Seed Size Research Articles

Multi-Omics Profiling Identifies Candidate Genes Controlling Seed Size in Peanut.

Seed size is the major yield component and a key target trait that is selected during peanut breeding. However, the mechanisms that regulate peanut seed size are unknown. Two peanut mutants with bigger seed size were isolated in this study by 60Co treatment of a common peanut landrace, Huayu 22, and were designated as the "big seed" mutant lines (hybs). The length and weight of the seed in hybs were about 118% and 170% of those in wild-type (WT), respectively. We adopted a multi-omics approach to identify the genomic locus underlying the hybs mutants. We performed whole genome sequencing (WGS) of WT and hybs mutants and identified thousands of large-effect variants (SNPs and indels) that occurred in about four hundred genes in hybs mutants. Seeds from both WT and hybs lines were sampled 20 days after flowering (DAF) and were used for RNA-Seq analysis; the results revealed about one thousand highly differentially expressed genes (DEGs) in hybs compared to WT. Using a method that combined large-effect variants with DEGs, we identified 45 potential candidate genes that shared gene product mutations and expression level changes in hybs compared to WT. Among the genes, two candidate genes encoding cytochrome P450 superfamily protein and NAC transcription factors may be associated with the increased seed size in hybs. The present findings provide new information on the identification and functional research into candidate genes responsible for the seed size phenotype in peanut.

Eucalyptus citriodora, E. phaeotricha and E. propinqua seeds subjected to classification by sieves

Seeds’ qualities are influenced by several factors such as the density and size of seeds. The aim of this study was to evaluate the physical and physiological quality of Corymbia citriodora, E. phaeotricha and E. propinqua seeds that were subjected to classification by sieve. The seeds passed through sieves that retained the following sizes: C. citriodora (2.00; 1.68; 1.41; 1.19; 1.00 mm), E. phaeotricha (1.41; 1.19; 1.00; 0.84 mm) and E. propinqua (1.00; 0.84; 0.71; 0.59 e 0.50 mm). The tests of retention percentage, physical purity, germination, first count of germination, germination speed index and average germination time were performed. The design used was randomized with four replications and five treatments for C. citriodora and E. propinqua, and four treatments for E. phaeotricha, due to the number of sieves that retained seeds. The data were submitted to analysis of variance by the F test. When significant, the statistics related to the classification of seeds by sieves were compared using the Tukey test with 5% probability. The use of sieve classification is effective for the separation of seeds with high physical and physiological quality. C. citriodora with a seed size of 1.41 to 2.00 mm have maximum physical and physiological quality and can be pelleted. For E. phaeotricha and E. propinqua, seeds with a size of 1.19 to 1.41 mm and 0.84 to 1.00 mm, respectively, have the highest physical and physiological quality.

Functional Conservation and Divergence of MOS1 That Controls Flowering Time and Seed Size in Rice and Arabidopsis.

The heading date and grain size are two essential traits affecting rice yield. Here, we found that OsMOS1 promotes rice heading and affects its grain size. Knocking out OsMOS1 delayed heading, while the overexpression of OsMOS1 promoted heading in rice under long-day conditions. The transcriptions of the heading activators Ehd1, Hd3a, and RFT1 were decreased and the heading repressor Hd1 was increased in the osmos1 mutant. Conversely, the overexpression of OsMOS1 promoted the expressions of Ehd1, Hd3a, and RFT1, but inhibited the expression of Hd1. This suggests that OsMOS1 may control heading in rice by modulating the transcriptions of Ehd1, Hd3a, RFT1, and Hd1. In addition, knocking out OsMOS1 led to larger grains with longer grain lengths and higher grain weights. The seed cell size measurement showed that the cell lengths and cell widths of the outer glume epidermal cells of the osmos1 mutant were greater than those of the wild type. Furthermore, we also found that the overexpression of OsMOS1 in the Arabidopsis mos1 mutant background could suppress its phenotypes of late flowering and increased seed size. Thus, our study shows a conserved function of MOS1 in rice and Arabidopsis, and these findings shed light on the heading and seed size regulation in rice and suggest that OsMOS1 is a promising target for rice yield improvement.

KAJIAN TEKNIS PENDEDERAN IKAN KERAPU CANTANG (Epinephelus fuscoguttatus >< Epinephelus lanceolatus) SECARA INTENSIF DI BPBAP SITUBONDO

Grouper production in Indonesia can be supported by hybridization technology which can produce grouper species with relatively faster growth and more resistance to disease. Cantang grouper is a type of grouper fish that was engineered by crossbreeding between female tiger grouper (Epinephelus fuscoguttatus) and male grouper Kertang (Epinephelus lanceolatus). The purpose of this study was to determine the stages and technology of nursery grouper Cantang which was carried out at BPBAP Situbondo. The method used in this research is the method of observation, participation, and interviews. The primary data needed in this study are data on infrastructure, data on the number and size of seeds, feed management, water quality management, and harvesting. The data is presented with a descriptive method by discussing the data that has been obtained compared to the theories that have developed at this time. The results of this study indicate that cantang grouper nursery activities start from tank preparation, water filling, seed selection and distribution, feed management, water quality, fish pest and disease control, grading, and harvesting of cantang grouper seeds. During the practice period, the seeds were spread from hatcheries with a stocking density of 3000 to 5000 individuals in one tank with a size of 4 x 2.5 x 1 m, or the equivalent of 300 to 500 individuals/m3. The distribution of seeds is carried out after the acclimatization process, namely the adaptation process before releasing the seeds. After the seeds are removed, the tub is given an antiseptic to prevent disease in the seeds. There are several factors that can affect the growth rate of seeds, namely water quality management and feeding. During the maintenance period, a flowing water system is used, so that the water used is continuously renewed. In the morning, the seeds are flushed and soaked using fresh water, with the aim of releasing mucus on the seeds so as to reduce the potential for disease outbreaks. Nursery grouper at BPBAP Situbondo can run optimally by paying attention to the stages of cultivation, especially in the feed management and water quality management.

Evaluation of Agronomic Performance of Mustard (Brassica juncea L.) Hybrids under Agro-climatic Conditions of Prayagraj, (U.P), India

Field experiments were carried out at the Crop Research Farm, Department of Agronomy, SHUATS, Prayagraj (U.P) during Rabi 2021. The soil of experimental plot was sandy loam in texture, nearly neutral in soil reaction (pH 7.1), low in organic carbon (0.36%), available N (171.48 kg/ha), available P (15.2 kg/ha) and available K (232.5 kg/ha). The hybrids were sown. The research was laid out in Randomized Block Design with ten treatments each replicated three times. In that study the experiment recorded significant effect in M8 for Plant height (173.97), Plant dry weight (38.97), Number of secondary branches /plant (18.87), Number of siliqua/plant (475.27), Number of seeds/siliqua (13.64), Seed Yield (2507.54), Stover Yield (3686.24), Test weight (5.80), Seed size (2.75). However, Number of primary branches/plant (8.1) in M5, length of siliqua /plant (5.65 cm) in M6. Crop Growth Rate (22.08) in M7, Relative Growth Rate (0.17) in M-7, Days taken for 50% flowering in M2 (32.78) and Harvest Index (42.17) in M9 were observed.
 At the same time higher gross returns (Rs162990.1/ha), net return (Rs113677.1/ha) and benefit cost ratio (2.305) was obtained in M8 hybrid.

Developing Genetic Engineering Techniques for Control of Seed Size and Yield.

Many signaling pathways regulate seed size through the development of endosperm and maternal tissues, which ultimately results in a range of variations in seed size or weight. Seed size can be determined through the development of zygotic tissues (endosperm and embryo) and maternal ovules. In addition, in some species such as rice, seed size is largely determined by husk growth. Transcription regulator factors are responsible for enhancing cell growth in the maternal ovule, resulting in seed growth. Phytohormones induce significant effects on entire features of growth and development of plants and also regulate seed size. Moreover, the vegetative parts are the major source of nutrients, including the majority of carbon and nitrogen-containing molecules for the reproductive part to control seed size. There is a need to increase the size of seeds without affecting the number of seeds in plants through conventional breeding programs to improve grain yield. In the past decades, many important genetic factors affecting seed size and yield have been identified and studied. These important factors constitute dynamic regulatory networks governing the seed size in response to environmental stimuli. In this review, we summarized recent advances regarding the molecular factors regulating seed size in Arabidopsis and other crops, followed by discussions on strategies to comprehend crops' genetic and molecular aspects in balancing seed size and yield.

Size–Number and Shape Distribution of Buried Seeds in Soil in a Field Not Cultivated for More Than 10 Years

Seeds act as reserves for plant dispersion in time and their burial in soil plays an essential role in preventing or reducing losses. Two hypotheses regarding the depth distribution of seeds in soil were investigated. One states that the burial of small seeds is restricted to shallower depths than large seeds. The other states that seed shape is important to burial. The fraction of seeds located at depths allowing viable non-photosynthetic growth was also investigated in relation to size and shape. Cores of 20 cm depth were taken from soil with an auger, divided in eight fractions of equal length and sorted through a series of ten sieves, and viable spherical and non-spherical seeds were separately counted. Burial was evaluated by the symmetry of depth–number distributions fitted by Weibull equations. The maximum depth for successful germination and emergence was calculated by combining Weibull equations with published or original material on the relationship between the volume and mass of seeds, and the maximum elongation of hypocotyls in soil. The burial of smaller seeds was found to be restricted to shallower depths, but in larger seeds, size itself appeared to be an unsurmountable barrier to burial. Smaller spherical seeds buried at shallower depths than smaller non-spherical seeds, their number decreasing monotonically with depth, while the number of non-spherical seeds increased from the surface to 10.0–12.5 cm, decreasing thereafter. Larger seeds, spherical or non-spherical, had essentially the same depth–number distribution. In very small seeds (≤0.014 mm3; approximately 75% of the 29,740 total seeds), almost all spherical and non-spherical seeds were at depths at which non-photosynthetic viable growth would be unsustainable. This fraction reduced as the size of seeds increased, but it never fell below 50% and was only rarely less than 80%. The implications of these high values for aboveground recruitment are discussed in terms of the density of seeds.

RNA-Seq combined with population-level analysis reveals important candidate genes related to seed size in flax (Linum usitatissimum L.)

Seed size is a key determinant of crop yields. Understanding the regulatory mechanisms of seed size is beneficial for improving flax seed yield. In this study, the development of large flax seeds lagged behind that of small seeds, and 1,751 protein-coding genes were differentially expressed in early seeds, torpedo-stage embryos, and endosperms of CIli2719 and Z11637 using RNA sequencing. Homologous alignment revealed that 129 differentially expressed genes (DEGs) in flax were homologous with 71 known seed size-related genes in Arabidopsis thaliana and rice (Oryza sativa L.). These DEGs controlled seed size through multiple processes and factors, among which phytohormone pathways and transcription factors were the most important. Moreover, 54 DEGs were found to be associated with seed size and weight in a DEG-based association study. Nucleotide diversity (π) analysis of seed size-related candidate DEGs by homologous alignment and association analysis showed that the π values decreased significantly during flax acclimation from oil to fiber flax, suggesting that some seed size-related candidate genes were selected in this acclimation process. These results provide important resources and genetic foundation for further research on seed size regulation and seed improvement in flax.

Endosperm and Maternal-specific expression of EIN2 in the endosperm affects endosperm cellularization and seed size in Arabidopsis.

Seed size is related to plant evolution and crop yield and is affected by genetic mutations, imprinting, and genome dosage. Imprinting is a widespread epigenetic phenomenon in mammals and flowering plants. ETHYLENE INSENSITIVE2 (EIN2) encodes a membrane protein that links the ethylene perception to transcriptional regulation. Interestingly, during seed development EIN2 is maternally expressed in Arabidopsis and maize, but the role of EIN2 in seed development is unknown. Here, we show that EIN2 is expressed specifically in the endosperm, and the maternal-specific EIN2 expression affects temporal regulation of endosperm cellularization. As a result, seed size increases in the genetic cross using the ein2 mutant as the maternal parent or in the ein2 mutant. The maternal-specific expression of EIN2 in the endosperm is controlled by DNA methylation but not by H3K27me3 or by ethylene and several ethylene pathway genes tested. RNA-seq analysis in the endosperm isolated by laser-capture microdissection show upregulation of many endosperm-expressed genes such as AGAMOUS-LIKEs (AGLs) in the ein2 mutant or when the maternal EIN2 allele is not expressed. EIN2 does not interact with DNA and may act through ETHYLENE INSENSITIVE3 (EIN3), a DNA-binding protein present in sporophytic tissues, to activate target genes like AGLs, which in turn mediate temporal regulation of endosperm cellularization and seed size. These results provide mechanistic insights into endosperm and maternal-specific expression of EIN2 on endosperm cellularization and seed development, which could help improve seed production in plants and crops.

Quality assessment of jabuticaba seeds when subjected to different temperatures

Jabuticaba is a typically Brazilian fruit, which can be found from the extreme south to the extreme north of the country, it can be used for various purposes, its commercialization ranges from in natura, industrial, pharmaceutical and cosmetics. In view of the above, this work aims to evaluate the influence of the size of jabuticaba seeds of the rajada variety, its germination potential, total seedling size, root and shoot length and seedling emergence, using different treatments. The extraction of the seeds was carried out by manually kneading the fruits against a flat and firm surface of a bench, so that they broke and exposed their seeds, soon after the mucilage was removed manually as well. After pulping, disinfestation was carried out using 1% sodium hypochlorite for three minutes, then triple washing with distilled water and arranged on paper towels, where they remained for 48 hours in the shade to remove excess moisture, separated according to diameters. To seeds to carry out the germination tests and the emergence speed index, when submitted to different treatments. In which it can be concluded that the size of the seed increases the germination potential of jabuticaba seeds, where larger seeds originate more vigorous seedlings, and should preferably be used for seedling production. The best treatment is the refrigerated one with a temperature of 5°C, as it presented a greater amount of seedlings throughout the days.

An enhancing effect attributed to a nonsynonymous mutation in SOYBEAN SEED SIZE 1, a SPINDLY-like gene, is exploited in soybean domestication and improvement.

Soybean (Glycine max) was domesticated from its wild relative Glycine soja. One-hundred-seed weight is one of the most important domesticated traits determining soybean yield; however, its underlying genetic basis remains elusive. We characterized a soybean seed size 1 (sss1) mutant featuring large seeds compared to its wild-type background. Positional cloning revealed that the candidate gene GmSSS1 encoded a SPINDLY homolog and was co-located in a well-identified quantitative trait locus (QTL)-rich region on chromosome 19. Knocking out GmSSS1 resulted in small seeds, while overexpressing GmSSS1/Gmsss1 induced large seeds. Modulating GmSSS1/Gmsss1 in transgenic plants can positively influence cell expansion and cell division. Relative to GmSSS1, one mutation leading to an E to Q substitution at the 182nd residue in Gmsss1 conferred an enhancing effect on seed weight. GmSSS1 underwent diversification in wild-type and cultivated soybean, and the alleles encoding the Gmsss1-type substitution of 182nd -Q, which originated along the central and downstream parts of the Yellow River, were selected and expanded during soybean domestication and improvement. We cloned the causative gene for the sss1 mutant, which is linked with a seed weight QTL, identified an elite allele of this gene for increasing seed weight, and provided new insights into soybean domestication and breeding.

P209 First report of Mycetoma due to Madurella fahalii from India

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM ObjectiveTo describe the first case report of Madurella fahalii from India.MethodsA 70-year-old non-diabetic man from Bhadrak Odisha who worked as a soldier in past came to us with a history of pus discharge containing black grains the size of mustard seeds from multiple sinuses in the posterior aspect of the thigh for last 5 years. He had been operated 2 years back for the same complaints, however, finding no relief he visited us. On examination, a depressed lesion measuring 10 × 10 cm, containing 6-8 sinuses which discharged pinkish yellow colored pus containing black grains measuring 0.5 × 1 cm was found on the posterior aspect of the thigh. The lesion was painless, doughy in consistency, and associated with enlarged and non-matted and non-tender inguinal lymph nodes measuring 2 × 2 cms. General physical examination and routine hematological laboratory examination revealed no abnormalities. Serological tests did not reveal the presence of HIV, Hepatitis B, or Hepatitis C infection. A clinical diagnosis of black grain mycetoma was made and the patient was sent to mycology laboratory for fungal culture. Black hard grains were found on KOH mount and culture on inhibitory mold agar grew a brown colony which diffused a brown pigment into the medium after 15 days of incubation. LPCB examination showed brown non-sporulating mold. DNA was extracted using phenol-chloroform isoamyl alcohol after grinding the mycelial mat in liquid nitrogen and subjected to PCR using ITS4 and ITS5 primers as described previously. The product was subjected to sanger sequencing and subjected to blast and it showed 99.45% similarity to M. fahalii (MF980633). The patient was started on Itraconazole in lieu of voriconazole as the patient could not afford the drug. While there is no reduction in the size of the lesion the patient reported symptomatic relief and is still on follow-up.ConclusionTo the best of our knowledge this is the first case of Mycetoma due to M. fahalii from India.

Formation of acrylamide during the roasting of chia seeds (Salvia hispanica L.)

Chia is a novel food rich in health-promoting constituents. There is concern regarding the formation of process contaminants when subjected to thermal processing. Acrylamide formation in chia seeds under different roasting conditions (160–200 °C/5–30 min) and formats (whole seeds and ground seeds) was investigated. Acrylamide increased with the intensity of the thermal treatment until a maximum at 180 °C/15 min where levels of precursors were significantly reduced. The fate of acrylamide formation also depended on the physical integrity of the chia seed. Acrylamide formed rapidly on the coat of the seed but represents only 20–25 % of the total. Acrylamide was generated progressively in the inner part of the cell and efficiently retained by the pericarp. The particle size and integrity of chia seeds should be considered in food applications subjected to thermal treatment and grinding or the addition of ground seeds should be revised to reduce the exposure of acrylamide to consumers.

Effects of drought-tolerant grapevine rootstocks on the mineral contents and fatty acid compositions of grape seeds

BACKGROUND: As the interest in foods with positive effects on human health has increased in recent decades, the importance of the mineral contents and oil compositions of grape seeds has been better understood. However, research on grape seeds to date has largely focused on effects on health and the usability of grape seeds in the food industry and animal feeds. In agricultural research, grape seeds have generally been evaluated as a source of genes in breeding new varieties and as propagation material. OBJECTIVE: Unlike previous studies, this study not only investigates the effect of variety on the changes of pomological properties, fatty acid compositions, and oil, protein, and mineral contents of grape seeds; it also aims to determine the effects of grape rootstocks and growing seasons on those changes. METHODS: The seeds of five grape varieties (Red Globe, Trakya Ilkeren, Ata Sarisi, Hatun Parmagi, and Horoz Karasi) grafted onto drought-tolerant grape rootstocks (1103P and 110R) were analyzed during the growing seasons of 2017 and 2018. RESULTS: Seed size, moisture and oil contents, major fatty acids (palmitic, oleic, and linoleic), and levels of saturated fatty acids, monounsaturated fatty acids, unsaturated fatty acids, and boron varied by variety, rootstock, and season. However, the effects of growing seasons and varieties on the seeds were not limited to these findings; effects were also seen for seed vitality, protein content, and N, K, Ca, and Fe levels of the seeds, among others. CONCLUSIONS: Genotype was found to be the main factor causing changes in the fatty acid compositions and mineral contents of grape seeds. When the factors that we investigated were ordered based on the changes they caused for seeds in general, the sequence that appeared was genotype > growing season > grape rootstock.

Transcriptome Analysis and Gene Expression Profiling of the Peanut Small Seed Mutant Identified Genes Involved in Seed Size Control.

Seed size is a key factor affecting crop yield and a major agronomic trait concerned in peanut (Arachis hypogaea L.) breeding. However, little is known about the regulation mechanism of peanut seed size. In the present study, a peanut small seed mutant1 (ssm1) was identified through irradiating peanut cultivar Luhua11 (LH11) using 60Coγ ray. Since the globular embryo stage, the embryo size of ssm1 was significantly smaller than that of LH11. The dry seed weight of ssm1 was only 39.69% of the wild type LH14. The seeds were wrinkled with darker seed coat. The oil content of ssm1 seeds were also decreased significantly. Seeds of ssm1 and LH11 were sampled 10, 20, and 40 days after pegging (DAP) and were used for RNA-seq. The results revealed that genes involved in plant hormones and several transcription factors related to seed development were differentially expressed at all three stages, especially at DAP10 and DAP20. Genes of fatty acid biosynthesis and late embryogenesis abundant protein were significantly decreased to compare with LH11. Interestingly, the gene profiling data suggested that PKp2 and/or LEC1 could be the key candidate genes leading to the small seed phenotype of the mutant. Our results provide valuable clues for further understanding the mechanisms underlying seed size control in peanut.

Comparative evaluation of quality properties of chickpea seed (Cicer arietinum L.) grown under different irrigation conditions by using machine learning

Chickpea is an important edible legume consumed worldwide because of rich nutrient composition. The physical parameters of chickpea are crucial attributes for design of processing and classification systems. In this study, effects of seven different irrigation treatments on size, shape, mass, and color properties of chickpea seeds were investigated, and machine learning algorithms were used to estimate mass and color attributes of chickpea seeds. The results showed that Multilayer Perceptron (MLP) had the greatest correlation coefficients for mass (0.9997) and chroma (0.9997). The MLP yielded better outcomes than Random Forest for both mass and color estimation. In terms of physical attributes, the best results were obtained in I1 (rainfed) and I5 (irrigation at 50% flowering and 50% pod fill) irrigation treatments. Additionally, single or couple irrigations at different physiological stages instead of full irrigation treatment might be sufficient to improve the physical attributes of chickpea.

QTL Analysis for Bread Wheat Seed Size, Shape and Color Characteristics Estimated by Digital Image Processing

The size, shape, and color of wheat seeds are important traits that are associated with yield and flour quality (size, shape), nutritional value, and pre-harvest sprouting (coat color). These traits are under multigenic control, and to dissect their molecular and genetic basis, quantitative trait loci (QTL) analysis is used. We evaluated 114 recombinant inbred lines (RILs) in a bi-parental RIL mapping population (the International Triticeae Mapping Initiative, ITMI/MP) grown in 2014 season. We used digital image analysis for seed phenotyping and obtained data for seven traits describing seed size and shape and 48 traits of seed coat color. We identified 212 additive and 34 pairs of epistatic QTLs on all the chromosomes of wheat genome except chromosomes 1A and 5D. Many QTLs were overlapping. We demonstrated that the overlap between QTL regions was low for seed size/shape traits and high for coat color traits. Using the literature and KEGG data, we identified sets of genes in Arabidopsis and rice from the networks controlling seed size and color. Further, we identified 29 and 14 candidate genes for seed size-related loci and for loci associated with seed coat color, respectively.

Assessment of Shelf-life and Efficacy of the Seed-Coating Delivery System of Biofertilizers in Maize

Film-coating of seeds is a widely accepted technology in agriculture for effectively protecting germinating seeds and seedlings against biotic and abiotic stresses and successfully delivering agro-chemicals, biomolecules, and bio-inoculants to the rhizosphere region. The present experiments explored the possibility of using hydroxypropyl methylcellulose (HPMC) and dextrin as film-coating agents for impregnating maize seed with four different biofertilizer strains. Azospirillum brasilense (Sp7), Bacillus megaterium var phosphaticum (Pb1), Paenibacillus mucilaginosus (KRB9), and Pseudomonas chlororaphis (ZSB15) were prepared as consortium containing an equimolar ratio of each strain. The in vitro growth experiment revealed that HPMC, dextrin, or a combination of both did not affect the growth of all four biofertilizers. When biofertilizer consortium was film-coated on maize seed using HPMC and dextrin as film-coating /binding and protecting agents, no apparent changes were observed in the size, shape, weight, and volume of maize seeds. The shelf-life study on film-coated maize seeds revealed that the microbial inoculants accounted for a one-log reduction (from 104 cells at initial to 103 cells after 3 months) when stored at low temperature. The pre-coated seeds with microbial-inoculants showed significant improvement in seedling growth. Hence, the film-coating of maize seed with microbial inoculants using HPMC and dextrin could be an effective delivery system for ensuring rhizosphere colonization of biofertilizers for sustainable maize cultivation.

Effect of Haulm Cutting, Size of Seed Tubers/Seed Pieces and Intra-Row Spacings on Tuber Yield and Economics of Potato Production

The field experiments were conducted during two consecutive rabi seasons (October – February) during 2019–20 and 2020–21 at ICAR-Central Potato Research Institute Regional Station, Gwalior, Madhya Pradesh, India located in west central plains of India. Highest emergence of potato plants was recorded with the planting of 40 g whole tubers. Growth attributes viz. plant height (58.6 cm) and number of compound leaves (56.7) were recorded highest with 40 g seed piece/whole tuber. Planting of 120 g seed tubers, 10 cm intra row spacing and 114 days haulm cut recorded highest number of small tubers i.e. 3,43,000 ha-1, 3,07,000 ha-1 and 3,26,000 ha-1, respectively. Highest total number of tubers was recorded at 114 DAP haulm cut (9,08,000 ha-1), planting of 120 g seed tubers (9,62,000 ha-1) and 10 cm intra row spacing (8,53,000 ha-1). Highest total tuber yield was recorded with 114 DAP haulm cut (59.1 t ha-1), 120 g planted seed tubers (55.5 t ha-1) and 20 cm intra row spacing (49.7 t ha-1). Highest cost of cultivation was recorded with the use of 120 g seed (Rs. 386483 ha-1) and intra row spacing of 10 cm ` 264261 ha-1. Highest net return (Rs. 364084 ha-1) was recorded with 114 DAP haulm cut, planting with 40g seed size tubers (` 329822 ha-1) and intra row spacing of 20 cm (Rs. 322499 ha-1). Highest benefit-cost ratio was recorded with 114 DAP haulm cut (2.6) planting with 20 g seed size tubers (3.3) and intra row spacing of 20 cm (2.8).

Experimental Evidence for Seed Metabolic Allometry in Barrel Medic (Medicago truncatula Gaertn.).

Seed size is often considered to be an important trait for seed quality, i.e., vigour and germination performance. It is believed that seed size reflects the quantity of reserve material and thus the C and N sources available for post-germinative processes. However, mechanisms linking seed size and quality are poorly documented. In particular, specific metabolic changes when seed size varies are not well-known. To gain insight into this aspect, we examined seed size and composition across different accessions of barrel medic (Medicago truncatula Gaertn.) from the genetic core collection. We conducted multi-elemental analyses and isotope measurements, as well as exact mass GC–MS metabolomics. There was a systematic increase in N content (+0.17% N mg−1) and a decrease in H content (–0.14% H mg−1) with seed size, reflecting lower lipid and higher S-poor protein quantity. There was also a decrease in 2H natural abundance (δ2H), due to the lower prevalence of 2H-enriched lipid hydrogen atoms that underwent isotopic exchange with water during seed development. Metabolomics showed that seed size correlates with free amino acid and hexoses content, and anticorrelates with amino acid degradation products, disaccharides, malic acid and free fatty acids. All accessions followed the same trend, with insignificant differences in metabolic properties between them. Our results show that there is no general, proportional increase in metabolite pools with seed size. Seed size appears to be determined by metabolic balance (between sugar and amino acid degradation vs. utilisation for storage), which is in turn likely determined by phloem source metabolite delivery during seed development.