Pod Traits Research Articles

Intraspecific pod and seed trait variation of two herbaceous legume seeds in response to competing neighbours and nutrient resource abundance

The presence of competing neighbours can exert pressure on parent plants, forcing them to adjust their reproductive strategies to maximize recruitment success (adaptive response); however, competitive neighbour effects may be suppressed if more nutrient resources are made available (passive response). In this study, we investigated if the response of some measured seed and pods traits of Lablab purpureus and Mucuna pruriens (focal plants) were adaptively determined by the presence of competitive neighbour species (using Megathyrsus maximus as the focal neighbour) or passively determined by nutrient resource availability. We measured four pod traits (pod weight, pod length, pod filling, and no of pods/ha) and eight seed traits (no of seeds/ha, seed mass, seed yield, dry matter content, Calcium content, Phosphorus content, Nitrogen content, and seed germination percentage) of the focal plants established as mixtures (neighbour treatment) or as monocultures (no-neighbour treatment) at different levels of phosphorus fertilizer application (0, 20, and 40 kg/ha applied on treatment basis). The data were analyzed using a linear mixed-effect model. Results showed that plant identity modified competitive neighbour and nutrient resource availability effects. Competitive neighbour species facilitated increased pod length response, but suppressed pod filling and number of pods/ha which were passively improved at higher levels of nutrient abundance. The no of seeds/ha and seed yield were also passively improved at higher levels of nutrient abundance, previously suppressed by competitive neighbour effects. The presence of focal neighbours and nutrient resource levels interacted positively to increase the Phosphorus content, Nitrogen content, and seed germination %. Other measured traits were not influenced by competitive neighbour effects or nutrient resource availability. In conclusion, competitive neighbour effects on the seeds and pod traits of the focal plants depended on plant identity and nutrient resource availability. Passive trait responses may magnify competitive effects on progenies after successful recruitment.

GWAS of pod morphological and color characters in common bean

BackgroundCommon bean (Phaseolus vulgaris L.) is an important legume species which can be consumed as immature pods and dry seeds after re-hydration and cooking. Many genes and QTL, and epistatic interactions among them, condition pod morphological traits. However, not all them have been mapped or validated nor candidate genes proposed. We sought to investigate the genomic regions conditioning pod morphological and color characters through GWAS.ResultsSingle and multi-locus genome wide association analysis was used to investigate pod traits for a set of 301 bean lines of the Spanish Diversity Panel (SDP). The SDP was genotyped with 32,812 SNPs obtained from Genotyping by Sequencing. The panel was grown in two seasons and phenotypic data were recorded for 17 fresh pods traits grouped in four pod characters: pod length, pod cross-section, pod color, and number of seeds per pod. In all, 23 QTL for pod length, 6 for cross-section, 18 for pod color, 6 for number of seeds per pod and 9 associated to two or more pod characters were detected. Most QTL were located in the telomeric region of chromosomes Pv01, Pv02, Pv04, Pv08, Pv09 and Pv10. Eighteen detected QTL co-localized with 28 previously reported QTL. Twenty-one potential candidate genes involving developmental processes were detected underlying 11 QTL for pod morphological characters, four of them homologous to A. thaliana genes FIS2, SPL10, TTG2 and AML4 affecting silique size. Eight potential candidate genes involved in pigment synthesis, were found underlying five QTL for pod color.ConclusionsGWAS for pod morphological and color characters in the bean Spanish Diversity Panel revealed 62 QTL, 18 co-localized with previously reported QTL, and 16 QTL were underlain by 25 candidate genes. Overall 44 new QTL identified and 18 existing QTL contribute to a better understanding of the complex inheritance of pod size and color traits in common bean and open the opportunity for future validation works.

Exploring genetic architecture for pod-related traits in soybean using image-based phenotyping.

The online version contains supplementary material available at 10.1007/s11032-021-01223-2.

Seed Dormancy Breaking and Germination in Bituminaria basaltica and B. bituminosa (Fabaceae)

Most legumes are well-known for the physical dormancy of their seeds; hence, the implementation of appropriate scarification techniques is essential for introducing new legume crops within agricultural systems. This study investigated morpho-anatomical traits and dormancy-breaking requirements in two taxa of the genus Bituminaria: the widespread B. bituminosa and the point endemic B. basaltica. As the species under investigation show monospermic indehiscent legumes, pods were used in this research. We performed pod trait measurements, light microscopy observations on the seed coat anatomical structure, and germination tests after mechanical, thermal, and chemical scarification treatments for seed dormancy breaking. Moreover, germination performance at different pod maturity stages and storage times was tested. Differences in morpho-anatomical traits were found, with B. basaltica having a thicker palisade cell layer and B. bituminosa showing larger pods. All of the scarification treatments proved to be able to break physical dormancy, with mechanical and chemical scarification being the most effective methods in both species. Nevertheless, dormancy-breaking treatments performed better in B. bituminosa. Seeds at early pod maturity stages showed higher germination capacity in both species. Overall, this research provided background knowledge on seed collection time, storage strategy, and effective pre-sowing treatment, which might contribute to enhance propagation and use of Bituminaria species for multiple purposes. Under this perspective, the future characterization of additional Bituminaria genetic resources from other Mediterranean populations will have remarkable importance.

Pod and Seed Trait QTL Identification To Assist Breeding for Peanut Market Preferences.

Although seed and pod traits are important for peanut breeding, little is known about the inheritance of these traits. A recombinant inbred line (RIL) population of 156 lines from a cross of Tifrunner x NC 3033 was genotyped with the Axiom_Arachis1 SNP array and SSRs to generate a genetic map composed of 1524 markers in 29 linkage groups (LG). The genetic positions of markers were compared with their physical positions on the peanut genome to confirm the validity of the linkage map and explore the distribution of recombination and potential chromosomal rearrangements. This linkage map was then used to identify Quantitative Trait Loci (QTL) for seed and pod traits that were phenotyped over three consecutive years for the purpose of developing trait-associated markers for breeding. Forty-nine QTL were identified in 14 LG for seed size index, kernel percentage, seed weight, pod weight, single-kernel, double-kernel, pod area and pod density. Twenty QTL demonstrated phenotypic variance explained (PVE) greater than 10% and eight more than 20%. Of note, seven of the eight major QTL for pod area, pod weight and seed weight (PVE >20% variance) were attributed to NC 3033 and located in a single linkage group, LG B06_1. In contrast, the most consistent QTL for kernel percentage were located on A07/B07 and derived from Tifrunner.

English

This study was undertaken to evaluate the extent and pattern of genetic diversity for immature pod traits in Ethiopia cowpea landrace collections. Eighty one landraces and improved cultivars were tested in a 9 x 9 simple lattice design. Analysis of variance revealed highly significant (P<0.01) or significant (p<0.05) differences among the genotypes for all traits. The first four principal components were able to explain 81% of variation for quantitative traits and 76% for qualitative traits. The genotypes were grouped into three distinct clusters, the first, second and third clusters with 60, 15 and 25% of the genotypes in that order. The landraces were distributed all over the clusters while the improved cultivars were absent in the second cluster. Shannon-Weaver diversity indices also showed existence of adequate genetic variability among the genotypes for qualitative traits. Shannon-Weaver diversity indices ranged from the lowest of 0.50 for pod curvature to the highest of 0.99 for pod shape. The study clearly showed that, even if the genotypes were classified into a few cluster, there was adequate divergence among the clusters showing existence of considerable genetic variability for immature pod traits for exploitation in future breeding for better green pod yield and quality in cowpea. Key words: Cowpea, diversity, genotypes, immature pod, qualitative traits, quantitative trait.

Selecting Yield and Nutritional Traits in Sphenostylis stenocarpa Landraces for Food Improvement.

Sphenostylis stenocarpa is an underexploited African indigenous food crop that is enriched in nutritional quality. Exploring the robust genetic base of this landrace can help to maximize the benefit of the agricultural sector on the economy through production that is enhanced by packaging and patent. This as well will increase the quality of food production and promote African campaign on food sustainability. Upon this, this research made use of multiple statistics to identify S. stenocarpa yield and nutritional trait relatedness that supported selection for maximum yield and nutritional trait output. Yield and related traits including protein and oil contents of twenty-three Sphenostylis stenocarpa landraces were studied under a four year planting seasons in Teaching and Research farm of Landmark University, Nigeria. Trait variances from Landrace × Year (L × Y) interaction, Principal Component and Cluster analyses were evaluated and the variation patterns were identified. Some vegetative (maturity phase, height and branching) and yield traits (Pod traits, seed yield and oil content) correlated significantly (P < 0.05) in the L × Y interactions. This suggests the usefulness of these traits in improving S. stenocarpa grain and oil quality yield. Tuber and nodule yield including protein content did not differ significantly in the variance table. The result indicates that one location trial is insufficient to determine such trait performance. The first four PCs that accounted for 51 percent of the total variations were traceable to branching, maturity date, pod numbers, seed and oil content as main contributors to yield.

Characterization of 60CO γ-ray induced pod trait of blackgram-A promising yield mutants

Purpose: Blackgram (Vigna mungo (L.) Hepper) possesses natural flower dropping character with self-pollination, which was highly challenging to create variability through hybridization. Gamma irradiation is a powerful tool to induce genetic alteration and improvement in crops with beneficial mutants. Hence, the present investigation focused on finding out the mutant characters related to the improvement of the agronomic characters and yield-related traits by using gamma irradiation. Pod mutant isolated with fruitful agronomic trait at M2 (Mutagenic) generation was identified and isolated by gamma irradiation is a central focus in the present study, which enhances the yield of the blackgram.Materials and methods: Viable and uniform size of blackgram Vamban-4 seeds were irradiated at a different dose of 60CO (Cobalt) γ-rays viz., 200, 400, 600, 800, 1000, and 1200 Gray (Gy). The further generations were screened and raised to M3 and M4 plants to select the stable mutants with yield traits.Results: In the M2 generation, the following viable and pod mutants were identified, such as tall, dwarf, multipod, small pod, bold pod, striata pod. Morphological traits, such as plant height (PH), number of branches per plant (NBP), number of leaves per plant (NLP), number of cluster per plant (NCP), number of pods per plant (NPP), number of seeds per pod (NSP), pod length (PL), a hundred seed weight (HSW), seed yield per plant (SYP), were measured. Among the mutants, the increased morphogenetic traits were recorded in tall mutants (600 Gy), and the enhancement of yield characteristics noticed in multipod (800 Gy) and bold pod mutants (600 Gy). Compared to other doses, 600 Gy shows enhanced quantitative traits for blackgram improvement.Conclusion: The 60CO γ-rays induced genetic variation in the yield and its related traits and obtained pod mutants, which are useful to enhance the commercial value of Vigna species and crop improvement.

Genome wide association mapping and candidate gene analysis for pod shatter resistance in Brassica juncea and its progenitor species.

We investigated phenotypic variations for pod shattering, pod length and number of seeds per pod in large germplasm collections of Brassica juncea (2n = 36; AABB) and its progenitor species, B. rapa (2n = 20; AA) and B. nigra (2n = 16; BB). Pod shatter resistance was measured as energy required for rupturing a mature dry pod, with a specially fabricated pendulum machine. Rupture energy (RE) ranged from 3.3 to 11.0mJ in B. juncea. MCP 633, NR 3350 and Albeli required maximum energy to shatter a pod. It ranged from 2.5 to 7.8mJ for B.rapa with an average of 5.5mJ. B. nigra possessed easy to rupture pods. Correlation analysis showed strong associations among these traits in B. juncea and B. rapa. Genome wide association studies were conducted with select sets of B. juncea and B. rapa germplasm lines. Significant and annotated associations predict the role of FRUITFULL, MANNASE7, and NAC secondary wall thickening promoting factor (NST2) in the genetic regulation of shatter resistance in B. juncea. NST2 and SHP1 appeared important for pod length and seeds per pod in B.rapa. Candidate gene based association mapping also confirmed the role of SHP1 and NST2 in regulating pod shattering and related pod traits in B.rapa and B.juncea. Footprints of selection were detected in SHP1, SHP2 (B. rapa, B. nigra and B. juncea), RPL (B. rapa) and NAC (B. juncea). Our results provide insights into the genetic architecture of three pod traits. The identified genes are relevant to improving and securing crop productivity of mustard crop.

A recessive high-density pod mutant resource of Brassica napus

In Brassica napus, pod number and pod density are critical factors to determine seed yield. Although the pod density is an essential yield trait, the regulation of yield formation in oil crops, as well as the genetic and molecular mechanisms, are poorly understood. In this study, we characterized a rapeseed high-density pod mutant (dpt247) from composite hybridization. To shed some light on the nature of this mutation, it was investigated morphologically, anatomically, physiologically, genetically and transcriptomically. The mutant plant showed noticeable phenotypic differences in comparison with the control plant, including reduced plant height and primary branch length, decreased number of primary branches, significantly increased number of pod on the main inflorescence, and more compact pod distribution. Besides, the mutant had higher levels of indole-3-acetic acid (IAA) and zeatin riboside (ZR) in the shoot apical meristem (SAM). The dense pod trait was controlled by two major recessive genes identified in the segregating genetic populations of GRE501 and dpt247. RNA sequencing indicated genes participated in auxin, cytokinin and WUS/CLV signalling pathway in dpt247 were more active in the mutant. These results provide important information for understanding the regulation of yield formation and high yield breeding in rapeseed.

Characterization of morphometric, reproductive and seedling traits of Parkia timoriana in northeast India

We studied variations on different traits of (D.C.) Merr. in twelve provenances systematically from their source of origin to a controlled environment where representative seedlings were grown. Among the provenances, P1 gave the best result for seed traits including germination traits, P7 for pod traits and P10 for seedling vigour. Effects of seasonal distribution of rainfall and temperature on seed and pod traits were also determined by computing multiple regression analysis. The results displayed winter rainfall and summer temperature as the most important factor determining pod and seed traits. Latitude also significantly (P &lt; 0.001) affected PWT (r = 0.52), SWP (r = 0.46) and SW (r = 0.50). A common garden study for germination and seedling growth indicated P1 and P10 provenance as the best among all. Seeds drawn from P10 gave the highest seedling vigour with an average growth rate of 0.61 cm/day from 90th to 180th day. Highest broad-sense heritability values (h) were observed in germination traits, followed by seedling collar diameter. The lowest h was observed for seedling height.Parkia timoriana22

Morpho-Agronomic Characterisation of Runner Bean (Phaseolus coccineus L.) from South-Eastern Europe

In South-Eastern Europe, the majority of runner-bean (Phaseolus coccineus L.) production is based on local populations grown mainly in home gardens. The local runner-bean plants are well adapted to their specific growing conditions and microclimate agro-environments, and show great morpho-agronomic diversity. Here, 142 runner-bean accessions from the five South-Eastern European countries of Slovenia, Bosnia and Herzegovina, Serbia, North Macedonia and Romania were sown and cultivated in their respective countries and characterised using 28 quantitative and qualitative morpho-agronomic descriptors for Phaseolus spp. based on inflorescences, leaves, plants, pods and seeds. For each of these morpho-agronomic descriptors, the accessions can be classified into two or three specific groups. The highest correlations were observed within the fluorescence, seed and pod traits. The highest variability, at 76.39%, was between the different countries, representing different geographic origins, while the variability within the countries was 23.61%. Cluster analysis based on these collected morpho-agronomic data also classified the accessions into three groups according to genetic origins. The data obtained serve as useful genetic information for plant breeders for the breeding of new bean varieties for further studies of the morpho-agronomic traits of the runner bean.

Morphometric analysis and characterization of the nutritional quality in African yam bean accessions

Underutilized crops with rich nutritional base in addition to high seed yield are currently promoted in reducing hunger and malnutrition ravaging Africans. Identifying specific accessions with rich genetic bases provide information for developing biofortified legumes. Fourteen morphological and two nutritional traits of 23 African yam bean accessions were assessed under a replicated field trial in one location over 4 years. Analysis of variance revealed significant variations for most traits with high genotypic correlation coefficients. Genotypic coefficient of variation was high for maturity date (59.95%), protein content (60.78%), tuber yield per plant (67.33%) and number of seeds per pod (77.22%). Seed yield did not correlate with protein and oil content, indicating that nutritional traits were independent of seed yield traits. Heritability was high for most traits but moderate for protein and oil content. First order predictor variables, identified number of seeds per pod, and pod traits to directly affect seed and tuber yield. First seven principal components axes explained 67% of total variation including nutritional traits. Four distinct accession clusters at the R-squared distance of 0.45 similarity index were identified. Simultaneous improvement in earliness, yield, protein and oil contents are achievable by selecting parents from clusters I and II. The only accession in cluster III (TSs12) produced nodules in addition to average seed yield, protein and oil content, and could be selected for cultivation in nitrogen deficient soils. Wide diversity in these accessions can be maximized for developing acceptable African yam bean varieties with enhanced yield and nutritional value.

Identification of major consensus QTLs for seed size and minor QTLs for pod traits in cultivated groundnut (Arachis hypogaea L.).

Hundred kernel weight is an important indicator for large-seeded genotype selection. A recombinant inbred line population was used to decipher the genetic architecture of seed size and three pod traits in cultivated groundnut based on the phenotypic data from six and three environments, respectively. The study revealed a consensus major QTL for HKW in B07 group that explained 10.5-23.9% phenotypic variation due to seed size. Further, two other minor QTLs were identified in B03 and B08 group for the seed size. Two minor QTLs for pod beak were positioned in B03 and A08. A minor QTL for pod reticulation was also mapped in the same map interval with the pod beak QTL in A08. Another minor QTL for pod constriction was co-mapped with the minor QTL for HKW in B08. The other minor QTL for pod constriction was placed in the neighboring map interval with the consensus QTL for seed size in B07 that suggests linkage of pod constriction with large seed trait. Analysis of the flanking markers profile in 71 cultivated groundnut genotypes revealed a strong association of pPGPseq_2E06 marker with large seed trait.

Consensus map integration and QTL meta-analysis narrowed a locus for yield traits to 0.7\u2009cM and refined a region for late leaf spot resistance traits to 0.38\u2009cM on linkage group A05 in peanut (Arachis hypogaea L.)

BackgroundMany large-effect quantitative trait loci (QTLs) for yield and disease resistance related traits have been identified in different mapping populations of peanut (Arachis hypogaea L.) under multiple environments. However, only a limited number of QTLs have been used in marker-assisted selection (MAS) because of unfavorable epistatic interactions between QTLs in different genetic backgrounds. Thus, it is essential to identify consensus QTLs across different environments and genetic backgrounds for use in MAS. Here, we used QTL meta-analysis to identify a set of consensus QTLs for yield and disease resistance related traits in peanut.ResultsA new integrated consensus genetic map with 5874 loci was constructed. The map comprised 20 linkage groups (LGs) and was up to a total length of 2918.62 cM with average marker density of 2.01 loci per centimorgan (cM). A total of 292 initial QTLs were projected on the new consensus map, and 40 meta-QTLs (MQTLs) for yield and disease resistance related traits were detected on four LGs. The genetic intervals of these consensus MQTLs varied from 0.20 cM to 7.4 cM, which is narrower than the genetic intervals of the initial QTLs, meaning they may be suitable for use in MAS. Importantly, a region of the map that previously co-localized multiple major QTLs for pod traits was narrowed from 3.7 cM to 0.7 cM using an overlap region of four MQTLs for yield related traits on LG A05, which corresponds to a physical region of about 630.3 kb on the A05 pseudomolecule of peanut, including 38 annotated candidate genes (54 transcripts) related to catalytic activity and metabolic process. Additionally, one major MQTL for late leaf spot (LLS) was identified in a region of about 0.38 cM. BLAST searches identified 26 candidate genes (30 different transcripts) in this region, some of which were annotated as related to regulation of disease resistance in different plant species.ConclusionsCombined with the high-density marker consensus map, all the detected MQTLs could be useful in MAS. The biological functions of the 64 candidate genes should be validated to unravel the molecular mechanisms of yield and disease resistance in peanut.

Domestication of Pea (Pisum sativum L.): The Case of the Abyssinian Pea.

Phylogenetic relationships of the Abyssinian pea (Pisum sativum ssp. abyssinicum) to other subspecies and species in the genus were investigated to test between different hypotheses regarding its origin and domestication. An extensive sample of the Pisum sativum ssp. sativum germplasm was investigated, including groups a-1, a-2, b, c, and d as identified by Kwon et al. (2012). A broad sample of P. fulvum but relatively few P. s. ssp. elatius accessions were analyzed. Partial sequences of 18 genes were compared and these results combined with comparisons of additional genes done by others and available in the literature. In total, 54 genes or gene fragment sequences were involved in the study. The observed affinities between alleles in P. ssp. sativum, P. s. ssp. abyssinicum, P. s. ssp. elatius, and P. fulvum clearly demonstrated a close relationship among the three P. sativum subspecies and rejected the hypothesis that the Abyssinian pea was formed by hybridization between one of the P. sativum subspecies and P. fulvum. If hybridization were involved in the generation of the Abyssinian pea, it must have been between P. s. ssp. sativum and P. s. ssp. elatius, although the Abyssinian pea possesses a considerable number of highly unique alleles, implying that the actual P. s. ssp. elatius germplasm involved in such a hybridization has yet to be tested or that the hybridization occurred much longer ago than the postulated 4000 years bp. Analysis of the P. s. ssp. abyssinicum alleles in genomic regions thought to contain genes critical for domestication indicated that the indehiscent pod trait was independently developed in the Abyssinian pea, whereas the loss of seed dormancy was either derived from P. s. ssp. sativum or at least partially developed before the P. s. ssp. abyssinicum lineage diverged from that leading to P. s. ssp. sativum.

Phenotyping and genotyping parents of sixteen recombinant inbred peanut populations

ABSTRACTIn peanut (Arachis hypogaea L.), most agronomically important traits such as yield, disease resistance, and pod and kernel characteristics are quantitatively inherited. Phenotypic selection of these traits in peanut breeding programs can be augmented by marker-assisted selection. However, reliable associations between unambiguous genetic markers and phenotypic traits have to be established by genetic mapping prior to early generation marker-assisted selection. Previously, a nested association mapping (NAM) population of 16 recombinant inbred line populations (RILs) consisting 4870 lines was established. In order to facilitate effective mapping of such a large genetic resource, the first objective of the current study was to phenotype the parental lines for yield, pod traits, field maturity, germination, plant morphology, salt tolerance and resistance to tomato spotted wilt virus (TSWV) and late leaf spot (LLS). For most measured traits, more than one parental combination demonstrated statistically significant variation which can be further quantified and mapped in the respective RIL populations. The second objective of this study was to genotype the parental lines using the Arachis Axiom SNP arrays to reveal the marker density of the mapping populations. The Version 1 array identified 1,000 to 4,000 SNPs among the population parents and the number of SNPs doubled on the Version 2 array. Further phenotyping and genotyping of the NAM populations will allow the construction of high density genetic maps containing quantitative trait loci.

Correlation and Path Coefficient Analyses of Cowpea (&amp;lt;i&amp;gt;Vigna unguiculata&amp;lt;/i&amp;gt; L.) Landraces in Ethiopia

Understanding the nature and extent of association between yield and yield related traits is the prerequisite study for any underutilized crop improvements of sustainable genetic enhancement. However, there is a lack of sufficient information on seed yield and related trait correlation and path coefficient analysis of cowpea in Ethiopia. To fill the existing knowledge gap, the present study was conducted to determine the nature and extent of phenotypic and genotypic correlation and path coefficient analysis among 18 quantitative traits. A total of 324 cowpea landraces were tested in 18 × 18 simple lattice design at Melkassa Agricultural Research Center and Miesso sub center during 2016 cropping season. The magnitude of genotypic correlations was higher than phenotypic correlations in most traits at both locations; this implies that the traits under consideration were genetically controlled. Seed yield was positively and highly significantly correlated with most of the traits at phenotypic and genotypic levels, indicating the presence of strong inherited association between seed yield and the other 17 traits. Almost all traits genotypic direct and indirect effects were higher than the phenotypic direct and indirect effects; this indicated that the other traits had a strong genetically inherited relationship with seed yield. Genotypic path coefficient analysis revealed that days to flowering, biomass and harvest index at Miesso, and seed thickness, plant height, days to maturity and biomass at Melkassa had relatively high positive direct effect on seed yield. However, seed width and hundred seed weight had exerted negative direct effect on seed yield at each location. Phenotypic path coefficient analysis showed that biomass and harvest index had exerted high positive direct effect on seed yield at both locations. From these results it can be concluded from this study that seed yield in cowpea can be improved by focusing on traits pod length, seed length, seed thickness, seed width, biomass and harvest index at both locations. The information obtained from this study can be used for genetic enhancement of cowpea thereby developing high yielding varieties.

Genetic analysis of the Lf1 gene that controls leaflet number in soybean.

A high-resolution genetic map that was constructed for the Lf1 -residing region will provide valuable information for map-based cloning and genetic improvement efforts in soybean. Changes in leaf architecture as photosynthesis factories remain a major challenge for the improvement of crop productivity. Unlike most soybeans, which have compound leaves comprising three leaflets, the soybean Lf1 mutant has a high frequency of compound leaves with five leaflets in a partially dominant manner. Here, we generated a fine genetic map to determine the genetic basis of this multifoliolate leaf trait. A five-leaflet variant Dusam was found in a recently collected landrace cultivar. Phenotypic data were collected from the F2 population of a cross between the Dusam and three-leaflet cultivar V94-5152. The mapping results generated using public markers indicated that the five-leaflet determining gene in Dusam is an allele of the previously studied Lf1 gene on chromosome 8. A high-resolution map delimited the genomic region controlling the leaflet number trait to a sequence length of 49kb. AP2 domain-containing Glyma.08g281900 annotated in this 49kb region appeared to be a strong candidate for the Lf1-encoding gene, as members of the AP2-type transcription factor family regulate lateral organ development. Dusam additionally exhibits visually distinct phenotypes for shattering and seed-coat cracking traits. However, the two traits were clearly unlinked to the Lf1 gene in our mapping population. Interestingly, the mapping results suggest that the Lf1 gene most likely exerts a pleiotropic effect on the number of seeds per pod. Thus, our results provide a strong foundation towards the cloning of this compound leaf development gene and marker-assisted selection of the seeds per pod trait.

Phenotypic diversity and evaluation of fresh pods of cowpea landraces from Southern Europe.

Cowpea fresh pods are consumed as green vegetables in many countries in Southern Europe. Among cowpea cultivated material, a relatively large number of landraces can be found, maintaining species genetic diversity. To assess the value of these landraces in breeding programs, the characterization and estimation of diversity levels is therefore required. In the present study, an estimation of the diversity and evaluation of cowpea landraces originating from Portugal, Spain and Greece, in terms of their fresh pod traits, was performed, aiming to assist with the problem of low cowpea production in Southern Europe. A notable mean total phenotypic diversity (HT = 0.57) was observed in the whole collection. The Spanish cv. - gr. unguiculata collection exhibited the highest value of total phenotypic diversity (0.56). Landraces did not differ significantly from each other regarding the three countries of origin. Landraces such as Cp4906, Vg60 and BGE038478 presenting higher values of some traits studied could contribute to the breeding of new cowpea varieties for fresh pod production. Positive correlations were observed, indicating the feasibility of breeding for preferable traits regarding fresh pod consumption. The present study has revealed a wide diversity among and within cowpea landraces that could enhance fresh pod production in South European countries. © 2017 Society of Chemical Industry.