Number Of Internodes Research Articles

Performance of Different Commercial Varieties of Sugarcane (Saccharum officinarum) for Yield and Quality Trait Influenced by Various Harvest Age Under Peninsular Zone of Maharashtra

A field experiment was carried out at Vasantdada Sugar Research Institute (VSI), Manjari, Pune, India during 2019–20, 2020–21 and 2021–22 crop seasons (36 months) to evaluate the performance of different harvesting periods of advanced varieties on yield and quality of sugarcane (Saccharum officinarum L.) under agro-climatic condition of peninsular zone of Maharashtra.Three harvesting dates i.e. H1-10 month, H2-12 month and H3-14 month and 10 different varieties including five early maturing sugarcane varieties V1-MS10001, V2-CoM 9057, V3-Co 09004 with two zonal check namely V4-CoC 671 and V5-VSI434 and five midlate maturing varieties V6-VSI08005, V7-CoVSI18121, V8-VSI12003 with two zonal check namely V9-CoM 0265 and V10-Co 86032 were evaluated in the split plot design with three replications. The varieties differed in stalk diameter and weight, and millable stalk number. Improvements in internodes number, stalk diameter and weight were increased with harvest age. Varieties produced better juice quality in canes harvested at 14 months. On the basis of pooled results obtained from three plant cane, it can be concluded that, Maximum cane yield (140.15 t ha-1) and CCS yield (19.33 t ha-1) can be secured by harvesting the sugarcane at 14 months after planting. With respect to varieties CoM 0265 recorded significantly higher cane yield (156.36 t ha-1) as well as CCS yield (18.81 t ha-1) which was followed by varieties VSI 08005 and CoVSI 18121. Whereas, significantly improved sucrose percentage was observed in VSI 434 (19.38%) which was harvested at 14 months after planting.

Effect of Organic Fertilization Based on Cattle Dung in Village Cultivation of Sugar Cane (Saccharum officinarum L.) in Immature Phase in Northern Ivory Coast

This study aimed to determine the dose of organic fertilizer adapted to the agroecological conditions of the Ferkéssédougou zone during the immature or vegetative phase with a view to improving agricultural productivity in rainfed sugar cane cultivation. The trial was conducted using a Fisher block experimental design with three (3) repetitions and six (6) treatments including the control treatment. The observations mainly focused on growth parameters. Health monitoring was also carried out to detect the presence of diseases. Regarding growth parameters, no statically significant effect of fertilizers was observed between treatments. However, the fertilizers used had a positive impact in terms of gain compared to the control. Thus, three (3) groups of fertilizers stood out. Group 1 was composed of mineral manure at the normal dose (350 kg/ha of NPK), organic manure at the normal dose (20t/ha), double dose of compost (40 t/ha) and the organo-mineral mixture, namely the normal dose of compost (20t/ha) + half dose of mineral fertilizer (175 kg/ha of NPK). These treatments promoted good emergence, good elongation of the plants with large diameters and a large number of internodes. Group 2, composed only of half a dose of compost (10 t/ha), allowed us to have a large number of stems. For group 3, corresponding to the control treatment, no growth parameter was correlated. No symptoms of major illnesses were observed during the observations. The M1400/86 variety used is resistant to termite attack.

A single nucleotide substitution introducing premature stop codon within CsTFL1 explains the determinate-2 phenotype in cucumber (Cucumis sativus L.)

The determinate growth habit of plants reduces the number of internodes and shortens the main stem by terminating the shoot apical meristem through a transition to inflorescence. Understanding the genetic basis of this habit can help optimize crop yield and cultivation technology for vegetable breeding. This study aimed to identify the determinate-2 (de-2) gene responsible for the determinate growth habit in the W-sk cucumber line. Termination of the main stem in the W-sk line occurred between 14 and 23 internodes, depending on cultivation conditions. Resequencing of the W-sk genome identified a novel SNP in the cucumber TERMINAL FLOWER1 (CsTFL1) gene, explaining the de-2 phenotype. This was verified with a CAPS-T marker cosegregation with determinate growth in the F2:3 population, and this polymorphism is unique among genotyped indeterminate cucumber cultivars or breeding lines. Crossing the W-sk line with the G421 line with the determinate (de) gene confirmed the allelism of both genes. An SNP in CsTFL1 in the W-sk line introduced a premature stop codon, resulting in the putative deletion of 13 amino acids, possibly causing determinate growth habit. Overall, this study provides insights into the genetic basis of cucumber plant growth architecture and advances in cucumber breeding.

Combining ability and gene action analysis in okra (Abelmoschus esculentus L. Moench)

The present research was conducted in Okra to study combining ability and gene action in a set of 28 F1s developed by crossing seven lines and four testers. The experiment was laid out in a Randomized Block Design with three replications and observations were recorded on 12 traits viz. days to 50% flowering, days to first picking, number of internodes, number of branches plant-1, fruit length at maturity and harvest, number of fruits plant-1, number of seeds fruit-1, seed index, fruit weight, yield per plant and plant height. The results revealed that two lines viz., VRO-4 and Sel-2 were excellent general combiners for most of the traits in both positive and negative direction as per desirable traits. Cross VRO-6 x Varsha Uphar recorded highly significant SCA effects for eight traits and GAO-5 x GJO-3 for yield trait. Variance due to GCA was less than SCA, and the GCA/SCA ratio was less than unity indicating preponderance of non-additive gene action for all the traits. This suggested the feasibility of exploitation of heterosis. Keywords: Gene action, Fruit yield, Okra, GCA and SCA

Molecular and genetic basis of plant architecture in soybean.

Plant architecture determines canopy coverage, photosynthetic efficiency, and ultimately productivity in soybean (Glycine max). Optimizing plant architecture is a major goal of breeders to develop high yield soybean varieties. Over the past few decades, the yield per unit area of soybean has not changed significantly; however, rice and wheat breeders have succeeded in achieving high yields by generating semi-dwarf varieties. Semi-dwarf crops have the potential to ensure yield stability in high-density planting environments because they can significantly improve responses to fertilizer input, lodging resistance, and enhance resistance to various abiotic and biotic stresses. Soybean has a unique plant architecture, with leaves, inflorescences, and pods growing at each node; internode number greatly affects the final yield. Therefore, producing high-yielding soybean plants with an ideal architecture requires the coordination of effective node formation, effective internode formation, and branching. Dozens of quantitative trait loci (QTLs) controlling plant architecture have been identified in soybean, but only a few genes that control this trait have been cloned and characterized. Here, we review recent progress in understanding the genetic basis of soybean plant architecture. We provide our views and perspectives on how to breed new high-yielding soybean varieties.

Effect of Row Orientation on Productivity Of Sugarcane With Potato as Intercrop

An experiment was carried out at the Regional Sugarcrop Research Station (RSRS) farm, Thakurgaon under the agro-ecological zone of Old Himalayan Piedmont Plain (AEZ-1) of Bangladesh, during 2016-2017 to 2017-2018 cropping seasons to evaluate the impact of row orientation on the productivity of sugarcane with potato as intercrop. Under the study eight treatments viz T1: Single row cane (SRC) only in north-south direction, T2: SRC + potato in North-South direction, T3: SRC only in east-west direction, T4: SRC + potato in east-west direction,T5: Paired row cane (PRC) only in North-South direction, T6: PRC + potato in north-south direction, T7: PRC only in east-west direction and T8: PRC + potato in east-west direction were tested following Randomized Complete Block Design with three replications Significant differences were found among the observed parameters except germination (%) of setts, number of internodes per stalk and unit stalk weight of sugarcane. The highest number of tiller and millable cane population, cane yield and brix reading were achieved from the treatment SRC + potato in the North-South direction. The highest intercrop yield, equivalent cane yield of intercrop, total adjusted yield and gross return were obtained from the treatment PRC + potato in north-south direction, but the highest net return and benefit cost ratio were obtained from the treatment SRC + potato in the North-South direction. Having the highest cane yield, net return and benefit cost ratio with less variable cost, sugarcane planting in a single row system with potato as intercrop in a North-South row direction could be considered the best package practice for successful sugarcane farming. Bangladesh Agron. J. 2024, 26(2): 7-15

Low intensity repetitive transcranial magnetic stimulation enhances remyelination by newborn and surviving oligodendrocytes in the cuprizone model of toxic demyelination

In people with multiple sclerosis (MS), newborn and surviving oligodendrocytes (OLs) can contribute to remyelination, however, current therapies are unable to enhance or sustain endogenous repair. Low intensity repetitive transcranial magnetic stimulation (LI-rTMS), delivered as an intermittent theta burst stimulation (iTBS), increases the survival and maturation of newborn OLs in the healthy adult mouse cortex, but it is unclear whether LI-rTMS can promote remyelination. To examine this possibility, we fluorescently labelled oligodendrocyte progenitor cells (OPCs; Pdgfrα-CreER transgenic mice) or mature OLs (Plp-CreER transgenic mice) in the adult mouse brain and traced the fate of each cell population over time. Daily sessions of iTBS (600 pulses; 120 mT), delivered during cuprizone (CPZ) feeding, did not alter new or pre-existing OL survival but increased the number of myelin internodes elaborated by new OLs in the primary motor cortex (M1). This resulted in each new M1 OL producing ~ 471 µm more myelin. When LI-rTMS was delivered after CPZ withdrawal (during remyelination), it significantly increased the length of the internodes elaborated by new M1 and callosal OLs, increased the number of surviving OLs that supported internodes in the corpus callosum (CC), and increased the proportion of axons that were myelinated. The ability of LI-rTMS to modify cortical neuronal activity and the behaviour of new and surviving OLs, suggests that it may be a suitable adjunct intervention to enhance remyelination in people with MS.

Human iPSC-derived myelinating organoids and globoid cells to study Krabbe Disease.

Krabbe disease (Kd) is a lysosomal storage disorder (LSD) caused by the deficiency of the lysosomal galactosylceramidase (GALC) which cleaves the myelin enriched lipid galactosylceramide (GalCer). Accumulated GalCer is catabolized into the cytotoxic lipid psychosine that causes myelinating cells death and demyelination which recruits microglia/macrophages that fail to digest myelin debris and become globoid cells. Here, to understand the pathological mechanisms of Kd, we used induced pluripotent stem cells (iPSCs) from Kd patients to produce myelinating organoids and microglia. We show that Kd organoids have no obvious defects in neurogenesis, astrogenesis, and oligodendrogenesis but manifest early myelination defects. Specifically, Kd organoids showed shorter but a similar number of myelin internodes than Controls at the peak of myelination and a reduced number and shorter internodes at a later time point. Interestingly, myelin is affected in the absence of autophagy and mTOR pathway dysregulation, suggesting lack of lysosomal dysfunction which makes this organoid model a very valuable tool to study the early events that drive demyelination in Kd. Kd iPSC-derived microglia show a marginal rate of globoid cell formation under normal culture conditions that is drastically increased upon GalCer feeding. Under normal culture conditions, Kd microglia show a minor LAMP1 content decrease and a slight increase in the autophagy protein LC3B. Upon GalCer feeding, Kd cells show accumulation of autophagy proteins and strong LAMP1 reduction that at a later time point are reverted showing the compensatory capabilities of globoid cells. Altogether, this supports the value of our cultures as tools to study the mechanisms that drive globoid cell formation and the compensatory mechanism in play to overcome GalCer accumulation in Kd.

EFFECT OF SUPPLEMENTARY LIGHT ON GROWTH, FLOWERING AND CUT FLOWER QUALITY IN TWO CULTIVAR OF CARNATION PLANT

This study was conducted to investigate the effects of different types of light and some factors on some vegetative growth and flowering of two cultivars of carnation plant (Dianthus caryophyllus L.). The results showed the maximum leaves number, leaf area per plant, internodes number and intermodal length were recorded under 14h incandescent (41.09 leaves/plant, 363.91 cm2, 18.70 node/plant, and 7.675 cm) respectively, and the increase was significant. While the effect of triple interaction, which showed a significant effect in all characteristics, the largest leaf area per plant (578.66 cm2) was obtained from the moonlight cultivar when cultured on the media containing 60% local compost and exposed to the 14h incandescent, Also, the maximum vase life was found in the Ormea cultivar (17.47 days) when the cultivar was exposed to the 14h incandescent and was cultured on medium that included 60% local compost. The best grade flower was obtained when the Ormea cultivar was cultured on a medium containing 30% and 60% local compost under 14 hours of incandescent light, reaching 3.89.

Identification and characterization of CsERECTA, a major gene controlling stem elongation through regulating GA biosynthesis in cucumber.

Dwarfing is an ideal agronomic trait in crop breeding, which can improve lodging resistance and increase crop productivity. In this study, we identified a dwarf mutant cp-3 from an EMS-mutagenized population, which had extremely short internodes, and the cell length and number of internodes were significantly reduced. Meanwhile, exogenous GA3 treatment partially rescued the plant height of the cp-3. Inheritance analysis showed that the cp-3 mutant was regulated via a recessive nuclear locus. A candidate gene, CsERECTA, encoding an LRR receptor-like serine/threonine-protein kinase, was cloned through a map-based cloning strategy. Sequence analysis showed that a nucleotide mutation (C ~ T) in exon 26 of CsERECTA led to premature termination of the protein. Subsequently, two transgenic lines were generated using the CRISPR/Cas9 system, and they showed plant dwarfing. Plant endogenous hormones quantitative and RNA-sequencing analysis revealed that GA3 content and the expression levels of genes related to GA biosynthesis were significantly reduced in Cser knockout mutants. Meanwhile, exogenous GA3 treatment partially rescued the dwarf phenotype of Cser knockout mutants. These findings revealed that CsERECTA controls stem elongation by regulating GA biosynthesis in cucumber.

Growth Performance of Mangrove Seedlings Planted with Guludan Technique at Elang Laut Area, Muara Angke, Jakarta

Elang Laut area is one of the mangrove areas on Muara Angke coast in the northern Jakarta. Mangrove rehabilitation with the guludan technique is applied in the Elang Laut to revegetated degraded mangrove in this area. This study aims to measure the growth of planted mangrove (Rhizophora mucronata) seedlings with guludan technique, seedling’s health condition, and their survival rate in the Elang Laut area. The data collected in this study includes the growth of seedlings and their health condition, substrate condition, climatic factors, and water quality. On year after planting, it is observed that the seedlings’ survival rate of 97,27%, average seedling’s stem diameter of 1,42 cm, average seedling’s height of 79,71 cm, average seedling’s leaf number of 25 leaves, and the average seedling’s internode number of 8 internodes, among them 64% of the seedlings are in a healthy condition.

Culm Morphological Analysis in Moso Bamboo Reveals the Negative Regulation of Internode Diameter and Thickness by Monthly Precipitation.

The neglect of Moso bamboo's phenotype variations hinders its broader utilization, despite its high economic value globally. Thus, this study investigated the morphological variations of 16 Moso bamboo populations. The analysis revealed the culm heights ranging from 9.67 m to 17.5 m, with average heights under the first branch ranging from 4.91 m to 7.67 m. The total internode numbers under the first branch varied from 17 to 36, with internode lengths spanning 2.9 cm to 46.4 cm, diameters ranging from 5.10 cm to 17.2 cm, and wall thicknesses from 3.20 mm to 33.3 mm, indicating distinct attributes among the populations. Furthermore, strong positive correlations were observed between the internode diameter, thickness, length, and volume. The coefficient of variation of height under the first branch showed strong positive correlations with several parameters, indicating variability in their contribution to the total culm height. A regression analysis revealed patterns of covariation among the culm parameters, highlighting their influence on the culm height and structural characteristics. Both the diameter and thickness significantly contribute to the internode volume and culm height, and the culm parameters tend to either increase or decrease together, influencing the culm height. Moreover, this study also identified a significant negative correlation between monthly precipitation and the internode diameter and thickness, especially during December and January, impacting the primary thickening growth and, consequently, the internode size.

The extent of multiallelic, co-editing of LIGULELESS1 in highly polyploid sugarcane tunes leaf inclination angle and enables selection of the ideotype for biomass yield.

Sugarcane (Saccharum spp. hybrid) is a prime feedstock for commercial production of biofuel and table sugar. Optimizing canopy architecture for improved light capture has great potential for elevating biomass yield. LIGULELESS1 (LG1) is involved in leaf ligule and auricle development in grasses. Here, we report CRISPR/Cas9-mediated co-mutagenesis of up to 40 copies/alleles of the putative LG1 in highly polyploid sugarcane (2n = 100-120, x = 10-12). Next generation sequencing revealed co-editing frequencies of 7.4%-100% of the LG1 reads in 16 of the 78 transgenic lines. LG1 mutations resulted in a tuneable leaf angle phenotype that became more upright as co-editing frequency increased. Three lines with loss of function frequencies of ~12%, ~53% and ~95% of lg1 were selected following a randomized greenhouse trial and grown in replicated, multi-row field plots. The co-edited LG1 mutations were stably maintained in vegetative progenies and the extent of co-editing remained constant in field tested lines L26 and L35. Next generation sequencing confirmed the absence of potential off targets. The leaf inclination angle corresponded to light transmission into the canopy and tiller number. Line L35 displaying loss of function in ~12% of the lg1 NGS reads exhibited an 18% increase in dry biomass yield supported by a 56% decrease in leaf inclination angle, a 31% increase in tiller number, and a 25% increase in internode number. The scalable co-editing of LG1 in highly polyploid sugarcane allows fine-tuning of leaf inclination angle, enabling the selection of the ideotype for biomass yield.

Yield and Multivariate Analysis among Twelve Sugarcane (Saccharum Officinarum L) Genotypes at Mankusa, North Western, Ethiopia

Smallholders cultivated sugarcane for household consumption, immediate cash, and feeding livestock in Ethiopia. However, its production and productivity are constrained by a lack of improved varieties. Sugarcane germplasm was collected from Districts of West Gojjam, Ethiopia, to evaluate yield and its contributing characters and quantify the phenotypic diversity at Mankusa, Jabitehnan, Ethiopia. The experiment was conducted using a randomised complete block design with three replications for two crop cycles, from April 2020 to March 2023. Data were recorded for the number of tillers, internode length, sellable stalks, plant height, stalk diameter, cane yield and biomass yield from twelve genotypes collected. The data recorded were subjected to analysis of variance, and means were separated using the Duncan Multiple Range Test at a 5% significance level. Variance and multivariate analysis indicated the existence of high phenotypic diversity between genotypes in all quantitative traits studied. Acc 7/20 and Acc 5/20 genotypes produced the highest number of tillers and longest internodes, while Acc 6/20 produced the highest number of sellable stalks. The genotype Acc 4/20 was the longest, and the thickest genotype, which could be elite donors for it respected quality traits through crossing. The highest cane yield was recorded from Acc 4/20 (178.04 t/ha), Acc 7/20 (151.41 t/ha), Acc 8/20 (134.1 t/ha) and Acc 12/20 (132 t/ha), producing 58, 34, 19 and 17% advantageous from the overall genotypes mean, respectively. Cluster analysis grouped the twelve sugarcane genotypes into four clusters, indicating the possibility of broadening the genetic basis by crossing genotypes in the different clusters. It also indicated that a cross between cluster II and III genotypes could create the thickest canes with many sellable stalks. Therefore, genotypes Acc 04/20, Acc 07/20, Acc 8/20 and Acc 12/20 have been recommended and must be evaluated in other sugarcane growing areas to exploit their potential.

Morpho-genetic Diversity and Traits’ Relationship in Castor Germplasm

Adequate knowledge of the extent of dissimilarity among germplasm accessions and traits’ relationships are of great importance in active breeding programme. In the present study, genetic diversity and traits’ relationship were assessed among 74 castor germplasm accessions collected at the National Cereals Research Institute Badeggi, Nigeria. The accessions were evaluated on replicated plots of 7.5m2 size, arranged in a randomized complete block design. The data were taken on 20 individual plants, using standard castor descriptors. The results revealed significant variations for all the traits studied among the entries. Phenotypic and genotypic coefficients of variation estimated showed low environmental effects on the observed variations. High (≥ 70%) broad sense heritability coupled with high (≥ 20%) genetic advance as percentage of mean were observed in all the traits except days to days to first raceme maturity, number of leaf lobes and seed yield. Six cluster groups, with 4 to 38 members, were identified among the accessions. Significant positive correlations were observed between the seed yield and leaf length (0.269*), and spike length (0.972**). The partitioning of the correlations into direct and indirect yield contributors showed positive direct effects for number of internodes to first raceme, spike length and height to first raceme. The findings showed that selection for long spike early accessions could result in constituting a high yielding breeding population. The identified superior accessions could serve as good germplasm sources for castor breeding programme in Nigeria.

Maximization of brackish water productivity for the sustainable production of striped catfish (Pangasianodon hypophthalmus) and grain sorghum (Sorghum bicolor (L.) Moench) cultivated under an integrated aquaculture–agriculture system

Freshwater scarcity, salinity, and poor soil fertility are the major challenges affecting both food and feed productions in arid and semi-arid regions of the world. Utilization of brackish water in the production of saline-tolerant fish and valuable field crops under an integrated system is promising in the maximization of yield per crop. The aim of this study, therefore, was to (1) assess the effect of saline aquaculture wastewater on the growth, yield, forage quality, and nutritive composition of sorghum seeds and (2) assess the effect of different water qualities on the survival, growth performance, and health status of Pangasianodon hypophthalmus. The experiment was conducted in a randomized completely block design of four salinity treatments with three replicates, i.e., control (freshwater mixed with inorganic fertilizers), 5000 ppm, 10,000 ppm, and 15,000 ppm. Our results indicated that although the control exhibited the highest growth (plant height, leaf number, internode number, leaf area, and soil–plant analysis development), grain, and forage yield, no significant differences were noted among the treatments. Likewise, no significant difference in the grain nutrient composition was noted among all the treatments. Assessment of the forage quality revealed improved crude protein content in the control compared to the saline treatments. However, no significant differences in the leaves and stalks fiber fractions were noted among all the treatments. Furthermore, rumen fermentation in terms of in vitro digestibility indicated no significant differences in the in vitro digestible dry matter, digestible organic matter, metabolic energy, net energy, microbial protein, short-chain fatty acids, and total dissolved nutrients among the treatments. However, rearing P. hypophthalmus in water salinities exceeding 10,000 ppm reduced the growth performance and health status of fish. Therefore, the integration of sorghum and P. hypophthalmus production in water salinities not exceeding 5000 ppm is a viable alternative to maximize brackish water productivity in freshwater-scarce regions.

The results of the variety testing of cannabis in the conditions of the Republic of Bashkortostan

Relevance. In recent years, this crop, which is cultivated in order to obtain oil and fiber, is gradually gaining its abundance, increasing the acreage. In many agro-industrial enterprises, hemp is being introduced into crop rotations, and plants for its processing are being built. This culture plays a huge national economic importance and finds its application in various industries. One of the main elements of cannabis cultivation technology is the use of highly productive varieties.Methodology. The laying of field experiments, related observations and records were carried out in accordance with existing methodological guidelines for conducting field and vegetation experiments with cannabis.Results. The most optimal variety for the conditions of the Southern forest-steppe zone of the Republic of Bashkortostan is the Nadezhda variety. This variety is superior to the others (Vera and Omegadar-1) in terms of quality and quantity. For example, from the 2021–2022 studies on biomorphometric indicators, it follows that Nadezhda achieved the best indicators for: plant height (194.50 cm and 194.33 cm), technical stem length (160.60 cm and 162.45 cm), inflorescence length (33.90 cm and 31.88 cm), stem diameter (0.8–0.9 cm), the number of internodes (8–9 pcs.), the average length of internodes (12.5 cm and 19.87 cm). The weight of 1000 seeds was 17.01 g and 18.10 g, oil content — 32.89% and 33.72%, yield — 0.88 t/ha and 1.71 t/ha. The greatest results in 2022 are associated with agrometeorological conditions.

ИНТЕНСИВНОСТЬ МОРФОГЕНЕЗА РЕГЕНЕРАНТОВ КАРТОФЕЛЯ ПРИ ИСПОЛЬЗОВАНИИ ОСВЕЩЕНИЯ РАЗЛИЧНОГО СПЕКТРАЛЬНОГО СОСТАВА

The aim of research is to establish the optimal parameters of LED lighting for in vitro cultivation of meristem plants of different potato varieties in order to optimize the elements of the original potato seed production technology. Research was conducted in 2023 in the laboratory of agricultural plant biotechnology of the Samara Research Institute of Agriculture. The object of research was meristem plants of six potato varieties. The explants were grown on a Murashige-Skoog nutrient medium for 40 days using various sources of artificial LED lighting. The photoperiod duration was 16 hours, the air temperature was 22–24 °C, the relative humidity was 70–75 %. After 10, 20, 30 and 40 days of cultivation, the biometric para¬meters of the regenerants were measured – plant length and the number of internodes. When growing meristematic potato plants in vitro, lighting of different spectral composition had a positive effect on the growth and development of regenerants at different periods of their development. At the initial stages of vegetation, the maximum parameters of growth and development of regenerants were revealed when using white and combined lighting. By the end of the vegetation period, plants in the variant with red-violet spectrum lighting were characterized by a significantly higher length and number of internodes. A pronounced variety-specific response of meristematic plants to different lighting conditions was shown. During the entire exposure period, an increase in the share of the influence of the interaction of genotypic and environmental factors on the variability of plant length was noted. The interaction of factors was also decisive for the number of internodes in the first 30 days of vegetation. In the last decade of vegetation, the maximum contribution to the variability of the trait was made by the lighting factor. For practical use in ori¬ginal seed production of potatoes, individual selection of LED lighting parameters for each variety is recommended with a gradual increase in the red-violet spectrum after the tenth day of exposure.

The Physiological Basis of Alfalfa Plant Height Establishment.

Plant height plays an important role in crop yield, product quality, and cultivation management. However, the physiological mechanisms that regulate the establishment of plant height in alfalfa plants remain unclear. Herein, we measured plant height traits, leaf characteristics, photosynthetic physiology, cell wall composition, and endogenous hormone contents of tall- and short-stalked alfalfa materials at different reproductive periods. We analyzed the physiology responsible for differences in plant height. The results demonstrated that the number of internodes in tall- and short-stalked alfalfa materials tended to converge with the advancement of the fertility period. Meanwhile, the average internode length (IL) of tall-stalked materials was significantly higher than that of short-stalked materials at different fertility periods, with internode length identified as the main trait determining the differences in alfalfa plant height. Leaf characteristics, which are closely related to photosynthetic capacity, are crucial energy sources supporting the expression of plant height traits, and we found that an increase in the number of leaves contributed to a proportional increase in plant height. Additionally, a significant positive correlation was observed between plant height and leaf dry weight per plant during the branching and early flowering stages of alfalfa. The leaves of alfalfa affect plant height through photosynthesis, with the budding stage identified as the key period for efficient light energy utilization. Plant height at the budding stage showed a significant positive correlation with soluble sugar (SS) content and a significant negative correlation with intercellular CO2 concentration. Moreover, we found that alfalfa plant height was significantly correlated with the contents of indole-3-acetic acid in stem tips (SIAA), gibberellin A3 in leaves (LGA3), zeatin in stem tips (SZT), and abscisic acid in leaves (LABA). Further investigation revealed that SS, SIAA, and LGA3 contents were important physiological indicators affecting alfalfa plant height. This study provides a theoretical basis for understanding the formation of alfalfa plant height traits and for genetic improvement studies.

Growth-regulating factor 15-mediated vascular cambium differentiation positively regulates wood formation in hybrid poplar (Populus alba × P. glandulosa).

Hybrid poplars are industrial trees in China. An understanding of the molecular mechanism underlying wood formation in hybrid poplars is necessary for molecular breeding. Although the division and differentiation of vascular cambial cells is important for secondary growth and wood formation, the regulation of this process is largely unclear. In this study, mPagGRF15 OE and PagGRF15-SRDX transgenic poplars were generated to investigate the function of PagGRF15. RNA-seq and qRT-PCR were conducted to analyze genome-wide gene expression, while ChIP‒seq and ChIP-PCR were used to identified the downstream genes regulated by PagGRF15. We report that PagGRF15 from hybrid poplar (Populus alba × P. glandulosa), a growth-regulating factor, plays a critical role in the regulation of vascular cambium activity. PagGRF15 was expressed predominantly in the cambial zone of vascular tissue. Overexpression of mPagGRF15 (themutated version of GRF15 in the miR396 target sequence) in Populus led to decreased plant height and internode number. Further stem cross sections showed that the mPagGRF15 OE plants exhibited significant changes in vascular pattern with an increase in xylem and a reduction in phloem. In addition, cambium cell files were decreased in the mPagGRF15 OE plants. However, dominant suppression of the downstream genes of PagGRF15 using PagGRF15-SRDX showed an opposite phenotype. Based on the RNA-seq and ChIP-seq results, combining qRT-PCR and ChIP-PCR analysis, candidate genes, such as WOX4b, PXY and GID1.3, were obtained and found to be mainly involved in cambial activity and xylem differentiation. Accordingly, we speculated that PagGRF15 functions as a positive regulator mediating xylem differentiation by repressing the expression of the WOX4a and PXY genes to set the pace of cambial activity. In contrast, PagGRF15 mediated the GA signaling pathway by upregulating GID1.3 expression to stimulate xylem differentiation. This study provides valuable information for further studies on vascular cambium differentiation mechanisms and genetic improvement of the specific gravity of wood in hybrid poplars.