Seed-related Traits Research Articles

DESERT ROSE DIALLEL CROSSES: SEED PRODUCTION AND PHYSIOLOGY

The desert rose, known for its striking sculptural appearance and diverse flowers, holds a prominent place in the market. Despite its ornamental potential, there is limited information on the genetic variability and selection of superior genotypes and their seeds. This study aimed to assess the general (GCA) and specific (SCA) combining ability among desert rose accessions, estimate genetic parameters, and evaluate seed characteristics' correlation. Additionally, we examined the quality of seeds resulting from crosses involving five desert rose genotypes based on floral color. The evaluation included various seed-related traits such as percentage, days until harvesting, number of fruits, seeds per fruit, water content, weight of 100 seeds, seed dimensions, germination, speed of germination index (SGI) in sand, germination, and SGI in paper, seedling length, and dry seedling mass. Genotype 1 displayed positive GCA for all traits, indicating a higher number of favorable alleles for seed production. Hybrid 1X3 exhibited positive SCA estimates, suggesting significant production potential. Notably, 2X5 and 1X5 hybrids demonstrated superior seed quality. Seeds per fruit, germination in sand, seedling length, and dry seedling mass were key contributors to genetic diversity. The study revealed high heritability and positive correlations.

QTL Mapping of Fiber- and Seed-Related Traits in Chromosome Segment Substitution Lines Derived from Gossypium hirsutum × Gossypium darwinii.

A narrow genetic basis limits further the improvement of modern Gossypium hirsutum cultivar. The abundant genetic diversity of wild species provides available resources to solve this dilemma. In the present study, a chromosome segment substitution line (CSSL) population including 553 individuals was established using G. darwinii accession 5-7 as the donor parent and G. hirsutum cultivar CCRI35 as the recipient parent. After constructing a high-density genetic map with the BC1 population, the genotype and phenotype of the CSSL population were investigated. A total of 235 QTLs, including 104 QTLs for fiber-related traits and 132 QTLs for seed-related traits, were identified from four environments. Among these QTLs, twenty-seven QTLs were identified in two or more environments, and twenty-five QTL clusters consisted of 114 QTLs. Moreover, we identified three candidate genes for three stable QTLs, including GH_A01G1096 (ARF5) and GH_A10G0141 (PDF2) for lint percentage, and GH_D01G0047 (KCS4) for seed index or oil content. These results pave way for understanding the molecular regulatory mechanism of fiber and seed development and would provide valuable information for marker-assisted genetic improvement in cotton.

Comparison of grain traits and genetic diversity between Chinese and Uruguayan soybeans (Glycine max L.).

Soybeans (Glycine max L.), originating in China, were introduced to South America in the late 19th century after passing through North America. South America is now a major soybean-producing region, accounting for approximately 40% of the global soybean production. Crops like soybeans gradually adapt to the local climate and human-selected conditions, resulting in beneficial variations during cultivation in different regions. Comparing the phenotypic and genetic variations in soybeans across different regions is crucial to determining the variations that may enhance soybean productivity. This study identified seed-related traits and conducted a genetic diversity analysis using 46 breeding soybean varieties from China and Uruguay. Compared to the Chinese soybean germplasm, the Uruguayan equivalent had a lower 100-grain weight, higher oil content, lower protein content, and higher soluble sugar content. Using ZDX1 gene chips, genetic typing was performed on the 46 breeding varieties. Cluster analysis based on SNP sites revealed significant differences in the genetic basis of Sino-Uruguayan soybean germplasm. Selection analysis, including nucleotide polymorphism (π) and fixation indexes (Fst), identified several genomic regions under selection between Sino-Uruguayan soybean germplasm. The selected intervals significantly enriched gene ontology (GO) terms related to protein metabolism. Additionally, differentiation occurred in genes associated with the oil content, seed weight, and cyst nematodes between Sino-Uruguayan soybean germplasm, such as GmbZIP123 and GmSSS1. These findings highlight the differences in seed-related phenotypes between Sino-Uruguay soybean germplasm and provide genomic-level insights into the mechanisms behind phenotypic differences, offering valuable references for understanding soybean evolution and molecular breeding.

Zinc finger knuckle genes are associated with tolerance to drought and dehydration in chickpea (Cicer arietinum L.).

Chickpea (Cicer arietinum L.) is a very important food legume and needs improved drought tolerance for higher seed production in dry environments. The aim of this study was to determine diversity and genetic polymorphism in zinc finger knuckle genes with CCHC domains and their functional analysis for practical improvement of chickpea breeding. Two CaZF-CCHC genes, Ca04468 and Ca07571, were identified as potentially important candidates associated with plant responses to drought and dehydration. To study these genes, various methods were used including Sanger sequencing, DArT (Diversity array technology) and molecular markers for plant genotyping, gene expression analysis using RT-qPCR, and associations with seed-related traits in chickpea plants grown in field trials. These genes were studied for genetic polymorphism among a set of chickpea accessions, and one SNP was selected for further study from four identified SNPs between the promoter regions of each of the two genes. Molecular markers were developed for the SNP and verified using the ASQ and CAPS methods. Genotyping of parents and selected breeding lines from two hybrid populations, and SNP positions on chromosomes with haplotype identification, were confirmed using DArT microarray analysis. Differential expression profiles were identified in the parents and the hybrid populations under gradual drought and rapid dehydration. The SNP-based genotypes were differentially associated with seed weight per plant but not with 100 seed weight. The two developed and verified SNP molecular markers for both genes, Ca04468 and Ca07571, respectively, could be used for marker-assisted selection in novel chickpea cultivars with improved tolerance to drought and dehydration.

QTL for plant structure type and their influence on seed-related traits in wheat

QTL for plant structure type and their influence on seed-related traits in wheat

A multi-trait GWAS-based genetic association network controlling soybean architecture and seed traits.

Ideal plant architecture is essential for enhancing crop yields. Ideal soybean (Glycine max) architecture encompasses an appropriate plant height, increased node number, moderate seed weight, and compact architecture with smaller branch angles for growth under high-density planting. However, the functional genes regulating plant architecture are far not fully understood in soybean. In this study, we investigated the genetic basis of 12 agronomic traits in a panel of 496 soybean accessions with a wide geographical distribution in China. Analysis of phenotypic changes in 148 historical elite soybean varieties indicated that seed-related traits have mainly been improved over the past 60 years, with targeting plant architecture traits having the potential to further improve yields in future soybean breeding programs. In a genome-wide association study (GWAS) of 12 traits, we detected 169 significantly associated loci, of which 61 overlapped with previously reported loci and 108 new loci. By integrating the GWAS loci for different traits, we constructed a genetic association network and identified 90 loci that were associated with a single trait and 79 loci with pleiotropic effects. Of these 79 loci, 7 hub-nodes were strongly linked to at least three related agronomic traits. qHub_5, containing the previously characterized Determinate 1 (Dt1) locus, was associated not only with plant height and node number (as determined previously), but also with internode length and pod range. Furthermore, we identified qHub_7, which controls three branch angle-related traits; the candidate genes in this locus may be beneficial for breeding soybean with compact architecture. These findings provide insights into the genetic relationships among 12 important agronomic traits in soybean. In addition, these studies uncover valuable loci for further functional gene studies and will facilitate molecular design breeding of soybean architecture.

Exploring the role of FBXL fbxl gene family in Soybean: Implications for plant height and seed size regulation.

F-box proteins constitute a significant family in eukaryotes and, as a component of the Skp1p-cullin-F-box complex, are considered critical for cellular protein degradation and other biological processes in plants. Despite their importance, the functions of F-box proteins, particularly those with C-terminal leucine-rich repeat (LRR) domains, remain largely unknown in plants. Therefore, the present study conducted genome-wide identification and in silico characterization of F-BOX proteins with C-terminal LRR domains in soybean (Glycine max L.) (GmFBXLs). A total of 45 GmFBXLs were identified. The phylogenetic analysis showed that GmFBXLs could be subdivided into ten subgroups and exhibited a close relationship with those from Arabidopsis thaliana, Cicer aretineum, and Medicago trunculata. It was observed that most cis-regulatory elements in the promoter regions of GmFBXLs are involved in hormone signalling, stress responses, and developmental stages. In silico transcriptome data illustrated diverse expression patterns of the identified GmFBXLs across various tissues, such as shoot apical meristem, flower, green pods, leaves, nodules, and roots. Overexpressing (OE) GmFBXL12 in Tianlong No.1 cultivar resulted in a significant difference in seed size, number of pods, and number of seeds per plant, indicated a potential increase in yield compared to wild type. This study offers valuable perspectives into the role of FBXLs in soybean, serving as a foundation for future research. Additionally, the identified OE lines represent valuable genetic resources for enhancing seed-related traits in soybean.

Digital phenotyping for robust seeds variability assessment in Setaria italica (L.) P. Beauv.

ABSTRACT: Foxtail millet (Setaria italica L.) is a cereal crop with potential as a functional food due to its high nutritional value and its wide adaptability to unfavorable environmental conditions. Seed-related traits of foxtail millet are difficult to observe due to its small size. Therefore, the development of an efficient and accurate method for characterizing foxtail millet seeds using digital imaging technology is essential. This study aimed to characterize the seed morphology for variability assessment of Indonesian local foxtail millet genotypes and to develop a model to estimate the 100-seed weight using ImageJ. A total of 28 Indonesian local foxtail millet genotypes were used in this study for seed morphology characterization and the development of the 100-seed weight estimation model. Foxtail millet genotypes from different regions in Indonesia exhibited diverse seed morphologies. The 100-seed weight estimation model (y = 0.123x - 0.0821 (R² = 0.9223)) demonstrated a highly significant positive correlation (r = 0.96, p < 0.01) between the predicted and actual 100-seed weights. The correlation coefficient from model validation was 0.8731 (p < 0.01), indicating that the obtained model could estimate the 100-seed weight of foxtail millet seeds in future studies.

Aridity Gradients Shape Intraspecific Variability of Morphological Traits in Native Ceratonia siliqua L. of Morocco.

The carob tree (Ceratonia siliqua L.) is a significant fruit tree in the Mediterranean region with cultural, biological, and ecological importance. Despite its importance, intraspecific trait variability (ITV) in carob trees has been largely overlooked in previous studies. Understanding ITV and its relationship with environmental conditions is crucial for conservation and breeding programs. In this study, we investigated the variability of carob pod and seed-related traits across different ecological scales in 25 studied populations in Morocco. Significant differences in morphological traits were observed between carob populations at various ecological levels, and pod-related traits exhibited greater variability than seed traits. Correlation analysis revealed strong associations between carob morphological traits and environmental conditions, with altitude and aridity index playing an influential role. The aridity gradient was strongly related to changes in pod size, seed number, and size, as well as seed yield. Our findings highlight an important ITV reaching 45% at the intra-population level, 36.5% at the inter-geographic level, and 30% at the inter-population level. Overall, this study contributes valuable insights into the ecology and adaptation of carob trees, emphasizing the importance of considering intraspecific variability when studying this remarkable species. This knowledge is critical for addressing the challenges posed by climate change and human activities on the long-term survival and ecological functioning of carob populations.

Analyzing genomic variation in cultivated pumpkins and identification of candidate genes controlling seed traits.

Pumpkins are important vegetable crops widely grown worldwide, and seeds are considered a popular nutraceutical food and an excellent source of protein, oil, and vitamins. Seed size is one of the most important targets for commercial breeding in Cucurbita species; studies have shown that pumpkin seed size variation has a similar trend with fruit size, shape, and seed yield. However, few studies have been conducted to identify genetic loci controlling seed-related traits in cultivated pumpkins. This study analyzed the genomic characteristics of pumpkin breeding materials of 321 Cucurbita accessions collected worldwide, including Cucurbita moschata, Cucurbita maxima, and Cucurbita pepo, using extensive single nucleotide polymorphisms obtained from the genotyping-by-sequencing method, significant genetic variations were identified within and between Cucurbita species. Four major cultivar fruit types were further revealed in C. moschata species, and significant differentiation patterns were detected in several chromosomal regions. A total of 15 significant loci associated with pumpkin seed traits were mapped through a genome-wide association approach; 32 genes previously reported to be associated with seed size regulation in Arabidopsis and Oryza sativa were located in the intervals defined by linkage disequilibrium. Through this study, we gained a deep understanding of the genomic variation distribution across Cucurbita species. The available genetic resources and the associated genetic contents could be used in commercial pumpkin breeding and will facilitate molecular marker-assisted selection in pumpkin seed trait improvement.

Genome-Wide Association Mapping of Oil Content and Seed-Related Traits in Shea Tree (Vitellaria paradoxa subsp. nilotica) Populations

Shea tree (Vitellaria paradoxa) is an important fruit tree crop because of its oil used for cooking and the industrial manufacture of cosmetics. Despite its essential benefits, quantitative trait loci linked to the economic traits have not yet been studied. In this study, we performed association mapping on a panel of 374 shea tree accessions using 7530 Single-Nucleotide Polymorphisms (SNPs) markers for oil yield and seed-related traits. Twenty-three SNP markers significantly (−log10 (p) = 4.87) associated with kernel oil content, kernel length, width, and weight were identified. The kernel oil content and kernel width had the most significant marker–trait associations (MTAs) on chromosomes 1 and 8, respectively. Sixteen candidate genes identified were linked to early induction of flower buds and somatic embryos, seed growth and development, substrate binding, transport, lipid biosynthesis, metabolic processes during seed germination, and disease resistance and abiotic stress adaptation. The presence of these genes suggests their role in promoting bioactive functions that condition high oil synthesis in shea seeds. This study provides insights into the important marker-linked seed traits and the genes controlling them, useful for molecular breeding for improving oil yield in the species.

Construction of a high-density genetic map for faba bean (Vicia faba L.) and quantitative trait loci mapping of seed-related traits.

Faba bean (Vicia faba L.) is a valuable legume crop and data on its seed-related traits is required for yield and quality improvements. However, basic research on faba bean is lagging compared to that of other major crops. In this study, an F2 faba bean population, including 121 plants derived from the cross WY7×TCX7, was genotyped using the Faba_bean_130 K targeted next-generation sequencing genotyping platform. The data were used to construct the first ultra-dense faba bean genetic map consisting of 12,023 single nucleotide polymorphisms markers covering 1,182.65 cM with an average distance of 0.098 cM. The map consisted of 6 linkage groups, which is consistent with the 6 faba bean chromosome pairs. A total of 65 quantitative trait loci (QTL) for seed-related traits were identified (3 for 100-seed weight, 28 for seed shape, 12 for seed coat color, and 22 for nutritional quality). Furthermore, 333 candidate genes that are likely to participate in the regulation of seed-related traits were also identified. Our research findings can provide a basis for future faba bean marker-assisted breeding and be helpful to further modify and improve the reference genome.

GmJAZ3 interacts with GmRR18a and GmMYC2a to regulate seed traits in soybean.

Seed weight is usually associated with seed size and is one of the important agronomic traits that determine yield. Understanding of seed weight control is limited, especially in soybean plants. Here we show that Glycine max JASMONATE-ZIM DOMAIN 3 (GmJAZ3), a gene identified through gene co-expression network analysis, regulates seed-related traits in soybean. Overexpression of GmJAZ3 promotes seed size/weight and other organ sizes in stable transgenic soybean plants likely by increasing cell proliferation. GmJAZ3 interacted with both G. max RESPONSE REGULATOR 18a (GmRR18a) and GmMYC2a to inhibit their transcriptional activation of cytokinin oxidase gene G. max CYTOKININ OXIDASE 3-4 (GmCKX3-4), which usually affects seed traits. Meanwhile, the GmRR18a binds to the promoter of GmMYC2a and activates GmMYC2a gene expression. In GmJAZ3-overexpressing soybean seeds, the protein contents were increased while the fatty acid contents were reduced compared to those in the control seeds, indicating that the GmJAZ3 affects seed size/weight and compositions. Natural variation in JAZ3 promoter region was further analyzed and Hap3 promoter correlates with higher promoter activity, higher gene expression and higher seed weight. The Hap3 promoter may be selected and fixed during soybean domestication. JAZ3 orthologs from other plants/crops may also control seed size and weight. Taken together, our study reveals a novel molecular module GmJAZ3-GmRR18a/GmMYC2a-GmCKXs for seed size and weight control, providing promising targets during soybean molecular breeding for better seed traits.

Major genetic locus with pleiotropismdetermined seed-related traits in cultivated and wild soybeans.

Here, a novel pleiotropic QTL qSS14 simultaneously regulating four seed size traits and two consistently detected QTLs qSW17 and qSLW02 were identified across multiple years. Seed-related traits were the key agronomic traits that have been artificially selected during the domestication of wild soybean. Identifying the genetic loci and genes that regulate seed size could clarify the genetic variations in seed-related traits and provide novel insights into high-yield soybean breeding. In this study, we used a high-density genetic map constructed by F10 RIL populations from a cross between Glycine max and Glycine soja to detect additive QTLs for seven seed-related traits over the last three years. As a result, we identified one novel pleiotropic QTL, qSS14, that simultaneously controlled four seed size traits (100-seed weight, seed length, seed width, and seed thickness) and two consistently detected QTLs, qSW17, and qSLW02, in multiple years of phenotypic data. Furthermore, we predicted two, two and three candidate genes within these three critical loci based on the parental resequencing data and gene function annotations. And the relative expression of four candidate genes GLYMA_14G155100, GLYMA_17G061000, GLYMA_02G273100, and GLYMA_02G273300 showed significant differences among parents and the extreme materials through qRT-PCR analysis. These findings could facilitate the determination of beneficial genes in wild soybean and contribute to our understanding of the soybean domestication process.

Assessment of DUS Traits in Rajmash (Phaseolus vulgaris L.) Genotypes: A Comprehensive Study on Genetic Diversity and Morphological Characteristics

The study was conducted at Dry Land Agriculture Research Station (DARS), Rangreth, Srinagar, Jammu and Kashmir, India aimed to comprehensively assess 40 genotypes, alongside 5 checks, for Distinctness, Uniformity and Stability (DUS) characterization. Employing an Augmented Block Design in the field in kharif season of April-August, 2022 and a Completely Randomized Design (CRD) in the laboratory from September–March 2023, the genotypes underwent evaluation for 21 DUS traits and 43 morphological, maturity, yield and quality traits. The evaluation followed descriptors specific to rajmash genotypes, utilizing frequency distribution based on “state” and “code” for each trait. The results indicated that majority of genotypes exhibited early flowering (<50 days), with 91% displaying an absence of anthocyanin coloration. Erect plant types were prevalent (51.11%), with 51% and 60% being viny and determinate, respectively. Most genotypes featured medium-sized, light green, ovate leaves (46.66%, 53%, and 22%, respectively). White-colored flowers (48.88%) with striped petal surfaces (57.77%) and medium curvature (40.00%) were predominant. Seed-related traits, such as cordate pod shapes (51%) and concave pod sutures (50%), along with acute pod distal shapes (69%), were observed. Pale green pods (57.77%) and 76% of genotypes exhibiting pod stringiness were noted. Seed shapes were mainly kidney-shaped (60%), and absent pigmentation in pod shells (73%) was observed. Large-sized seeds (40%) with dark red testa color (44%) were common, and seed testa variegation was “absent” in 75.55% of genotypes.

QTL localisation of seed-related traits in Tibetan hulless barley based on a high-density single-nucleotide polymorphism genetic map

The effective use of high-quality and high-yielding germplasm resources is of great importance for the development of hulless barley varieties. Therefore, the search for such resources has long been a goal of the breeding community. In this study, a genotyping-by-sequencing (GBS) analysis was performed on an F2 (Nierumuzha × Kunlun 10) population. A high-density genetic map of hulless barley was constructed, which contained 1 475 efficient single-nucleotide polymorphism markers with 7 052 bin markers. The total length of the seven chromosomes was 1 139.4 cM, with an average marker distance of 0.59 cM. Based on this high-density linkage map, a total of 54 quantitative trait loci (QTLs) related to the seed traits were detected, including seed colour (SC), thousand kernel weight (TKW), seed average area (SAA), seed perimeter (SP), seed length (SL), seed width (SW), seed length/width (SLW), seed diameter (SD), and seed circular degree (SCD). These QTLs explained 3.32–35.73% (mean = 11.45%) of the phenotypic interpretation, including 24 main QTLs and 30 epistatic QTLs. A total of 24 candidate genes were identified within the QTL region, including one SC-associated transcription factor (ANT1), two TSW-related genes, a transcription factor (NAC021), a gene associated with the non-homologous end joining (NHEJ) pathway (ku70), three SAA-associated genes (LOL2, NAC021, TSK), two SL-associated genes (MADS21, MADS4), six SW-associated genes (FIP1, NAC021, DREB 1A, HVA22A, CYP78A6, SAUR71), five LW-related genes (NAM-B2, CRY1, LHY, CYP710A1, WRKY72), two SP-related genes (SKIP11, TCP18), two SD-related genes (NAC021, SKIP8), and three SCD-related genes (MYB1R1, RAX3, NAC100). These genes are involved in the regulation of the cell development, material transport, signal transduction, and plant morphogenesis and play an important role in the regulation of agronomic traits in hulless barley. The high-density genetic mapping and QTL identification of the seed traits in hulless barley provide a valuable genetic resource and the basis for further molecular marker-assisted selection and genomic studies.

Detection of Hub QTLs Underlying the Genetic Basis of Three Modules Covering Nine Agronomic Traits in an F2 Soybean Population

Deciphering the genetic basis underlying agronomic traits is of importance for soybean improvement. However, covariation, modulated by genetic correlations between complicated traits via hub QTLs, commonly affects the efficiency and accuracy of soybean improvement. The goals of soybean improvement have nearly all focused on agronomic traits, including yield, plant type traits, and seed-related traits especially. To decipher the hub QTLs of yield, plant type, and seed, nine pertinent traits of an F2 population (181 plants) derived from a cross between KeXin No.03 and JiDou 17, which were different in multiple traits such as plant height, seed protein, and 100-seed weight, were investigated with a high-density genetic map covering 2708.63 cM. A highly significant negative phenotypic correlation (−0.95) was found between seed protein (Pro) and seed oil (Oil). A total of 35 final QTLs after combining the ones closely linked physically were identified for eight traits explaining from 0.10% to 24.63% of the phenotypic variance explained (PVE) using composite interval mapping (CIM) and inclusive composite interval mapping (ICIM) procedures, and 13 QTLs were novel genes. A genomic region on chromosome 14 (qPro14, qOil14.2, and qSw14) was associated with three seed-related traits based on the relationship within and among the three trait modules. In addition, four genomic regions were detected as hub QTLs which linked to the seed-related module and plant-type model, including the E loci (E1 and E2). From the QTL results, 31 candidate genes were annotated, including the verified genes E1, E2, and QNE1, and they were grouped into three categories of biological processes. These results illustrate the genetic architecture as correlations among various soybean traits, and the hub QTLs should provide insights into the genetic improvement of complex traits in soybean.

Evolution and function of ubiquitin-specific proteases (UBPs): Insight into seed development roles in plants

The tung oil produced by the tung tree (Vernicia fordii) provides resources for the manufacture of biodiesel. Ubiquitin-specific proteases (UBPs) are the largest group of deubiquitinases and play key roles in regulating development and stress responses. Here, 21 UBPs were identified in V. fordii, roughly one-half the number found in Manihot esculenta and Hevea brasiliensis. Most UBP duplications are produced from whole-genome duplication (WGD), and significant differences in gene retention existed among Euphorbiaceae. The great majority of UBP-containing blocks in V. fordii, V. montana, Ricinus communis, and Jatropha curcas exhibited extensive conservation with the duplicated regions of M. esculenta and H. brasiliensis. These blocks formed 14 orthologous groups, indicating they shared WGD with UBPs in M. esculenta and H. brasiliensis, but most of these UBPs copies were lost. The UBP orthologs contained significant functional divergence which explained the susceptibility of V. fordii to Fusarium wilt and the resistance of V. montana to Fusarium wilt. The expression patterns and experiments suggested that Vf03G1417 could affect the seed-related traits and positively regulate the seed oil accumulation. This study provided important insights into the evolution of UBPs in Euphorbiaceae and identified important candidate VfUBPs for marker-assisted breeding in V. fordii.

Water uptake of soybean pods and seeds with different lignin contents

The identification of pod- and seed-related traits of soybean genotypes and their interaction with water uptake can be applied in breeding programs with a view to establishing cultivars developed for the production and maintenance of high-quality seeds. The objective was to evaluate the water uptake of pods and seeds of soybean cultivars with different lignin contents after different soaking periods. The experimental was arranged in a completely randomized, 7×10 factorial design, with four replications. The factors consisted of seven soybean cultivars and 10 soaking periods (1, 2, 3, 4, 5, 6, 7, 8, 24, 48 hours). The pods and seeds were grown in a greenhouse and harvested at the phenological growth stage R8 (at full maturation, when 95% of the pods had mature color). The following traits were evaluated: lignin content in pod and seed coat, moisture content, and rate of water uptake of pods and seeds. Soybean cultivars with pods with high lignin contents have a lower rate of water uptake. The lignin contents of the seed coats, within the chosen limits, did not affect the seed water uptake.

Comparative analysis of variation in African Bambara groundnut [Vigna subterranea (L) Verdc.] landraces assessed through seed traits

Bambara groundnut [Vigna subterranea (L.) Verdc.] originated from the African continent and plays social-economic roles in regions where it is consumed. This study examined 297 landraces of African Bambara groundnut from four African regions (West, Central, East, and Southern) to estimate the extent of diversity in each population, identify useful seed traits for differentiation in the population and estimate association among seed quantitative traits using eight qualitative and seven quantitative seed traits. The result of seed qualitative traits showed considerable diversity in the African Bambara groundnut population with West African regions having the highest diversity (0.71) followed by Central Africa (0.64), East Africa (0.62), and Southern Africa (0.61). Heatmap analysis on the distribution of seed qualitative traits revealed that all the regions shared similarities in reference to the phenotypic classes of the traits with greater similarity found within the group. These groups were West and Central Africa as group A; while East and Southern Africa as group B. The descriptive statistics on seed quantitative traits revealed a wide range of variations within each population. Significant (p < 0.05) genetic variation was recorded among the landraces within each region for the most studied traits. Moderate heritability accompanied with high genetic advance was obtained on hundred seed weight in most of the studied regions. Factor analysis of mixed data (FAMD) in principal component analysis revealed that seed coat colour had strong discriminatory power in the crop characterization. FAMD in cluster analysis grouped the germplasm into three clusters with cluster II showing superiority for seed-related (seed length, seed width, and seed thickness) traits. The overall results confirmed that Bambara groundnut can be classified through seed morphology and considerable seed diversity depicted among the population that can be utilized in the future genetic improvement of Bambara groundnut.