Search

Chloride-induced grapevine toxicity is a leading contributor to abiotic stress in viticultural regions characterized by aridity and limited water availability. Although an essential element for plants, in large enough quantity chloride can reduce net photosynthesis, leaf area, and water uptake in grapevines. Furthermore, the scarcity of water for irrigation has promoted the use of water use efficient irrigation methods such as dripline application, which can limit leaching of nutrients and toxins, and a build-up of salts on the periphery of the wetting-zone. Deficit irrigation practices can also be utilized to improve fruit quality. This dissertation explores the range of tolerance to toxic soil-chloride concentrations in genus Vitis, limitations and thresholds for chloride tolerance in grapevines, and the potential for breeding chloride tolerant grapevine rootstocks. Each topic is expanded in chapters 1, 2, and 3 of this dissertation, respectively.The historic threat of Grapevine Phylloxera in vineyards has resulted in the proliferation of grapevine rootstock cultivars to address this pest and other stressors. Relative to many other perennial crops, grapes have a wide selection of stock to choose from. However, there are innumerable, untested, and often undiscovered species and landraces undisturbed in their native habitats of the Americas that may hold further benefits to vineyards worldwide. To better define the range of chloride tolerance in Vitis germplasm, we examined the resistance to chloride toxicity in six species of wild grapevine collected from the south and southwestern United States alongside several cultivated and widely utilized rootstock cultivars. Presented in chapter 1, results from this survey suggest untapped potential for quasi-halophytic properties in some wild grapevine species such as V. acerifolia and V. doaniana. In chapter 2 common varieties were tested against a gradient of applied sodium chloride ranging from 0 – 100 mM NaCl to better define the chloride concentration threshold at which photosynthetic function begins to decline in commercial rootstock cultivars and chloride becomes toxic. Chapter 2 establishes a range of NaCl exposure between 25-75 mM NaCl in which photosynthetic function begins to break down in many rootstock varieties. Finally, chapter 3 crosses a highly tolerant and highly susceptible parent to explore the breeding potential of chloride tolerance phenotypes in grapevine offspring. Throughout the 77 tested offspring we observed a wide range of continuous increments of foliar chloride accumulation, suggesting possible heritability of chloride-excluding phenotypes. These experiments suggest an untapped source of chloride tolerance in grapevines exists, the range at which these semi-tolerant varieties have the highest efficacy and support the heritability of chloride-excluding phenotypes in subsequent generations. Taken together, this project increases the likelihood a breeding program can introduce chloride-tolerant grapevine rootstock phenotypes that could be successful.

Cucurbita moschata D. seed oil contains approximately 75% unsaturated fatty acids, with high levels of monounsaturated fatty acids and antioxidant compounds such as vitamin E and carotenoid, constituting a promising food in nutritional terms. Associated to this, the Brazilian germplasm of C. moschata exhibits remarkable variability, representing an important source for the genetic breeding of this vegetable and other cucurbits. In this context, the present study evaluated the productivity and profile of the seed oil of 91 C. moschata accessions from different regions of Brazil and maintained in the Vegetable Germplasm Bank of the Federal University of Viçosa (BGH-UFV). A field experiment was conducted between January and July 2016. The tested C. moschata accessions showed high genetic variability in terms of characteristics related to seed oil productivity (SOP), such as the mass of seeds per fruit and productivity of seeds, providing predicted selection gains of 29.39 g and 0.26 t ha-1, respectively. Based on the phenotypic and genotypic correlations, greater SOP can be achieved while maintaining high oleic acid content and low linoleic acid content, providing oil of better nutritional and chemical quality. In variability analysis, the accessions were clustered into five groups, which presented different averages for SOP and fatty acid content of seed oil; approach that will guide the use of appropriate germplasm in programs aimed at genetic breeding for SOP and seed oil profile. Per se analysis identified BGH-4610, BGH-5485A, BGH-6590, BGH-5556A, BGH-5472A, and BGH-5544A as the most promising accessions in terms of SOP, with average (μ+g) of approximately 0.20 t ha-1. The most promising accessions for higher oleic acid content of seed oil were BGH-5456A, BGH-3333A, BGH-5361A, BGH-5472A, BGH-5544A, BGH-5453A, and BGH-1749, with average (μ+g) of approximately 30%, and almost all of these accessions were also the most promising in terms of lower linoleic acid content of seed oil, with average (μ+g) of approximately 45%. Overall, part of the C. moschata accessions evaluated in the present study can serve as a promising resource in genetic breeding programs for SOP and fatty acid profile, aiming at the production of oil with better nutritional and physicochemical quality.

Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) is a devastating fungus pathogen that causes Fusarium wilt in both domesticated cotton species, Gossypium hirsutum (Upland) and G. barbadense (Pima). Greenhouse and field-based pathogenicity assays can be a challenge because of nonuniform inoculum levels, the presence of endophytes, and varying environmental factors. Therefore, an in vitro coculture system was designed to support the growth of both domesticated cotton species and FOV4 via an inert polyphenolic foam substrate with a liquid medium. A Fusarium wilt–susceptible Pima cotton cultivar, G. barbadense ‘GB1031’; a highly resistant Pima cotton cultivar, G. barbadense ‘DP348RF’; and a susceptible Upland cotton cultivar, G. hirsutum ‘TM-1’, were evaluated for 30 days during coculture with FOV4 in this foam-based system. Thirty days after inoculation, disease symptoms were more severe in both susceptible cultivars, which displayed higher percentages of foliar damage, and greater plant mortality than observed in ‘DP348RF’, the resistant Pima cotton cultivar. This foam-based in vitro system may be useful for screening cotton germplasm for resistance to a variety of fungus pathogens and may facilitate the study of biotic interactions in domesticated cotton species under controlled environmental conditions.

Apple (Malus × domestica) is one of the most important fruit crops grown commercially in temperate regions. The present study was conducted to gain knowledge on genetic variability pertaining to flowering, maturity and some morphological characters. Earliest initial and full bloom was observed in Benoni whereas ASP-69 was the last to bloom. Irish peach was found to mature earliest (88 DAFB) while Maharaji (176 DAFB) was the last to mature. The maximum average leaf blade length (101.00 mm) was observed in ASP-4 and ASP-10. Lal Ambri recorded maximum leaf blade width (67.66 mm). Minimum leaf blade length (58.66 mm) and width (36.0 mm) were recorded in Scarlet Siberean. Average length of fruits varied between 28.1 mm (Scarlet Siberean) and 85.2 mm (Lal Ambri). The maximum average fruit weight ranged from 14.06 g (Scarlet Siberean) to 202.73 g (Lal Ambri). Fruit firmness was maximum in Scarlet Siberean (9.43 kg/cm2) followed by 9.06 kg/cm2 in Ambri, minimum fruit firmness was recorded in June eating (5.35 kg/cm2). TSS ranged from 10.76 ⁰Brix (June Eating) to 14.93⁰Brix (Shalimar Apple-1). The maximum acidity was recorded in Braeburn (0.33%) while minimum (0.12%) in Ambri and ASP-69. As per Mahalanobis D2 analysis, the cultivars were grouped into 3 clusters. Cluster I (36 cultivars) comprised of the highest number of cultivars followed by cluster II (3 cultivars) and cluster III was monogenic with 1 cultivar. Wide variation existed in the germplasm under study which could be made use of in future breeding populations

Actinidia arguta is a berry fruit with high nutritional values. To evaluate the comprehensive quality, the fruit weight, titratable acid (TAC), soluble solids (SSC), vitamin C, mineral elements, and taste value of 67 accessions of A. arguta were measured, and sensory attributes including olfactive intensity, juiciness, sweetness, sourness, and astringency were assessed. Cluster analysis was carried out based on mineral elements, and principal component analysis (PCA) was used for comprehensive score ranking. The result demonstrated that fruit weight ranged from 3.5 g to 24.2 g, SSC ranged from 11.94% to 20.56%, TAC ranged from 0.15% to 1.20%, and vitamin C ranged from 3.51 g/kg to 230.76 g/kg (fresh weight) among the tested samples. There were significant differences in sourness, sweetness, bitterness, and umami among the 67 accessions based on electronic tongue analysis, and this result was rapidly and objectively characterized by the sensory assessment. The dendrogram was obtained and clustered the accessions into two major clusters, and five principal components were extracted by PCA. Overall, the information provided by this study identified the 10 best germplasm resources for fresh-eating and processing fruits. It can provide theoretical reference for nutritional efficacy evaluation and food development of A. arguta.

The Diospyros genus contains approximately 400 to 500 species, among which D. kaki is cultivated as the edible persimmon. Knowledge about the genetic diversity of Diospyros genotypes is of high significance for breeding programs. In this research, the genetic diversity of 57 Diospyros genotypes collected from different regions of Iran was evaluated using inter simple sequence repeats (ISSR) and start codon targeted (SCoT) markers. Seven ISSR and 10 SCoT markers produced a total of 42 and 75 fragments with the averages of 6 and 7.5 fragments per primer, respectively. The average polymorphism information content (PIC) for ISSR markers was 0.3 and for SCoT markers was 0.36. The average marker index (MI) for ISSR and SCoT markers were 1.81 and 1.79, respectively. Cluster analysis based on Jaccard’s genetic similarity coefficient and UPGMA method classified 57 Diospyros genotypes into four main groups based on ISSR and SCoT markers. However, the clustering pattern based on the combination of ISSR and SCoT markers data separated the species genotypes better than each marker alone. Accordingly, groups 1 and 2 contained all D. kaki genotypes, both encompassing various subgroups, group 3 included D. lotus and group 4 included D. virginiana genotypes. Genotype distribution visualized with principal coordinate analysis (PCoA) was in accordance with the cluster analysis. Based on our results Iran is a rich source of Diospyrus germplasm, and a combination of ISSR and SCoT markers can be used as an accurate technique for evaluating genetic diversity among the Diospyros genotypes.

Watermelon is an important cucurbit vegetable crop grown in most of the United States. Phytophthora fruit rot of watermelon caused by Phytophthora capsici has been a major factor, limiting production for the past 15 years in the southeastern United States. The U.S. Department of Agriculture, Agricultural Research Service released five Phytophthora fruit rot-resistant germplasm lines for use in breeding programs. These lines were developed by phenotyping using a local isolate of P. capsici from South Carolina. The present study was undertaken to determine if these resistant lines had broad resistance to diverse P. capsici isolates collected from different states and crops. Five resistant germplasm lines (USVL020-PFR, USVL203-PFR, USVL782-PFR, USVL489-PFR, and USVL531-MDR) and two susceptible cultivars, Sugar Baby and Mickey Lee, used as checks were grown in a field in 2014 and 2015 to produce fruit for evaluation. Mature fruit were harvested and placed in a walk-in growth chamber and inoculated with 20 different P. capsici isolates. The chamber was maintained at 26 ± 2°C and high relative humidity (>95%) using a humidifier. All five resistant germplasm lines were significantly more resistant than the two susceptible checks to all 20 P. capsici isolates. Among the five resistant germplasm lines, USVL020-PFR, USVL782-PFR, and USVL531-MDR had broad resistance. Some P. capsici isolates induced minor lesions and rot on USVL489-PFR compared with the other resistant lines. Variation in virulence and genetic diversity among the 20 P. capsici isolates was also observed. The five watermelon germplasm lines will be useful for developing commercial watermelon cultivars with broad resistance to P. capsici.

Societal Impact Statement Global production of bananas, among the top 10 food crops worldwide, is under threat. Increasing the use of germplasm conserved in genebanks is crucial. However, the lack of or difficult access to genetic diversity information limits the efficient utilization of these valuable resources. Here, we present a digital catalog of high‐density markers for banana germplasm conserved at the international banana collection. By facilitating access to subsets of genetic diversity information, the catalog has potential to maximize conservation and use of climate‐ready varieties and to optimize breeding strategies. The catalog is extendable with data from any banana collection and the software is easily deployable in other crop genebanks.

Organic tomato production is increasing worldwide, thus making necessary the development of varieties adapted to this farming system. It is now well known that the implementation of local tomato plant breeding programs for organic farming is required to increase the performance of varieties in this typology of cultivation regime. In this research, the agronomic performance, nutraceutical contents, and radical scavenging activity of a tomato germplasm line (OSTGL), selected under organically grown conditions, were evaluated for two consecutive years (2018 and 2019) in comparison with the variety ‘Rio Grande’, frequently grown organically in Tunisia. Carotenoids, phenolics, vitamin C, and radical scavenging capacity were assayed spectrophotometrically, while tocopherols were analyzed by HPLC. All data were not affected by year-to-year variability. The OSTGL line showed significantly higher marketable yield, total phenol, flavonoid, vitamin C, α-tocopherol and γ-tocopherol contents, along with radical scavenging activity. The OSTGL red-ripe berries also showed comparable values for average weight, soluble solids, pH, titratable acidity, firmness and coloration, as well as lycopene and β-carotene contents. This open pollinated tomato germplasm line demonstrated to be an effective sustainable variety for improving fruit yield, agronomic, and nutraceutical characteristics under an organic management system.

High-throughput and high-density (HD) genetic marker genotyping systems are critical to optimize the efficiency of oil palm breeding and improvement programmes. This study reports the development of the 78 K Infinium® HD customized SNP array, which was used to genotype a thousand palms of a commercial Deli dura x AVROS pisifera family. A total 64,108 (∼82.0%) polymorphic SNP markers were identified of which, 57, 465 (89.6%) were mapped onto the genetic map that has the largest number of markers published so far in oil palm and holds 14,781 SNPs on 2,363 orphan scaffolds (whose chromosomal locations were unknown), which will improve the existing oil palm reference genome (EG5.1). The SNPs were highly informative based on the parent-to-progeny allelic inheritance analysis. The data demonstrated that 4.3% of the progeny resulted from unintentional self-fertilization of the dura female parent. These unintended ‘selfs’ are highly inbred, which will affect their yield. This study also for the first time, describes the homozygosity in the Deli dura and AVROS pisifera, two important parental lines widely used in commercial seed production. As expected, both the parental palms were highly homozygous, having 138 Mb homozygous regions in common, with 70.3% identical alleles. Such a detailed genetic analysis of the individual palm has been made possible with this customized HD SNP array, which will be a valuable tool for routine application in oil palm improvement programmes. The strategy used to design and apply the array will also be of interest for wider scientific research.

Rice is one of the main staple food crops and is consumed by more than half of the global population. Optimizing the flowering time may help to maximize grain production. In this study, we characterized a rice mutant, Zixiangnuo early-flowering mutant (ZXN-E). Compared with the wild-type variety, Zixiangnuo (ZXN), the mutant plants flowered earlier, were shorter and produced smaller panicles. Bulked segregant analysis revealed a 7-bp deletion in the first exon of the Grain number, plant height, and heading date 7 (Ghd7) locus. The allele with the 7-bp deletion was not detected in the rice varieties included in the 3 000 Rice Genomes Project. Thus, the 7-bp deletion identified in the naturally occurring mutant ZXN-E is a novel variation. Our findings suggest that ZXN-E may be a useful germplasm for breeding new rice varieties.

The identification of genotypes with greater capacity for flowering and seed production is crucial for greater efficiency in the genetic improvement of the sweet potato crop. Thus, the objective of this work was to evaluate the flowering capacity and the production of botanical seeds in sweet potato genotypes. The work was carried out in the municipality of Lavras, located in the southern region of Minas Gerais, Brazil. Twenty-two sweet potato genotypes belonging to the germplasm bank of the Federal University of Lavras (UFLA) were evaluated. The characteristics evaluated were the flowering period (days), the number of viable seeds, the total weight of viable seeds, the weight of 1000 seeds and the percentage of germination. The obtained data were analyzed by means of descriptive statistics, study of correlations and analysis of main components. The sweet potato genotypes evaluated showed a high capacity for flowering and production of botanical seeds. Flowering usually starts 125 days after planting and extends on average for 72 days. Considering future recombination to promote flowering capacity, seed production and greater germination, genotypes BD-05, BD-26 and BD-44 should be prioritized. RESUMO A identificação de genótipos com maior capacidade de florescimento e produção de sementes é determinante para maior eficiência do melhoramento genético da cultura da batata-doce. Assim, o objetivo deste trabalho foi avaliar a capacidade de florescimento e a produção de sementes botânicas em genótipos de batata-doce. O trabalho foi conduzido no munícipio de Lavras, localizado na região sul de Minas Gerais, Brasil. Foram avaliados 22 genótipos de batata-doce pertencentes ao banco de germosplasma da Universidade Federal de Lavras (UFLA). Foram avaliados o período de florescimento (dias), número de sementes viáveis, peso total de sementes viáveis, peso de 1000 sementes e porcentagem de germinação. Os dados obtidos foram analisados por meio de estatística descritiva, estudo de correlações e análise de componentes principais. Os genótipos de batata-doce avaliados apresentaram elevada capacidade de florescimento e de produção de sementes botânicas. Verificou-se que a floração geralmente inicia-se 125 dias após o plantio e estende-se em média por 72 dias. Considerando futuras recombinações para promoção da capacidade de florescimento, produção de sementes e maior germinação, devem ser priorizados os genótipos BD-05, BD-26 e BD-44.

Powdery mildew and leaf rust, caused by Blumeria graminis f. sp. tritici and Puccinia triticina, respectively, are widespread diseases of wheat worldwide. The use of resistant cultivars is considered the most economical, environment-friendly, and effective method to control these diseases. In the present study, a collection of 2,978 wheat accessions consisting of 1,394 advanced breeding lines, 1,078 Chinese cultivars, 291 introduced cultivars, 132 lines containing alien chromosomes, and 83 landraces was tested for reactions to powdery mildew and leaf rust. The results indicated that 659 wheat accessions (22.1%) were highly resistant to a widely prevalent B. graminis f. sp. tritici isolate, E09, at the seedling stage, and 390 were consistently resistant to the mixture of B. graminis f. sp. tritici isolates at the adult plant stage. Meanwhile, 63 accessions (2.1%) were highly resistant to leaf rust at the adult plant stage, of which 54 were resistant to a predominant and highly virulent P. triticina race, THTT, at the seedling stage. Notably, 17 accessions were resistant to both powdery mildew and leaf rust. To detect known genes for resistance to powdery mildew and leaf rust, these accessions were tested with gene-specific or tightly linked markers for seven powdery mildew genes (Pm genes; Pm2, Pm4, Pm5, Pm6, Pm8, Pm21, and Pm24) and 10 Lr genes (Lr1, Lr9, Lr10, Lr19, Lr20, Lr24, Lr26, Lr34, Lr37, and Lr46). Of the 659 powdery mildew-resistant accessions, 328 might carry single Pm genes and 191 carry combined Pm genes. Pm2 was detected at the highest frequency of 59.6%, followed by Pm8, Pm6, Pm21, Pm4, and Pm5, whereas Pm24 was not detected. In addition, 139 accessions might contain unknown Pm genes different from those tested in this study. In the 63 accessions resistant to leaf rust, four leaf rust genes (Lr genes; Lr1, Lr10, Lr26, and Lr34) were detected in 41 accessions singly or in combination, whereas six genes (Lr9, Lr19, Lr20, Lr24, Lr37, and Lr46) were not detected. Twenty-two accessions might contain unknown Lr genes different from those tested in this study. This study not only provided important information for rationally distributing resistance genes in wheat breeding programs, but also identified resistant germplasm that might have novel genes to enrich the diversity of resistance sources.

Three species of Begonias endemic to Java and Sumatra, namely Begonia leuserensis, Begonia atricha and Begonia scottii, were conserved in Cibodas Botanic Gardens as sources of germplasm for ornamental plant and/or medicines. However, the information on efficient hormones concentration and their culture media application through an in vitro propagation effort is still limited. Therefore, this study aimed to explain the growth response of three species of Begonias using various hormones concentrations and culture media through in vitro propagation. The culture media using Murashige & Skoog (MS) media that combinedwith 6-Benzyladenine (BA) dan Thidiazuron (TDZ) hormones in different concentrations i.e. 0.5 mg/L, 1 mg/L, 2 mg/L, and 3 mg/L. Observation parameter included shoot number, plantlets height, and leaves number. The data were analyzed using analysis of variance (ANOVA) with the F test at a 5% significance level. The results showed that three species of Begonias were observed to have different growth responses in the combination of MS+BA and MS+TDZ media. The combination of MS+TDZ media produces more shoots number, while the combination of MS+BA media influenced higher in leaves number. A concentration of 0.5 mg/L of hormone showed a good regeneration, therefore were recommended for in vitro propagation of Begonia species.

The present work shows the results of a seven-year project aimed at rescuing the winter squash (Cucurbita maxima Duchesne) landrace ‘Berrettina di Lungavilla’, which is grown in the Po flood plain (Northern Italy). The local community was involved in the rescue project, according to a participative breeding technique. The steps of project development were: (i) establishment of a working group and plant material collection, (ii) genetic and morphological analysis of survived germplasm, (iii) recovery by selection of original traits and (iv) biochemical assessment in comparison to other winter squash varieties. As long as the rescue of ‘Berrettina di Lungavilla’ progressed, it was observed an increasing differentiation of morphological, genetic and biochemical traits compared to control cultivars. At the same time, the polymorphic characters of the initial pool of plants, from which the selection had started, turned to well defined morphological and genetic traits of the recovered landrace. In comparison to the other tested varieties, ‘Berrettina di Lungavilla’ landrace showed a higher dry matter content, a higher level of sucrose and a significant retention of some antioxidants after storage, such as vitamin C and total carotenoids. The combination of these biochemical traits could justify the good storability of the landrace. Anyway, the recovery of this landrace is only a preliminary step of its rescue. A careful analysis of factors which led to the decline of the crop is needed: it is the fundamental basis on which planning a strategy of long-term germplasm conservation.

Hancornia speciosa is a fruit native to the Cerrado biome which is used for the fresh consumption and the manufacture of ice cream, sweets, and jams, among others. This species can harbor insects and mites, associated with different phenological phases of the plant. Therefore, the aim of this study was to verify the occurrence of insects of the order Hemiptera in Hancornia speciosa . For this purpose, collections were made in the ex situ germplasm collection of native species of the School of Agronomy, UFG, Goiânia – Goias state, in four varieties of Hancornia speciosa ( speciosa , cuyabensis , gardneri and pubescens ). Eight plants were selected for each variety at random. From each plant, two branches/plant were collected in the middle third. Those packed in plastic bags, were labeled and transported to the laboratory for evaluation. The collections occurred on average every 15 days, from January to December 2016. The superfamily Coccoidea and the families Aleyrodidae and Aphididae were predominant in the collections. In the study, 1,163 individuals of Parasaissetia nigra were observed in Hancornia speciosa variety cuyabensis . This is the first report of the occurrence of Parasaissetia nigra in Hancornia speciosa . As for the interaction between insects and Hancornia speciosa , it appears that the varieties differed in terms of the abundance of Hemiptera. The Aleyrodidae family was abundant in the gardneri variety, corresponding to 49.84% of the individuals and the pubescens variety in relation to aphids (Aphididae).

The germination and viability of pollen are characteristics required for fecundation when individuals of different or the same species are crossed. For this reason, assessing these parameters in selected individuals to be used in breeding programs will increase the chances for the obtainment of new progeny. In this study, pollen from different accessions of the red-purple tree tomato (Solanum betaceum Cav.) was used: local cultivar (Morado Puntón), two commercial varieties (Large Red and Oratia Red) and six segregants [(Solanum unilobum x Solanum betaceum) x Solanum betaceum]. Three types of flowers were taken (A-day of anthesis, B-one day after anthesis, and C-two days after anthesis). The pollen was conserved in two temperatures (4° and 22° C) and four storage times (0, 5, 10, 20 days). The percentage of germination and pollen viability of the selected individuals were evaluated. It was observed that the commercial materials showed higher germination percentages than the segregants in flower A and B at a temperature of 4 ° C at all storage times, except for the segregants GT7P47 and GT7P48 at the same temperature on day 0. In addition, high percentages of viability were obtained both in flowers A and B, at both temperatures and at all storage times. However, the immediate use of pollen after it is collected is recommended because better germination is achieved. This study is helpful to improve breeding procedures in the initial stages of directed crosses.

Nepenthes khasiana Hook. f. is a critically endangered, carnivorous, endemic species of the Assam and Meghalaya and belongs to the monotypic family Nepenthaceae. An efficient micropropagation protocol was optimized for the propagation and ex-situ conservation of elite germplasm of the species from axenic shoot tip culture. The axenic cultures were established through in vitro seed germination, which envisage the prolonged seed germination time (180 Days) and poor seed germination (25%) in the species. Application of GA3 (500 ppm) enhanced the seed germination upto 89%. Half-strength Murashige and Skoog (MS) medium fortified with 4.4 µM BAP was reported to be the ideal medium and 96.81% shoot formation was observed in N. khasiana shoot tip explants. The highest shoot proliferation of 21.22 ± 0.78 shoots per explants with 10.5 ± 0.5 cm mean shoot length was recorded. The in vitro raised shoots rooted in half salt strength MS medium fortified with IBA (4.9 μM) and 92.11% rooting was recorded with average 17.58 ± 0.87 roots per shoot and 5.5 ± 0.29 cm root length. In-vitro raised plantlets were shifted to the glass house with 65% success rate. Thus, the protocol developed might be useful for the ex-situ conservation of germplasm and commercialization of species to cope up with the ever increasing medicinal and ornamental demands of the species.

Okra [Abelmoschus esculentus (L.) Monech.] is an annual herb of the family Malvaceae and has tremendous nutritional and industrial potential. However, the unknown genome size, variation in ploidy level makes it more challenging for okra breeders to enhance their genetic potential. In this context, the genetic analysis of allelic polymorphism and population structure analysis of okra germplasm is pivotal for its genetic improvement. In the present investigation, a total of 96 okra genotypes were undertaken for morpho-genetic diversity analyses using 13 morphological parameters and 65 SSR markers. Out of 65 SSRs, 50 primers were polymorphic and the mean polymorphic information content (PIC) value was 0.38. The polymorphic loci AVRDC OKRA 64 revealed a maximum PIC value of 0.71 and the number of alleles per locus varied from 2 to 7, with an average of 3.34 alleles per locus. The neighbour-joining (N-J) tree grouped the genotypes into three distinct clusters (I-III), of which Cluster I comprised of cultivated species, A. esculentus and A. caillei, while, Cluster II and III consisted of other related wild species. Furthermore, the population structure analysis distinguished the okra genotypes into two distinct genetic groups comprising cultivated (A. esculentus) and wild-type okra. The variability analysis based on 13 agro-morphological traits revealed that the genotype DOV-92 exhibited the highest per se performance for total fruit yield, followed by Pusa Bhindi-5. The PCA (Principal Component Analysis) analysis revealed that the first three components account for more than 50% of the total genetic variation. The present investigation deciphered a high morphological and genetic diversity in cultivated and wild okra germplasm. Thus, it could serve as important genetic resources for okra improvement programmes.

Simple sequence repeat (SSR) markers can serve as an important tool for characterization and genetic diversity evaluation in Indian mustard germplasm and varieties. For DNA fingerprinting of various Indian mustard varieties, it is necessary that a common set of SSRs be used by various laboratories so that the developed genetic profiles of various genotypes can be compared with one another. In this study, we evaluated the polymorphic potential of 350 SSR markers to derive a set of SSR markers for characterization of Indian mustard germplasm and varieties. Out of a total of 350 SSR markers evaluated, 310 (88.57%) SSRs produced polymorphic amplicons, while remaining 40 (11.43%) SSRs resulted into monomorphic products. The allele number varied from 2 to 7 with 3.22 average number of alleles per locus. Polymorphism information content (PIC) value ranged from 0.24 (Ol09A01) to 0.75 (nia-m141a) with an average PIC value of 0.40 per locus. A total of 95 (31%) SSR markers evaluated were having PIC values more than the average PIC value, which constitute the representative set of SSR markers. Unweighted pair group method with arithmetic averages (UPGMA)-dendrogram grouped all the 46 genotypes into two main clusters, while STRUCTURE analysis formed three subpopulations having admixture of alleles. This SSR marker set will facilitate systematic characterization and classification of various Indian mustard germplasm accessions and varieties.

Societal Impact Statement A future with a secure and safe food supply requires humanity to preserve and exploit the vast variation available across agricultural plant species. Apples are one of the most widely consumed fruits and provide significant nutritional value worldwide. Here, we characterize key agricultural traits in a diverse collection of apples to provide a foundation for future apple improvement. We show that commercially successful apple varieties capture only a small fraction of apple diversity, and demonstrate that significant improvement is possible by tapping into existing genetic diversity. Summary ●Here we present a comprehensive evaluation of apple diversity through phenotyping of Canada's Apple Biodiversity Collection (ABC) which contains over 1000 apple accessions. ●We assessed, over a 4‐year period, more than 20,000 individual apples and quantified variation across 39 phenotypes, including phenology and fruit quality both at harvest and after 3 months of cold storage. ●We observe that apples in the ABC display a wide range of phenotypic variation that may prove useful for future apple improvement. For example, apples can differ by nearly 61‐fold in weight, 18‐fold in acidity, and 100‐fold in phenolic content. We quantified the dramatic changes to apple physiology that occur during 3 months of cold storage: on average, apples lost 39% of their firmness, 31% of their acidity, and 9% of their weight, but gained 7% in soluble solids. Harvest date, flowering date, and time to ripen were all positively correlated with firmness, which suggests that the developmental pathways that drive phenological events throughout the growing season may play a role in determining an apple's texture. Finally, we show that apple breeding has selected for a significant decline in phenolic content over the past 200 years: apple cultivars released after 1940 had a 30% lower median phenolic content than cultivars released before 1940. ●The data and analyses presented here not only provide a comprehensive quantification of the range across, and relationships among diverse apple phenotypes, but they also enable genetic mapping studies that will provide the foundation for future apple improvement via genomics‐assisted breeding.

Ethiopia is the center of origin and diversity for Arabica coffee with high morphological diversity between accessions as compared to commercial cultivars. Coffee germplasm collection and molecular characterization are crucial steps towards its conservation, breeding, and development of superior genotypes for various end uses. Hence, this study was initiated with the objective of studying the genetic diversity of Coffea arabica accessions collected from different regions of Ethiopia, using SSR markers. A total of 20 SSR markers were used to genotype 86 accessions and produced a total of 112 alleles, with an average of 5.6 alleles per locus. All the loci across the entire populations were found to be highly polymorphic with a mean of 0.6 PIC value. Average observed heterozygosity and allelic richness across all populations ranged from 0.22 to 0.27 and 3.52–4.26, with a mean of 2.43 and 3.97, respectively. AMOVA showed high variation within population based on geographical origin. The smaller Fst (0.037) observed indicates the presence of lower population genetic differentiation as a result of higher gene flow (Nm = 2.45) across populations and the lowest mean genetic distance (0.21) observed between populations. The UPGMA, PCoA, and structure analysis poorly grouped the individuals into distinct clusters indicating the presence of population admixture. The observed higher genetic variability in all populations indicates that the country has huge coffee genetic diversity which can be used for future coffee improvement. Our results revealed an unexploited highly diverse genetic resource particularly from Omo, Ilubabor, and Benchi Maji that should be considered in future coffee breeding program and germplasm conservation.

Rice production and quality are seriously affected by the lepidopteran pest, striped stem borer (SSB), in Northeast China. In this study, a synthetic cry1C gene encoding Bacillus thuringiensis (Bt) δ-endotoxin, which is toxic to lepidopteran pest, was transformed into a japonica rice variety (Jigeng 88) in Northeast China by Agrobacterium-mediated transformation. Through molecular detection and the Basta resistance germination assay, a total of 16 single-copy homozygous transgenic lines were obtained from 126 independent transformants expressing cry1C. Finally, four cry1C-transgenic lines (JL16, JL23, JL41, and JL42) were selected by evaluation of the Cry1C protein level, insect-resistance and agronomic traits. The cry1C-transgenic lines had higher resistance to SSB and higher yield compared with non-transgenic (NT) control plants. T-DNA flanking sequence analysis of the transgenic line JL42 showed that the cry1C gene was inserted into the intergenic region of chromosome 11, indicating that its insertion may not interfere with the genes near insertion site. In summary, this study developed four cry1C-transgenic japonica rice lines with high insect resistance and high yield. They can be used as insect-resistant germplasm materials to overcome the problem of rice yield reduction caused by SSB and reduce the use of pesticides in Northeast China.

Background The rice gall midge (RGM, Orseolia oryzae, Wood-Mason), an important stem-feeding pest worldwide, has caused serious production losses over the past decades. Rice production practices indicate that the most reliable method for managing RGM is the deployment of cultivars that incorporate host resistance. However, the conventional phenotypic screening method of rice resistance to RGM suggested by the International Rice Research Institute (IRRI) has been used for approximately 30 years, and only 12 rice varieties/lines (including controls) can be evaluated in one tray. It is not suitable for high-throughput phenotyping of rice germplasm. Moreover, a suitable method to prepare samples for molecular biological studies of rice resistance against RGM is imperative with the rapid development of modern molecular techniques. Results The proper density of seedlings/RGM was determined for four seeding arrangements. A high-throughput phenotyping method (HTPM) for 60 lines/varieties infested with 36 female RGM adults in one tray, as described by method 4–3 (seeded 60 lines/varieties), was developed and verified using mutant screening. Furthermore, one RGM resistance gene flanked by markers 12RM28346 and 12RM28739 on chromosome 12 was simultaneously detected using method 2–2 (seeded 30 lines/varieties in one tray) treated with 24 RGM and analyzed using conventional and simplified grading systems. Genetic analysis of the RGM resistance gene was confirmed using a method identical to that suggested by IRRI. Finally, one bucket with 24 seedlings treated with at least five female RGM adults was efficacious and could offer adequate samples for insect development observation or molecular biological studies. Conclusion A highly efficient and reliable procedure for evaluation of resistance in rice to RGM was developed and improved, and was verified through mutant screening, gene mapping, genetic analysis, and insect growth and development observations.

Background Litchi is a well-known subtropical fruit crop. However, irregular bearing attributed to unstable flowering is a major ongoing problem for the development of the litchi industry. In a previous study, our laboratory proved that litchi flowering was induced by low temperature and that a FLOWERING LOCUS T (FT) homologue gene named LcFT1 played a pivotal role in this process. The present study aimed to understand the natural variation in FT among litchi germplasm resources and designed markers to verify easy- and difficult-flowering litchi germplasms. A grafting experiment was also carried out to explore whether it could shorten the seedling stage of litchi seedlings. Results Two types of LcFT1 promoter existed in different litchi germplasm resources, and we named them the ‘easy-flowering type of LcFT1 promoter’ and ‘difficult-flowering type of LcFT1 promoter’, which resulted in three different LcFT1 genotypes of litchi germplasm resources, including the homozygous easy-flowering type of the LcFT1 genotype, homozygous difficult-flowering type of the LcFT1 genotype and heterozygous LcFT1 genotype of litchi germplasm resources. The homozygous easy-flowering type of the LcFT1 genotype and heterozygous LcFT1 genotype of the litchi germplasm resources completed their floral induction more easily than the homozygous difficult-flowering type of the LcFT1 genotype of litchi germplasm resources. Herein, we designed two kinds of efficient molecular markers based on the difference in LcFT1 promoter sequences and applied them to identify of the easy- and difficult-flowering litchi germplasm resources. These two kinds of molecular markers were capable of clearly distinguishing the easy- from difficult-flowering litchi germplasm resources at the seedling stage and provided the same results. Meanwhile, grafting the scion of seedlings to the annual branches of adult litchi trees could significantly shorten the seedling stage. Conclusions Understanding the flowering characteristics of litchi germplasm resources is essential for easy-flowering litchi breeding. In the present study, molecular markers provide a rapid and accurate approach for identifying the flowering characteristics. The application of these molecular markers not only significantly shortened the artificial crossbreeding cycle of easy-flowering litchi cultivars but also greatly saved manpower, material resources and land.

Persian walnut is an economically important nut crop of temperate regions of the world. In the present study 225 local walnut accessions from 37 sites of Azad Jammu and Kashmir were analysed for morphological traits to investigate variability and identify superior one. Nut length, nut weight, shell thickness and nut diameter varied from 20.87–47.34 mm, 6.44–17.7 g, 1.61–2.54 mm and 27.25–44.31 mm respectively. Kernel weight and percentage varied from 2.81–8.65 g and 32.53–77.34%. Data were analysed statistically using multivariate analysis such as Principal Components Analysis and Cluster Analysis. Pearson correlation coefficient among traits revealed a positively significant correlation between nut weight and nut thickness (r = 0.45987), kernel weight and nut weight (r = 0.94777), kernel% and nut thickness (r = 0.48346), shell thickness and kernel% (r = 0.21961), a negative correlation with significant differences was found between kernel weight and nut thickness (r = –0.40968), kernel% and nut length (r = –0.10844) and between kernel% and nut weight (r = –0.95209). The highest and most significant positive correlation (0.96024) was observed between kernel weight and kernel% and (r = 0.94777) between kernel weight and nut weight. A wide range of variability was observed among walnut accessions and BA2, BN2, CN3 and BN4 accessions are reported as superior and conserved for future breeding programs due to their distinct characteristics.

The production of cotton is negatively affected by salinity. For this purpose, 8 parents and their 16 F1 hybrids were evaluated under saline stress (15 dSm−1) in Line × Tester fashion. Mean values ...

Meloidogyne enterolobii (syn. mayaguensis) is an emergent species of root-knot nematode that has become a serious threat to sweet potato (Ipomoea batatas) production in the southeastern United States. The most popular sweet potato cultivars grown in this region are highly susceptible to M. enterolobii. As a result, this pest has spread across most of the sweet potato growing counties in the Carolinas, threatening the industry as well as other crops in the region. The development and release of new sweet potato cultivars with resistance to M. enterolobii would help to manage and slow the spread of this pest. To support sweet potato resistance breeding efforts, 93 accessions selected from the U.S. Department of Agriculture germplasm collection and breeding programs in the United States were screened to identify 19 lines with strong resistance to M. enterolobii. The resistance in these accessions was tested against two M. enterolobii isolates that were collected from sweet potato production fields in the Carolinas. These isolates were found to have distinct pathotypes, with galling and nematode reproduction differences observed on cotton as well as sweet potato. This study is the first report of intraspecific pathotypic variation in M. enterolobii, and it identifies sweet potato germplasm with resistance against both pathogenic variants of this nematode.

Investigation of genetic variability and population relationship of 50 accessions of the apricot (Prunus armeniaca L.) was carried out using ISSR markers. The results revealed that the number of alleles per locus varied from 4 to 8 with a mean value of 6.75, and the mean effective number of alleles (Ne) per locus was 1.54. Similarly, the polymorphic information content (PIC) values ranged from 0.464 to 0.424, with a mean value of 0.424. The mean heterozygosity, marker index, resolving power, and effective multiplex ratio (EMR) ranged from 0.001 to 0.002, 0.01–0.06, 1.76–3.84, and 1–4.12. The dendrogram clustered genotypes into two main clades based on their origins. The population structure revealed two sub-populations with some admixtures. The average expected heterozygosity and population differentiation within two sub-populations was 0.1428 and 0.216, respectively. The results outcome reveals that the four ISSR markers comprehensively separated the indigenous germplasm from the exotic germplasm. The genetic divergence within indigenous genotypes and exotic genotypes could allow for future insights into apricot breeding programs.