Citrus aurantium also known as sour orange or bitter orange is among important Citrus species of the angiosperm subfamily Aurantioideae of the Rutaceae family. Due to importance of Citrus species as the source of food and medicine, they have been subject of been extensive genetic studies throughout the world. Sour orange plants are cultivated in the north and south parts of Iran but we have very limited genetic data on them. Therefore, the present study was conducted with the aim to study the population genetics of these important fruit plants in the country and provide information on their genetic structure and diversity. We used SCoT molecular markers in 61 plants of 12 sour orange populations. We obtained 33 SCoT bands of which one to two private bands were observed in populations 1 and 5. Genetic diversity parameters determine in the studied populations revealed a low to moderate genetic diversity. Genetic grouping of the populations by UPGMA dendrogram and multidimensional scaling identified two major genetic groups. The studied populations differed significantly in their genetic content as revealed by AMOVA. Distinguishing SCoT loci are identified by Neis'and Gst as well as DAPC analysis. Some of the SCoT loci were significantly associated with geographical variables as revealed by RDA and LFMM analyses.

Melia azedarach L. commonly called Maha Neem is an economically and industrially important tree species with global significance. Although species possess versatile importance worldwide, information on reproductive biology and breeding system is scarce and limited for eastern coastal plain of India. Therefore, current study provides a detailed report on reproductive biology of M. azedarach. Maha Neem was found to bear violet to whitish violet, slightly fragrant, 14.99 ± 0.05 mm. long and 17.01 ± 0.08 mm. wide flowers. This tree commenced opening of floral buds during March and continued until May with a peak during March-end. The anthesis of species peaked between 08:00 and 10:00 am, which coincides with insect activity. Anthers were observed to dehisce during or shortly before anthesis; however, stigma started receptivity before anthesis and continued invitation up to 12 h after anthesis. Pollen viability ranged from 96.67 ± 1.6% to 98.26 ± 1.2 at the time of anthesis; after that decreased rapidly. Pollen: ovule ratio of 1096.38 ± 108.70 indicated the possibility of autogamy. The breeding system of M. azedarach revealed that fruit sets under natural pollination (NP) were significantly higher than Xenogamy. However, substantial difference was not reported in fruit set percentage under natural pollination and Autogamy, which is strong evidence in favour of self-pollination. Moreover, Maha-Neem is entomophilous with frequent visits by Apis and Syrphid flies. Current findings will be helpful in designing potent conservation strategies and planning successful breeding programmes.

Understanding genetic structure and chromosomal characteristics is essential for developing effective breeding programmes and improving plant species. This research compared karyotypic features of 10 plant populations of Populus euphratica from various regions of Iran. Fresh roots grown from cuttings of the populations were used to get metaphase cells. Then several chromosomal parameters were recorded and analysed using a nested statistical model. All the studied populations were diploid, with 2n = 38 chromosomes, consisting of medium and sub-medium chromosome types. Significant differences (P ⩽ 0.01) were observed between the plant populations in chromosomal dimensions and arm ratios, suggesting chromosomal rearrangements. Chromosome lengths in the studied populations ranged from 0.69 to 3.38 μm. Intra-chromosomal index (A1) showed clear asymmetrical differences between the plant populations. Furthermore, using Stebbins's standards, the studied populations classified as 1A and 1B classes, demonstrated more asymmetry than those categorized as 1B and 2B, respectively. Cytological differences between the plant populations, collected from different parts of the country, showed that chromosome structural rearrangements are responsible for the speciation and adaption of the species against the mentioned variable ecological conditions and play a key role in response to diverse climatic and geographical conditions.

Panax L., renowned as ginseng genus, is a famous medicinal group of family Araliaceae. Within this genus, the taxa of Panax bipinnatifidus complex are mainly distributed in Himalayas and Hengduan Mountain areas. Due to the complex evolutionary history and short-term rapid radiation, the relationships among species within the complex have not been clearly resolved, and the taxa identification is difficult due to the intermediate morphological traits. This study aimed to use the available restriction-site associated DNA sequence data from 29 individuals of P. bipinnatifidus complex to mine high-polymorphic simple sequence repeat (SSR) markers, with the goal of evaluating their utility in taxa identification. Eleven polymorphic SSR loci were ultimately selected and validated through polymerase chain reactions amplifying across 63 individuals of P. bipinnatifidus complex and 13 individuals of three outgroup species. The subsequent genetic diversity analysis uncovered 76 alleles in total, ranging from 5 to 15 per locus. Observed heterozygosity spanned 0.241–0.512, while expected heterozygosity ranged between 0.345 and 0.644. The genetic kinship analysis revealed a sister relationship between Panax zingiberensis and Panax vietnamensis. The analysis result also supported the classification of samples from Hunan and Hubei provinces into a single genetic unit within the P. bipinnatifidus complex. These newly developed SSR markers will facilitate the identification of wild ginseng plants.

This study investigates the impact of environmental factors and genotype-by-environment interactions (GEI) on the expression of maydis leaf blight (MLB) resistance in a diverse maize germplasm comprising 359 genotypes. Extensive field trials were conducted, involving artificial inoculations and disease scoring across two locations over two years. Using genotype and genotype–environment (GGE) biplot analysis based on the site regression model (SREG), we identified stable MLB-resistant 10 donors with consistent genotypic responses. These inbred lines, which consistently exhibited disease scores of ⩽3 across locations, are recommended as potential parents for breeding MLB-resistant varieties. Furthermore, the identification of a non-crossover interaction and high correlations among testing locations allowed us to define a single mega-environment for the initial screening of MLB resistance in a large set of maize germplasm. This study suggests that initial screenings can be efficiently conducted in one representative location, with validation of resistant lines at multiple sites during advanced breeding stages. This approach optimizes the use of land, labour and resources in MLB resistance testing.

Asiatic cotton (Gossypium arboreum L.) has evolved in the Indian subcontinent and is known for its adaptability to low-input management conditions. In the present study, 300 diverse G. arboreum lines, including 100 Nandyal arboreum breeding lines (NAB), 132 Arboreum germplasm collections (AGC) and 68 long-linted arboreum genotypes (LLA), were evaluated for fibre quality to assess the diversity among them and to identify promising genotypes with desirable fibre traits. Significant variations were observed among the genotypes for the studied fibre-quality traits. Principal component analysis showed that the traits micronaire (Mic) and elongation percentage (E%) followed by upper half mean length (UHML) and bundle tenacity (tenacity) were the most significant contributors to variation. Cluster analysis based on the Euclidian distance method showed 16 clusters among 300 G. arboreum genotypes. The genotypes in cluster 4 have desirable UHML, tenacity and UI (uniformity index) traits, and cluster 12 has Mic and E% traits. Furthermore, the number of genotypes with desirable fibre-quality traits was found to be higher in the AGC group than in the LLA and NAB groups. The trait tenacity followed by the UHML showed relatively higher Shannon–Weiner diversity index values across different genotypic groups. Based on the superior performance, the genotypes PA 847, PA 809, PA 837, PA 863, NDLA 3147-2, NDLA 2974 and NDLA 3081 were found to be having desirable fibre traits. The identified promising genotypes are valuable genetic resources for improving fibre quality in G. arboreum cotton.

This study investigated the combining ability, heterosis and heterotic grouping of maize (Zea mays L.) inbred lines to enhance hybrid performance and productivity. Twenty-four hybrids were developed by crossing eight inbred lines with three testers, and their performance was evaluated for two years at Banaras Hindu University's agricultural research farm. Data on yield and yield-attributing traits were collected from selectively centred competitive plants in each row, avoiding border plants to reduce errors. Biometrical techniques, cluster analysis, and statistical tools were employed to measure general combining ability (GCA), specific combining ability (SCA), and standard heterosis, providing insights into hybrid performance. Analysis of variance revealed significant mean square values for GCA and SCA across most traits studied. Various methods were utilized, including SCA effects, HGCAMT (Heterosis Grouping by Combining Ability of Multiple Traits), and HSGCA (Heterotic Grouping based on Specific and General Combining Ability). The study identified HUZM-242 × CML-286 and HUZM-53 × CML-286 as crosses displaying higher grain yield compared to the check line DKC 7074 and exhibiting positive heterosis. The findings offer valuable guidance for maize breeding programmes by accurately identifying heterotic groups, enabling breeders to select inbred lines more likely to produce high-performing hybrids. This targeted selection reduces the number of necessary cross-breeding trials, saving time and resources. Additionally, hybrids derived from crosses between lines from different heterotic groups exhibit superior performance due to higher heterosis. These conclusions support advancements in maize breeding strategies, ultimately contributing to agricultural sustainability through increased productivity, resource efficiency, and economic benefits for farmers.

Kokum [Garcinia indica (Thouars) Choisy] is a multi-purpose tree with culinary, cosmetics and pharmaceutical uses found popular in Konkan region of India. ICAR-NBPGR Regional Station, Thrissur made a systematic exploration and collection missions on kokum over a period from 1987–2004 and collected 31 accessions from various parts of Konkan region to characterize them using morphological characters and also to investigate their flowering and fruiting behaviour. Totally, 85 trees planted in Field Gene Bank in which only 67 trees (23 accessions) survived during field establishment. Among them, 32 (47.8%) were male and remaining 25 identified as female (37.3%) and 10 as co-sexual (14.9%). Fruit bearing ability noticed only in both female and co-sexual trees with huge variation in fruits. Morphological characterization of 33 trees with fruiting (23 accessions) for 35 morphological traits revealed presence of considerable amount of variation among them on basis of CV%. Highest positive correlation observed between fresh seed weight and fresh kernel weight (0.92). Cluster analysis formed four major clusters with Cluster I and II comprising male/bisexual genotypes and Cluster III and IV with female genotypes and it clearly distinguished male/bisexual genotypes from female ones. PCA analysis accounted 65.6% of genetic variation present among accessions by first three most informative PCs. Superior accessions identified for important traits will be more useful in industrial aspects of preparing kokum butter and juice. Further, seasonal difference identified in fruiting and maturity of fruits well-before onset of monsoon may be exploited by kokum industries for drying and processing of fruits.

Ortet selection remains an integral component of cacao breeding programme to develop improved clones and expand the gene pool of available germplasm. This study assessed the population structure of 168 cacao clones developed recently from selected ortets in on-station and on-farm progeny trials in Ghana using 45 SNP markers. Selection of ortets was primarily based on high bean yield, high yield efficiency, adaptability to marginal growing conditions, and low incidence of black pod and cocoa swollen shoot virus diseases. Additionally, 58 SNPs were employed to verify the parentage of 752 bi-clonal seedlings supplied to farmers for commercial plantations. Pairwise multilocus matching based on 45 SNPs showed that the 168 clones were all distinct. Overall, the clones had moderate genetic diversity (He = 0.349 ± 0.022) and shared ancestry with Marañón, Guiana, Contamana, Iquitos, Amelonado, Trinitario, Nanay and Purús based on Bayesian clustering, principal coordinates, and parentage analyses. Parentage analysis of bi-clonal seedlings assigned parent-offspring trios (>80% confidence level) to 65.2% of the farmers' varieties based on breeder's active clone collection. The results of the parentage analysis suggested the existence of mislabelled clones in the seed gardens, necessitating the need for correct clone identification or rogueing. Taken together, this study presents a new group of cacao genetic resources with potential to broaden the gene pool of cacao in cacao improvement programmes. Further, the study conveys evidence of the need for countries with established seed garden systems to constantly monitor the genetic purity of seedlings produced from the seed gardens.

Nutmeg (Myristica fragrans Houtt; family: Myristicaceae) is an important tree spice of great export value due to the presence of secondary metabolites with scope in health, wellness and cosmetic industries. Its dioecious in nature due to which it is propagated by budding and grafting which requires specialised skill and as a result authentic planting material production is very expensive. Based on the constant demand from farmers and stakeholders for a suitable, fast and easy technique for determining the authenticity of nutmeg varieties, an attempt was made to develop morphological and molecular markers for the identification of three commercial varieties that are in high demand in India; viz. IISR Vishwashree, IISR Keralashree, Sindhushree and a monoecious nutmeg (MN) accession, along with their biochemical profiles. Among the various morphological characters as per distinctiveness, uniformity and stability guidelines, the varieties showed distinctness mainly in leaf shape, shape of female flowers, fruit shape and seed shape. Out of 35 ISSR primers screened, six primers viz., IS 02, ISSR 12, ISSR 05, ISSR 14, ISSR 01 and UBC 834 generated clear, unique reproducible polymorphic bands capable of distinguishing the varieties. Among the varieties analysed, MN was found to be superior in terms of seed butter and essential oil in nut, mace and leaves. IISR Vishwashree was on par with MN in nut essential oil content. IISR Keralashree was superior in terms of oleoresin in nuts and mace. The morphological and molecular markers identified may be used for effective checking of authenticity of planting materials of commercially grown nutmeg varieties.

Uncaria rhynchophylla (Rubiaceae), a woody liana with significant medicinal value, has been used as a traditional Japanese and Chinese medicine. While effective seed production is required for breeding and efficient seedling production, the physiology of sexual reproduction remains largely unknown in this species. Therefore, we first observed the flowering behaviour, and next attempted artificial pollination using flowering individuals in a greenhouse. In this study it became clear that this species sets seeds by allogamy, but not by autogamy. The obtained seeds showed about a 90% germination rate. We also examined seed desiccation tolerance and storage conditions which are important to preserve the genetic resources. Seeds of this species were found to have a characteristic of the orthodox type, having high desiccation tolerance. Seeds after 6 months of storage at + 22, −20 and −160°C showed comparable germination rates to the seeds before storage.

Annona crassiflora is a fruit-bearing tree species native to the Cerrado that has ecological and economic potential, mainly due to the production of attractive and useful fruits for a number of species, including humans. To provide a basis for its conservation and breeding, the objective was to assess the diversity and genetic structure of natural populations of the species using inter-simple sequence repeat (ISSR) molecular markers. Eight populations were analysed in the state of Minas Gerais, Brazil, with 24 individuals randomly sampled in each population, reaching a total of 192 trees. Ten ISSR primers were used, resulting in high genetic diversity for the combined data (H* = 0.35 and I* = 0.52). However, a wide range of representative values was observed in the individual assessment of populations, with JAN, GM and MC standing out for their low genetic diversity, resulting in H* of 0.19, 0.23 and 0.24 and I* of 0.28, 0.34 and 0.35, respectively. An analysis of molecular variance showed greater variation within populations, indicating gene flow (Nm), but genetic differentiation between populations was moderate. Bayesian analysis, although resulting in four genetic groups, revealed the presence of a majority group for the GM and JAN populations. We propose measures to maintain these populations, such as raising awareness of local extractivism and planting genetically divergent seedlings. Furthermore, we recommend including of all populations in conservation and breeding programmes, aiming to cover the maximum genetic variation for the species.

Walnut (Juglans regia L.) is one of the oldest and most economically important edible nut species due to its high nutritional value. Iran is known as one of the most important centres of the origin and diversity of walnuts worldwide. This research was carried out to determine the genetic relationships of some old walnut genotypes in Iran in order to select superior genotypes and better conserve them. The results of morphological evaluation of the fruits showed that the highest coefficients of variation were related to nut weight, kernel weight, percentage kernel, thickness and weight of the shell, and thickness and weight of the packing tissue in both years. The average morphological traits among the studied genotypes were different, such that the highest nut weights in the first and second years were 15.59 and 14.79 g and the corresponding lowest values were 7.37 and 7.79 g, respectively. The highest and lowest kernel weights were observed in the first years to be 8.09 and 3.80 g and in the second years were 6.94 and 2.65 g, respectively. The highest kernel percentages in the first and second years were 64.97 and 59.79% and the lowest percentages were 39.52 and 27.80% in the first and second years, respectively. Molecular evaluation results showed that the 16 start codon of target (SCoT) primers amplified a total of 166 bands with an average of 10.44 bands per primer. The number of polymorphic bands was changed from 2 to 19 in primers SCoT-19 and SCoT-15. The average polymorphism information content value was 0.30 and the highest amount of this index (0.36) was observed in SCoT-14 and SCoT-19 primers. The results of principal component analysis and analysis of molecular variance indicated the presence of relatively high diversity within the investigated genotypes. The amount of genetic diversity within the investigated regions was 84% and that between areas was 16%. Based on the obtained results, it was concluded that SCoT markers could provide helpful information on the genetic relationships among walnut genotypes, which can be used in future walnut breeding and conservation programmes.

Casuarina equisetifolia L. commonly called whistling pine is an economically and industrially important tree species with global significance. Although species possess versatile importance worldwide, efforts imparted for selection and designing a robust model of selection index are inadequate. The selection process, based on quantitative and qualitative traits, identified 15 superior trees from the eastern coastal plain of Odisha. These superior trees showcased exceptional qualitative and quantitative attributes. Correlation analysis highlighted key similarities among various traits like volume and above ground biomass (AGB), volume and diameter at breast height (DBH), DBH and AGB, DBH and Tree Height (TH), crown length (CL), height, AGB and height. Principal component analysis emphasized substantial contributions of traits like DBH, height, CL, crown width, AGB and volume across different clusters. Furthermore, culmination resulted in a comprehensive selection index, integrating both qualitative and quantitative characters, reaching 52.04, signifying superior performance among specific accessions. The current study provides valuable insights into selection and designing optimal selection index of C. equisetifolia, guiding future decisions concerning optimal wood production and resource management.

Discriminatory morpho-metric features are obvious on legume seeds. This study utilized seven quantitative and 11 qualitative seed traits to characterize 139 African yam bean (AYB) breeding lines which were developed through single seed descent procedure. The seven quantitative data were subjected to analysis of variance, their means were combined with qualitative scores for genetic distance, principal component (PC) and clustering analyses. Significant (P ≤ 0.001) variation existed among the breeding lines for the seven traits. Mean ranges of seed length (SL), width (SW), thickness (ST) and a single seed weight (SSW) among the 139 breeding lines were respectively: 6.77–10.22 mm, 5.70–7.86 mm, 4.96–7.45 mm and 0.15–0.42 g. Positive and significant (P ≤ 0.05) genotypic correlation existed among SSW, SL, SW and ST. Seed colours, pattern, shapes, sizes, surface texture, brilliance varied among the breeding lines. Ranges of phenotypic and genotypic coefficient of variation and broadsense heritability were: 5.49–23.84%, 2.95–19.88% and 28.91–69.54% respectively. Fourteen (quantitative and qualitative) traits contributed higher (≥ 0.30) eigenvector loadings to the first three PC axes which explained 57.9% of the total variation among the breeding lines. Similarity among the lines was 0.75. Four clusters ensued in the dendrograph and each group had genetic similarities of: 0.85 (I), 0.82 (II), 0.78 (III) and 0.80 (IV). This research unveiled significant variation among AYB breeding lines with promising reliability for breeding opportunities of the qualitative and quantitative seed traits, which could contribute to higher grain yield and acceptability.

Tree architecture is an important factor in increasing performance and better garden management of pistachios. In a pistachio breeding programme, the genotypes obtained from five open pollinated populations were evaluated in terms of growth characteristics. Among the evaluated genotypes, ‘Apatiye’ was identified. This genotype has shoots with crouch angle more than 90° and a height of 110 cm. In previous year's shoots, the terminal buds abort and fall in early spring, stimulating more lateral buds to grow (6–7) than other genotypes (3–4). The growth characteristics of ‘Apatiye’ create a valuable potential resource for breeding pistachio cultivars with low alternate bearing, suitable for manual harvesting and pruning management. In addition, ‘Apatiye’ can be used as a suitable genetic marker in the study of heritability of growth habit in pistachio trees for future studies.

Wild species of rice possess tremendous genetic variations and harbour resistance genes for biotic stresses. Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is a major disease affecting rice production globally. The current study characterized 116 accessions from 17 species of Oryza for BB disease during three seasons viz., kharif 2020, rabi 2020–21, kharif 2021 using an isolate of Xanthomonas oryzae pv. oryzae (Xoo) strain IX-020. A total of 40 accessions including Oryza rufipogon, O. nivara, O. officinalis and O. australiensis showed consistence resistance to the bacterial blight disease across the seasons. These accessions were further subjected to molecular characterization using 11 Xa genes viz., Xa4, xa5, xa13, Xa21, Xa23, Xa27(t), Xa32(t), Xa33, Xa35(t), Xa38 and xa41 with gene-specific markers to ascertain the novelty. Some key resistance genes such as Xa4, Xa23, Xa27(t), Xa32(t), Xa33, Xa35(t) and xa41 were detected in multiple accessions, with O. rufipogon and O. eichingeri harbouring particularly complex combinations of these genes. Notably, several accessions viz., IC521672 (O. nivara), EC861665 (O. officinalis), EC861677 (O. latifolia), EC861711 (O. punctata) and EC861738 (O. eichingeri) did not show the presence of any known genes indicating the possibility of novel genetic loci conferring BB resistance in these wild species. These promising accessions identified in the study are potential novel sources for bacterial leaf blight resistance in rice and will be useful for the development of durable bacterial blight resistance rice cultivars.