Pepper Genotypes Research Articles

Resilience response to yellow leaf curl disease and identification of resistance gene analogs (RGA) in pepper (Capsicum annuum)

Abstract. Ayu DK, Maharijaya A, Syukur M, Hidayat SH. 2021. Resilience response to yellow leaf curl disease and identification of resistance gene analogs (RGA) in pepper (Capsicum annuum). Biodiversitas 22: 4731-4739. Pepper yellow leaf curl disease (PYLCD) caused by infection of Begomovirus is a serious threat to pepper production worldwide. Identification of the resistance gene analogs (RGA) and resilience response of pepper against PYLCD is needed especially for selection resistance genotype. Evaluation of resistance response involving 28 pepper genotypes was carried out through transmission of Begomovirus using whitefly (Bemisia tabaci) as vector. The result showed that IPB C12 and F4-012328-6-3 were potential resistance genotypes. A total of 15 R gene analogs (CaRGA) containing NBS motif, namely CARGA1 to CARGA15, were identified by degenerated PCR amplification and database mining. The alignment of deduced amino acid sequence revealed conservation of subdomains Ploop (GKTT), kinase2 (LVVLDDV), RNBSB/kinase3 (IILTTR) and GLPL. BLASTp analysis indicated that 15 RGA showed high homology at deduced amino acid level with R gene identified such as whitefly resistance protein Mi-1.2, Pvr 9 gene for potyvirus, Begomovirus resistance protein, TRGA15 and RGA 13 for putative late blight resistance. Phylogenetic analysis exhibited that isolated sequences distinguished into CNL-NBS groups. These pepper RGA could be considered as candidate sequences of resistance genes.

Selection of pepper genotypes for ornamentation

Obtaining a variety that has high performance characteristics is the main focus of a breeding program. It is of interest to the breeder an ideotype plant that contains all the characteristics of interest for commercialization. With the objective of to evaluate the potential of genotypes of Capsicum annuum, with desirable ornamentation characteristics, 29 genotypes of C. annuum was evaluated. The experiment was conducted in a greenhouse in a completely randomized design, with 29 treatments (genotypes) and five replications. Eleven characteristics of plant, flower and fruit were evaluated. The cultivar Calypso was chosen as an ideotype because it has characters that are highly desirable in the ornamentation market. Genetic variability was observed for all traits. The factor analysis was efficient in reducing the 11 characteristics in three factors. Based on the factor analysis and the distance between genotype-ideotype, nine genotypes were selected for presenting means close to those of the ideotype, for all the characteristics evaluated.

Agronomic Performance, Capsaicinoids, Polyphenols and Antioxidant Capacity in Genotypes of Habanero Pepper Grown in the Southeast of Coahuila, Mexico

The genetic improvement program of the Seed Technology Training and Development Center works on the agronomic characterization and the content of bioactive compounds in eight genotypes of habanero pepper. The objective is to select genotypes with good agronomic performance that allow the generation of inbred lines to obtain hybrids. In this study, the agronomic performance and the content of bioactive compounds (capsaicinoids, polyphenols, and antioxidant capacity) were evaluated in eight genotypes of habanero pepper grown in the southeast of Coahuila, Mexico, identified as HNC-1, HNC-2, HNC-3, HNC-4, HNC-5, HNC-6, HNC-7, and HCC-8. The plants were grown in a greenhouse for 127 days, under a completely randomized design with four replications each. The results revealed that the yield (g·plant−1) and number of fruits per plant did not show significant differences between genotypes. However, for the fruit length, the genotypes HCC-8, HNC-7, HNC-6, and HNC-5 stood out with over 40 mm, while in equatorial diameter of the fruit, HCC-8, HNC-4, and HNC-2 stood out with 26.45, 26.46, and 25.12 mm, respectively. The results of the chemical analyses allowed us to identify that HNC-5 and HNC-6 had the highest capsaicin concentration (931.38 and 959.77 mg·kg−1), dihydrocapsaicin (434.95 and 445.89 mg·kg−1), Scoville Heat Units greater than 210,000, total phenols (67.54 and 71.15 mg/100 g) and total flavonoids (34.21 and 38.29 mg/100 g), respectively. The HNC-1 and HNC-6 genotypes had the highest carotenoids concentration with 103.96 and 105.07 mg/100 g, and HCC-8 registered the highest anthocyanin content with 22.08 mg C3GE/100 g. The antioxidant capacities showed significant differences (p ≤ 0.05) between genotypes, with a range of 43.22 to 110.39 µmol TE/100 g, 72.37 to 186.56 µmol TE/100 g, and 191.41 to 244.98 µmol TE/100 g for the tests of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and FRAP (ferric reducing antioxidant power). The results of this research will be used to select habanero pepper genotypes that can be used in genetic improvement programs to increase the productive potential and the content of bioactive compounds in the fruits to expand their applications in the food industry.

Transcriptomics Analysis of Heat Stress-Induced Genes in Pepper (Capsicum annuum L.) Seedlings

Pepper (Capsicum annuum L.) is one of the most economically important crops worldwide. Heat stress (HS) can significantly reduce pepper yield and quality. However, changes at a molecular level in response to HS and the subsequent recovery are poorly understood. In this study, 17-03 and H1023 were identified as heat-tolerant and heat-sensitive varieties, respectively. Their leaves’ transcript abundance was quantified using RNA sequencing to elucidate the effect of HS and subsequent recovery on gene expression. A total of 11,633 differentially expressed genes (DEGs) were identified, and the differential expression of 14 randomly selected DEGs was validated using reverse-transcription polymerase chain reaction. Functional enrichment analysis revealed that the most enriched pathways were metabolic processes under stress and photosynthesis and light harvesting during HS and after recovery from HS. The most significantly enriched pathways of 17-03 and H1023 were the same under HS, but differed during recovery. Furthermore, we identified 38 heat shock factors (Hsps), 17 HS transcription factors (Hsfs) and 38 NAC (NAM, ATAF1/2, and CUC2), and 35 WRKY proteins that were responsive to HS or recovery. These findings facilitate a better understanding of the molecular mechanisms underlying HS and recovery in different pepper genotypes.

Poultry manure and arbuscular mycorrhiza fungi remediation of sodium chloride induced substrate salinity for Pepper production

Pepper (Capsicum annum) is an important spice in the world, but the production is constrained by soil salinity. Hence, this study aims to explore the use of organic manure and Arbuscular Mycorrhiza Fungi in reducing the soil saline state for pepper cultivation. Two genotypes of cherry pepper were planted in the following treatment combinations; Cocopeat + poultry manure, Cocopeat + 10 mg/ml NaCL, 10 mg/ml NaCL + 250 g/4kg cocopeat, 10 mg/ml NaCL + 250 g/4kg cocopeat + 5 g of AMF, Cocopeat + 20 mg/ml NaCL, 20 mg/ml NaCL + 250 g/4kg cocopeat and 20 mg/ml NaCL + 250 g/4kg cocopeat + 5 g of AMF. The experiment was arranged in a completely randomized design with three replicates. The agronomic and yield parameters were collected and analysed using ANOVA and means were separated using DMRT at 5% significance level. Results obtained showed that the tallest plants, highest number of nodes, number of fruits and fruit weight (kg) were observed in the control (14.85±0.49), (20.50±0.68), (8.67±0.52) and (1.38±0.08), respectively, although they were not significantly different from the addition of 250 g of poultry manure and 5 g of AMF to 4 kg cocopeat substrate.

Identification of α-Glucosidase Inhibitors from Leaf Extract of Pepper (Capsicum spp.) through Metabolomic Analysis.

Metabolomics and in vitro α-glucosidase inhibitory (AGI) activities of pepper leaves were used to identify bioactive compounds and select genotypes for the management of type 2 diabetes mellitus (T2DM). Targeted metabolite analysis using UPLC-DAD-QToF-MS was employed and identified compounds that belong to flavone and hydroxycinnamic acid derivatives from extracts of pepper leaves. A total of 21 metabolites were detected from 155 samples and identified based on MS fragmentations, retention time, UV absorbance, and previous reports. Apigenin-O-(malonyl) hexoside, luteolin-O-(malonyl) hexoside, and chrysoeriol-O-(malonyl) hexoside were identified for the first time from pepper leaves. Pepper genotypes showed a huge variation in their inhibitory activity against α-glucosidase enzyme(AGE) ranging from 17% to 79%. Genotype GP38 with inhibitory activity of 79% was found to be more potent than the positive control acarbose (70.8%.). Orthogonal partial least square (OPLS) analyses were conducted for the prediction of the AGI activities of pepper leaves based on their metabolite composition. Compounds that contributed the most to the bioactivity prediction model (VIP >1.5), showed a strong inhibitory potency. Caffeoyl-putrescine was found to show a stronger inhibitory potency (IC50 = 145 µM) compared to acarbose (IC50 = 197 µM). The chemometric procedure combined with high-throughput AGI screening was effective in selecting polyphenols of pepper leaf for T2DM management.

NONLINEAR MODELS BASED ON QUANTILES IN THE FITTING OF GROWTH CURVES OF PEPPER GENOTYPES

This study aimed to fit nonlinear regression models to model the growth of the characters fruit length (FL) and fruit width (FW) of pepper genotypes (Capsicum annuum L.) over time using the method of ordinary least squares (OLS); and identify the model with the best fit and compare it to the model obtained via nonlinear quantile regression (QR) in the 0.25, 0.5, and 0.75 quantiles. Three regression models (Logistic, Gompertz, and von Bertalanffy) and four fit quality evaluators were adopted: Akaike information criterion, residual mean absolute deviation, and parametric and intrinsic curvature measurements. Five commercial genotypes of pepper were evaluated. Characters FL and FW were evaluated weekly from seven days after flowering, totaling ten measurements. In the estimation by OLS, the Logistic and von Bertalanffy models were considered adequate according to the quality evaluators. In the comparison between the models above by OLS and QR, the superiority of models obtained by QR was verified for the character FL. For the character FW, QR was efficient in three out of the five genotypes, being a valuable alternative in the study of fruit growth.

Morphological Characterization of Twenty One Sweet Pepper (Capsicum annuum L.) Genotypes Collected from Native and Alien Sources

Sweet pepper is one of the most important nutritious vegetable and its demand is increasing day by day in Bangladesh indicating need to characterize and assess morphological variability for varietal improvement programme. Twenty-one sweet pepper genotypes from native and alien sources were characterized for twenty-six morphological traits using vegetative and reproductive appearances at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh from October 2018 to March 2019. Marked variation was exhibited among twenty-six qualitative traits (26) studied. Twenty-two (22) characters showed undeniable variation among the genotypes. The presence of higher percentage (61.90%) of light purple color at node were observed indicated high amount of anthocyanin content. Leaf shape is used as genotypes identifier at vegetative stage and herein three types of leaves were found with dark green color (76.19%) that is highly correlates with yield. In case of flower, same level of stigma exertion (61.90%) with 100% white color corolla indicates higher number of fruit sett were exhibited. Entire genotypes exerted one or more exclusive characters especially fruit shape and color in Bangladesh perspective which could be used as an important breeding tools. Fruit color was observed in various categories at intermediate and mature stage as for instance yellow, green, purple, orange, red etc. in addition higher percentage of blocky fruit shape (38.09%) were observed and these are the consumer fascinating attributes of sweet pepper. However, selection of genotypes with desirable morphological trait can be used for their exploitation of future breeding programme.

Seleksi 16 Galur Harapan Cabai Rawit (Capsicum annuum L.) untuk Toleransi terhadap Salinitas

The utilization of saline soil for chili pepper production might be established by selecting tolerant varieties so that the growth and production remain stable even though they are planted on marginal lands. The purpose of this study was to determine the selection criteria for tolerant chili pepper to salinity and select a chili pepper genotype that are tolerant to salinity based on morphological characters and yield components. This study was carried out in Kolaka Regency, Southeast Sulawesi, from November 2020 to May 2021. The study was carried out on saline land nearby the coast with an average of electrical conductivity (EC) of 6.66 dS m-1. The study used a randomized complete block design with 22 lines of elite chili pepper and three replications. The results showed that characters as selection criteria for salinity tolerant were plant height, days to flowering, days to harvest, and fruit length because they had a significant effect on fruit weight per plant and high broad-sense heritability of 81.53%, 94.75%, 95.05%, and 87.45%, respectively. Based on these characters, the genotype selected as a candidate for the tolerant variety was G17. This genotype can be recommended for the development of chili pepper in saline soil.
 Keywords: heritability, saline land, tolerance, yield

STUDIES ON THE VARIABILITY OF THE PRODUCTIVITY COMPONENTS IN A COLLECTION OF HOT PEPPER LANDRACES (CAPSICUM ANUUM VAR. MICROCARPUM)

The aim of the research was to evaluate the variability value of the main characters that contribute to the achievement of plant production to a collection of hot pepper genotypes. The biological material was composed of 17 landraces of hot peppers collected from western Romania. The study was conducted for two years, with biometric measurements on the morphological characteristics of fruit production on the plant. Intra-population variability was assessed (mean, standard deviation of mean and coefficient of variability) and differences between populations for these characters. The results show that the variability within the collection is high. Within populations, fruit sizes (length, diameter) are uniform, but the number of fruits and their weight per plant show greater variability. Within the collection, variations in morphological characteristics are large, especially for fruit length, fruit weight, number and weight of fruit per plant. Among the landraces studied, some may be recommended for breeding programs, as parents or as material for the application of selection: for long fruits (Juliţa, Aldeşti I and Satchinez I), for short fruits (Satchinez III), but also the landraces Rieni III (17.07 g average weight of the fruit), Temerești II (89.82 fruits per plant), Aldești I (931.17 g fruits per plant).

Nutritional quality, fruit shape and relationships among exotic and local Capsicum pepper genotypes in Uganda

Twenty-one hot pepper genotypes comprising of local (15) and exotic (6) types (C. annuum, C. frutescens and C. chinense) were characterized for selected fruit traits after propagation in a glasshouse at the Makerere University Agricultural Research Institute Kabanyolo in Central Uganda using a completely randomized design with three replicates. Ripe fruits were harvested and analyzed; traits evaluated were all significantly different at P<0.05 with variations in quality attributes. The genotype OHA-B305-10 had the highest ascorbic acid content (128.86 mg/100 g) and is recommended for improvement of both local and exotic genotypes targeting the fresh market. Genotypes CAP0408-12 and UG2 WE0511-22, with highest total soluble solids (16.17 ºBrix) and dry matter content (28.59%), respectively should be used in improvements for industrial use or processing to products such as chilli powder or flakes. BRS-M205-04 with highest titratable acidity (1.04%) can be used in enhancing shelf life of genotypes with low titratable acids as well as for the fresh market. In spite of the intraspecific relationships among genotypes, significant differences were observed in their quantitative traits. These genotypes will, therefore, be useful in improving the quality of hot pepper fruit in Uganda.

Quality of seedlings of different pepper genotypes grown in millicompost: An organic substrate generated by millipedes' activity

Quality of seedlings of different pepper genotypes grown in millicompost: An organic substrate generated by millipedes' activity

Serada Sonbahar Dönemi Dolmalık Biber Yetiştiriciliğinde Hibrit Çeşit Adaylarının Meyve Kalitesi ve Verim Performansları

Sebzelerde düşük sıcaklık zararı; büyüme ve gelişmeyi olumsuz etkileyerek verim ve kalite kayıplarına neden olan önemli bir abiyotik stres faktörüdür. Örtüaltı sebze yetiştiriciliğinde düşük sıcaklıklar nedeniyle tür ve çeşitlere göre değişmekle birlikte verim ve kalite performansları yönünden önemli düzeyde azalışlar meydana gelmektedir. Bu çalışmada, üniversite sanayi iş birliğiyle yürütülen biber çeşit ıslahı programı kapsamında geliştirilen 28 hibrit dolmalık biber çeşit adayının ısıtmasız serada sonbahar dönemi yetiştiriciliğinde meyve kalite ve verim özellikleri yönünden performanslarının karşılaştırılması amaçlanmıştır. Isıtmasız serada ilk hasatlar, fide dikiminden itibaren 46-58 gün sonra yapılmıştır. Dolmalık biber genotipleri arasında meyve boyu değerleri yönünden istatistiksel olarak önemli düzeyde farklılıkların olduğu bulunmuştur. Meyve eni değerleri, 47.31-55.86 mm arasında değişim göstermiştir. Renk tonları yönünden dolmalık biber genotipleri arasında belirgin farklılıkların olduğu saptanmıştır. Hibrit biber çeşit adaylarında bitki başına meyve sayılarının ortalama 15.6-30.0 adet arasında değiştiği belirlenmiştir. Çalışmada, Samsun ekolojik koşullarında serada hibrit biber çeşit adaylarının dekara verim değerlerinin, 2560.5 kg (HD-16) ile 5102.5 kg (HD-8) arasında değişim gösterdiği saptanmıştır. Araştırma sonucunda incelenen tüm parametreler birlikte değerlendirildiğinde; HD-4, HD-8 ve HD-24 genotiplerinin düşük sıcaklığa tolerant olduğu ve sonbahar dönemi yetiştiriciliği için ümit var hibrit dolmalık biber çeşit adayları olduğu belirlenmiştir.

Bazı Biber (Capsicum annuum L.) Genotiplerinin Anter Kültürü Performanslarının Belirlenmesi

Bu çalışmada, farklı tiplerde 23 biber genotipinde anter kültürü performansı belirlenmiştir. Çiçek tomurcuklarının dezenfeksiyonunda, tomurcuklar öncelikle % 70’lik etil alkolde 30 saniye bekletilmiş ve sonrasında 10 dakika % 15’lik sodyum hipoklorit çözeltisinde tutulmuşlardır. Anterler ilk aşamada; 30 g/L sakkaroz, 2.5 g/L aktif kömür, 15 mg/L gümüş nitrat (AgNO3), 4 mg/L 1-Naphthaleneacetic acid (NAA), 0.5 mg/L 6-Benzylaminopurine (BAP) ve 6.5 g/L agar içeren Murashige and Skoog (MS) besin ortamında kültüre alınmışlardır. Sonrasında anterler, 30 g/L sakkaroz ve 6.5 g/L agar içeren ve büyümeyi düzenleyici içermeyen MS besin ortamına aktarılmışlardır. Elde edilen embriyolarda, aynı besin ortamına alınmışlardır (ikinci ortama). Anterler, ön uygulama olarak, +35ºC’de ve karanlık koşullarda 2 gün süresince bekletilmişlerdir. Çalışma sonuçları değerlendirildiğinde, genotiplere göre 100 anter için ortalama embriyo sayıları 0.83 ile 44.44 arasında değişmiştir. En yüksek oran, FT-509 genotipinde gözlemlenmiş ve bu genotipi FT-508 (23.61 embriyo/100 anter), FT-1181 (23.37 embriyo/100 anter) ve FT-905 (22.89 embriyo/100 anter) genotipleri takip etmiştir. En düşük performansı, 0.83 adet embriyo/100 anter ile FT-1178 genotipi göstermiştir. Oluşan embriyoların tamamı, bitkiye dönüşebilmiştir. Bu nedenle, 100 anter için ortalama bitki oluşturan embriyo sayısı değerleri, 100 anter için ortalama embriyo sayıları ile aynı olmuştur. En yüksek ortalama bitki sayısı 20 adet ile FT-508 no’lu genotipte gözlemlenmiş ve FT-509 (17.5 bitki), FT-1181 (16 bitki), FT-905 (12 bitki), FT-263 (10.5 bitki) ile FT-507 (8.25 bitki) genotipleri tarafından takip edilmiştir. En düşük bitki sayısı ise 0.5 adet ile FT-1178 no’lu genotipte kaydedilmiştir.

Effect of Drought Stress on Capsaicin and Antioxidant Contents in Pepper Genotypes at Reproductive Stage.

Pepper is one of the most important vegetables and spices in the world. Principal pungency is contributed by secondary metabolites called capsaicinoids, mainly synthesized in the placenta of pepper fruit. Various factors, including drought, limit pepper production. Flowering is one of the most sensitive stages affected by drought stress. The current study was conducted to determine the effect of drought on different pepper genotypes at the flowering and pod formation stages. Hot pepper (Pusajuala and Ghotki) and Bell pepper (Green Wonder and PPE-311) genotypes were subjected to drought (35% field capacity) at two different stages (flowering (DF) and pod formation (DP) stage). In comparison, control plants were maintained at 65% field capacity. The data regarding flowering survival rates, antioxidant protein activity, and proline content, were collected. Results indicated that parameters like flower survival percentage, number of fruits per plant, and fruit weight had significant differences among the genotypes in both treatments. A high proline level was observed in Green Wonder at the pod formation stage compared to other genotypes. Capsaicin contents of hot pepper genotypes were affected at the pod formation stage. Antioxidants like GPX were highly active (190 units) in Ghotki at pod formation. Bell pepper genotypes had a high APX activity, highly observed (100 units) in PPE-311 at pod formation, and significantly differ from hot pepper genotypes. In the catalase case, all the genotypes had the highest values in DP compared to control and DF, but Pusajuala (91 units) and Green Wonder (83 units) performed best compared to other genotypes. Overall, the results indicate that drought stress decreased reproductive growth parameters and pungency of pepper fruit as most of the plant energy was consumed in defense molecules (antioxidants). Therefore, water availability at the flowering and pod formation stage is critical to ensure good yield and pepper quality.

Influence of Salt Stress on Different Pepper Genotypes: Ion Homeostasis, Antioxidant Defense, and Secondary Metabolites

Salt stress, one of the most serious abiotic stresses, leads to a reduction in plant growth, development, and yield in many parts of the world. The purpose of this study was to determine the morphological, physiological, and biochemical salinity tolerance of nine local Turkish pepper genotypes and one variety. Greenhouse plants at the four-leaf stage were subjected to salt stress by adding a total of 150 mM NaCl to the nutrient solution over three days. The growth parameters, ion regulation, photosynthetic pigments, and antioxidative enzyme activities were investigated, as were the malondialdehyde, flavonoid, and phenolic contents. The growth parameters, K+ and Ca2+ contents, and total chlorophyll and carotenoid contents decreased under salt stress. Conversely, the Na+ and Cl– contents and the total flavonoid and phenolic compounds increased under salt stress in all of the genotypes; lipid peroxidation also increased in all genotypes. Antioxidant enzyme activities, however, increased more under salt stress in the tolerant genotypes than it did in the less tolerant plants. The results show that genotypes BIB-6 and BIB-8 were more salt tolerant than the other genotypes and have high potential as genetic material in future breeding programs.

Creation of pepper doubled haploids and morphological characterization of androgenic plants

The Balkan pepper breeding program aims to use in vitro embryogenesis (anther culture) to develop doubled haploid pepper lines with valuable traits. We analyzed the effectiveness of microspore embryogenesis on 17 pepper genotypes comprised of varieties, breeding lines, and F1 hybrids of different varietal types (conical, bell shape, and kapia) and characterized the agronomic traits of newly generated doubled haploid lines. The highest androgenic potential was observed in the variety Stryama and breeding line 560/06 with 9.55 and 13.00% reacted anthers, respectively. Of the 186 regenerated plants, 147 were successfully adapted with a survival index of 79.03%. Flow cytometry analysis showed that the haploid:diploid ratio of regenerants was 1.5:1. All diploid plants were confirmed to be androgenic in origin. There were significant differences in terms of quantitative fruit characteristics of length, width, weight, pericarp weight, pericarp thickness, and productivity per plant among the diploid lines. Also, androgenic lines 21, 23, and 74 derived from Stryama and line 55 obtained from Zlaten medal 7 were distinguished with higher values of some fruit traits compared to initial genotypes. Additionally, several androgenesis lines (Stryama lines 21, 23, and 74, and Zlaten medal 7 line 55) scored higher for some fruit traits compared to the initial genotype. These results show that anther culture is a promising tool for the creation of Balkan pepper breeding lines with improved traits.

Single nucleotide polymorphisms reveal genetic diversity in New Mexican chile peppers (Capsicum spp.)

BackgroundChile peppers (Capsicum spp.) are among the most important horticultural crops in the world due to their number of uses. They are considered a major cultural and economic crop in the state of New Mexico in the United States. Evaluating genetic diversity in current New Mexican germplasm would facilitate genetic improvement for different traits. This study assessed genetic diversity, population structure, and linkage disequilibrium (LD) among 165 chile pepper genotypes using single nucleotide polymorphism (SNP) markers derived from genotyping-by-sequencing (GBS).ResultsA GBS approach identified 66,750 high-quality SNP markers with known map positions distributed across the 12 chromosomes of Capsicum. Principal components analysis revealed four distinct clusters based on species. Neighbor-joining phylogenetic analysis among New Mexico State University (NMSU) chile pepper cultivars showed two main clusters, where the C. annuum genotypes grouped together based on fruit or pod type. A Bayesian clustering approach for the Capsicum population inferred K = 2 as the optimal number of clusters, where the C. chinense and C. frutescens grouped in a single cluster. Analysis of molecular variance revealed majority of variation to be between the Capsicum species (76.08 %). Extensive LD decay (~ 5.59 Mb) across the whole Capsicum population was observed, demonstrating that a lower number of markers would be required for implementing genome wide association studies for different traits in New Mexican type chile peppers. Tajima’s D values demonstrated positive selection, population bottleneck, and balancing selection for the New Mexico Capsicum population. Genetic diversity for the New Mexican chile peppers was relatively low, indicating the need to introduce new alleles in the breeding program to broaden the genetic base of current germplasm.ConclusionsGenetic diversity among New Mexican chile peppers was evaluated using GBS-derived SNP markers and genetic relatedness on the species level was observed. Introducing novel alleles from other breeding programs or from wild species could help increase diversity in current germplasm. We present valuable information for future association mapping and genomic selection for different traits for New Mexican chile peppers for genetic improvement through marker-assisted breeding.

Comparative Transcriptome Analysis Reveals Different Low-Nitrogen-Responsive Genes in Pepper Cultivars

The molecular mechanisms underlying the variation in N-use efficiency (NUE) in pepper (Capsicum annuum L.) genotypes are poorly understood. In this work, two genotypes (750-1, low-N tolerant; ZCFB, low-N sensitive) with contrasting low-N tolerance were selected from 100 pepper cultivars on the basis of their relative leaf areas, shoot dry weights, root dry weights, and plant dry weights at the seedling stage. Subsequently, using RNA-Seq, the transcriptome of these two pepper genotypes under N starvation for 28 days was analyzed. We detected 2621/2470 and 3936/4218 different expressed genes (DEGs) in the leaves/roots of 750-1 and ZCFB, respectively. The changes in the expression of basic N metabolism genes were similar between 750-1 and ZCFB. However, different DEGs not directly involved in N metabolism were identified between the 750-1 and ZCFB cultivars. In 750-1, 110 unique DEGs were detected in the leaves, of which 103 were down-regulated, including genes associated with protein metabolism, photosynthesis, secondary metabolism, cell wall metabolism, stress response, and disease resistance. In ZCFB, 142 unique DEGs were detected in the roots, of which 117 were up-regulated, resulting in enhancement of processes such as protein degradation, secondary metabolites synthesis, lipid metabolism, endocytosis, the tricarboxylic acid cycle (TCA), transcriptional regulation, stress response, and disease resistance. Our results not only facilitate an understanding of the different regulatory process in low-N-tolerant and low-N-sensitive pepper cultivars, but also provide abundant candidate genes for improving the low-N tolerance of pepper cultivars.

The comparison of morphological characters and capsaicinoid contents of the 4th generation chili pepper genotypes G1/01 and G7/01 (Capsicum frutescens L.)

The study aims to identify the morphological and physiological variation of the 4th generation of C. frutescens L. G1/01 and G7/01. The morphological data measured based on IPGRI, AVRDC and CATIE descriptors, and capsaicinoid content measured using spectrophotometry were used to build Jaccard similarity-based cladogram. The results showed that 40% of the G1/01 and 100% of the G7/01 plant height were categorized into very high category (> 85 cm). One hundred percent of the G1/01 and G7/01 were categorized into very early and late flowering, respectively. Eighty-five percent of the G1/01 and 100% of the G7/01 fruit length were categorized into normal (1-5cm). Ninety percent of the G1/01 and 56% of the G7/01 fruit diameters were categorized into normal (>0.5-1cm). Eighty-nine percent of G1/01 and 100% of G7/01 fruit weight were categorized into moderate (0.1-2g). Eighty percent of the G1/01 and 100% of the G7/01 number of seeds were categorized into moderate (>50-200 seeds) and small (<50 seeds), respectively. The capsaicinoid content of G1/01 and G7/01 was significantly lower than the original type. Mutant T39 (G7/01) had the highest capsaicinoid content (19.35mg/g). In the dendrogram, genotypes G1/01 and G7/01 were separated based on the character of the node color, petal color, peel surface, leaf color, and flowering time. G1/01 formed five clusters while G7/01 formed two clusters. G1/01 is more varied than G7/01.