Sensors Applied to Plant Breeding: Leaf Reflectance Indices (LRIs) and Resistance to Anthracnose in Capsicum annuum L. var. annuum

The present work investigated the efficiency of leaf reflectance indices in the identification of Capsicum annuum L. var. annuum resistant to anthracnose in the fruit. Twenty-five F5:6 families originating from contrasting parents were assessed;the parents were accession UENF 2285 (susceptible to anthracnose) and accession UENF 1381, a hot pepper resistant to anthracnose in the fruit. The experiment was carried out in an experimental field in Campos dos Goytacazes, Rio de Janeiro, Brazil, between May and October of 2021. The treatments were arranged in a randomized block design, with three replications and five plants per plot. Fifteen LRIs were estimated using a CI-710 portable mini leaf spectrometer. The assessments covered all plant growth after flowering, and a total of six assessments were performed at 15-days intervals, beginning at 35 and ending 120 days after flowering (DAFs). Analysis of variance in a split-plot scheme was performed, as were tests of mean groupings and principal components analysis (PCA). The best period for evaluating leaf reflectance indices in C. annuum var. annuum is 120 days after flowering. The leaf reflectance indices PRI, CNDVI and Ctr2 stood out as effective in distinguishing between resistant and susceptible genotypes.

Genomic selection in plant breeding:Key factors shaping two decades of progress

Genomic selection,the application of genomic prediction(GP)models to select candidate individuals,has significantly advanced in the past two decades,effectively accelerating genetic gains in plant breeding.This article provides a holistic overview of key factors that have influenced GP in plant breeding during this period.We delved into the pivotal roles of training population size and genetic diversity,and their relationship with the breeding population,in determining GP accuracy.Special emphasis was placed on optimizing training population size.We explored its benefits and the associated diminishing returns beyond an optimum size.This was done while considering the balance between resource allocation and maximizing prediction accuracy through current optimization algorithms.The density and distribution of single-nucleotide polymorphisms,level of linkage disequilibrium,genetic complexity,trait heritability,statistical machine-learning methods,and non-additive effects are the other vital factors.Using wheat,maize,and potato as examples,we summarize the effect of these factors on the accuracy of GP for various traits.The search for high accuracy in GP—theoretically reaching one when using the Pearson’s correlation as a metric—is an active research area as yet far from optimal for various traits.We hypothesize that with ultra-high sizes of genotypic and phenotypic datasets,effective training population optimization methods and support from other omics approaches(transcriptomics,metabolomics and proteomics)coupled with deep-learning algorithms could overcome the boundaries of current limitations to achieve the highest possible prediction accuracy,making genomic selection an effective tool in plant breeding.

Understanding Brown Planthopper Resistance in Rice: Genetics, Biochemical and Molecular Breeding Approaches

Brown planthopper(BPH,Nilaparvata lugens St自I)is the most devastating pest of rice in Asia and causes significant yield loss annually.Around 37 BPH resistance genes have been identified so far in indica,African rice varieties along with wild germplasms such as Oryza officinalis,O.minuta,O.nivara,O.punctata,O.rufipogon and O,latifolia.Genes/QTLs involved in BPH resistance,including Bph1,bph2/BPH26,Bph3,Bph6,bph7,BPH9,Bph12,Bph14,Bph15,Bph17,BPH18,bph19,Bph20,Bph21(t),Bph27,Bph27©Bph28(t),BPH29,QBph3,QBph4,QBph4.2,Bph30,Bph32,Bph33,Bph35 and Bph36,have been fine-mapped by different researchers across the globe.The majority of genes/QTLs are located on rice chromosomes 1,3,4,6,11 and 12.Rice plants respond to BPH attack by releasing various endogenous metabolites like proteinase inhibitors,callose,secondary metabolites(terpenes,alkaloids,flavonoid,etc.)and volatile compounds.Besides that,hormonal signal pathways mediating(antagonistic/synergistic)resista nee responses in rice have been well studied.Marker-assisted breedi ng and genome editi ng techniq ues can also be adopted for improving resista nee to novel BPH biotypes.

Rice Heat Tolerance Breeding: A Comprehensive Review and Forward Gaze

The yield potential of rice is seriously affected by heat stress due to climate change. Since rice is a staple food globally, it is imperative to develop heat-resistant rice varieties. Thus, a thorough understanding of the complex molecular mechanisms underlying heat tolerance and the impact of high temperatures on various critical stages of the crop is needed. Adoption of both conventional and innovative breeding strategies offers a long-term advantage over other methods, such as agronomic practices, to counter heat stress. In this review, we summarize the effects of heat stress, regulatory pathways for heat tolerance, phenotyping strategies, and various breeding methods available for developing heat-tolerant rice. We offer perspectives and knowledge to guide future research endeavors aimed at enhancing the ability of rice to withstand heat stress and ultimately benefit humanity.

Cold-Resistant Breeding of <i>Oenothera speciosa</i>Using Silico Ion Implantation

Oenothera speciosa, belonging to thermophilous plant, cannot overwinter in Beijing. To enhance the overwintering rate of Oenothera speciosa, the seeds were treated through silico ion implantation (SII), with five various fluence ranges (1 × 109 - 1 × 1011 ions/cm2) of 40 MeV and four various fluence ranges (1 × 1010 - 5 × 1011 ions/cm2) of 35 MeV, respectively. M1 generations of various SII-treated Oenothera speciosa lines can overwinter, and the highest overwinter rate (41.3%) was observed in Oenothera speciosa lines treated with 35 MeV and fluence 5 × 1010 ions/cm2. M2 and M3 generations of all treated lines were able to overwinter smoothly. The results indicated that SII treatment can enhance the cold-resistance of Oenothera speciosa heritably. Furthermore, physiological indexes including relative electrical conductivity, MDA contents and proline contents of SII-treated Oenothera speciosa pot seedlings were detected after low temperature stress. The results revealed that relative electrical conductivities and MDA contents of M1, M2 and M3 generations of SII-treated Oenothera speciosa plants were lower than that of control, whereas the proline contents were higher than control in the &#455&#176C cold stress. Taken together, the cold resistance of SII-treated Oenothera speciosa plants was improved, which made it possible to be used as a perennial flower in landscaping in Beijing.

Breeding Resilience:Exploring Lodging Resistance Mechanisms in Rice

Lodging is more than just plants falling over;it incurs significant economic losses for farmers leading to a decrease in both yield and quality of the final produce.Human management practices,such as dense sowing,excessive nitrogen fertilizer applications,inappropriate sowing dates,and upland rice cultivation,exacerbate the risk of lodging in rice.While breeders have developed high-yielding rice varieties utilizing the sd1 gene,relying solely on this gene is insufficient to enhance lodging resistance.Identifying the traits that contribute to lodging resistance is crucial.Key factors include biochemical,anatomical,and morphological traits,such as the levels of lignin,cellulose,hemicellulose,silicon,and potassium,along with the number and area of vascular bundles and the thickness,diameter,and length of the culm.Moreover,markers associated with lodging-related genes,like SCM2,SCM3,SCM4,and prl4,can be utilized effectively in marker-assisted backcrossing to develop rice varieties with desirable culm traits.This literature review aims to aid rice breeders in addressing the issue of lodging by examining traits that influence lodging resistance,developing phenotyping strategies for these traits,identifying suitable instrumentation,exploring methods for screening lodging-resistant plants,understanding the mathematical relationships involved,and considering molecular breeding aspects for pyramiding genes related to lodging.

Advances in DNA methylation and its role in cytoplasmic male sterility in higher plants

The impact of epigenetic modifications like DNA methylation on plant phenotypes has expanded the possibilities for crop development.DNA methylation plays a part in the regulation of both the chromatin structure and gene expression,and the enzyme involved,DNA methyltransferase,executes the methylation process within the plant genome.By regulating crucial biological pathways,epigenetic changes actively contribute to the creation of the phenotype.Therefore,epigenome editing may assist in overcoming some of the drawbacks of genome editing,which can have minor off-target consequences and merely facilitate the loss of a gene’s function.These drawbacks include gene knockout,which can have such off-target effects.This review provides examples of several molecular characteristics of DNA methylation,as well as some plant physiological processes that are impacted by these epigenetic changes in the plants.We also discuss how DNA alterations might be used to improve crops and meet the demands of sustainable and environmentally-friendly farming.

JAZ proteins:Key regulators of plant growth and stress response

The jasmonate ZIM-domain(JAZ)family of proteins serves as co-receptors and transcriptional repressors of jasmonic acid(JA)in plants.Their functional diversity and multiple roles make them important components of the regulatory network of JA and other hormonal signaling pathways.In this review,we provide an overview of the latest findings on JAZ family proteins and emphasize their roles in plant growth and development,and response to biotic and abiotic stress,along with their underlying mechanisms.Moreover,existing challenges and future applications are outlined with the aim of offering a reference for further research on JAZ proteins in the context of plant physiology.

Next Generation Nutrition: Genomic and Molecular Breeding Innovations for Iron and Zinc Biofortification in Rice

Global efforts to address malnutrition and hidden hunger, particularly prevalent in low- and middle-income countries, have intensified, with a focus on enhancing the nutritional content of staple crops like rice. Despite serving as a staple for over half of the world's population, rice falls short in meeting daily nutritional requirements, especially for iron(Fe) and zinc(Zn). Genetic resources, such as wild rice species and specific rice varieties, offer promising avenues for enhancing Fe and Zn content. Additionally, molecular breeding approaches have identified key genes and loci associated with Fe and Zn accumulation in rice grains. This review explores the genetic resources and molecular mechanisms underlying Fe and Zn accumulation in rice grains. The functional genomics involved in Fe uptake, transport, and distribution in rice plants have revealed key genes such as OsFRO1, OsIRT1, and OsNAS3. Similarly, genes associated with Zn uptake and translocation, including OsZIP11 and OsNRAMP1, have been identified. Transgenic approaches, leveraging transporter gene families and genome editing technologies, offer promising avenues for enhancing Fe and Zn content in rice grains. Moreover, strategies for reducing phytic acid(PA) content, a known inhibitor of mineral bioavailability, have been explored, including the identification of low-PA mutants and natural variants. The integration of genomic information, including whole-genome resequencing and pan-genome analyses, provides valuable insights into the genetic basis of micronutrient traits and facilitates targeted breeding efforts. Functional genomics studies have elucidated the molecular mechanisms underlying Fe uptake and translocation in rice. Furthermore, transgenic and genome editing techniques have shown promise in enhancing Fe and Zn content in rice grains through the manipulation of key transporter genes. Overall, the integration of multi-omics approaches holds significant promise for addressing global malnutrition and hidden hunger by enhancing the nutritional quality of rice, thereby contributing to improved food and nutritional security worldwide.

Karachi provides a good opportunity for low-cost generation advancement of cotton for breeding and seed purity

Cotton is said to be the backbone of Pakistan's economy.Cotton production is facing many challenges such as climate change,pests and diseases,and competition from food crops(Ali et al.,2019).One of the major issues faced by cotton production is seed purity,as cotton is often cross-pollinated,therefore breeders are hard to maintain seed purity.For example,non-Bt cotton varieties are often contaminated with Bt seeds which is an important limiting factor.Another important consideration in cotton breeding is rapid generation advancement.

Implementation of the Acclimatization Process for Ginger Plantlets (Zingiber officinale Roscoe)

Ginger (Zingiber officinale Roscoe) is an important culinary and medicinal spice but is rarely cultivated due to the unavailability of seeds. Given the difficulties in adapting to plantlets produced in natural environments, it is important to analyze the survival conditions of ginger plantlets. For this reason, we varied the incubation temperature and humidity as well as the substrate during the weaning phase. Then, we varied the nutrients contained in the watering solution during the hardening phase. The statistical analysis showed that physical factors and substrates significantly influenced (p < 0.0001) plantlet survival. Nutrient solutions significantly influenced the phylogenesis, rhizogenesis, and height growth of the plantlets. The suitable physical factors for good development of plantlets are a temperature of 26.54˚C and a humidity of 96.16%. The 1C2T2TC substrate (1 Compost + 2 Soil + 2 Coconut Peat) had a significant survival rate of approximately 92.5%. During hardening, the Plantzym solution promoted good growth in terms of plantlet height (0.6 cm) and good development of roots (30 roots) and leaves (03 leaves). This work will make it possible to develop a technical seed production sheet for better development of ginger cultivation in Benin.

Phytohormones and their metabolic engineering for abiotic stress tolerance in crop plants

Abiotic stresses including drought,salinity,heat,cold,flooding,and ultraviolet radiation causes crop losses worldwide.In recent times,preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance.However,the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities.Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance.Recent investigations have shown that phytohormones,including the classical auxins,cytokinins,ethylene,and gibberellins,and newer members including brassinosteroids,jasmonates,and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants.In this review,we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance,besides their engineering for conferring abiotic stress tolerance in transgenic crops.We also describe recent successes in identifying the roles of phytohormones under stressful conditions.We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.

The Selection of Transgenic Recipients from New Elite Wheat Cultivars and Study on Its Plant Regeneration System

In the protocol of wheat transformation, to use elite wheat cultivars as exogenous gene recipients can speed up the process of commercial field applications of transgenic wheat. However, it is necessary to screen wheat cultivars with good tissue culture response （TCR） continuously from plenty of elite wheat cultivars released for wheat transformation, and it is also important to find a plant regeneration system that is suitable for these cultivars. So, the TCR of mature and immature embryos of six wheat cultivars Chuannong 11 （CN11）, Chuannong12 （CN12）, Chuannong17 （CN17）, Chuannong18 （CN18）, Chuannong19 （CN19）, and Chuannong21 （CN21）, which possess superior agronomic traits, were investigated by using a good TCR wheat cultivar Bobwhite as control. The results indicated that only the immature and mature embryos of CN12, CN17, and CN18 exhibited good TCR compared with Bobwhite. No significant differences were observed between embryos of Bobwhite and of the three cultivars in TCR. Mature embryo-derived calli of CN12 were used as explants for transformation by particle bombardment of SAMDC gene. Seven transformants were obtained and the efficiency was 2.3%. This research supplies three new elite recipient cultivars for wheat transformation. The wheat plant regeneration system used in this research is different from those successful ones reported previously and it could be a reference for other wheat genotypes. Furthermore, Bobwhite and the three wheat cultivars were proved to be 1RS/1BL translocation, by methods of A-PAGE, C- banding, and genomic in situ hybridization （GISH）. These results imply that probably there is some relationship between 1RS/1BL translocation and TCR of wheat embryos. So this research gives us a hint that we should pay more attention to the 1RS/1BL translocations when we screen the wheat cultivars with good TCR and also that the mechanism of the effect of 1RS/ 1BL translocation on TCR is worthy of being investigated.

Status and strategies in breeding for rust resistance in wheat

Wheat along with rice and maize is fulfilling half of the calories demands of the world. Global Wheat production has increased tremendously since green revolution in 1960’s and helped in minimizing hunger and malnutrition. Developing countries, which consume 60% of the global wheat production, have shown a higher yield increase than the developed countries in the past [1]. It was driven by the hunger prevalence in these countries and was attributable to the introduction of high yielding and rusted resistant semi dwarf varieties developed under the collaborative efforts of International and National research systems during the last 50 years. Whereas, climate change and the emergence of new pests and diseases are threatening the food sustainability. The evolution of new races of disease pathogens like stem rust (Ug 99) is of serious concern. In order to feed the ever increasing population we have to increase wheat production at the rate 1.6% which can be achieved by developing high yielding varieties having a good tolerance level for biotic and abiotic stresses.

Donors for Resistance to Brown Planthopper Nilaparvata lugens(St?l) from Wild Rice Species

Out of 1 989 wild accessions sown in seed boxes for screening, only 1 003 wild accessions with good germination were screened against brown planthopper(BPH), Nilaparvata lugens(St?l) under greenhouse conditions. The collection comprised of accessions from 11 wild species and African cultivated rice. The germplasm was screened for BPH following standard seed box screening technique in the greenhouse. As many as 159 accessions were identified as resistant during the year 2012 based on one year screening. A selected set of BPH resistant accessions were screened again during 2013. Based on the two years screening, seven accessions of O. nivara(AA), one accession of O. officinalis(CC), seven accessions of O. australiensis(EE), five accessions of O. punctata(BB and BBCC) and nine accessions of O. latifolia(CCDD) were confirmed to be resistant to BPH. So far no BPH resistance genes have been identified and designated from O. nivara and O. punctata, hence these may act as new sources of resistance.

Mapping of dwarfing gene Rht14 in durum wheat and its effect on seedling vigor, internode length and plant height

Short coleoptiles associated with GA-insensitive Rht-1 alleles in wheat reduces yield due to poor seedling establishment under dry, or stubble-retained conditions. Hence there is a need for alternative dwarfing genes for wheat improvement programs. GA-sensitive dwarfing gene Rht14 confers semidwarf stature in wheat while retaining longer coleoptiles and early seedling vigor. Two RIL populations were used to identify the map position of Rht14 and to estimate its effect on plant height, coleoptile length, seedling shoot length,spike length and internode length. Rht14 on chromosome 6 A was mapped in the genomic region 383–422 Mbp flanked by GA2oxA9 and wmc753 in a Bijaga Yellow/Castelporziano RIL population. Recombination events between Rht14 and GA2oxA9 in the RIL population indicated that Rht14 might not be allelic to GA2oxA9. The conserved DNA sequence of GA2oxA9 and its flanking region in Castelporziano also suggested that the point of mutation responsible for the Rht14 allele must be a few Mbp away from GA2oxA9. The dwarfing effects of Rht14 on plant height, internode length and seedling vigor were compared with those of Rht-B1 b in an HI 8498/Castelporziano RIL population. Both genes significantly reduced plant height and internode length. Rht-B1 b conferred a significant reduction in coleoptile length and seedling shoot length, whereas Rht14 reduced plant height, but not coleoptile and seedling shoot length. Therefore, Rht14 can be a used as an alternative to Rht-B1 b for development of cultivars suitable for deeper sowing in dry environments and in conditions of conservation agriculture where crop residues are retained.

Antixenosis and Tolerance of Rice Genotypes Against Brown Planthopper

Nine genotypes were evaluated under greenhouse conditions for antixenosis and tolerance against brown planthopper （BPH, Nilaparvata lugens Stal）. In antixenosis studies, proportion of insects settled on a test genotype in relation to the susceptible control TN1 was recorded, with significantly lower proportion of nymphs （55.22%-59.18%）, adult males （60.33%-60.75%）, and adult females （80.56%- 79.26%） settled on RP2068-18-3-5 and Ptb33 in relation to those on TN1. Based on number of feeding sites, the test genotypes were ranked in order from the highest to the lowest as RP2068-18-3-5, Ptb33, MR1523, Rathu Heenati, Sinnasivappu, ARC10550, MO1, INRC3021 and TNI. The order was exactly reverse in terms of fecundity expressed as number of eggs laid per female. In tolerance studies, days to wilt, functional plant loss index and plant dry weight loss to BPH dry weight produced were recorded. RP2068-18-3-5, Rathu Heenati and Ptb33 performed better than the other test genotypes. These results helped in relative quantification of BPH resistance levels in the genotypes. RP2068-18-3-5, a new effective source of BPH resistance, can be used in resistance breeding after tagging of resistant genes/QTLs linked to different parameters of antixenosis and tolerance with selectable molecular markers.

Identification of QTLs for Plant Height and Its Components by Using Single Segment Substitution Lines in Rice (Oryza sativa)

QTLs for plant height and its components on the substituted segments of fifty-two single segment substitution lines （SSSLs） in rice were identified through t-test （P〈0.001） for comparison between each SSSL and recipient parent Huajingxian 74. On the 14 substituted segments, 24 QTLs were detected, 10 for plant height, 2 for panicle length, 4 for length of the first internode from the top, 5 for length of the second internode from the top and 3 for length of the third internode from the top, respectively. All these QTLs were distributed on nine rice chromosomes except chromosomes 5, 9 and 11. The additive effect ranged from -4.08 to 3.98 cm, and the additive effect percentages varied from -19.35% to 10.43%.

The BUD2 mutation affects plant architecture through altering cytokinin and auxin responses in Arabidopsis

The ratio of auxin and cytokinin plays a crucial role in regulating aerial architecture by promoting or repressing axillary bud outgrowth. We have previously identified an Arabidopsis mutant bud2 that displays altered root and shoot architecture, which results from the loss-of-function of S-adenosylmethionine decarboxylase 4 （SAMDC4）. In this study, we demonstrate that BUD2 could be induced by auxin, and the induction is dependent on auxin signaling. The mutation of BUD2 results in hyposensitivity to auxin and hypersensitivity to cytokinin, which is confirmed by callus induction assays. Our study suggests that polyamines may play their roles in regulating the plant architecture through affecting the homeostasis of cytokinins and sensitivities to auxin and cytokinin.

Carotenoid Pigment Accumulation in Horticultural Plants

Carotenoids are a group of widely distributed natural pigments.They give many horticultural plants the bright red,orange,and yellow colors,as well as the aroma and flavor.Carotenoids enhance the health value and represent an essential quality trait of horticultural products.Significant efforts have been made to correlate specific carotenoid production with pathway gene expression.Some transcription factors that directly regulate transcription of the pathway genes have been identified.Horticultural crops have evolved with complicated and multifaceted regulatory mechanisms to generate the enormous diversity in carotenoid content and composition.However,the diverse and complex control of carotenoid accumulation is still not well understood.In this review,we depict carotenoid accumulation pathways and highlight the recent progress in the regulatory control of carotenoid accumulation in horticultural plants.Because of the critical roles of chromoplasts for carotenoid hyperproduction,we evaluate chromoplast ultrastructures and carotenoid sequestrations.A perspective on carotenoid research in horticultural crops is provided.