Parental Hybrids Research Articles

Spatial and Temporal Regulation of Flower Coloration in Cymbidium lowianum.

Flower color is a crucial trait that attracts pollinators and determines the ornamental value of floral crops. Cymbidium lowianum, one of the most important breeding parent of Cymbidium hybrids, has two flower morphs (normal and albino) that differ in flower lip color. However, the molecular mechanisms underlying flower color formation in C. lowianum are not well understood. In this study, comparative metabolomic analysis between normal and albino flower lip tissues indicated that cyanidin-3-O-glucoside content was significantly higher in red epichiles than in other lip tissues. This finding suggests that cyanidin-3-O-glucoside is responsible for color variation and differentiation in the lip in C. lowianum. We also found that red coloration in C. lowianum flower is correlated with high levels of F3'H expression; further, anthocyanins, carotenoids and chlorophyll coordinate to influence sepal and petal coloration during flower development. In transgenic Arabidopsis lines, overexpression of F3'H increased anthocyanin concentration, overexpression of BCH increased carotenoid concentration, whereas overexpression of HEMG and CHLI both increased chlorophyll concentration. Identification and assessment of several transcription factors revealed that MYB308-1 activates BCH, MYB111 and PIF4-2 activate HEMG and CHLI expression during flower development. Importantly, MYB14-1 shows interaction with PIF4-2, and appears to act as a connector between anthocyanin and chlorophyll biosynthesis by either activating F3'H expression or inhibiting CHLI expression. These results indicate that, in C. lowianum, variation in flower color and differentiation of lip color patterns are primarily regulated by the types and concentrations of flavonoids; further, carotenoids and chlorophyll also influence flower coloration during development.

Genetic Tendency Analysis and Comprehensive Antioxidant Activity Evaluation of Leaves and Flowers of Loquat F1 Generation.

Loquat leaves, flowers, and other organs contain abundant antioxidant substances, which have wide applications in medicine, health, and food industries. This study aims to provide theoretical guidance for loquat hybrid parent and combination selection and a basis for high-quality loquat strain screening and development. For comprehensive antioxidant profiling, we used "Ninghaibai" and "Oobusa" loquat and their F1 generation as experimental materials to determine the total phenol, flavonoid, DPPH, ABTS, and FRAP content in the leaves and flowers of 56 strains. Five traits, including total phenols, flavonoids, DPPH, ABTS, and FRAP, were widely separated and normally distributed in the flowers of 56 F1 loquat strains, exhibiting the genetic basis of these quantitative traits. However, these traits displayed widely separated and slightly skewed distribution in the leaves of the F1 generation. The total phenols, flavonoids, DPPH, and FRAP showed a trend of small inheritance in the leaves. However, the ABTS showed a trend of medium and high inheritance in leaves and flowers, respectively. Through cluster and principal component analyses, a comprehensive antioxidant activity evaluation was conducted. Ten strains with comprehensive scores greater than 1 for antioxidant activity in leaves and flowers were selected. Among them, the top three strains with high antioxidant capacity were ND107, "Oobusa", and ND128. These results suggest that hybrid breeding guided by the genetic characteristics of each trait can improve the possibility of cultivating new varieties with high antioxidant activity.

Impact of nutrient omission technique on the formation of a simple hybrid of corn (Zea mays L.)

Due to the scarcity of information in Ecuador on the effect of nutrient omission in the fertilization of parents for the formation of a new maize hybrid, this research aimed to evaluate the impact of nutrient omission on the formation of a maize hybrid and its seed yield. The study was carried out at the Estación Experimental Tropical Pichilingue (EETP) del Instituto Nacional de Investigaciones Agropecuarias (INIAP), Los Ríos province, Ecuador. Six omission treatments were established -N, -P, -K, -Mg, -S, -B, complete fertilization (N, P, K, Mg, S, B), a treatment based on the application of a farmer and control. A randomized complete block design was used and the averages were differentiated using Tukey’s test. The variables evaluated were: plant height (m), ear height (m), days to flowering, cob length (cm), cob diameter (mm), 100 seed weight (g), percentage of rotten ears, stem diameter (mm), stem and root lodging, chlorophyll levels, yield, partial productivity factor, agronomic efficiency and nutrient harvest index. The results obtained showed that the highest yield was obtained with the omission of the B (2,093 kg ha-1) fertilization plan causing a decrease of up to 42.02% in the partial productivity factor (PPF) and 425.14% of agronomic efficiency (AE) of the studied elements. Since the nutritional priorities of the parents of the corn hybrid had the sequence Mg>N>K=P>S>>B.

Dryopteris×subdiffracta (Dryopteridaceae), a new natural hybrid fern from Guangxi, China.

A new natural hybrid fern, Dryopteris×subdiffracta (Dryopteridaceae), is reported from Guangxi, China. Molecular phylogenetic analysis based on DNA sequences from the low-copy nuclear marker Ak1 and plastid genome revealed respectively that D.polita and D.diffracta are parents of the new hybrid, with D.polita as the maternal parent. Cytometric analysis of the nuclear DNA content indicated that D.×subdiffracta might be a diploid hybrid. Morphologically, D.×subdiffracta shares a high degree of similarity with D.×subreflexipinna from Taiwan, especially in zigzag-shaped rachis and deflexed pinna stalks. However, D.×subdiffracta is distinguishable in the degree of lamina division and shapes of lamina and pinnulets. A comprehensive taxonomic description accompanied by line drawings are provided.

Assessment of Genetic Diversity in Greengram (Vigna radiata L.) Using Metroglyph Analysis

Pulses like greengram are essential for sustainable agriculture and global food security due to their high protein, complex carbohydrates, fiber, vitamins, and minerals. However, their genetic diversity is underexplored, with existing studies mainly focusing on conventional methods. This study aims to estimate the variability parameters for 16 quantitative characters of greengram to classify the genotypes using Metroglyph analysis and assess genetic divergence to identify divergent parents for future hybridization programs using 45 greengram genotypes using Randomized Block Design replicated thrice. Among 45 genotypes of greengram on the basis of mean performance MGG-351(12.959) followed by MGG-347(43.16 q/ha), VBN -2 (41.12 q/ha), GM-3(40.8 q/ha) and MGG-385(39.8 q/ha) were found superior for grain yield. High GCV and PCV is recorded for Harvest Index and Number of primary branches. High heritability coupled with genetic advance as percent of mean are recorded for number of primary branches, harvest index (%), number of seeds per pod, biological yield per plant, seed index, number of pods per plant, number of clusters per plant. On the basis of Metroglyph analysis, the total index score was varied from 24 (SHAKTI) to 38 (SIKHA) with a mean of 31.84. Among the 45 germplasm lines, the genotypes GM-3, MGG-385, SML-1663 and MGG-371were observed as high yielder and identified for higher index score. Scatter diagram plotted with Plant Height and Harvest Index has revealed that 5 clusters could be distinguished on the basis of morphological variation. Cluster -1 was represented by 24 genotypes, Cluster -2 was represented by 10 genotypes, Cluster-3 was represented by 7 genotypes, Cluster-4 was represented by 3 genotype, Cluster -5 was represented by 1 genotype. From those complexes, the germplasm lines, SIKHA and MGG-371 recorded high index score and fell into different cluster, hence used as parents in hybridization for getting desirable transgressive segregants.

Heterosis, combining ability and genetic component in okra (Abelmoschus esculentus (L.) Moench) genotypes

ABSTRACT Information on gene action controlling the inheritance of quantitative traits is essential for selecting parents for hybridization and multiline varieties. Twenty hybrids obtained through 5 × 5 diallel mating with their parents were established on Teaching and Research Farm, Federal University of Agriculture, Abeokuta, Nigeria, in September 2018 using Randomized Complete Block Design in three replicates. The plants were observed for numbers of days to 50% flowering, plant height at flowering, stem girth, number of branches per plant, plant height at maturity, number of fruits per plant, fruit weight, fruit length, fruit width, and fruit yield per plant. Data were subjected to variance analysis, General and Specific Combining abilities were estimated, and gene effects and parameter ratios were done using Hayman’s method. Mid- and better-parent heterosis were estimated using Allard’s procedure. Genotype ‘NGB00356’ was the most desirable parent for earliness and the number of fruits per plant, while hybrid ‘NGB00347’ × ‘NGB00356’ was the best hybrid for fruit yield per plant. ‘NGB00356’, with its significant and positive general combining ability value for the number of fruits per plant, can be used as a parent in a hybridization program for yield improvement in okra.

Breed Selection of Poplars Imposes Greater Selection Pressure on the Rhizosphere Bacterial Community.

Breed selection alters the coevolution of plant-microbiome associations that have developed over long periods of natural evolution. We investigated the effects of breed selection on the rhizosphere microbiomes and metabolites of hybrid parents (I101 and 84K) and their offspring (Q1-Q5) using metagenomics and untargeted metabolomics. Rhizosphere archaeal, bacterial and fungal community β-diversity significantly differed among hybrid parents and offspring, but only the dominant bacterial phyla and bacterial community α-diversity revealed significant differences. Approximately 5.49%, 14.90% and 7.86% of the archaeal, bacterial and fungal species significantly differed among the poplar hybrid parents and offspring. Rhizosphere microbial functional genes and metabolites were both clustered into the following three groups: I101 and 84K; Q2 and Q4; and Q1, Q3 and Q5. Compared with the hybrid parents, 15 phytochemical compounds were enriched in the hybrid offspring and explained 7.15%, 18.24% and 6.68% of the total variation in the archaeal, bacterial and fungal community compositions, respectively. Rhizosphere metabolites significantly affected the bacterial community, rather than the archaeal and fungal communities. Our observations suggested that poplar breed selection imposed greater selection pressure on the rhizosphere bacterial community, which was mainly driven by metabolites.

Organoleptic profiling for demand led breeding of eggplant (Solanum melongena L.) suitable for Kerala market

In order to develop eggplant hybrids with consumer acceptance, an organoleptic evaluation of fruits in two different sets of eggplant genotypes was conducted by a panel of 15 judges with 21 descriptors, following a quantitative descriptive analysis (QDA). In 2023, twenty genotypes were evaluated as the first set to identify suitable parents for hybridization. The results showed significant variation in odour, appearance, texture, flavor and taste, and overall quality attributes. From the first set, five genotypes (Ponni, Vengeri, IC618016, IC636521, and IC624240) were selected to produce ten F1 hybrids, and they were further evaluated, along with parents and three popular varieties as check in 2024. In the second set, many descriptors showed no significant variation. F1 hybrid, Vengeri x IC636521, showed higher yield and overall quality attributes, and most of the other hybrids (seven) were high yielders over popular checks with on par for overall quality. The findings suggest the role of organoleptic evaluation in selection and development of quality breeding materials. Keywords: Odour, Appearance, Texture, Flavour, Taste, Overall quality

Genetic variability, diversity and principal component analysis in B and R lines of rabi sorghum [Sorghum bicolor (L.) Moench

Hybrid technology is exploited in kharif (rainy) sorghum while the same is not the scenario in Rabi sorghum which is still dominated by landraces and varieties which have poor yield potentiality. Considering the necessity of development of heterotic hybrids, an attempt was made to screen hybrid parents (B and R lines) to assess variability and genetic diversity, for productivity traits. The study was conducted with 32 B and R lines at Regional Agricultural Research Station, Vijayapur during 2021-22. PCV was observed to surpass GCV across all traits. The traits grain yield per plant, fodder yield per plant, grain number per plant, and harvest index exhibited notably high PCV and GCV. Plant height, panicle length, panicle harvest index, and harvest index recorded high heritability and genetic advance, suggesting their control by additive gene action and potential for improvement via selection. Cluster analysis classified the 32 genotypes into four groups. PCA condensed 14 traits into five principal components, capturing 81.50% of total variation. The genotypes remained scattered in all four quadrants in PCA- Biplot, showing large genetic variability in quantitative traits studied. Keywords: Genetic variability, heritability, diversity, clusters, PCA and rabi sorghum

Maintenance Breeding in Pigeonpea [Cajanus cajan (L.) Millspaugh] — An Assessment and Advanced Strategies

AbstractThe sustainable maintenance breeding of pigeonpea germplasm, genetic stocks, released cultivars, and hybrid parents is a tough job. The prime reason for their genetic contamination is the insect‐aided cross‐pollination. Although various public and private seed agencies are involved in maintenance breeding to produce different grades of pigeonpea seeds, but the limitation of resources and low priority make it difficult to meet the national seed requirements. This manuscript, aside from reviewing the present pigeonpea maintenance breeding methods, their limitations, and accomplishments, also highlights some advanced breeding and genomics approaches to enhance the efficiency of maintenance breeding.

Studies on pollen performance in some endangered medicinal and aromatic plants of cold desert Ladakh

The study was carried out at the Trans-Himalayan Herbal Garden, located at the National Institute of Sowa Rigpa-Leh, from 2021 to 2023. An assessment of pollen viability was conducted using seven significant medicinal and aromatic plants from the Ladakh region. Analysis of pollen vitality was conducted using the acetocarmine staining technique. The pollen viability of Inula racemosa Hook. f. ranged from 91.08 ± 1.39 % to 82.44 ± 1.48 % in Ephedra gerardiana Wall. Among the genus Inula racemosa, the highest percentage (91.08%) of viable pollens indicates a normal meiosis, whereas Ephedra gerardiana recorded the lowest percentage. Among the chosen species, Inula racemosa, Verbascumthapsus, Hyoscyamus niger, and Dracocephalum heterophyllum stand out for their exceptional pollen viability. These species can be effectively utilized for conservation purposes and as male parents in hybridization. The result for the average pollen density varied from 1533.07 ± 106.32 in Capparis spinosa L. to 276.00 ± 10.20 in Dracocephalum heterophyllum.

Combining Ability and Gene Action Studies for Fruit Yield and its Component Traits in Okra [Abelmoschus esculentus (L.) Moench

Background: Okra commonly known as Lady’s finger is queen of vegetables. The study focuses on assessing the combining ability in okra (Abelmoschus esculentus L.) across 12 traits, encompassing characteristics like earliness and fruit yield. The choice of parents for hybridization plays a critical role in breeders efforts to enhance complex quantitative traits such as fruit yield and its components, necessitating thorough genetic evaluations of existing germplasm and newly developed lines. Criteria for parental selection hinge on the magnitude and nature of gene actions, aiming to breed recombinants with desirable traits post-hybridization. Methods: In the study, 35 F1 hybrids were developed from 12 genotypes of okra, involving 7 lines and 5 testers. Evaluation occurred in a randomized block design with 3 replications during Kharif 2023. Twelve quantitative traits were analyzed from five randomly selected plants of each parent and F1 generation. Analysis included ANOVA for Line×Tester interaction and assessment of combining ability following Kempthorne suggestions in 1957. The effects of General combining ability (GCA) and specific combining ability were estimated (SCA). Result: Non-additive gene activity prevailed in the study, with specific parents showing strong general combining abilities. Certain hybrid combinations displayed promising effects on fruit yield per plant, warranting further investigation. The analysis highlighted the significance of both additive and dominant genetic components in fruit yield, with dominance variance notably influencing certain traits. Overdominance and gene symmetry were observed, alongside a predominance of dominant alleles. High narrow-sense heritability was noted for most traits studied.

Genetic analysis of popping quality traits and development of superior quality popcorn hybrids for a sustainable popcorn breeding program in India.

Popcorn is the most popular specialty maize and it makes a significant contribution to the Indian and global economies. Despite perfect exploration of heterosis in field corn, progress in popcorn breeding remains constrained due to its narrow genetic base, leading to a significant dependence on imports. In this study, 15 landrace- and population-derived inbreds from temperate and tropical germplasm were crossed with five testers, which are the parents of superior popcorn hybrids, in a line × tester mating design. Significant variation was observed in popping quality and agronomic traits among crosses evaluated across three locations representing diverse maize-based agro-climatic zones in India. Additive genetic variance governed the traits related to popping quality, whereas dominance variance was responsible for the agronomic traits. In addition to significant heterosis specific to certain traits, we identified promising crosses that exhibited superior performance in both popping quality and grain yield (GY). The genotype + genotype × environment (GGE) biplot methodology identified PMI-PC-104 and PMI-PC-101 as the best discriminating testers for popping quality traits and Dpcl-15-90 for GY. Lines PMI-PC-205, PMI-PC-207, and PMI-PC-209 were the best general combiners for popping quality traits and GY. The heterotic groups identified based on GGE-biplots and the magnitude, direction and stability of combining ability effects would serve in the development of competitive popcorn hybrids for a sustainable popcorn market. Using the additive nature of popping quality traits and the dominant nature of GY, recurrent intrapopulation selection can be employed to derive desirable popping quality inbreds with high GY for genetic enhancement. Desirable popping quality alleles from novel germplasm can thus be combined with high-yielding domestic elite inbreds to establish a sustainable popcorn breeding program. © 2024 Society of Chemical Industry.

Phenotypic characterization and gene mapping of hybrid necrosis in Triticum durum–Haynaldia villosa amphiploids

Key messagePhenotypical, physiological and genetic characterization was carried out on the hybrid necrosis gene from Haynaldia villosa, and the related gene Ne-V was mapped to chromosome arm 2VL.Introducing genetic variation from wild relatives into common wheat through wide crosses is a vital strategy for enriching genetic diversity and promoting wheat breeding. However, hybrid necrosis, a genetic autoimmunity syndrome, often occurs in the offspring of interspecific or intraspecific crosses, restricting both the selection of hybrid parents and the pyramiding of beneficial genes. To utilize the germplasms of Haynaldia villosa (2n = 2x = 14, VV), we conducted wide hybridization between durum wheat (2n = 4x = 28, AABB) and multiple H. villosa accessions to synthesize the amphiploids (2n = 6x = 42, AABBVV). This study revealed that 61.5% of amphiploids derived from the above crosses exhibited hybrid necrosis, with some amphiploids even dying before reaching maturity. However, the initiation time and severity of necrosis varied dramatically among the progenies, suggesting that there were multiple genetic loci or multiple alleles in the same genetic locus conferring to hybrid necrosis in H. villosa accessions. Genetic analysis was performed on the F2 and derived F2:3 populations, which were constructed between amphiploid STH59-1 with normal leaves and amphiploid STH59-2 with necrotic leaves. A semidominant hybrid necrosis-related gene, Ne-V, was mapped to an 11.8-cM genetic interval on the long arm of chromosome 2V, representing a novel genetic locus identified in Triticum-related species. In addition, the hybrid necrosis was correlated with enhanced H2O2 accumulation and cell death, and it was influenced by the temperature and light. Our findings provide a foundation for cloning the Ne-V gene and exploring its molecular mechanism.

Intraspecific diploidization of a halophyte root fungus drives heterosis

How organisms respond to environmental stress is a key topic in evolutionary biology. This study focused on the genomic evolution of Laburnicola rhizohalophila, a dark-septate endophytic fungus from roots of a halophyte. Chromosome-level assemblies were generated from five representative isolates from structured subpopulations. The data revealed significant genomic plasticity resulting from chromosomal polymorphisms created by fusion and fission events, known as dysploidy. Analyses of genomic features, phylogenomics, and macrosynteny have provided clear evidence for the origin of intraspecific diploid-like hybrids. Notably, one diploid phenotype stood out as an outlier and exhibited a conditional fitness advantage when exposed to a range of abiotic stresses compared with its parents. By comparing the gene expression patterns in each hybrid parent triad under the four growth conditions, the mechanisms underlying growth vigor were corroborated through an analysis of transgressively upregulated genes enriched in membrane glycerolipid biosynthesis and transmembrane transporter activity. In vitro assays suggested increased membrane integrity and lipid accumulation, as well as decreased malondialdehyde production under optimal salt conditions (0.3 M NaCl) in the hybrid. These attributes have been implicated in salinity tolerance. This study supports the notion that hybridization-induced genome doubling leads to the emergence of phenotypic innovations in an extremophilic endophyte.

Genetic variability, diversity, and character association for dry fruit yield and quality in chili

ABSTRACT Despite the high nutritional value and extensive consumer preference for chili, productivity levels in India are significantly low. An experiment was carried out to study the variability, genetic diversity, and character association in 30 genotypes. Analysis of variance showed significant differences among genotypes for all the traits under study. A high magnitude of genotypic and phenotypic coefficient of variation, coupled with heritability and genetic advance, was observed for all the traits, except days to first flowering, days to first fruit set, and days to final harvest. Diversity analysis showed that the maximum intercluster distance was observed between clusters IX and XII. Results of correlation and path coefficient analysis indicated that number of fruits per plants, fruit length, fruit weight, green fruit yield per plant, number of seeds per fruit, days to first flowering, and days to final harvest were positively correlated with dry fruit yield. It is concluded that improvement in fruit yield in chili pepper could be achieved by selecting genotypes from clusters IX and XII as parents for hybridization, and traits as components that have positive effect on yield.

Evaluation of Genetic Variability in Different Genotypes of Finger Millet (Eleusine coracan L.) through Path and Multivariate Analysis

The experiment was carried out using a Randomized Block Design (RBD) with three replicates. The trials were entirely composed of fifty-two genotypes for yield and their contributing characters for 13 different characters. For every attribute under study, an analysis of variance showed a highly significant difference. Among the genotypes studied, the evaluated characteristics showed varying degrees of heritability, genetic advancement, and variability. Both the genotypic and phenotypic coefficients of variation (PCV and GCV, respectively) ranged from low to high. The modest GCV and PCV values particular for the percentage of fingers per ear (17.47% and 17.50%), ear weight per plant (g) (13.42% and 16.28%), and 1000 seed weight (g) (11.79% and 14.09%), were observed respectively. Plant height (cm) (81.60%, 28.47) had the greatest wide sense heritability value, with the highest genetic advance, followed by ear weight per plant (g) (67.95%, 20.13). Thus, the findings of this study indicate that these genotypes have diversity in yield and other yield-related features, which should be exploited in subsequent breeding. The correlation and path coefficient analyses for yield and yield characteristics showed that grain yield per plant showed a strong positive relationship both at the genotypic and phenotypic levels, with days to 50% flowering, days to maturity, ear weight per plant, and harvest index. Path analysis exhibited that for genotypic and phenotypic coefficients, harvest index (0.33, 0.46) and ear weight/plant (0.86, 0.39) showed the most positive direct effects. These characteristics might thus be applied as selection criteria to identify finger millet genotypes that show promising results in future breeding. Multivariate approaches such as principal component analysis and cluster analysis are crucial statistical tools for examining genetic diversity in plant breeding programs, as are their significant quantitative features. Based on principal component analysis, the entire variance was provided by six main components, of which PC-1 and PC-2 contributed 21.97% and 18.32%, respectively, to the total variability. Euclidean distance was used to divide the fifty-two genotypes into five groups. The largest number of genotypes (twenty-two) in Cluster I was followed by Cluster III, with 16 genotypes. As a result, genotypes from these clusters may be used as parents for hybridization.

Exploring genotypic diversity in sorghum breeding lines for water‐saving traits to enhance drought adaptation during the post‐rainy season

AbstractSorghum [Sorghum bicolor (L.) Moench], a crucial staple crop in South Asia and sub‐Saharan Africa, faces challenges amid increasing climate variability. Post‐rainy sorghum serves as a dominant food and fodder crop in India. Aligned with International Crops Research Institute for the Semi‐Arid Tropics's post‐rainy sorghum product profile, this research extensively characterizes sorghum lines, emphasizing the traits vital for post‐rainy drought adaptation in hybrid parents. We examined genotypic differences and trait correlations in 25 sorghum hybrid parents and varieties (B line for seed parent, R line for restorer, and check for varieties) through atmospheric and soil drought experiments. Results from atmospheric drought experiments revealed significant variation in transpiration rate (TR) under high vapor pressure deficit (VPD), with certain lines showing limited TR (BTX623 and ICSR 21002), while others exhibited high TR. In soil drought experiments, transpiration decline occurred at fractions of transpirable soil water ranging between 0.38 (ICSR 174) and 0.65 (40162 and ICSR 21005). R lines consistently displayed superior plant growth, water use, and biomass compared to B lines. Transpiration efficiency (TE) and total biomass showed positive correlations (r2 = 0.69) in well‐watered and (r2 = 0.45) in water‐stressed conditions. Most R lines displayed higher biomass and TE. Genotypes exhibiting enhanced vigor and limited TR in high VPD conditions and high TE hold potential for enhancing drought adaptation in post‐rainy sorghum. Notably, genotypes with higher biomass, lower TR, and increased TE within both R and B line groups represent valuable genetic resources for enhancing sorghum crops, post‐rainy sorghum adaptation to water deficit.

Families in transition (FIT) study protocol: feasibility, acceptability and preliminary effects of a group-based parent training in parents of youth in psychiatric residential treatment

IntroductionAlthough adolescents make treatment gains in psychiatric residential treatment (RT), they experience significant difficulty adapting to the community and often do not sustain treatment gains long term. Their parents are...

Identification of S-RNase Genotypes of 65 Almond [Prunus dulcis (Mill.) D.A. Webb] Germplasm Resources and Close Relatives

Self-incompatibility (SI) systems in plants prevent self-pollination and mating among relatives, enhancing genetic diversity in nature but posing challenges in almond production and breeding. S-allele composition alongside the flowering periods of these cultivars enables the anticipation of cross-compatibility and optimal cultivar combinations for the allocation of pollinating trees in production. In the current study, 65 materials containing 61 almond (Prunus dulcis) germplasm resources, of which two were hybrids and the remaining four were peach (Prunus persica) germplasms, were used for the S-RNase genotype. The results showed that 55 genomic samples were amplified by PCR to obtain double-banded types, which identified their complete S-RNase genotypes, while the rest of the samples amplified only a single band, identifying one S-RNase gene in the S gene. A total of 30 S-RNase genes were identified in Prunus dulcis, Prunus webbii, Prunus persica, Prunus armeniaca, Prunus salicina, and Prunus cerasifera. Sequence analysis revealed polymorphisms spanning from 313 to 2031 bp within the amplified fragment sequence. The S57-RNase gene exhibited the highest frequency at 31.75% among the identified materials, with S1S57, S10S57, and S7S57 being the predominant S genotypes. A new S-RNase gene, named S65, was identified with a sequencing length of 1483 bp. Its deduced amino acid sequence shared 98.24% similarity with the amino acid sequence of the S-RNase gene on GenBank, with the highest homology. Furthermore, according to the findings, 65 materials belong to eight S genotype cross-incompatibility groups (CIG) and one semi-compatibility or compatibility group (0). Among them, most of the seven main almond germplasm resources and 35 cultivars can be cross-pollinated. The results of the study can lay the foundation for pollinator tree allocation and breeding hybrid parent selection in almond production.