Selection Of Germplasm Research Articles

Performance Evaluation and Identification of New Quality Protein Maize Inbred Lines

Background: Maize plays a critical role in meeting high food demand. It is a globally widely adopted and cultivated crop. Hybrid and open-pollinated varieties development from fixed inbred lines is one of the strategies for the improvement of maize production. Compared with the world average, the national average maize yield is low in Ethiopia. According to this development and selection of promising germplasm has indispensable value for developing high-yielding maize varieties. The study consists of 21Quality Protein Maize (QPM) lines, two QPM testers lines, and one Conventional Maize (CM) line check (FS67). They were evaluated in RCBD with two replications at Ambo and Arsi-Negele. The objective was to identify new lines with good performance compared with released QPM checks and CM lines.
 Results: There is a significant difference between the lines for 28 traits in Ambo and 24 traits at Arsi-Negele. In combined mean performance analysis, the highest yielding line (L8) exceeded the mean of all line checks, mean QPM checks, CM line check (FS67), and best QPM line check (CML144) by 34.89%, 54.80%, 7.30%, and 25.31%, respectively for GY. The value of EPP ranged from 0.91 (L14) to 1.85 (L3) with an overall mean of 1.19). The highest yielding line (L8) had the 2nd highest EPP (1.63). Mean EPP of the top five QPM lines was less by 5.45%, 4.96%, 22.41%, and 6.41% compared with the mean of all checks, mean of QPM line checks, best QPM check, and CM line check, respectively. The high yielder line (L8) had a higher mean value than the mean of lines checks (CML144, CML159, and FS67), mean of QPM lines checks, best QPM check (CML144), and FS67 by 25.71%, 26.36%, 3.16%, and 24.43%, respectively.
 Conclusion: In general, the study confirmed the existence of promising new QPM parental lines. These promising lines can be used as source material in the breeding program for further improvement.

Standard Heterosis Estimation for Quality Protein Maize Hybrids Over Best Released and Commercialized Hybrids

Maize plays an indispensable role in meeting high food demand. It is globally one of the most widely adopted and cultivated crops. Hybrid development from fixed inbred lines is one of the tactics to boost maize production. The national average maize yield in Ethiopia is low and thus, selection of promising germplasm, knowledge of combining ability, and heterotic grouping are prerequisites to develop high-yielding maize varieties. Forty-two Quality Protein Maize (QPM) single crosses (21 inbred lines each crossed with two testers) along with three popular standard hybrid checks were evaluated in two replications using alpha lattice design during the 2017 cropping season at Ambo, Arsi-Negele, and Kulumsa. The objective of this study was to estimate standard heterosis for grain yield (GY), and other agronomic and morphological characters. Significant difference among crosses was observed for 19 traits at Ambo, 14 traits at Arsi-Negele, and 19 traits at Kulumsa in the hybrid trial. For GY, at Ambo, almost all crosses showed negative heterosis against the best check (AMH853). At Arsi-Negele 14 crosses had positive standard heterosis, from these only three crosses: L8xT1 (50.8%), L8xT2 (46.6%), and L7xT1 (33.9%) showed significant difference against Jibat but at Kulumsa, the difference for standard heterosis was positive but non-significant only by two crosses: (L7xT1 (6.6%) and L19xT1 (4.7%). Based on mean grain yield and standard heterosis, L8xT2, L7xT1, L8xT1, L19xT1, L6xT2, and L18xT1 are promising. The study of the results highlighted that the breeding program was successful in generating superior QPM hybrids. Based on the finding we suggest that it is better to use the parents of theses hybrids as potential source materials in the breeding program through to form different crosses formation.

Association Analysis Between Genotype and Environment: Differentiation Between Cyclocarya paliurus Resources That Accumulate Triterpenoids.

Cyclocarya paliurus is mainly distributed in subtropical areas of China. Its leaves are rich in beneficial triterpenoids that have bioactivities against human diseases, including hyperlipemia, diabetes, and hypertension. In this study, data on the genetic diversity, distributing environment, and triterpenoids of C. paliurus samples were collected from a wide area in China. The data covered 316 C. paliurus germplasms collected from 26 distinct populations. Association analysis between genotype and triterpenoids was carried out to describe triterpenoids accumulation pattern. Based on our analyses, we identified the important trend that genotypes with higher triterpenoid contents belonged to a unique genotype subgroup. The results showed that pterocaryoside B and pterocaryoside A significantly vary among the genotypic subgroups. In addition, the different genotypic subgroups showed distinct geographical distributing areas. These findings provide information about the relationship between genetic and environmental factors and how this affects triterpenoids accumulation. This information will be valuable for targeted breeding and for further germplasm selection of C. paliurus resources.

Estimation of General and Specific Combining Ability Effects for Quality Protein Maize Inbred Lines

Background: Maize (Zea mays L.) plays a critical role in meeting high food demand. It is globally one of the most widely adapted and cultivated crops. Hybrid development from fixed inbred lines is one of the strategies for the improvement of maize production. The national average maize yield in Ethiopia is low and thus, selection of promising germplasm and knowledge of combining ability are prerequisites to developing high yielding maize varieties. Forty-two Quality Protein Maize (QPM) crosses (21 inbred lines each crossed with two testers) along with three popular standard hybrids were evaluated in two replications using alpha lattice during the 2017 cropping season at Ambo, Arsi-Negele, and Kulumsa. The objectives of this study were to identify lines with high GCA and estimate the SCA of crosses for grain yield, and other agronomic and morphological characters.
 Results: Significant difference among crosses was observed for 19 traits at Ambo, 14 traits at Arsi-Negele, and 19 traits at Kulumsa in the hybrid trial. Regarding the GCA effect, L8 had a significant difference to the positive side with the highest magnitude of GCA effect at three locations (3.40, 2.03, and 1.88 GCA effect values at Arsi-Negele, Ambo, and Kulumsa, respectively) which is followed by L7 for GY. All crosses did not show a significant SCA effect for GY in both directions at Ambo and Arsi-Negele but at Kulumsa, five crosses: L2xT1(1.89), L13xT2(1.88), L7xT1(1.86), L4xT2(1.49) and L19xT1(1.41) showed significant difference. In the combined analysis for six traits, Additive gene action was more important which was manifested by a higher sum square contribution of DS (79.6) EPP (79.3%), EL (80.0%), KPR (80.1%), ED (78.5%) and TSW (79.1%).
 Conclusion: Based on mean grain yield, and combining ability, L8xT2, L7xT1, L8xT1, L19xT1, L6xT2, and L18xT1 are promising crosses that could be forwarded for further use in maize breeding programs for further works.

Performance Evaluation and Identification of Highland Quality Protein Maize Hybrids in Ethiopia

Background: Maize plays an indispensable role in meeting high food demand. It is globally one of the most widely adopted and cultivated crops. Hybrid development from fixed inbred lines is one of the strategies for the improvement of maize production. The national average maize yield is low in East Africa; thus, the selection of promising germplasm has a great role to meet the high food demand of growing the population. Forty-two Quality Protein Maize (QPM) crosses (21 inbred lines each crossed with two testers) along with three popular standard hybrids checks were evaluated in two replications using alpha lattice during the 2017 cropping season at Ambo, Arsi-Negele, and Kulumsa. The objective of this study was to evaluate and select the best new QPM hybrids for grain yield, and other agronomic and morphological characteristics.
 Results: Significant difference among crosses was observed for 19 traits at Ambo, 14 traits at Arsi-Negele, and 19 traits at Kulumsa. Out of 28 traits studied, six of them did not show genotype by location interaction but they showed a significant genotypic effect. These traits were: Days to Silking (DS), Number of Ears per plant (EPP), Ear Length (EL), Kernels Per Row (KPR), Ear Diameter (ED), and Thousand Seed Weight (TSW). Based on the mean performance in the combined analysis, from 42 new QPM crosse, six of them (L8xT2, L7xT1, L8xT1, L19xT1, L6xT2, and L18xT1) were scored higher grain yield compared with the mean of the three standard checks and best conventional maize (CM) check (AMH853). L8xT2, L7xT1, L8xT1 crosses showed a higher grain yield advantage over the best check (AMH853) by 20.87, 14.13, and 13.63%, respectively.
 Conclusion: The study implicated the existence of a difference between the newly developed hybrids and the standard check varieties. In general, the study enabled us to identify promising crosses that could be forwarded for further use in maize breeding programs in future work.

Mid-parent and Better Parent Heterosis Study on Highland Quality Protein Maize Hybrids in Ethiopia

Determination of heterosis in maize hybrids is necessary for the identification of superior F1 hybrids for breeding programs. Therefore, this study was conducted to estimate the amount of mid parent (MPH) and better parent heterosis (BPH) for grain yield, yield-related, agronomic, and morphological traits. Hybrid development from fixed inbred lines is one of the strategies for the improvement of maize production. The national average maize yield in Ethiopia is low and thus, selection of promising germplasm, knowledge of combining ability, and heterotic grouping are prerequisites to developing high-yielding maize varieties. Forty-two Quality Protein Maize (QPM) crosses (21 inbred lines each crossed with two testers) along with three popular standard hybrids were evaluated in two replications using alpha lattice during the 2017 cropping season at Ambo and, Arsi-Negele. Parental line trials consisting of 21 lines, two testers, and one conventional maize (CM) parent check (FS67) were established in two replications laid out using RCBD side by side with the hybrid trials at Ambo and Arsi-Negele. At Ambo, almost all crosses showed positive and significant BPH except three crosses (L1xT1, L4xT1, and L13xT1). The maximum BPH (276.2%) was obtained from L17xT2. Similarly, at Arsi-Negele, most of the crosses had positive and significant BPH except for five crosses for BPH which are showing negative heterosis. The highest BPH was obtained from L10xT2 at Arsi-Negele. Generally, the high yielding crosses had reasonable BPH. Based on the result promising crosses and lines were identified. Some of the crosses showed good performance in terms of heterosis against the mid parent and better parent: L17xT2 (329.88% MPH, 276.18% BPH), L3xT2(320.05% MPH, 273.91%BPH), and L19xT2(2802.57% MPH, 247.31% BPH) at Ambo, whereas at Arsi-Negele L10xT2 (128.38% MPH, 111.27%BPH) and L11xT2(115.33% MPH, 98.00% BPH) showed the higher heterosis compared with the mid parent and better parent. Crosses that showed best yield performance were: L8xT2, L7xT1, L8xT1, L19xT1, L6xT2, and L18xT1. These crosses should be reconsidered for further evaluation and possible release.

The Rhizome Essential Oil Composition of Zingiber officinale Roscoe. Core Collection from Northeast Indian Germplasm

Zingiber officinale Roscoe. is a medicinally important plant with distinct aroma and pungency. The present study aims to evaluate the essential oil of 150 germplasm of ginger collected from different states across Northeast India which has been maintained at field gene bank. The rhizome essential oil was isolated by hydrodistillation using Clevenger apparatus and was evaluated by gas chromatography. The study revealed the presence of twenty-one chemical constituents in the studied germplasm out of which E-citral followed by Z-citral, 1,8-cineole, ar-curcumene, camphene and geraniol were the major constituents. The identified minor compounds were 1-borneol followed by γ-muurolene, α-bisabolene, zingiberene, α-terpineol, farnesene, linalool, α-pinene, geranyl acetate, eudesmol and β-cedrene. This is the first report on the evaluation of essential oil constituents of diverse germplasm (150) of Z. officinale which will be highly beneficial for the identification of compound-rich germplasm of ginger. This would further pave the way for selection of ginger germplasm with superior trait in terms of chemical composition.

Variation in Glucosinolate Accumulation among Different Sprout and Seedling Stages of Broccoli (Brassica oleracea var. italica).

Glucosinolates (GLs) are plant secondary metabolites that may act against different types of cancers. Broccoli (Brassica oleracea var. italica) is rich in GLs which makes it an excellent source of these nutraceuticals. The composition and concentration of GLs vary among broccoli cultivars and throughout the developmental stages of the plant. To obtain the GL profiles of broccoli, GL compositions and contents in four early developmental stages (seeds, 3-day sprouts, 11-day and 17-day seedlings) were determined for nine cultivars of broccoli in this study. A total of 12 GLs including 9 aliphatic GLs and 3 indole GLs were identified from the nine broccoli cultivars using LC-QTOF-MS. UPLC results showed that aliphatic GLs concentrations decreased with broccoli sprouts and seedling growth for most cultivars. Interestingly, indole GLs amounts increased after germination and reached the highest level in 3-day sprouts or 11-day seedlings, and they fell back to a low level in 17-day seedlings. The GL profiles of nine cultivars documented in this study will provide useful information for high quality germplasm selection for cultivation or genetic engineering, and further understanding of the GL metabolic pathways.

Spectral Reflectance Indices as a High Throughput Selection Tool in a Sesame Breeding Scheme

On-farm genotype screening is at the core of every breeding scheme, but it comes with a high cost and often high degree of uncertainty. Phenomics is a new approach by plant breeders, who use optical sensors for accurate germplasm phenotyping, selection and enhancement of the genetic gain. The objectives of this study were to: (1) develop a high-throughput phenotyping workflow to estimate the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Red Edge index (NDRE) at the plot-level through an active crop canopy sensor; (2) test the ability of spectral reflectance indices (SRIs) to distinguish between sesame genotypes throughout the crop growth period; and (3) identify specific stages in the sesame growth cycle that contribute to phenotyping accuracy and functionality and evaluate the efficiency of SRIs as a selection tool. A diversity panel of 24 sesame genotypes was grown at normal and late planting dates in 2020 and 2021. To determine the SRIs the Crop Circle ACS-430 active crop canopy sensor was used from the beginning of the sesame reproductive stage to the end of the ripening stage. NDVI and NDRE reached about the same high accuracy in genotype phenotyping, even under dense biomass conditions where “saturation” problems were expected. NDVI produced higher broad-sense heritability (max 0.928) and NDRE higher phenotypic and genotypic correlation with the yield (max 0.593 and 0.748, respectively). NDRE had the highest relative efficiency (61%) as an indirect selection index to yield direct selection. Both SRIs had optimal results when the monitoring took place at the end of the reproductive stage and the beginning of the ripening stage. Thus, an active canopy sensor as this study demonstrated can assist breeders to differentiate and classify sesame genotypes.

Simple sequence repeat marker development and diversity analysis in buffalograss

AbstractBuffalograss [Buchloë dactyloides (Nutt.) Engelm. syn. Bouteloua dactyloides (Nutt.) Columbus] is a stoloniferous low input turfgrass species native to the central Great Plains of the United States. Several molecular marker techniques have been used to compare relationships among elite buffalograss germplasm, but most rely on random amplification, are transferred from other species, or are developed from limited DNA sequence information. The objectives of this study were to develop buffalograss derived simple sequence repeat markers (SSRs) from buffalograss sequence data using an in‐silico bioinformatics pipeline and use high resolution melt analysis to screen the SSRs based on their melt profiles on buffalograss cultivars and germplasm. Transcriptomes from buffalograss cultivars ‘378’ and ‘Prestige’ were mined for SSRs using the MIcroSAtellite tool. There were 259 conserved SSRs that were polymorphic between 378 and Prestige. Of those, 96 were tested by HRM on a panel of eight genotypes and 24 were selected for producing melt profiles that could distinguish the genotypes. The selected reactions produced 356 distinct melt profiles when tested on a panel of 96 genotypes, including 88 buffalograss germplasm selections, six buffalograss cultivars, and two blue grama [Bouteloua gracilis (H. B. K.) Lag. ex Steud.] selections, with melt profile frequencies ranging from 0.01 to 0.97. A subset of 86 melt profiles segregating among the blue grama and elite buffalograss cultivars distinguished each genotype. The buffalograss‐specific SSR markers presented here will be useful to study buffalograss genetic diversity, line purity maintenance, and for marker supported plant breeding strategies.

Study on the Relationship of Root Morphology and Phosphorus Absorption Efficiency With Phosphorus Uptake Capacity in 235 Peanut (Arachis hypogaea L.) Germplasms

Peanut (Arachis hypogaea L.) is a significant oil and protein crop. Its yields greatly depend on the availability of phosphorus (P). Root morphology and P absorption efficiency are important factors affecting the P uptake capacity, but their relationships in peanuts are rarely reported. Here, we report the effect of root morphology and P absorption efficiency on the P uptake capacity in peanuts using 235 germplasms. In this work, we use the P uptake rate per plant to reflect the P uptake capacity. The P uptake capacity was significantly increased after low-P treatment and showed great differences among the germplasms. The germplasms with higher P absorption efficiency and a well-developed root system have higher P uptake capacity. Under both P conditions, the P absorption efficiency plays more important roles than root morphology in P uptake capacity, and the P uptake rate per unit root dry weight and the P uptake rate per unit root surface area contributed the most. Root morphology contributes more to the P uptake capacity under low-P treatment than under sufficient-P conditions, and root surface area contributed the most. Forty-eight germplasms with higher P uptake capacity were screened, and they had three different uptake strategies under low-P treatment. These findings indicated that low-P stress induces root growth and improves the P absorption efficiency of peanuts to ensure the plant gets enough P; provides new insights into the relationship between the P uptake capacity, P absorption efficiency, and root morphology; and furnishes important evaluation indexes for high P-efficient germplasm selection.

Protein Biofortification in Lentils (Lens culinaris Medik.) Toward Human Health.

Lentil (Lens culinaris Medik.) is a nutritionally dense crop with significant quantities of protein, low-digestible carbohydrates, minerals, and vitamins. The amino acid composition of lentil protein can impact human health by maintaining amino acid balance for physiological functions and preventing protein-energy malnutrition and non-communicable diseases (NCDs). Thus, enhancing lentil protein quality through genetic biofortification, i.e., conventional plant breeding and molecular technologies, is vital for the nutritional improvement of lentil crops across the globe. This review highlights variation in protein concentration and quality across Lens species, genetic mechanisms controlling amino acid synthesis in plants, functions of amino acids, and the effect of antinutrients on the absorption of amino acids into the human body. Successful breeding strategies in lentils and other pulses are reviewed to demonstrate robust breeding approaches for protein biofortification. Future lentil breeding approaches will include rapid germplasm selection, phenotypic evaluation, genome-wide association studies, genetic engineering, and genome editing to select sequences that improve protein concentration and quality.

MAIZE CULTIVARS WITH NATIVE INSECT RESISTANCE – POTENTIAL, ADVANCES, AND CHALLENGES

The development of resistant cultivars is one of the strategies applied in pest control. The method has the advantages of reduced cost and the lack of unwanted effects on the environment. Over the past decades, significant effort has been made toward developing the natural maize resistance to pests by evaluating germplasm and cultivar selection. This review highlights a maize breeding program, potential, advances, and challenges in addressing these characteristics. Also, it describes the main components and procedures applied in the mass rearing of insect pests of maize, artificial diets, techniques of artificial infestation employed in genotype selection, and methods to evaluate the mechanisms and causes of resistance. Studies on the inheritance of resistance, the breeding methods, and the potential for integrating classical and transgenic resistance are also emphasized.

Distribution of Phenolic Compounds and Antioxidant Activity in Plant Parts and Populations of Seven Underutilized Wild Achillea Species.

Evaluation of phytochemical composition of underutilized Achillea species provides the primary selection of germplasms with the desired quality of raw material for their further applications. The aim of the study was to evaluate the comprehensive distribution patterns of phenolic compounds in seven wild Achillea spp. and their plant parts, and to assess their antioxidant activity. Plant material was collected from different sites in Turkey. A complex of hydroxycinnamic acids, flavonols and flavones was identified and quantified in methanolic extracts using HPLC-PDA method. Antioxidant activity was assessed by radical scavenging assay. The results showed that qualitative and qualitative profiles of caffeoylquinic acids and flavonoids were species-specific, explaining the characteristic patterns of their variation in the corresponding species and plant parts. The highest total amount of caffeoylquinic acids was detected in A. setacea. A. arabica exposed the highest accumulation of mono-caffeoylquinic acids and flavonoids with the greatest levels of quercetin and luteolin derivatives and the flavonol santin. Santin was detected in all plant parts of A. cappadocica, A. setacea, A. santolinoides subsp. wilhelmsii, and A. arabica. A notable antiradical capacity was confirmed in A. arabica, A. setacea and A. cappadocica plant extracts. The leaves of all studied species were found to have priority over inflorescences and stems in terms of radical scavenging activity. The new data complemented the information that may be relevant for the continuation of chemophenetic studies in the heterogeneous genus Achillea.

Ecological and Environmental Benefits of Planting Green Manure in Paddy Fields

Soil fertility management is one of the most important factors affecting crop production. The use of organic manures, including green manure, is an important strategy to maintain and/or improve soil fertility for sustainable crop production. Green manure generally refers to crops that can provide fertilizer sources for agricultural cash crops and improve soil productivity. The application of green manure is a traditional and valuable practice for agroecosystem management, particularly in paddy systems where green manure is rotated with rice. This paper systematically reviews the effects of green manure on soil microenvironments and greenhouse gas emissions, and the role of green manure in the phytoremediation of paddy fields. The paper concludes that green manure can not only affect soil nutrients and the microbial community, but also reduce greenhouse gas emissions and enhance soil remediation to some extent. Moreover, this review provides theoretical guidance on the selection of green manure germplasm and tillage methods for paddy fields of different climates and textures. However, this review only provides a macro-overview of the effects of green manure on soil nutrients, greenhouse gas emissions, and soil remediation in rice paddies based on a large number of previous studies, and does not provide a comprehensive quantitative assessment due to differences in green manure varieties and soil texture. The prospects for quantitative analysis of the ecological and economic effects of the sustainable development of green manure cultivation are discussed.

Protein Profiling of Pollen–Pistil Interactions in Almond (Prunus dulcis) and Identification of a Transcription Regulator Presumably Involved in Self-Incompatibility

The cultivated almond displays a gametophytic self-incompatibility system, which avoids self-fertilization, and it is controlled by a multi-allelic locus (S-locus) containing two genes specifically expressed in pistil (S-RNase) and pollen (SFB). Studies on almonds with the same S-haplotype but different phenotype pointed to the existence of unknown components in this system to explain its functioning. The increase of knowledge on this reproductive barrier would allow better management of fruit production and germplasm selection. This work proposes candidates to components of the almond gametophytic self-incompatibility system, by identifying differentially expressed proteins (DEPs) after compatible and incompatible pollen–pistil interactions in almonds with the same S-haplotype but a different incompatibility phenotype using iTRAQ and 2D-nano-LC ESI/MSMS analyses. The protein quantitation analysis revealed 895 DEPs, which were grouped into different functional categories. The largest functional group was “metabolic proteins”, followed by “stress resistance and defense proteins”, with higher up-regulation after pollination. The identity of certain DEPs, such as Thaumatin, LRR receptors, such as kinase and pathogenesis related protein PR-4, indicated that some pollen–pistil interactions in almond could have the same bases as host–parasite interactions. Furthermore, additional RT-qPCR analysis revealed the differentially expressed transcription regulator GLABROUS1 enhancer-binding protein-like (GEBPL) could be involved in the gametophytic self-incompatibility system in almond.

Estimation of heterosis for yield and yield components in okra [Abelmoschus esculentus (L.) Moench

Exploitation of heterosis is primarily dependent on the selection of available germplasm that could be produced by better combinations of important agronomic characters. The heterosis was recorded for fruit and its fifteen component characters. The crosses showing significant heterosis over standard check were Varsha Upahar x Kashi Kiranthi for plant height and days to 50% flowering, 307-10-01 x Arka Anamika for number of leaves, Parbhani Kranthi x ZARS for internodal length, Varsha Upahar x ZARS for number of branches per plant, Pusa Makhmali x ZARS for number of nodes on main stem, Phule Utkarshi x Kashi Kiranthi for stem diameter, Punjab Padmini x ZARS for fruit length, Pusa Makhmali x Kashi Kiranthi for fruit diameter,VRU-109x Arka Anamika for number of fruits per plant, Punjab Padmini x ZARS for average fruit weight per plant and for total fruit yield per plant was maximum in the hybrid VRU-109 x Arka Aanamika, followed by Phule Utkarshi x Kashi Kiranthi were these hybrids may be used for exploitation of hybrid vigour on commercial scale.

Variation burst during dedifferentiation and increased CHH-type DNA methylation after 30years of in vitro culture of sweet orange.

Somaclonal variation arising from tissue culture may provide a valuable resource for the selection of new germplasm, but may not preserve true-to-type characteristics, which is a major concern for germplasm conservation or genome editing. The genomic changes associated with dedifferentiation and somaclonal variation during long-term in vitro culture are largely unknown. Sweet orange was one of the earliest plant species to be cultured in vitro and induced via somatic embryogenesis. We compared four sweet orange callus lines after 30years of constant tissue culture with newly induced calli by comprehensively determining the single-nucleotide polymorphisms, copy number variations, transposable element insertions, methylomic and transcriptomic changes. We identified a burst of variation during early dedifferentiation, including a retrotransposon outbreak, followed by a variation purge during long-term in vitro culture. Notably, CHH methylation showed a dynamic pattern, initially disappearing during dedifferentiation and then more than recovering after 30years of in vitro culture. We also analyzed the effects of somaclonal variation on transcriptional reprogramming, and indicated subgenome dominance was evident in the tetraploid callus. We identified a retrotransposon insertion and DNA modification alternations in the potential regeneration-related gene CLAVATA3/EMBRYO SURROUNDING REGION-RELATED 16. This study provides the foundation to harness in vitro variation and offers a deeper understanding of the variation introduced by tissue culture during germplasm conservation, somatic embryogenesis, gene editing, and breeding programs.

Screening and Transcriptome Analysis of Different Materials with Low Temperature Tolerance in Eggplant (<i>Solanum melongena</i>)

The growth and fruit quality of eggplant were seriously affected by low temperature stress. In order to screen low temperature tolerance germplasm of eggplant and reveal its correlation with low temperature tolerance at molecular level. In this study, two eggplant inbred lines with different genotypes were selected on the basis of preliminary experiments. The effects of low temperature stress on the seed germination and seedling chilling injury were studied. The transcriptome of seedling leaves under 4°C low temperature was sequenced, and the differentially expressed genes were classified and enriched. The results showed that CHEN18 was much stronger than 819 in seed germination and seedling low temperature tolerance. The analysis of transcriptome data showed that there were some differences in genetic background between the two eggplant materials, and the differentially expressed genes were mainly concentrated in biological regulation, cell process, metabolic process and single organism process. Up-regulated differentially expressed genes are mainly enriched in cell processes, environmental information processing, genetic information processing and metabolism. The results of this study laid a foundation for the selection of cold tolerance germplasm and the excavation of cold tolerance genes in eggplant.

Assessment of repeatability and representativeness of testing sites for provitamin a maize in savanna agro-ecologies of Nigeria

Identification of ideal testing sites for selection of superior maize (Zea mays L.) germplam is vital to the success of a maize breeding programme. Sixteen provitamin A maize genotypes were evaluated at seven locations in savanna agro-ecologies of Nigeria for 3 yr to assess the representativeness, discriminating ability, and repeatability of the testing sites and to identify ideal testing sites for selection of superior maize germplasm. Location, year, and their interaction effects were significant for grain yield and mostmeasured traits while genotype and genotype ´x year interactive effects were significant for grain yield. The genotype main effects plus genotype ´x environment interaction (GGE) biplot analysis revealed PVA SYN-18 F2 as the highest-yielding and most stable genotype across environments. The GGE biplot identified Zaria, Saminaka, and Kaboji as the most discriminating locations. Also, the biplot identified Kaboji, Batsari, Saminaka, and Zaria as the most repeatable locations. Zaria and Saminaka, being among the most discriminating, representative and repeatable locations, were considered as the core testing sites for selection of superior maize genotypes for release and commercialization. The core testing sites identified in this study should facilitate the identification of stable and high-yielding maize germplasm adaptable to the savannas agro-ecologies of Nigeria.