Hard-coated Seeds Research Articles

Genetic analysis and QTL mapping of seed hardness trait in a soybean (Glycine max) recombinant inbred line (RIL) population

Seed hardness is a critical quality trait impacting both the suitability of soybeans for consumption and their processing. The primary objective of this study was to explore the genetic foundations underlying seed hardness in soybeans. A 234 recombinant inbred line (RIL) population was evaluated for seed hardness across three years (2015 in Gansu, 2016, and 2017 in Hainan). Notably, the parent varieties, Zhonghuang35 and Jindou21, displayed significant differences in seed hardness. Also, the RIL population exhibited a wide range of genetic variation in seed hardness, with coefficients of variation between 70.53 % and 94.94 %. The frequency distribution of this trait conformed to a relatively normal distribution, making it suitable for QTL analysis. Six QTLs associated with seed hardness were identified with three located on chromosome 2 and three on chromosome 16. The major QTL, qHS-2-1, consistently exhibited the highest percentage of PVE and LOD in Gansu 2015, Hainan 2016, and Hainan 2017, suggesting its central role in determining seed hardness. Further investigation revealed four genes within the qHS-2-1 interval potentially related to seed hardness. GO enrichment analysis provided insights into their functions, including factors such as Glyma.02G307000, a pectin lyase-like superfamily protein, which could influence seed hardness through its role in pectin lyase enzyme activity. Expression analysis of these candidate genes demonstrated significant differences between the two parent varieties, further highlighting their potential role in seed coat hardness. This study offers valuable insights into the genetic mechanisms governing soybean seed coat hardness, providing a foundation for future research and crop improvement efforts.

Cookability of 24 pea accessions-determining factors and potential predictors of cooking quality.

Cooking time and cooking evenness are two critical quantities when determining the cooking quality (termed cookability) of pulses. Deciphering which factors contribute to pulse cookability is important for breeding new cultivars, and the identification of potential cookability predictors can facilitate breeding efforts. Seeds from 24 morphologically diverse pea accessions were tested to identify contributing factors and potential predictors of the observed cookability using a Mattson cooker. Size- and weight-based measures were recorded, and seed-coat hardness was obtained with a penetrometer. Content of protein, starch (amylose and amylopectin), and phytate was also determined. Distinct differences were found between wrinkled and non-wrinkled seeds in terms of water-absorption capacity, seed-coat hardness, and plunger-perforation speed. Potential predictive indicators of cooking time and cooking evenness were seed-coat hardness (r = 0.49 and r = 0.38), relative area gained (r = -0.59 and r = -0.8), and percentage of swelled seeds after soaking (r = -0.49 and r = -0.58), but only for non-wrinkled seeds. Surprisingly, the coefficients of variation for the profile area of both dry and swelled seeds appeared to be potential cookability predictors of all pea types (correlation coefficients around r = 0.5 and supported by principal component analysis). However, no strong correlation was observed between cookability and protein, starch, or phytate levels. Using three types of instruments together with chemical components enabled the identification of novel cookability predictors for both cooking time and cooking evenness in pea. This study unveils the diverse quantitative aspects influencing cookability in pea. Considering both cooking time and cooking evenness, as well as seed-coat hardness, underscores the multifaceted nature of pulse cookability and offers important insights for future breeding strategies to enhance pea cultivars. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of H2SO4, GA3, and cold stratification on the water content, coat composition, and dormancy release of Tilia miqueliana seeds

IntroductionTilia miqueliana is an endemic species whose population is declining. The permeability barrier and mechanical constraint of the pericarp (seed coat) are important causes of its seed dormancy. Although there has been considerable research on this subject, questions remain regarding how the permeability barrier and mechanical constraint of the seed coat are eliminated during dormancy release and how water enters the seed. Therefore, protecting the species by improving its germination/dormancy breaking in the laboratory is urgentMethodsIn this study, the changes in the cellular structure, mechanical properties, and components of the Tilia miqueliana seed coat after an H2SO4-gibberellic acid (GA3) treatment were analyzed during dormancy release. Various analyses (e.g., magnetic resonance imaging, scanning electron microscopy, and paraffin section detection) revealed the water gap and water channel.ResultsThe H2SO4 treatment eliminated the blockage at the micropyle and hilum of the seeds. Water entered the seeds through the water gap (micropyle) rather than through the hilum or seed coat, after which it dispersed along the radicle, hypocotyl, and cotyledon to the endosperm. During the cold stratification period, the cellular structure was damaged and an increasing number of holes appeared on the inner and outer surfaces of the seed coat. Vickers hardness tests showed that GA3 decreased the seed coat hardness. Additionally, the seed coat lignin and total phenol contents continuously decreased during the cold stratification period. Notably, the Liquid chromatography–mass spectrometry (LC–MS) analysis of the seed coat detected polyethylene glycol (osmoregulator), which may have destabilized the water potential balance inside and outside the seed and increased the water content to levels required for germination, ultimately accelerating seed dormancy release.DiscussionThis sophisticated and multi-level study reveals how H2SO4 and GA3 eliminate the permeability barrier and mechanical constraints of the seed coat during dormancy release of Tilia miqueliana seeds. This will be beneficial to artificially assist the natural regeneration and population expansion of Tilia miqueliana.

The Effect of Phosphorus Fertilization on Transcriptome Expression Profile during Lentil Pod and Seed Development

Seed coat hardness and water permeability, which are determined by the accumulation of tannins through the phenylpropanoid pathway in the seed, are important lentil quality characteristics. The impact of seeds’ developmental stage and phosphorus (P) fertilization levels on tannin accumulation is still under research. Through RNA sequencing, this study explored the effect of three P treatments (P0, 6 mg kg−1; P1, 15 mg kg−1; and P2, 21 mg kg−1) and three seed maturity stages (S1, immature 2 mm seed in a flat pod; S2, fully developed seed within the pod; and S3, mature seed at the beginning of the pod’s discoloration) on lentil gene expression. The key findings highlighted a significant influence of the seed maturity stage on phenylpropanoid genes, with S1 displaying the highest expression levels, and on phosphorus-related Gene Ontology (GO) terms that presented the highest number of downregulated genes in the S3 to S1 comparison. P exhibited a targeted effect on the flavanone 3-hydroxylase (F3H) and flavonol synthase (FLS) genes and specific gene clusters, as shown by the differential gene expression analysis. This study investigates the molecular mechanisms related to phosphorus fertilization and seed maturity stages that influence tannin accumulation, offering valuable information for the enhancement of lentil product quality through breeding programs.

Imbibition and Germination of Seeds with Economic and Ecological Interest: Physical and Biochemical Factors Involved

In this study, we describe the seed imbibition of 14 different species, from crop, forest, and native species potentially able to recover landscapes and form sustainable green cities. Seed imbibition is a fundamental physical and physiological process for reactivating metabolism and hydrolytic enzymes that will provide seed germination. We verified that the water imbibition is more closely governed by differences between osmotic potential (Ψw) and surrounding media than seed weight or seed hardness. In turn, seeds of Spondias tuberosa and Euterpe oleracea that have a Ψw of −75 MPa and a tegument as hard as 200 N imbibed an insignificant volume of water. Consequently, their metabolism is not significantly affected comparing the non-imbibed seeds and 120-h-imbibed seeds. Malpighia glabra or Annona squamosa also show very negative Ψw where the seed coat hardness is less evident; however, in these species, the seed imbibition increased the respiration rate by eight- to ten-fold in 120 h-imbibed-seeds than non-imbibed-seeds. The high-water absorption in M. glabra (49%) seems to be due to its highly convoluted tissue in the dry state, while in J. curcas and A. squamosa the presence of a highly porous seed coat must have favored seed imbibition and prompt metabolic reactivation.

Physicochemical basis of resistance in certain green gram genotypes to pulse bruchid, Calloso bruchus chinensis (L.)

A study was conducted to know the influence of physical and biochemical parameters on development of the pulse bruchid in green gram at RARS, Lam during 2017-18. The physical parameters of seed viz., colour, shape, surface texture, seed length and width, seed coat hardness and 100 seed weight and biochemical parameters such as protein content, phenol content and total sugars were evaluated for twelve genotypes of greengram. The greengram genotypes with smooth texture, oblong or globose shape and light coloured seed might be less preferred by the pulse bruchid for egg laying. The data showed that genotypes having low sugar and protein contents and high phenol content were resistant to pulse bruchid. The correlation studies showed that biological parameters i.e., number of eggs, adult emergence and growth index had significant positive association with protein content, sugar content, moisture content and electrical conductivity and negative correlation phenol content, 100 seed weight and seed coat hardness. In contrast, mean development period had negative association with protein content, sugar content, electrical conductivity and moisture content and positive correlation with phenol content, 100 seed weight and seed coat hardness. Multiple linear regression studies revealed that all the physical and biochemical properties of seed together were contributing to a large and significant variation (65 to 87 %) in growth parameters of pulse bruchid.

Polyphenols leaching and seed dormancy in carob (Ceratonia siliqua L.) in relation to hot water treatment

Carob (Ceratonia siliqua L.) is a relevant element of the Mediterranean spontaneous vegetation. Moreover, it is useful in reforestation, and it is currently re-valued for sustainable agriculture in dryland areas. However, the difficulties tied to carob propagation (mainly seed dormancy) hamper its large-scale cultivation. In this paper, the effects of four seed treatments (no treatment [control], soaking at 70 °C and 90 °C in water, or in 96% sulphuric acid) on five carob genotypes germination were studied. As compared to the very low germination of untreated seeds (0–13% germination), sulphuric acid (93–100% germination) and 90 °C water soaking (from 72 to > 90% germination in four out the five genotypes) were effective in promoting germination. Soaking at 90 °C resulted in the leaching of a higher amount of total polyphenols from the genotypes seed coat as compared to soaking at 70 °C. A significant correlation (0.75**) was ascertained between polyphenol leaching of the different genotypes and germination. These results suggest that dormancy in this species is not primarily associated with seed coat hardness, as it is generally thought, but also with the release of polyphenols. Polyphenols determination of the dormant and the few non-dormant seeds of the different genotypes also seem to confirm this hypothesis since these last showed an almost halved total polyphenols content (on average 17.0) as compared to dormant ones (34.8 mg g−1 of seed FW). Further studies may determine the polyphenols involved, but also assess new, easier to carry out, seed treatments. The important role of the galactomannans on seed germination of carob is also discussed. Finally, similar studies may enhance the knowledge of dormancy processes in other Fabaceae species whose germination is positively affected by hot water treatments.

Comparative analyses of extreme dry seed thermotolerance in five Cactaceae species

Extreme dry seed thermotolerance is an important trait in the context of plant adaptation to desert environments, yet the mechanisms underlying interspecific differences in seed extremophily remain little understood. Seeds of a selection of desert Cactaceae species (Leucostele litoralis, Leucostele skottsbergii, Eulychnia breviflora, Eriosyce paucicostata and Ferocactus wislizeni) were subjected to comparative biophysical and molecular analyses prior to (mature dry seeds) and post (imbibing seeds) heat treatment (103 °C).Biophysical properties of mature dry seeds, such as seed coat hardness and thermal transitions, were characterized through puncture force resistance and differential scanning calorimetry, respectively. In addition, the protein composition of dry seeds was compared by 2-D electrophoresis and de novo sequencing. Finally, oxidative DNA damage repair and gene expression during seed imbibition were analysed via ELISA (8-oxo-dG levels) and comparative transcriptomics.Results revealed that enhanced dry seed thermotolerance could not be explained by seed coat hardness, seed thermal transitions or (ROS-induced oxidative) DNA damage repair. Comparative proteomic analysis showed that the majority of overlapping proteins were more abundant in relatively heat sensitive species, suggesting that higher basal levels of (stress) proteins do not underly improved heat resilience in Cactaceae. However, comparative transcriptomics during imbibition following heat stress detected consistent expression patterns of heat- and drying-responsive genes that correlated with dry seed thermotolerance. These patterns included upregulation of positive (HSP101/CLPB1, MGE2, MBF1c, HSFB2A, RPN1a, RPT2a, DEGP14/PARK13, XPO1A, MAIGO2/MAG2, CAMTA1, ADH1) and downregulation of negative (RCF3, VOZ1, FAD7, ZAT12, RNP1) heat and drought tolerance regulators.Thus, our comparative analyses of extremophile Cactaceae species suggest that higher dry seed thermotolerance is realised through enhanced recovery from heat stress during imbibition, which is a critical stage in the plant life cycle.

Factors Affecting Seed Germination and Establishment of an Efficient Germination Method in Sugar Pine (Pinus lambertiana Dougl.)

Mature sugar pine (Pinus lambertiana Dougl.) trees produce large amounts of viable seeds but have seed dormancy. In this study, we used three sugar pine genotypes, 8877, 9306, and 9375, to test seed germination response. Seed germination from local sources varied greatly, and germination percentages were poor. There was a large variation in seed size and seed weight among the genotypes. Seeds of 9375 and 9306 were significantly larger and heavier (30.7 and 28.8 g/100 seeds, respectively) than 8877 (23.6 g/100 seeds). Three types of seeds—intact seeds, hulled seeds, and naked embryos—were examined for germination. Intact seeds failed to germinate due to the physical restraint and water impermeability of the seed. Chemical scarification with 5 m hydrochloric acid and 5 m sodium hydroxide did not soften the hard seedcoat and also failed to induce any germination of intact seeds. Hulled seeds resulted in an extremely low germination percentage (≤5%) with abnormal seedling development even though the endosperm was water permeable. Germination of the hulled seeds was not increased by adding 1 mg·L−1 gibberellic acid to the culture medium. Artificial opening of the hulled seeds created by longitudinal or horizontal cuts on the endosperm after removal of the seedcoat to avoid physical restraint and allow air exchange also failed to improve germination, indicating that inhibitors related to germination were present in the endosperm. However, naked embryos of all three genotypes germinated rapidly and uniformly with 70% to 95% germination percentage regardless of cold stratification treatment. Our data indicate that sugar pine seeds from the current source did not have physiological dormancy of embryos themselves, but dormancy was imposed by the seedcoat and endosperm. Using the naked embryos as donor explants, we have successfully established an efficient in vitro culture system. The protocol described here can be applied for the tissue culture and genetic transformation of sugar pine.

Seed coat anatomy ofCercis chinensisand its relationship to water uptake

The hard seed coat of Cercis chinensis Bunge is an important factor of its dormancy. A study of the characteristics of water absorption is vital for understanding seed dormancy and germination. This investigation found that soaking in water at an initial temperature of 80 °C for 5 min was optimal for breaking the hardness of C. chinensis seeds. Scanning electron microscopy (SEM), dye-tracking, and blocking experiments were used to examine the major water entry sites and the relationship between water uptake and seed coat structure during C. chinensis seed imbibition. The SEM images showed that the seed coat consisted of three layers: epidermis, palisade, and sclereid. Special light line, vascular bundle, and counter-palisade layer structures were found in the side of the hilum. The blocking experiments showed that the hilar region was an important water absorption site because, if the region was not blocked, it showed the highest water absorption when imbibed for 3–12 h. However, all parts of the seed coat can absorb water if enough time is allowed after the seed coat hardness has been broken. The dye-tracking test showed that after 3 h water entered the seed only via the hilum fissure. Therefore, the hilum fissure acts as the initial site of water absorption. When more time was allowed, water moved more rapidly on the side with vascular bundles than on the opposite side.

Climate, and not fire, drives the phylogenetic clustering of species with hard-coated seeds in Mediterranean Basin communities

Hardseededness is a common trait in Mediterranean plant communities, although the origin of its selection is controversial. It may be a mechanism of persistence to fire temperatures, but could also form part of a gap-detecting mechanism to provide germination cues under arid conditions. To disentangle this, we studied the phylogenetic structure of plant communities against fire frequency and aridity gradients. The phylogenetic structure in Mediterranean Basin ecosystems was analysed for the hardseededness trait as a whole and was separated by the families composing this trait (Fabaceae and Cistaceae). This study focused on woody perennial species. The phylogenetic structure was also contrasted against soil classes. Hardseededness on the whole, and for the Fabaceae family alone, showed phylogenetic clustering as aridity increased. Cistaceae displayed the opposite pattern with phylogenetic clustering in most humid areas, together with a significant soil effect. Surprisingly, fire frequency had no influence in any case. This climate-driven phylogenetic clustering indicates that the hardseededness trait could confer some fitness advantage under dry conditions. For this reason, coexisting species were more closely related in the community with increasing aridity. This effect was especially evident for the Fabaceae family. These results shed some light on the evolutionary selection of this adaptive trait under Mediterranean conditions. Our results question the role of fire in the selection of the hardseededness trait in Mediterranean Basin ecosystems and indicates that climate is the most important factor. Therefore, we should be cautious in assigning to fire a preponderant role in the selection of some plant traits.

Pre-Sowing Treatments Accelerate Germination Percent for Restoration of Fourteen Threatened Tree Species in Bangladesh

Ecologically valuable native tree species are becoming threatened due to deforestation, forest fragmentation and preference of fast-growing exotics than the native ones in plantation. One of the main reasons for the preference of exotic species than the native ones is its higher rate of germination and rapid growth. The effect of different pre-sowing treatments was studied on fourteen threatened tree species of Bangladesh to find out the appropriate treatments for speed up germination rate and initial seedling growth. These species are ecologically valuable multipurpose indigenous trees of Bangladesh. Methanol extract of Castanopsis indica leaves could decrease the tumor Ehrlich Ascites Carcinoma volume and weight. Lophopetalum wightianum is a globally threatened tree species. Hard coated seeds of Canarium resiniferum, Castanopsis indica, Protium serratum, Quercus acuminata and Vitex peduncularis were treated with sand paper, nicking, normal water, hot water, H2SO4 and HCl. Soft coated seeds of Brownlowia elata, Dichopsis polyantha, Firmiana colorata, Lophopetalum wightianum, Pterospermum acerifolium, Pterospermum semisagittatum, Pterygota alata, Schleichera oleosa and Sterculia villosa were sown in polybags, propagator house and nursery bed in normal, flat and 45o angle positions. Among all hard-coated seeds, Castanopsis indica showed significantly higher germination percentage (67%) after seeds treated with sandpaper in comparison to control (25%). Soft-coated seeds of Lophopetalum wightianum showed significantly higher germination percentage (90%) among all studied species when sown in propagator house, whereas in natural condition it provides only 26% germination rate. This paper will help to restore ecologically valuable threatened species.

Fluidized bed and microwave-assisted fluidized bed drying of seed grade soybean

Soybean seeds were dried under fluidized bed drying (FBD) and microwave-assisted fluidized bed drying (MFBD) conditions in this study. During FBD, the effect of air temperature (30–50 °C) and air velocity (1–7 m/s) on drying parameters and some quality attributes (viz. vigor index, germination, fissure and cracking percentage, and seed coat hardness) of dried seeds were analyzed through response surface method. In MFBD, the effect of air temperature and microwave power levels was studied on the drying kinetics and quality parameters at a constant air velocity of 7 m/s. A face-centered central composite design with three levels of each variable was used to generate models for the responses. The study showed that the drying of seeds under two methods resulted in high germination percentage (>77%) and low cracking percentage (<20%). However, an increase in the germination time as depicted through the vigor index was found in the dried seeds. Also, the seed coat was highly damaged during drying and resulted in fissures (∼100%) and a decrease in hardness of the seed coat.

Archaeobotanical proxies and archaeological interpretation: A comparative study of phytoliths, pollen and seeds in dung pellets and refuse deposits at Early Islamic Shivta, Negev, Israel

This article presents a systematic methodological comparison of three archaeobotanical proxies (phytoliths, pollen and seeds) applied to an assemblage of dung pellets and corresponding archaeological refuse deposits from Early Islamic contexts at the site of Shivta. We set out with three main methodological questions: one, to evaluate the relative input of botanical remains from dung in refuse assemblages; two, to evaluate each archaeobotanical dataset and to test whether they are comparable, complementary or contradictory in their interpretations from dung; and three, infer herding practices at the site during the Early Islamic period. Our findings show that ovicaprine dung accumulated in Early Islamic Shivta during at least two periods: mid-7th–mid-8th centuries CE, and late-8th–mid-10th centuries CE. Methodologically, we see incomplete and incompatible reconstructions arise when each method is considered alone, with each proxy possessing its own advantages and limitations. Specifically, the amount of preserved seeds in dung pellets is low, which restricts statistical analysis and tends to emphasize small or hard-coated seeds and vegetation fruiting season; yet this method has the highest taxonomic power; pollen preserves only in uncharred pellets, emphasizes the flowering season and has an intermediate taxonomic value; phytoliths have the lowest taxonomic value yet complete the picture of livestock feeding habits by identifying leaf and stem remains, some from domestic cereals, which went unnoticed in both seed and pollen analyses. The combined archaeobotanical reconstruction from samples of the mid-7th–mid-8th centuries suggests that spring-time herding at Shivta was based on free-grazing of wild vegetation, supplemented by chaff and/or hay from domestic cereals. For the late-8th–mid-10th century samples, phytolith and pollen reconstruction indicates autumn-winter free-grazing with no evidence of foddering. Unlike the dung pellets, macrobotanical remains in the refuse deposits included domestic as well as wild taxa, the former mainly food plants that serve for human consumption. Plant remains in these refuse deposits originate primarily from domestic trash and are only partially composed of dung remains. The significance of this study is not only in its general methodological contribution to archaeobotany, but also to lasting discussions regarding the contribution of dung remains to archaeological deposits used for seed, pollen and phytolith analyses. We offer here a strong method for determining whether deposits derive from dung alone, are mixed, or absolutely do not contain dung. This has important ramifications for archaeological interpretation.

Effect of heat on seed germination and viability in species of Cistaceae

ABSTRACTBackground: Species of the Cistaceae family have hard-coated seeds and consequently require scarification for germination. It is widely assumed that the high temperature caused by fire is a scarifying agent that triggers seed germination in the Cistaceae. However, to date there is insufficient knowledge regarding species, populations and diverse variables associated with germination to consider such a fire trigger generally applicable.Aims: To test the relationship between exposure to fire and germination in 10 species of the Cistaceae family.Methods: We quantified after different heat treatments the germination and seed viability in 10 species of Cistus, Fumana, Halimium, Helianthemum and Tuberaria Final germination percentage, t50 and seed viability were determined.Results: Heat treatment increased germination in all except the species of Helianthemum; however, the rate of increase was dependent on species. Germination speed (t50) was less affected by heat than final germination, and seed viability did not decrease except for H. hirtum.Conclusions: Most of the species showed high tolerance and a positive response to heat although germination patterns were idiosyncratic of each species. This work evidences the wide range of germination responses to heat within Cistaceae, and consequently the differential role of fire within this plant family.

Effect of seed coating on germination of Ciliate Medick [Medicago ciliaris (L.) All.] and Snail Medick [Medicago scutellata (L.) Mill.

A study was conducted in the Seed Technology Laboratory of Department of Field Crops, Pasture and Forage Crops Section, Faculty of Agriculture of Ege University, Turkey. Aim of the study was to remove the seed coat hardness by various treatments of Ciliate and Snail Medick to enhance germination which is significant in terms of agronomical handicaps of sowing small seeded legumes under field conditions. Pre-sowing seed treatments (Control, scarification by sandpaper, acid treatment with 95.0-98.0% H2SO4 for 5-10-15 minutes and soaking in water for 24-48 hours) were practiced on these small seeded legumes. All observations and tests were conducted following ISTA regulations and notifications. Germination of tested seeds highly increased by acid treatment for 10-15 minutes duration, while scarification treatment provided favorable germination rates.

Effect of pre-sowing treatments and growing media on seed germination and seedling growth of Albizia lebbeck (L.) Benth

The seeds of Albizia lebbeck have been observed to exhibit physical dormancy due to presence of hard seed-coat. To overcome this problem, the seeds were subjected to seven pre-sowing treatments viz., T1-immersion of seeds in cold water for 12 h; T2-immersion of seeds in cold water for 24 h; T3-immersion of seeds in hot water (100 °C) and subsequent cooling at room temperature for 12 h; T4-immersion of seeds in hot water (100 °C) and subsequent cooling at room temperature for 24 h; T5-immersion of seeds in cold water for 12 h followed by immersion in hot water (100 °C) and allowed to cool for 1 h; T6-immersion of seeds in cold water for 24 h followed by immersion in hot water (100 °C) and allowed to cool for 1 h. Untreated seeds served as control (T0). Treatment T3 gave highest germination (96%) which was comparable with T5 (95 %), T4 (94 %) and T6 (93%). Nine growing media viz., T1: soil, T2: soil+sand (2:1), T3: soil+perlite (2:1), T4: soil+Farm Yard Manure (FYM) (2:1), T5: soil+vermicompost (2:1), T6: soil+sand+FYM (1:1:1), T7: soil+sand+vermicompost (1:1:1), T8: soil+perlite+FYM (1:1:1) and T9: soil+perlite+ vermicompost (1:1:1) were, also, studied for their effect on seedling growth of A. lebbeck. Among these media, maximum values of shoot length (23.82 cm), root length (21.14 cm), collar diameter (3.59 mm) and seedling quality index (0.350) were observed in T7.

Inheritance of fruit neck, rind and seed coat hardness, and seed coat colour in bottle gourd

Bottle gourd (Lagenaria siceraria (Molina) Standl.) is an edible, medicinal and decorative plant exhibiting wide genetic variation for fruit and seed characters, but it remains under-researched. This study assessed inheritance of fruit neck, fruit rind hardness, seed coat hardness and seed coat colour in bottle gourd, by crossing the egusi type with the calabash type. Results indicated that fruit neck is controlled by two genes, each with two alleles (N/n and R/r), with complementary gene action. Neckless fruit plants could be nnR−, N−rr or nnrr. A pair of alleles control each of fruit rind hardness (Hf /hf), seed coat hardness (Hs /hs) and seed coat colour (Y/y). Complete dominance of hard over soft was observed for fruit rind and seed coat hardness, whereas codominance of dark brown and yellow was observed for seed coat colour. These findings can hasten the efficiency of breeding and development of improved cultivars in L. siceraria.

Lignin biosynthesis rate is responsible for varietal difference in fruit rind and seed coat hardness in the bottle gourd Lagenaria siceraria (Molina) Standley

Previous investigations on bottle gourd [Lagenaria siceraria (Mol.) Standl.], were mainly focused on genetic resources characterisation and crop husbandry. Accessing the anatomical and chemical determinants of fruit and seed traits that directly influence the yield of L. siceraria is a prerequisite for full exploitation of its genetic resources for breeding purposes. This study aimed at gathering the anatomical and chemical bases of fruit rind and seed coat hardness in calabash and egusi varieties of bottle gourd. Variation between the two bottle gourd varieties was observed in fruit rind sclerified outer mesocarp and seed coat thickness. Lignified tissues were thicker in calabash than those of egusi in both fruit rind and seed coat. In addition, the extent of the sclerified outer mesocarp was greater in calabash (up to 503 μm thick) compared to egusi (up to 417 μm thick). In egusi seed coat, only the inner epidermis was lignified while in calabash, both mesophyll and inner epidermis were lignified. Klason lignin procedure confirmed histological analyses, showing a higher amount of lignin in calabash tissues compared to those of egusi, whatever fruit age considered. Fruit rind and seed coat were harder in calabash than in egusi due to the greater degree of lignification in calabash tissues compared to those of egusi.

Occurrence and tolerance mechanisms of seed cracking under low temperatures in soybean (Glycine max).

In soybean, occurrence of, or tolerance to, seed cracking under low temperatures may be related to the presence or absence, respectively, of proanthocyanidin accumulation in the seed coat dorsal region. Soybean seeds sometimes undergo cracking during low temperatures in summer. In this study, we focused on the occurrence and tolerance mechanisms of low-temperature-induced seed cracking in the sensitive yellow soybean cultivar Yukihomare and the tolerant yellow soybean breeding line Toiku 248. Yukihomare exhibited seed cracking when subjected to a 21-day low-temperature treatment from 10days after flowering. In yellow soybeans, seed coat pigmentation is inhibited, leading to low proanthocyanidin levels in the seed coat. Proanthocyanidins accumulated on the dorsal side of the seed coat in Yukihomare under the 21-day low-temperature treatment. In addition, a straight seed coat split occurred on the dorsal side at the full-sized seed stage, resulting in seed cracking in this cultivar. Conversely, proanthocyanidin accumulation was suppressed throughout the seed coat in low-temperature-treated Toiku 248. We propose the following mechanism of seed cracking: proanthocyanidin accumulation and subsequent lignin deposition under low temperatures affects the physical properties of the seed coat, making it more prone to splitting. Further analyses uncovered differences in the physical properties of the seed coat between Yukihomare and Toiku 248. In particular, seed coat hardness decreased in Yukihomare, but not in Toiku 248, under the low-temperature treatment. Seed coat flexibility was higher in Toiku 248 than in Yukihomare under the low-temperature treatment, suggesting that the seed coat of low-temperature-treated Toiku 248 is more flexible than that of low-temperature-treated Yukihomare. These physical properties of the Toiku 248 seed coat observed under low-temperature conditions may contribute to its seed-cracking tolerance.