Open-pollinated Populations Research Articles

Segregation analysis and floral phenotype of T2 transgenic yellow cosmos (Cosmos sulphureus Cav.) carrying neomycin phosphotransferase II gene in second generation

Abstract. Muchyiddin MGAA, Sawitri WD, Irsyadi MB, Swandari T, Purwantoro A. 2024. Segregation analysis and floral phenotype of T2 transgenic yellow cosmos (Cosmos sulphureus Cav.) carrying neomycin phosphotransferase II gene in second generation. Biodiversitas 25: 1711-1717. The seed of transgenic yellow cosmos (Cosmos sulphureus Cav.) lines harbouring neomycin phosphotranferase II (nptII) gene have been obtained from our previous studies. The nptII selectable marker gene is commonly used for developing a method to estimate the number of targeted gene integrated into the genome. In order to produce successful clones, it is important to ensure that transgenes are inherited sexually as the dominant trait in T2 progeny. This study aimed to obtain the segregation patterns of nptII gene in two populations derived from open- and self-pollinated and evaluated floral phenotypic of T2 transgenic yellow cosmos. The molecular analysis of transgenic yellow cosmos was conducted by PCR and the obtained data was analyzed using a Chi-Square test. The results showed that transgenes were inherited in 1:1 for transgenic and wild-type in both self- and open-pollinated populations. Therefore, it indicated that T2 transgenic plants were still unstable and evolved continuously to segregate independently in the over generation. Surprisingly, the morphological changes were detected in transgenic plants. The mixture of ligulate and tubular types in ray floret was found in some of the flower types in T2 yellow cosmos. In this case, nptII gene may diverge in apparently random genome insertion. This insertion would induce morphological changes in the ray floret type of flower since recombination estimates varied among transformation events.

Estimation of Additive and Dominance Effects in an Acacia crassicarpa Multi-Environment Progeny Trial Using Genomic Pedigree Reconstruction

Abstract Acacia crassicarpa is an important tree species in Southeast Asia, where hundreds of thousands of hectares of planted forests are supported by advancements in silviculture and genetic improvement. Although possible, controlled pollination is impractical for advancing breeding populations, requiring an unreasonable effort to produce more than a few crosses per year. For this reason, breeding populations often are bred by open pollination. This study used large-scale pedigree reconstruction in multi-environment trials to assess full-sib families to model the genetics of the quantitative traits survival, straightness, height, diameter at breast height, tree volume, mean annual increment (MAI), and basic density. The traits were predominantly controlled by additive effects, with heritabilities between 0.09 for survival and 0.45 for basic density. The genetic correlation across sites was high for all traits, showing the low impact of genotype-by-environment interaction. The trait-trait correlation showed that straightness was independent of any other traits, survival was only correlated with MAI, and growth traits were highly correlated among themselves. Basic density was positively correlated with growth traits and MAI. Study Implications: Parentage analysis using an informative single nucleotide polymorphism panel was used to reconstruct pedigree and allow a full-sib family model to estimate additive and dominance effects and genetic correlations across sites and among important traits in an open-pollinated population. The genetic control of all traits assessed in this study was mainly additive. In this scenario, the recommended breeding strategy is forward selection of outstanding progeny for advanced generation breeding and backward selection of outstanding parents to produce seed for deployment via family forestry. Full-sib families can be identified by pedigree reconstruction at a seedling stage, followed by tissue culture multiplication, rooted cutting propagation, and plantation establishment.

Genetic diversity among maize (Zea mays L.) inbred lines adapted to Japanese climates.

Understanding the genetic diversity of inbred lines is vital for development of superior F1 varieties. The present study aimed to analyze Japanese maize parental inbred lines and determine their genetic diversity for future breeding. Genetic analyses were conducted using multiple methods. Principal component analysis (PCA), phylogenetic trees, and Bayesian clustering reflected borders between heterotic groups according to the derivation of each inbred line. A self-pollinated line derived from a classic F1 variety and another line from an open-pollinated population from the same derivation were classified as separate components by PCA and Bayesian clustering. The result suggests that open pollination could be essential in modern breeding. Of those classified as dent or flint based on their derivation, some had a combination of all components or clusters. Therefore, the classification of inbred lines should be based on their derivation and DNA markers. The findings will be valuable for breeding and genetic studies in Japan. Additionally, these techniques may be used to obtain a more significant number of SNPs and related phenotypic data.

GENETIC STUDY OF ROCK MELON (CUCUMIS MELO L. VAR. CANTALUPENSIS ): FRUIT VARIABILITY IN SEGREGATING POPULATIONS AND AFTER SELFING PERFORMANCE

Rock melon (Cucumis melo L. var. Cantalupensis) is a commercial-type melon with a wide distribution worldwide. Rock melons with larger fruit sizes are more in demand in restaurants, the food processing industry, and large families. In breeding for larger fruits, the increased genetic variability through introgression and recombination is the main factor; then, it can continue to purify before becoming a parental line. The presented study sought to recognize the variability of the open-pollinated population and their performance after selfing. The experiment ran from September 2021 to July 2022 at the Field Experimental Station, Politeknik Negeri Lampung, Indonesia. The experiment consisted of two sub-experiments carried out without experimental design. There was wide variability in both quantitative and qualitative variables in the open-pollinated populations, except fruit flesh color, weight, and sugar content. Population after selfing (S1 population) had more uniform qualitative traits. All the fruits sampled were medium elliptic with netted rinds followed by two-color variants (greenish yellow and green). Also, narrow variability occurred for the traits, fruit diameter, weight, and sugar content, followed by low heritability for the quantitative traits.

Yield of Syn-1 synthetic varieties of tropical onion resulting from openpollinated Brazilian populations

Due to technological limitations for the development of onion hybrids, first-cycle synthetic varieties (Syn1-SV) could be an alternative to partially explore heterotic vigor. The growing areas of onion hybrids in Brazilare mainly defined by bulb yield and uniformity. From this perspective, the present study aimed to developtropical onion Syn1-SV and estimate mid-parent heterosis (Hm), heterobeltiosis (Hp), and standard heterosis(Hs) as an alternative to hybrid development. Six Syn1-SVs, eight open-pollinated (OP) populations, and onecommercial hybrid were evaluated in a randomized block design with three replications, in two semesters, forthe commercial bulb yield (CBY) and days to bulb harvest (DBH). Significant differences were observed fortreatments (T), semesters (S) and the T*S interaction for both variables (p-value<0.05). The OPs ‘Alfa SF RT’ inthe first semester and ‘IPA11’ in the second semester were the most precocious treatments. The highest CBYwas estimated in the commercial hybrid (105.8 t ha-1) and in ‘Alfa SF RT’ (45.5 t ha-1) in the first and secondsemesters, respectively. Three Syn1-SVs showed positive Hm values, ranging from 2.0% to 6.3% for CBY. ThreeSyn1-SV showed positive Hp values in the first semester, ranging from 3.0% to 5.2%, for CBY. Only the Syn1-SV ‘AlfaSF RT’ × ‘BRS Alfa São Francisco’ (48.9 t ha-1) showed positive Hs values, surpassing by a small value the controlOP population ‘IPA11’ (48.0 t ha-1), indicating the potential of Syn1-SV as an option for onion hybrids.

Effects of floral traits on geitonogamous selfing rates and reproductive success in a protandrous species

Abstract Through its role in regulating pollinator behavior, floral display size and nectar gradient within inflorescences may alter the extent of geitonogamy and thus female reproductive success in protandrous species. However, this has seldom been examined. By quantifying selfing rate, seed number and male donor number, we estimated the effects of floral display size, nectar gradient and their interactions on plant reproduction in protandrous Aconitum gymnandrum. At plant level, selfing rate and seed number increased with a larger floral display of both main and lateral inflorescences but reduced with a declining nectar gradient. The effects of floral display of the main inflorescence on selfing rate and seed number were altered by the nectar gradient and floral display of lateral inflorescences as shown by their interactions. Larger floral display of the main inflorescence reduced male donor diversity. At flower level, the selfing rate and the seed number varied among flower positions, in which bottom flowers had lower selfing rate and higher seed number than top flowers. The effects of floral traits on geitonogamous selfing rate and seed number were inconsistent among flower positions. Although low cost of geitonogamous selfing for reproduction was tested by hand-pollination, the selfing rate was negatively correlated with seed number and male donor number in open-pollinated population. Our results suggest the potential role of trade-off between geitonogamy cost and reproductive benefit in evolution of floral traits. The variation of selfing rate and reproductive success among flowers may alter the trade-off and thus complicate evolution of traits.

Simultaneous effect of water deficit and mating systems in fennel (Foeniculum vulgare mill.): Genetics of phytochemical compositions and drought tolerance

Limited information is available on the impact of deliberate selfing compared with open-pollination and its interaction with water deficit on productivity and phytochemical constituents of essential oil in fennel (Foeniculum vulgare Mill.) and also the genetic analysis of traits. During this research, 21 selfed (S1) and 42 open-pollinated (OP) progenies of fennel developed in 2017–18 were evaluated in the field under well-watered and water deficit conditions in two years (2019 and 2020) for phytochemical and productivity traits. GC–MS analysis revealed that among the eight different compounds in the essential oil, trans-anethole, fenchone, estragole, and limonene were found to be the main constituents. Water deficit greatly decreased grain yield and essential oil content, α-pinene, trans-anethole, and anisaldehyde; while significantly increased β-myrcene, limonene, γ-terpinene, fenchone, and estragole, in both populations. Compared with open-pollination, selfing reduced the mean performance of seed and essential oil yield, β-myrcene, and limonene under normal and water deficit conditions, and α-pinene under normal condition, demonstrating the effects of inbreeding on these traits. The relationship between γ-terpinene and anisaldehyde was positive in the S1 population; while in the OP population, there was significant and negative association between these two constituents. The genetic analysis of traits indicated that additive gene action played an important role in controlling most of the traits, but that both additive and non-additive gene effects played a role in the genetic control of grain yield; indicating that selection based on an index may be more useful for improvement of grain yield in recurrent selection programs.

ZmCCT10-relayed photoperiod sensitivity regulates natural variation in the arithmetical formation of male germinal cells in maize.

Extensive mutational screening studies have documented genes regulating anther and pollen development. Knowledge concerning how formation of male germinal cell is arithmetically controlled in natural populations, under different environmental conditions, is lacking. We counted pollen number within a single anther and a maize-teosinte BC2 S3 recombinant inbred line population to identify ZmCCT10 as a major determinant of pollen number variation. ZmCCT10 was originally identified as a photoperiod-sensitive negative regulator of flowering. ZmCCT10 inactivation, after transposon insertion within its promoter, is proposed to have accelerated maize spread toward higher latitudes, thus allowing temperate maize to flower under long-day conditions. We showed that the active ZmCCT10 allele decreased pollen formation. As different active and inactive ZmCCT10 alleles have been found in natural maize populations, this represents the first report of a gene controlling pollen number in a crop natural population. These findings suggest that higher pollen number, which provides a competitive advantage in open-pollinated populations, may have been one of the major driving forces for the selection of an inactive ZmCCT10 allele during tropical maize domestication. We provide evidence that ZmCCT10 has opposite effects on cell proliferation of archesporial and tapetum cells and it modulates expression of key regulators during early anther development.

Mango seedling genotyping reveals potential self-incompatibility and pollinator behavior

Mango (Mangifera indica) is tropical fruit widely cultivated and appreciated for its sweet and aromatic fruit. There is great diversity among mango cultivars for important fruit quality and agronomic traits that could be leveraged as part of a mango breeding program. Historically, most genetic improvement of this species has been the result of chance seedlings. The recent publication of multiple mango genomes and availability of genomic resources is facilitating the efficient breeding of mango, but controlled pollination of mango is challenging with only a few out of thousands of panicle-borne flowers developing into fruit. Therefore, genotyping open-pollinated seedlings could be a labor-saving method to select favorable hybrids in a breeding program. An array of 384 single-nucleotide-polymorphism markers was used to genotype 140 mango cultivars and 575 mango seedlings from eleven open-pollinated populations in a mango diversity collection. Analysis of mango cultivars confirmed hybrid parentage in many instances and identified potential paternal parents for cultivars with unknown parentage. For the seedlings analyzed, the Dixon test of Gower's genetic dissimilarity (GD) values among identified triads revealed 161 significant triads (P≤0.05), indicating high confidence for paternal identification. The remaining triads had GD values less than 0.15 (n = 323), between 0.15 and 0.2 (n = 10), or between 0.2 and 0.3 (n = 5). In total, 70% of the hybrids were paired to a single paternal parent. Analysis of selfing rates indicated ‘Tommy Atkins’ had the highest selfing rate (40.4%) and ‘Glenn’ had the lowest (1.1%). Analysis of population structure and phylogeny divided the mango germplasm into three distinct clusters. The identified paternal pollen donors were mapped within a mango diversity collection and indicated mango pollinators can affect pollination beyond adjoining trees. This strategy can be used to aid mango breeding research and has identified intriguing hybrids for future evaluation.

Seedling Selection in Olive Breeding Progenies.

The long juvenile period in olive (Olea europaea L.) delays the evaluation of characters of interest and prolongs the selection of new cultivars in the breeding programs. Therefore, it is important to use accurate selection criteria and appropriate selection pressure to make an effective identification of the superior genotypes and to identify which parents transmit lower juvenile periods to their descendants. In this study, the juvenile period, vigor, fruit fresh weight, and oil content of fruit on a dry weight basis were evaluated in 1568 genotypes from two independent open-pollinated populations; G07, that included 520 genotypes from 25 cultivars and 1 breeding selection and G14, with 1048 genotypes from 13 cultivars. This evaluation was used to test different selection criteria and define optimal selection pressure at the initial stage of an olive breeding program. Wide ranges of variation were obtained for all the characters measured, with higher variability within progenies than between progenies. “Askal” and “Barnea” seem to be the cultivars transmitting the shorter juvenile period to the descendants. In the case of fruit fresh weight and oil content, transgression of variability limits of the parents was observed. Significant correlation was found between mean values of fruit fresh weight of progenies and their parents for G07 (0.59) and G14 (0.95). Selection was made using two selection index formulas (SI1 and SI2). A high coincidence was found between the individuals selected by both formulas and the correspondent selection pressures applied; 15% for SI1, and 14% for SI2. A wide variability in the percentage of selected genotypes was found, from no individuals selected from some progenies to more than 20% of genotypes selected in some others. These results underline the need to explore the wide genetic variability currently hosted in germplasm collections for an optimal choice of parents in olive breeding works.

Microsatellite Loci Reveal High Genetic Diversity, Mutation, and Migration Rates as Invasion Drivers of Callery Pear (Pyrus calleryana) in the Southeastern United States.

Pyrus calleryana Decne. (Callery pear) is a deciduous tree native to China, Japan, Korea, and Taiwan. It is a popular ornamental tree in the United States (US) with early spring blooms and vibrant fall color. There are at least 26 cultivars of P. calleryana available in the US of which “Bradford” is the most well-known. Open-pollinated P. calleryana escapees are becoming one of the most common invasive tree species in the eastern United States. Developing better management practices for invasive P. calleryana requires detailed knowledge about reproductive biology and genetic diversity of the species, however, little is currently known about genetic variability within those open-pollinated populations. We investigated genetic diversity and population structure of non-cultivated, escaped P. calleryana populations within a ∼177 km radius in the southeastern United States. Because P. calleryana exhibits a range of morphological variation with great evolutionary potential, we hypothesized that a high genetic diversity would be manifested among escaped P. calleryana. Using 15 previously developed microsatellite loci, we genotyped 180 open-pollinated P. calleryana individuals that were collected across six naturally occurring sites in Tennessee, Georgia, and South Carolina, United States. Our results demonstrated the presence of a population structure with high genetic diversity, high gene flow, and high genetic differentiation between individuals across collection sites. Our results revealed that P. calleryana populations had differentiated shortly after the introduction to the US, most likely from specimens imported from Asia, consistent with historical records and our prior findings. The high invasive potential of the species is perhaps best underscored by transformation of P. calleryana specimens introduced from Asia into escape populations at continental scale across the United States. Our data also provided novel insight into potential issues that could be problematic for the future as P. calleryana may pose a potential threat to the economy, ecology, and native biodiversity in invaded areas.

Evaluation of open-pollinated offspring in Cyclamen persicum using vegetative phenology models in a primitive breeding population

Abstract Cyclamen is commercially cultivated to produce the pot and garden flowering plants by sowing the seeds, and the number of leaves is an important trait for the beginning of the initiations of flower buds and flowering. The yield potential is affected by the life cycle of a plant and the plant breeders can have good decisions making with the prediction of plant phenology. In this study, a polynomial function was proposed for modeling behavior of cyclamen offspring during the vegetative growth. This modeling is based on information on environmental changes and plant morphology up to the flowering stage. For this purpose, 30 pots (individuals) from a 121-individual population, which were the same in the size, were considered for sampling of data. The data were recorded as time series that include temperature (°C), relative humidity (%), leaf width (mm) and number of leaves. The output of this model is the number of leaves and the recorded inputs are the time (growth cycle; days), temperature, relative humidity and leaf width. Using the Quantum-behaved Particle Swarm Optimization (QPSO) algorithm, the constant coefficients of the proposed function (linear model) was calculated to match the input and output values to each other. To illustrate the robustness and efficiency of model, the growth rates of all individuals were compared using this proposed model. The result of root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R 2 ) between the estimated and observed values for each individual showed that 63% of the tested open-pollinated (OP) population is marketable. Therefore, phenology model could be a good estimation of the vigor of the OP population for commercial production. It should be noted that in obtaining the model, only five individuals were used randomly as training data, and the obtained model was fitted to the others as test dataset without changing the coefficients. Furthermore, a Gaussian model of the whole dataset showed that the OP seeds of cyclamen could be utilized to produce the potted flowering cyclamen without any worry about non-uniformity of harvest for the market if the optimum temperature would be adjusted.

Evidence for self-compatibility and variation for inbreeding depression within breeding populations of fennel (Foeniculum vulgare Mill.)

Fennel is an open-pollinating medicinal crop that needs to be pollinated by insects such as bees to have maximum fruit and oil yield. This may limit fruit production in the absence of insect pollinators. In order to examine the possibility of the plant evolution to self-pollination, using partially self-compatible ecotypes, eight populations of self and bee-pollinated fennel each consisted of 9 plant genotypes forming a final collection of 72 contrasting lines were field evaluated in two years. Averaged over all plant genotypes and populations, progenies derived from selfing had 20.86 and 3.58 % less fruit yield than those derived from bee pollination in two consecutive years mainly due to the depression in the number of effective umbels per plant as the main yield component. Multivariate data analysis differentiated self- and open-pollinated populations; however, this discrimination and inbreeding depression were significantly high only at the year of establishment in this perennial herb. Also, inbreeding depression was not observed for fruit yield, yield components and essential oil content in some of the genotypes within the populations with no or minimum genotype*year interaction. This suggested that it is possible to utilize self-pollination in developing environmentally stable productive pure line varieties with possibly modified essential oil content applicable for future genetic improvement of fennel.

Morphological and Phenological Characterizations of Some Male and Female Promising Pistachio Genotypes from an Open-pollinated Population

ABSTRACT Pistachio is one of the most important and high economic nut crops in the world. In the present research, the phenological and pomological traits of twenty superior male genotypes (MG) and twenty superior female genotypes (FG) of a pistachio open-pollinated population were evaluated along with five Iranian commercial pistachio cultivars in Damghan, Iran. A multilayer perceptron neural network (MLP) was also used for sensitivity analysis of kernel and nut traits based on leaf and shoot properties. The nut dry weight in selected female genotypes was between 0.7 and 1.28 g, in kernel dry weight between 0.34 and 0.63 g, and in the percentage of split nuts were between 58% and 93%. FG17 with the largest nut and kernel length and FG18 genotype with big green kernel have the heaviest kernel and nut dry weight. Flowering time and nut harvesting times had wide variation among genotypes. The MG20 was identified as male genotypes with a long flowering period (12 days). According to MLP analysis, leaf length, inflorescence rachis length, and width had the highest sensitivity coefficient. The results indicated that most of the genotypes were suitable in terms of nut and kernel weight and size, and kernel color which can be examined for field trials. Furthermore, they could be useful as a parent to be crossed to generate appropriate populations or improve cultivars.

Genomic Studies Reveal Substantial Dominant Effects and Improved Genomic Predictions in an Open-Pollinated Breeding Population of Eucalyptus pellita.

Most of the genomic studies in plants and animals have used additive models for studying genetic parameters and prediction accuracies. In this study, we used genomic models with additive and nonadditive effects to analyze the genetic architecture of growth and wood traits in an open-pollinated (OP) population of Eucalyptus pellita. We used two progeny trials consisting of 5742 trees from 244 OP families to estimate genetic parameters and to test genomic prediction accuracies of three growth traits (diameter at breast height - DBH, total height - Ht and tree volume - Vol) and kraft pulp yield (KPY). From 5742 trees, 468 trees from 28 families were genotyped with 2023 pre-selected markers from candidate genes. We used the pedigree-based additive best linear unbiased prediction (ABLUP) model and two marker-based models (single-step genomic BLUP – ssGBLUP and genomic BLUP – GBLUP) to estimate the genetic parameters and compare the prediction accuracies. Analyses with the two genomic models revealed large dominant effects influencing the growth traits but not KPY. Theoretical breeding value accuracies were higher with the dominance effect in ssGBLUP model for the three growth traits. Accuracies of cross-validation with random folding in the genotyped trees have ranged from 0.60 to 0.82 in different models. Accuracies of ABLUP were lower than the genomic models. Accuracies ranging from 0.50 to 0.76 were observed for within family cross-validation predictions with low relationships between training and validation populations indicating part of the functional variation is captured by the markers through short-range linkage disequilibrium (LD). Within-family phenotype predictive abilities and prediction accuracies of genetic values with dominance effects are higher than the additive models for growth traits indicating the importance of dominance effects in predicting phenotypes and genetic values. This study demonstrates the importance of genomic approaches in OP families to study nonadditive effects. To capture the LD between markers and the quantitative trait loci (QTL) it may be important to use informative markers from candidate genes.

Cameroon Virescens Oil Palm (Elaeis guineensis) from IOPRI’s Germplasm

In the assumption of oil palm breeders, virescens oil palm type has no real economic value. Therefore, the nigrescens is more considered. However, the virescens gives a visual cue that fruits are ripe without waiting to detach. In 2010, Indonesian Oil Palm Research Institute (IOPRI) successfully planted an open-pollinated population of Cameroon oil palm. The population was characterized for virescens type frequency, as well as the bunch components, quantity and quality of crude palm oil. The virescens frequency per accession was sufficiently wide, ranging from 3.33-65.71%, and was affected by the parent type, nigrescens or virescens. Most of the virescens’s fruit form is observed to be of dura, except one sample, which was observed to be tenera. The mesocarp to fruit (MF) and industrial extraction ratio (IER) percentage are similar to the nigrescens dura, namely 37.7% and 9.5%, respectively. Its oil quality is better than nigrescens, and it has total carotene ranging from 155-1246 ppm. The oleic fatty acid is higher than 50%, and the palmitic is lower than 40%. Due to the ease of determining mature fruits, as well as the higher oil quality, virescens oil palm type is recommended to be introgressed in a breeding program.

Regional Differences in the Structure of Juglans nigra Phytobiome Reflect Geographical Differences in Thousand Cankers Disease Severity

Thousand cankers disease threatens Juglans nigra (Eastern Black Walnut) in urban and natural landscapes. Incidence and severity of thousand cankers disease is higher in the host’s introduced range in the western United States. We hypothesized that these differences are driven partly by geographical variation in the host phytobiome due to its roles in host stress tolerance, nutrient acquisition, and defense. To evaluate the role of the phytobiome in mediating thousand cankers disease, we characterized the J. nigra phytobiome of diseased and healthy trees in portions of its native (Indiana and Tennessee) and introduced (Washington) ranges. Grafted clones present in each state and open-pollinated populations were sampled. DNA was extracted from soil and branch (caulosphere) tissues and internal transcribed spacer and 16s regions were sequenced for characterization of fungal and bacterial communities. We found that microbial communities in the caulosphere and soil differ between native and introduced ranges of J. nigra and harbor different mutualistic and pathogenic microorganisms. Additionally, caulosphere microbial communities were more species rich and diverse in the native range of J. nigra, suggesting greater levels of functional redundancy and multifunctionality in the native-range phytobiome compared with the introduced range. We also found higher network complexity in the caulosphere of trees in the introduced range and evidence for two alternative stable community states associated with diseased and healthy trees. Our results provide support for the hypothesis that geographical variation in thousand cankers disease incidence and severity is partially driven by differences in the phytobiome of J. nigra in its introduced and native ranges. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Maize Open-Pollinated Populations Physiological Improvement: Validating Tools for Drought Response Participatory Selection

Participatory selection—exploiting specific adaptation traits to target environments—helps to guarantees yield stability in a changing climate, in particular under low-input or organic production. The purpose of the present study was to identify reliable, low-cost, fast and easy-to-use tools to complement traditional selection for an effective participatory improvement of maize populations for drought resistance/tolerance. The morphological and eco-physiological responses to progressive water deprivation of four maize open-pollinated populations were assessed in both controlled and field conditions. Thermography and Chl a fluorescence, validated by gas exchange indicated that the best performing populations under water-deficit conditions were ‘Fandango’ and to a less extent ‘Pigarro’ (both from participatory breeding). These populations showed high yield potential under optimal and reduced watering. Under moderate water stress, ‘Bilhó’, originating from an altitude of 800 m, is one of the most resilient populations. The experiments under chamber conditions confirmed the existence of genetic variability within ‘Pigarro’ and ‘Fandango’ for drought response relevant for future populations breeding. Based on the easiness to score and population discriminatory power, the performance index (PIABS) emerges as an integrative phenotyping tool to use as a refinement of the common participatory maize selection especially under moderate water deprivation.

Seleksi Pendonor Serbuk Sari Sifat Kuantitas Endosperma Skor Tinggi pada Kelapa dalam Kopyor

Endosperm quantity in kopyor coconut determines the quality of kopyor coconut. However, data of the best parental based on their progeny test is unavailable yet. In this study, we employed polycross approach and SSR molecular marker to estimate general combining ability of the best pollen contributor for the breeding purpose of this trait. Totally 151 kopyor coconuts were collected from the naturally open-pollinated population of kopyor Tall coconut Agom Lampung. The harvested nuts were rated for their endosperm quantity (scored 1-9). The analysis identified 31 paternal trees of the 53 progenies. The TJ-185 with the highest GCA has been considered as a promising paternal tree for development of high endosperm quantity of kopyor coconut.Keywords: combining ability, molecular marker, paternal trees, polycross, tall coconut

Association among Agro-morphological Traits by Correlations and Path in Selection of Maize Genotypes

In the State of Espírito Santo (Brazil), family farmers have grown a number of maize varieties for decades, consisting of open-pollinated populations with valuable importance for the livelihood of smallholder farmers. The study aimed to analyze the cause and effect of associations between agro-morphological traits for increasing yields in maize populations cultivated. A total of 16 maize accessions of in vivo conservation works in eight different locations were evaluated, in a randomized complete block design with three replicates, totaling 48 experimental units. Genetic parameters, genotypic, phenotypic, and environmental correlation were estimated, and a path analysis was conducted. In general, accessions presented enough genetic variability, showing significant differences for all traits analyzed statistically (P≤0.05). The first cob insertion height with plant height and final plant stand variables presented heritability (h2) higher than 80%, suggesting that superior genotypes could be determined. Highest estimates of phenotypic correlations (rp) were found between the first cob insertion height with plant height and total number of cobs with number of cobs per plant (0.85). For estimates of genotypic correlations (rg), the highest were between (i) the first cob insertion height and plant height; (ii) number of grains per row and number of cobs per plant; (iii) total number of cobs and final plant stand. Maize final plant stand and one thousand seed weight were observed to be traits that could be determinant in grain yield increase.