn.1001-4330.2021.12.017
[21] 朱龙英, 张辉, 刘娜, 等. 耐番茄黄化曲叶病毒病樱桃番茄新品种‘沪樱6号’的选育. 上海农业学报, 2015, 31(5):92-95.
[22] 张倩男, 王晓敏, 芮文婧, 等. 基于表型性状及抗病标记的番茄种质资源遗传多样性分析. 西南农业学报, 2018, 31(1):14-21.
[1] Chen Zhihao, Wang Ting, Chang Xuhong, Wang Yanjie, Liu Xiwei, Yang Yushuang, Wang Yujiao, Wang Demei, Zhao Guangcai. Comprehensive Analysis of Yield and Quality Traits of Wheat Lines in the Northern Huang-Huai Winter Wheat Region [J]. Crops, 2025, 41(6): 148-155.
[2] Chen Haonan, Zhao Hongyan, Zhang Wenjing, Zhang Qi, Du Jidao, Wang Qirui, Ren Ruoran, Han Yiqiang. Screening and Fingerprint Construction of SSR Molecular Markers in Pea [J]. Crops, 2025, 41(6): 19-27.
[3] Sun Qiang, Ruan Xinsen, Zhou Zhihao, Sun Huijuan, Xu Ran, Ling Dong, Zhao Cuirong. Analysis of Genetic Diversity of Phenotypic Traits in Different Rice Varieties [J]. Crops, 2025, 41(6): 28-36.
[4] Zhao Caixia, Baima Yangzhen, Yang Guanghuan, Tang Lin. Identification and Cluster Analysis of Agronomic Traits in Different Types of Rapeseed Resources [J]. Crops, 2025, 41(5): 120-127.
[5] Wu Liguo, Li Xiaohui, Zhao Qing, Chen Xiaolong, Pan Jing, Liu Wangqing, Bai Haibo, Li Qianrong. Genetic Diversity Analysis of Agronomic Traits of Spring Wheat Varieties (Lines) in Ningxia [J]. Crops, 2025, 41(5): 147-154.
[6] Wang Dan, Zhang Zhicheng, Han Haixia, Han Na, Wang Chunyong, Wang Zheng, Pan Mengyang, Li Qiang, Wang Yiqian, Liu Yufei, Zhang Dan. Genetic Diversity Analysis of Potato Germplasm Resources Based on SSR Technology [J]. Crops, 2025, 41(4): 29-40.
[7] Gao Shuguang, Xu Dongyang, Hu Minjie, Wang Ruixia, Zhang Chunhua, Xu Bohan, Li Weifeng, Zhang Liuping. Preliminary Identification and Evaluation of Quality Traits of Sesame Germplasm Resources [J]. Crops, 2025, 41(4): 58-64.
[8] Huang Yuxin, Zhang Gemin, Zhou Shan, Duan Weixing, Yang Cuifang, Gao Yijing, Zhang Baoqing. Analysis of the Improvement Efficiency of F1 Hybrids between Intergeneric Hybrid (Tripidium arundinaceum×Saccharum spontaneum) and Sugarcane [J]. Crops, 2025, 41(3): 23-29.
[9] Sun Bangsheng, Song Jiling, Yang Mengping, Xing Jinyue, Hu Zunyan, Hao Zhiyong, Li Jinghua, Liu Chunsheng. Genetic Diversity Analysis of High Starch Potato Primary Core Germplasm Resources [J]. Crops, 2025, 41(3): 52-60.
[10] Zhao Yajie, Wen Rui, Jia Yiming, Jin Xiaolei, Zhang Yonghu, Zhang Lijun, Zhang Biao, Zhang Hui, Yu Lixia. Analysis of Genetic Diversity of Phenotypic Traits of Foxtail Millet Germplasm Resources [J]. Crops, 2025, 41(3): 61-69.
[11] Chang Hongbing, Wang Chen, He Meijing, Cao Ximin, Yu Fengfang, Cao Xiaoliang, Song Wei, Lü Aizhi. Genetic Diversity Analysis of 69 Maize Germplasm Resources Based on SSR Markers [J]. Crops, 2025, 41(2): 47-53.
[12] Jiang Hui, Zhong Qiaofang, Yin Fuyou, Li Jinlu, Liu Li, Zhang Yun, Wang Bo, Jiang Cong, Cheng Zaiquan, Zhang Hui, Xiao Suqin. Research Progress on Germplasm Resources and Multi-Omics of Oryza officinalis [J]. Crops, 2025, 41(2): 1-8.
[13] Sun Yanjie, Wei Guocai, Wu Yuheng, Shi Yunqiang, Shao Yong, Liu Yingrui, Nan Yuantao, Zhang Weiyao. Genetic Diversity Analysis of 100 Maize Germplasm Resources by SNP Markers [J]. Crops, 2025, 41(2): 14-19.
[14] Lei Yun, Liu Yueyan, Wang Jianjian. Effects of CO2 Enrichment and Phosphorus Level on Seedling Growth and Nutrient Element Absorption of Capsicum anmuum L. [J]. Crops, 2025, 41(2): 189-195.
[15] Lu Jing, Yu Bo, Jiang Mi, Peng Lianxin, Ren Yuanhang, Wu Qi. Assessment of Genetic Diversity in 58 Germplasm Resources of Highland Barley [J]. Crops, 2025, 41(2): 20-28.
Viewed
Full text


Abstract

Cited
  Shared   
  Discussed   
No Suggested Reading articles found!