Parental Genotypes Research Articles

ESTIMATION OF HETEROSIS AND COMBINING ABILITY TOWARD MORPHOLOGICAL, YIELD AND QUALITY TRAITS IN TEN SWEET SORGHUM PARENTAL GENOTYPES BY LINE × TESTER ANALYSIS

This study was done to estimate general combining ability (GCA), specific combining ability (SCA) and heterosis regarding better for ten sweet sorghum parental genotypes. Seven lines and three testers were crossed in line ×tester mating fashion on randomized complete block design (RCBD) with three replications at Giza Agriculture Research Station during 2020, 2021 and, 2022 summer seasons. The results showed, significant differences among mean square of parental genotypes and their crosses for all studied traits, suggested present of additive and non-additive genetic variance. In addition, significant mean squares of parents vs. crosses, indicated significant average of heterosis. Besides, the highest values of mean performance were parental genotypes, Brands, Sugar drib, MN1054, MN4080, MN5509 and MN4423, and crosses Brands X MN1054, Ramada X MN4080, Ramada X MN5509, Ramada X MN4423, Sugar drib X MN1054, Sugar drib X MN4080 and Sugar drib X MN1383. Additionally, the best parental genotype that had good GCA effects was MN4423 for most studied traits which may be used in breeding programs for developing high yield varieties. While, the excellent crosses based on SCA effects values were Brands X MN5509, Ramada X MN2756, Ramada X MN1054 and Sugar drib X MN1383. Finally, Heterosis values varied from cross to cross and from trait to trait, which considered promising crosses in breeding programs.

Genotyping-by-sequencing uncovers a Thinopyrum 4StS·1JvsS Robertsonian translocation linked to multiple stress tolerances in bread wheat

KeymessageGBS read coverage analysis identified a Robertsonian chromosome from twoThinopyrumsubgenomes in wheat, conferring leaf and stripe rust resistance, drought tolerance, and maintaining yield stability.Agropyron glael (GLAEL), a Thinopyrum intermedium × Th. ponticum hybrid, serves as a valuable genetic resource for wheat improvement. Despite its potential, limited knowledge of its chromosome structure and homoeologous relationships with hexaploid wheat (Triticum aestivum) has restricted the full exploitation of GLAEL's genetic diversity in breeding programs. Here, we present the development of a 44-chromosome wheat/GLAEL addition line (GLA7). Multicolor genomic in situ hybridization identified one chromosome arm from the St subgenome of Th. intermedium, while the other arm remained unclassified. Genotyping-by-sequencing (GBS) read coverage analysis revealed a unique Robertsonian translocation between two distinct Thinopyrum subgenomes, identified as 4StS·1JvsS. The GLA7 line demonstrated strong adult plant resistance to both leaf rust and stripe rust under natural and artificial infection conditions. Automated phenotyping of shoot morphological parameters together with leaf relative water content and yield components showed that the GLA7 line exhibited elevated drought tolerance compared to parental wheat genotypes. Three years of field trials showed that GLA7 exhibits similar agronomic performance and yield components to the wheat parents. This unique addition line holds promise for enhancing wheat's tolerance to multiple stresses through the introduction of new resistance genes, as well as its ability to mitigate the effects of temporary water limitation during flowering, all without negatively impacting wheat performance.

Assessment of Parental Polymorphism between Swarna / Oryza rufipogon IC309814 Derived Mapping Population

Detection of molecular markers with parental polymorphism is a pre-requisite for QTL mapping and further identification of genomic regions. PCR based InDel markers tend to have a greater degree to show polymorphism among the parental genotypes for any specific cross. Polymorphic studies were carried out between the two parents Swarna (cultivated rice) and Oryza rufipogon IC309814 (Wild rice) using 192 randomly selected InDel markers and 40 gene specific markers for Iron and Zinc covering the entire 12 chromosomes. Results revealed that InDel markers were polymorphic between both the parents and highest percentage of polymorphism observed on chromosome 10 (75%) followed by chromosome 5 (60%) and chromosome 9 (55.6%) and lowest polymorphism percentage was shown in chromosome 3 (8.3%) with an overall 22.4 % polymorphism percentage among all the markers used in this study. Detected polymorphic (SSR) markers were for genotyping the mapping population derived from the cross between Swarna cultivar and Oryza rufipogon to map Quantitative Trait Loci (QTLs) associated with yield and grain quality traits.

Seed Quality Assessment of the Blue Corn Hybrid Vampiro H10 (Zea mays L.) Through Its Parental Genotypes

Objective: To monitor the physical and physiological quality of the trilinear corn hybrid Vampiro H10 seeds through its parental genotypes and to rank the evaluated characteristics according to their importance for germination and seedling development. Design/methodology: Using a completely randomized design with four replications (100 seeds), in parental genotypes of the hybrid Vampiro H10 seeds, it was evaluated their physical (width, thickness, length, volume, relative density, and width/length and thickness/length ratios) and physiological characteristics (normal and abnormal seedlings, inert seeds, and dry weight and length of plumule, radicle, and total). Seed germination was estimated by the proportion of normal seedlings produced. The results underwent analysis of variance, comparison of means (Tukey's test, P ≤ 0.05), and principal components analysis. Results: Each cross involved in the formation of Vampiro H10 made different contributions to the seed characteristics. In the single cross, the physical dimensions and dry matter of the seedling were increased, and in the trilinear cross, the formation of normal seedlings, radicle elongation and biomass were favored. This indicated that the hybridization sequence first affected the dimensions and then the physiological quality of the seed. Limitations of the study: No limitations were presented for the present study. Conclusions: An increase in volume, weight and length of seed was observed in the single cross and an increase in germination and seedling development in length and biomass was observed in the trilinear cross.

Genetic Variation Analysis of Avenin Components in the Population of F2 Common Oat Hybrids

The use of avenins as biochemical markers successfully complements the use of molecular markers in oat breeding. Currently, the genes controlling the synthesis of oat prolamins are insufficiently studied. The purpose of the work was to study the genetic variation of avenin components in populations of F2 common oat hybrids and to describe new allelic variants of component blocks. The avenins component of F2 grain in 19 hybrid oat populations was studied using the native electrophoresis method. Cultivars with new combinations of avenin components were used as parental genotypes to produce hybrids. The protein separation was conducted in vertical plates of 13.2% polyacrylamide gel. The number of avenin components in the spectra of cultivars varied from 8 to 12. The observed ratio of the grain number that compose the phenotypic classes for allele pairs at each of the loci corresponded to the theoretically expected one for codominant monohybrid inheritance. Our results confirm the assumption that avenin synthesis is controlled by three independent gene clusters located on three chromosomes. In the course of the studies, hybrid combinations were not identified in the spectra of which avenin components were manifested that were absent in both parents. The prolamin component blocks in oat are formed by 2–5 components, are characterized by high stability, and are inherited unchanged. Fifteen new allelic variants of blocks of components of the avenin electrophoretic spectrum have been identified: six for the Avn A locus, six for the Avn B locus, and three for the Avn C locus. This expands the possibilities of using prolamins as biochemical markers of economically valuable oat traits and certification of new cultivars and valuable breeding lines.

Genetic divergence and hybrid potential for yield and fiber quality in cotton (Gossypium hirsutum. L)

ABSTRACT Fiber trait is multigenic and each parent of the population carrying different genes aid in arriving at varied blend of association between yield and fiber quality traits. Eleven parental lines were crossed in half-diallel fashion to arrive at 55 hybrid combinations, which were evaluated under seven environments. The results manifested highly significant differences among the traits studied, indicating wide range of genetic diversity in the parental genotypes. Combining ability studies revealed parental genotypes SCS-PL-01, SCS-PL-04 as best general combiners for seed cotton yield; SCS-PL-04, SCS-PL-12, SCS-PL-51, SCS-PL-59 for fiber length; SCS-PL-51 for fiber strength and SCS-PL-02 for micronaire value. Genetic diversity of parental genotypes estimated using microsatellites was compared with SCA effects to understand the role of genetic distance (GD) in realizing the heterosis. Comparative characterization of parental genotypes indicated efficiency of capillary gel electrophoresis over metaphor agarose gel electrophoresis and could identify 55 unique bands. The study indicated predicting heterosis using GD estimates is competent when markers linked to the QTLs are used. Also, marker-assisted parental selection in combining ability studies would be a better approach in realizing potential crosses with high yield and fiber quality traits.

Transgressive segregation and the inheritance of paraquat resistance in Canada fleabane (Conyza canadensis)

Abstract Transgressive segregation refers to the phenomenon whereby the progeny of a diverse cross exhibit phenotypes that fall outside the range of the parents for a particular trait of interest. Segregants that exceed the parental values in life history traits contributing to survival and reproduction may represent beneficial new allelic combinations that are fitter than respective parental genotypes. In this research, we use geographically disparate paraquat resistant biotypes of horseweed (Canada fleabane) [Conyza canadensis (L.) Cronquist; syn. Erigeron canadensis L.] to explore transgressive segregation in biomass accumulation and the inheritance of the paraquat resistance trait in this highly self-fertilizing species. Results of this research indicated that the paraquat resistance traits in E. canadensis biotypes originating in California, USA and Ontario, Canada were not conferred by single major gene mechanisms. Segregating generations from crosses among resistant and susceptible biotypes all displayed transgressive segregation in biomass accumulation in the absence of the original selective agent, paraquat. However, when challenged with a discriminating dose of paraquat, progeny from the crosses of susceptible x resistant and resistant x resistant biotypes displayed contrasting responses with those arising from the cross of two resistant biotypes no longer displaying transgressive segregation. These results support the prediction that transgressive segregation is frequently expressed in self-fertilizing lineages and is positively correlated with the genetic diversity of the parental genotypes. When exposed to a new environment, transgressive segregation was observed regardless of parental identity or history. However, if hybrid progenies were returned to the parental environment with exposure to paraquat, the identity of fittest genotype (i.e., parent or segregant) depends on the history of directional selection in the parental lineages and the dose to which the hybrid progeny was exposed. It is only in the original selective environment that the impact of allelic fixation on transgressive segregation can be observed.

Genetic Analysis of Yield, Protein, and Oil Traits in Soybean Diallel Crosses for Enhanced Crop Quality and Productivity

The study was conducted at Sakha Research Station, ARC, Egypt, during three successive seasons from 2021 to 2023. A half diallel cross of fifteen F1 and F2 generations in addition to the six soybean parental genotypes namely, Japanese 13, Giza 111, Crawford, H18L54, Nc92-2231 and Linford were evaluated to determine the genetic behavior of yield and its components traits in both F1 and F2 generations, as well as seed protein and oil contents in F1. Results indicated that mean squares of General Combining Ability (GCA) and Specific Combining Ability (SCA) were significant and highly significant for all the studied characters of soybean genotypes in F1’s and F2’s, except SCA for 100-seed weight in F2’s only. The GCA/SCA ratios were less than unity in all traits, indicating that, the non-additive gene effects seemed to be responsible for the inheritance of these traits. The parental genotypes; H18L54, Nc 92-2231 and Linford seemed to be excellent combiners for days to flowering and maturity; however, Giza 111 and Japanese 13 were good combiners for seed yield. Meanwhile, Giza 111 was a good combiner for protein and oil content; also, H18L54 and Nc 92-2231 were good combiners for protein content. The crosses C7, C9, C10, C11 and C13 were earlier for maturity date, and also showed the most negative significant desirable Ŝij effects. The best (Ŝij) values in F2 were shown in the C1, C5, C8 and C15 crosses for seed yield/plant, these crosses also had the highest seed yield values in F2. The crosses; C5 and C8 showed significant to highly significant positive heterotic effects relative to the better parent for protein% and seed yield per plant. In addition three crosses; C13, C14, and C15 had highly significant positive heterotic effects relative to the better parent for oil % and seed yield per plant.

Estimation of the development of androgenic dihaploid lines of winter wheat of the R1 generation in vivo

Development of dihaploid lines using biotechnological methods can reduce not only the time required to breed a new variety, but also labor costs and technical resources. Earlier in our studies, there has been obtained seed material of androgenic dihaploid of the regenerated plants of the R0 generation, grown ex vitro. The next stage of the work delt with sowing the seeds of these plants in vivo. The purpose of the current study was to estimate the development of winter wheat plants of androgenic dihaploid lines of the R1 generation and parental varieties in vivo according to such characteristics as a length of phenophases, a vegetation period, morphometric estimation for comparison with each other and with parental genotypes, as well as for seed propagation. As a result of the study carried out in 2022–2024, there has been estimated a new nitial material of winter common wheat obtained on the basis of previously conducted biotechnological work. There have been studied androgenic dihaploid R1 lines according to the traits of vegetative and generative organs, for grain productivity of plants and seed germination. There have been selected promising lines for further breeding evaluation. Androgenic dihaploid lines of winter wheat of the R1 generation 79.1.5.1, 79.1.5.2, 79.2.1.1, 84.3.1.1, 84.3.3.1, 85.2.1.1 were the best according to vegetative, generative traits, grain productivity and seed germination. The best indicators of productivity and germination were characterized by androgenic dihaploid lines based on the hybrid ‘Rostovchanka 7 x Bezostaya 100’.

Multi-omics approaches define novel aphid effector candidates associated with virulence and avirulence phenotypes

BackgroundCompatibility between plant parasites and their hosts is genetically determined {Citation}both interacting organisms. For example, plants may carry resistance (R) genes or deploy chemical defences. Aphid saliva contains many proteins that are secreted into host tissues. Subsets of these proteins are predicted to act as effectors, either subverting or triggering host immunity. However, associating particular effectors with virulence or avirulence outcomes presents challenges due to the combinatorial complexity. Here we use defined aphid and host genetics to test for co-segregation of expressed aphid transcripts and proteins with virulent or avirulent phenotypes.ResultsWe compared virulent and avirulent pea aphid parental genotypes, and their bulk segregant F1 progeny on Medicago truncatula genotypes carrying or lacking the RAP1 (Resistance to Acyrthosiphon pisum 1) resistance quantitative trait locus. Differential gene expression analysis of whole body and head samples, in combination with proteomics of saliva and salivary glands, enabled us to pinpoint proteins associated with virulence or avirulence phenotypes. There was relatively little impact of host genotype, whereas large numbers of transcripts and proteins were differentially expressed between parental aphids, likely a reflection of their classification as divergent biotypes within the pea aphid species complex. Many fewer transcripts intersected with the equivalent differential expression patterns in the bulked F1 progeny, providing an effective filter for removing genomic background effects. Overall, there were more upregulated genes detected in the F1 avirulent dataset compared with the virulent one. Some genes were differentially expressed both in the transcriptome and in the proteome datasets, with aminopeptidase N proteins being the most frequent differentially expressed family. In addition, a substantial proportion (27%) of salivary proteins lack annotations, suggesting that many novel functions remain to be discovered.ConclusionsEspecially when combined with tightly controlled genetics of both insect and host plant, multi-omics approaches are powerful tools for revealing and filtering candidate lists down to plausible genes for further functional analysis as putative aphid effectors.

Adult-plant resistance to leaf scald and net form net blotch in food barley genotypes at a hot spot location in Ethiopia

Globally, the fungal pathogens Rhynchosporium graminicola and Pyrenophora teres f. teres produce foliar diseases that significantly reduce barley yield. These diseases are known as leaf scald and net form net blotch, respectively. One hundred food barley genotypes in reaction to the diseases were assessed in Ethiopia’s natural environment. Since Ethiopia is a secondary center of genetic diversity in barley and consequently its pathogens, this assessment is certainly of interest in identifying new sources of resistance and using the identified genotypes in breeding. In addition, effect of the diseases on yield and yield components of food barley and the association between the parameters were studied. A simple lattice design was used for the field testing. Ten center rows (5 m2) were assessed for grain yield, and the results were converted to t ha−1. Eyal classes and Eyal and Brown reaction types were used to evaluate the reactions of barley genotypes in one year breeding scheme. The association between the independent and dependent variables was examined using Pearson correlation in ellipses predictor. The Logistic and Gompertz models were employed to analyses disease rates. The maximum grain yield (6.7 t ha−1) and lowest grain yield (1.7 t ha−1) were recorded by genotypes HB#P356 and SARC#P42, respectively. Among evaluated genotypes, 21 % were susceptible, 44 % were moderately susceptible, 20 % were moderately resistant, and 15 % were resistant to leaf scald disease. Genotypes like HB#P1235, HB#P1244, HB#P1251, HB#P386 and the other 11 demonstrated resistance reactions to leaf scald disease. In reverse, the 17 genotypes, including HB#P394, SARC#P5, SARC#P29, and SARC#P12, were susceptible to scald disease. The reactions of genotypes to net form net blotch disease were as follows: 12 % were susceptible, 77 % were moderately susceptible, 8 % were moderately resistant, and 3 % were resistant. A few genotypes, including HB#P340, SARC#P10, and SARC#P14, were susceptible to net form net blotch. Genotypes, HB#P1319, HB#P825, and HB#P830, showed resistance to net form net blotch disease. Consequently, in later breeding schemes, these genotypes, which are resistant to leaf scald and net form net blotch, can be utilized as a parental genotype for crossing and variety development. Moreover, these genotypes can also be important as a genetic resource for future breeding and genetic research. Plant height and the severity of both diseases showed an adverse association (r = −0.1), suggesting that barley breeders should take these two factors into account when designing targeted their breeding program.

Recent Progress on Plant Apomixis for Genetic Improvement.

Apomixis is a reproductive process that produces clonal seeds while bypassing meiosis (or apomeiosis) without undergoing fertilization (or pseudo-fertilization). The progenies are genetically cloned from their parents, retaining the parental genotype, and have great potential for the preservation of genes of interest and the fixing of heterosis. The hallmark components of apomixis include the formation of female gametes without meiosis, the development of fertilization-independent embryos, and the formation of functional endosperm. Understanding and utilizing the molecular mechanism of apomixis has far-reaching implications for plant genetic breeding and agricultural development. Therefore, this study focuses on the classification, influencing factors, genetic regulation, and molecular mechanism of apomixis, as well as progress in the research and application of apomixis-related genes in plant breeding. This work will elucidate the molecular mechanisms of apomixis and its application for plant genetic improvement.

Dependence of the yield in late-generation lines on the spike productivity in original segregating populations of spring bread wheat

Background. An ascertained possibility of culling segregating populations on the basis on their yield or grain weight per spike as a character closely correlated with yield can increase the efficiency of breeding practice with spring bread wheat. Materials and methods. Sixteen F2 –F4 segregating populations of spring bread wheat were assessed for their grain weight per spike, average grain weight per spike among the top 10%, coefficient of variation for grain weight per spike, and yield. The pedigree method was applied to select 2 to 3 F7 lines from each population. The obtained lines were tested for their yield in F8 and F9 . The data of grain weight per main spike in the parents that had been crossed to produce the studied segregating populations were retrospectively taken into account while the results were processed. Results Segregating populations persistently differed in their average grain weight per spike and the coefficient of its variation in different years of research. None of the 36 late-generation lines significantly surpassed the reference cultivar in yield. All the considered indicators of segregating populations had no significant correlations with the yield of late-generation lines. Average values of grain weight per main spike in the parent genotypes and the best parent as well as the differences between the parents in the average grain weight per main spike tended to have a negative correlation with the yield of late-generation lines (r up to –0.58). Conclusion. The culling of segregating populations based solely on the yield or grain weight per spike is associated with a risk of losing high-yielding genotypes. Late-generation lines with high yields occur in combinations where the grain weight per main spike in one parent or on average among the parents is not expressed to its highest level or when both parents differ only slightly from each other in the expression of this character.

Genetic variability, character association and path analyses effects on fiber yield and yield attributing morpho-agronomic traits of tossa jute (Corchorus olitorius L.)

Jute (Corchorus spp.) is a natural fiber crop having a lower extent of genetic variability due to its self-pollinating nature. The success of any breeding program for variety development primarily depends on the presence of genetic variation in the parental genotypes. A field experiment was conducted in a randomized complete block design at ManikganjStation of Bangladesh Jute Research Institute (BJRI) during 2019-2020. The genetic divergence of 58 tossa jute (C. olitorius) genotypes including two pre-released standard varieties (O-9897, BJRI Tossa pat 4) and 56 accessions were studied to select genotypes having the most divergence in natural rainy condition. The jute genotypes were categorized into five clusters based on Mahalanobis D2 analysis. Cluster I and IV showed maximum inter-cluster distance (181.44) while the maximum intra-cluster distance (16.15) was recorded in cluster I. Cluster V revealed the highest values for number of nodes, stem mid-diameter, core diameter, green weight with leaves, dry stick weight and dry fiber weight per plant while cluster IV showed higher means for plant height, green bark thickness and leaf area. The highest contribution (47.14%) was wielded by plant height of total deviations. The results recommended that hybridization between genotypes of cluster V, IV and III could provide a wide range of discrepancies in the segregating generation which could offer chance for isolation of good genotypes with high fibre yielding lines.

Rapid transfer of the leaf rust resistance gene Lr52 for the improvement of bread wheat cultivar HD3086

For varietal improvement, parental genotypes are crossed and advanced to generate homozygous lines with selection for desirable traits like disease resistance and yield. In the current study, leaf rust resistance gene Lr52 from Lr52/Yr47/2∗Mace, the donor parent (DP), transferred to the recurrent parent (RP) HD3086, a popular Indian wheat cultivar, which has become susceptible to leaf rust. During the backcross breeding, the plants were grown sequentially under natural field conditions during the winter season and under controlled environmental conditions to take two crop generations during the summer season. Generations comprising F1, BC1F1, and BC2F1-3 plants were developed by crossing and successive backcrossing with RP HD3086 and further selfing to generate homozygous resistant lines. Plants with leaf rust resistance in backcross generations were selected phenotypically to identify the superior or similar plants as of RP HD3086. The Lr52/Yr47-linked SSR marker icg16c004_2 was initially utilized to confirm hybridity and foreground analysis in the BC1F1 generation but was found to be recombinant. Homozygous resistant (HR) lines in BC2F3 generation were selected based on leaf rust disease score and phenome recovery. Finally, the SSR markers unveiling parental polymorphism across the genome were employed to estimate the background recovery of phenotypically selected superior plants, revealing a recovery of 91.48–94.81 % of RP genome. The selected improved lines of HD3086+Lr52 displayed similar performance for most agro-morphological traits, and a few lines were also found to yield significantly superior to that of RP HD3086. Overall, the study shows the practical utility of phenotypic selection with intermittent selection under controlled and natural field conditions for improving popular cultivars with relatively higher speed and precision.

The microbiome and metatranscriptome of a panel from the Sarracenia mapping population reveal complex assembly and function involving host influence.

Sarracenia provide an optimal system for deciphering the host-microbiome interactions at various levels. We analyzed the pitcher microbiomes and metatranscriptomes of the parental species, and F1 and F2 generations from the mapping population (Sarracenia purpurea X Sarracenia psittacina) utilizing high-throughput sequencing methods. This study aimed to examine the host influences on the microbiome structure and function and to identify the key microbiome traits. Our quality datasets included 8,892,553 full-length bacterial 16s rRNA gene sequences and 65,578 assembled metatranscripts with microbial protein annotations. The correlation network of the bacterial microbiome revealed the presence of 3-7 distinct community clusters, with 8 hub and 19 connector genera. The entire microbiome consisted of viruses, bacterial, archaea, and fungi. The richness and diversity of the microbiome varied among the parental species and offspring genotypes despite being under the same greenhouse environmental conditions. We have discovered certain microbial taxa that are genotype-enriched, including the community hub and connector genera. Nevertheless, there were no significant differences observed in the functional enrichment analysis of the metatranscriptomes across the different genotypes, suggesting a functional convergence of the microbiome. We found that the pitcher microcosm harbors both rhizosphere and phyllosphere microbiomes within its boundaries, resulting in a structurally diverse and functionally complex microbiome community. A total of 50,424 microbial metatranscripts were linked to plant growth-promoting microbial proteins. We show that this complex pitcher microbiome possesses various functions that contribute to plant growth promotion, such as biofertilization, bioremediation, phytohormone signaling, stress regulation, and immune response stimulation. Additionally, the pitcher microbiome exhibits traits related to microbe-microbe interactions, such as colonization of plant systems, biofilm formation, and microbial competitive exclusion. In summary, the demonstrated taxonomical divergence and functionally convergence of the pitcher microbiome are impacted by the host genetics, making it an excellent system for discovering novel beneficial microbiome traits.

The use of seedling root and shoot traits to predict the saleable yield of elite red papaya genotypes

ABSTRACT Determining the saleable fruit yield of red hermaphrodite papaya (Carica papaya L.) relies on waiting until tree maturity. Recombinant inbred lines (RIL) seedlings (F6-F7 RIL) were assessed for fresh root length, fresh shoot weight, fresh shoot width, dry root weight and dry shoot weight during three growth stages after sowing (0-30 days after sowing; DAS, 31–60 DAS and 61–90 DAS). During the 31–60 DAS period, significant intra-genotypic variation was observed for each trait across the RIL assessed. A strong genotypic correlation at growth stage II was predicted among the traits (P < 0.05; rg > 0.60), with a moderate to high broad-sense heritability (H2 b.s; > 0.30) and with genetic advances of up to 10% in the RIL compared to the parental genotypes. Growth stage II was most reliable for predicting saleable fruit yield (R 2 = 0.73) with levels of influence of traits measured across the RIL in the following order: fresh root length (40% to 70%) > dry root weight (20% to 50%) > dry shoot weight (10% to 48%) > fresh shoot width (13% to 38%) > fresh shoot weight (1% to 42%). Hence, these F7 genotypes will be used to develop new F1 hybrids with significant increases in saleable fruit yield.

Differential photosynthetic yield across a wide range of temperatures for Northern and invasive Watermilfoils

Eurasian watermilfoil (Myriophyllum spicatum) is one of the most challenging invasive aquatic plant species in Minnesota. Eurasian watermilfoil has hybridized with the native Northern watermilfoil (Myriophyllum sibiricum), creating a more complex issue when it comes to invasions. The hybridization of watermilfoil has increased difficulty for management and an underlying biological mechanism explaining this difficulty has yet to be determined. We compared the photosynthetic temperature response of the parental Northern and Eurasian parental genotypes to five hybrid watermilfoils using pulse amplitude modulated (PAM) chlorophyll fluorometry to determine if there are intrinsic physiological differences in photosynthesis between genotypes. We examined both the ratio of variable to maximal fluorescence (Fv/Fm) and light-adapted quantum yield of photosystem II (PSII) electron transfer (ΦPSII) every 5 °C from 0 to 45 °C representing sub- to supraoptimal water temperatures. On average, hybrids had 6% and 8% higher Fv/Fm and ΦPSII values respectively, than parental genotypes across all temperatures. In both parental and hybrid genotypes Fv/Fm values were consistent from 0 to 35 °C and declined 36% as water temperature approached 45 °C. Optimal water temperature for ΦPSII was between 25-35 °C and hybrids had 17% higher values for suboptimal temperatures between 5-15 °C. Our findings indicate that although the many strains of watermilfoil are morphologically similar, they differ in their photosynthetic capacity and may indicate heterosis. Innate differences between parental strains and hybrids could impact overall primary productivity, life history characteristics, and overall invasiveness. These factors could also be contributing to the documented management failures seen in field populations.

Elucidation of gene action and estimation of combining ability effects for fruit yield attributes and biochemical traits in brinjal (Solanum melongena L.)

Abstract The present investigation was undertaken in brinjal (Solanum melongena L.) to estimate combining ability and gene action following a half diallel mating design using ten parents. The ratio of genetic variance components, σ2gca/σ2sca and σ2D/σ2A, showed dominant gene action, indicating the presence of non-additive genetic variance for days to 50% flowering, fruit yield per plant, total phenol, antioxidant activity and total soluble sugar. The traits fruits per plant, fruit girth, and fruit weight showed additive genetic variance. Among the parental genotypes, AB 15-08, ABSR 2 and AB 20-13 were found to be good general combiners for fruit yield, fruits per plant, and total soluble solids. The three highest-ranking hybrids were AB 15-08 × AB 20-13, AB 15-08 × AB 20-03 and AB 20-07 × GP BRJ 224. The above hybrids would be rewarding for harnessing heterosis. Keywords: Diallel cross, brinjal, combining ability, fruit yield, antioxidant activity

Correlation between Pulp Weight and Physio-Biochemical Traits of Mango (Mangifera indica L.) Germplasms

Aim: The present study was conducted to evaluate the relationship between pulp weight and various physio-biochemical attributes among 30 diverse mango (Mangifera indica L.) germplasms under the Tarai region of Uttarakhand. Place and Duration of Study: This investigation was carried out at Horticulture Research Centre, GB Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, during the years 2021 and 2022. Methodology: The selected 30 germplasms included two commercially grown cultivars and 28 primary germplasms sourced from different eco-geographical locations of Uttar Pradesh and Uttarakhand states of India. Pulp weight, physical characteristics (fruit shape index, pulp/stone ratio) and biochemical parameters (Brix/Acid ratio and pH) were measured for each germplasm and statistically laid out in completely randomized design (CRD), and their relationships were analyzed using simple linear regression and Pearson’s correlation coefficients. Results: The maximum values recorded among the studied germplasms were 300.73 g for pulp weight (PMGC-19), 2.41 for fruit shape index (PMSS-31), 0.309 for pulp/stone ratio (PMGC-71), 140.87 for Brix/Acid ratio (PMGC-96) and 5.87 for pH (PMGC-96). Among the physical attributes, pulp weight exhibited a moderate positive correlation with fruit shape index (r = 0.419), indicating that fruits with a higher shape index tend to have increased pulp weight. Whereas, a moderate negative correlation was observed between pulp weight and pulp/stone ratio (r = -0.457), suggesting that as the pulp/stone ratio increases, pulp weight decreases. However, biochemical attributes such as Brix/Acid ratio and pH showed no significant correlation with pulp weight (r = 0.005 and r = 0.018, respectively), indicating an independent influence of these parameters on pulp characteristics. Conclusion: These findings provide important insights into the complex relationships between pulp weight and other physio-biochemical traits in mango, some traits for breeding programs aimed to improving fruit quality and pulp content and identified superior and promising germplasms for cultivation as well as potential parental genotypes in mango improvement programs.