Heritability Coefficients Research Articles

Transgressive variation in productivity traits in F2 naked oat hybrids

One of the most effective methods for increasing yield and resistance to abiotic and biotic factors in the environment is genetic selection and improvement of varieties. Solving these tasks is possible using positive transgressions, which are of great practical importance at this stage of selection. The aim of the research was to determine the coefficient of heritability in the broad sense (H2 ) and the degree and frequency of transgressions for productivity traits in second-generation hybrids of naked oat, created by crossing based on the eco-geographical principle and selection of economically valuable biotypes for further breeding work. During 2021, research was conducted on 15 intervarietal hybrids. F2 and parental components were analysed for traits such as plant height, spike length, number of spikelets per spike, number of grains per spikelet, and grain weight per spikelet. Field research methods (phenological observations), laboratory methods (structural analysis of the material under study), and mathematical-statistical methods (objective evaluation of the experimental data obtained) were used. A prominent level of the coefficient was observed for the trait “grain weight per spikelet”, ranging from 0.66 to 0.88 in hybrid populations OM 11-3007/Abel, OM 2803/Abel, Percy Can/Inermis, Percy Can/Abel. The analysis of the second-generation F2 intervarietal hybrids of naked oat allowed the identification of transgressions for all the studied traits. The highest number of positive transgressions was found for the following productivity traits: spike length (Tf 31.82 – 59.09%, Td 7.53 – 15.49%); number of spikelets per spike (Tf 27.30 – 54.50%, Td 8.85 – 26.49%); number of grains per spikelet (Tf 45.50 – 77.27%, Td 16.63 – 27.62%); and grain weight per spikelet (Tf 63.64 – 81.80%, Td 18.12 – 25.36%). The selection-genetic analysis of studying the nature of heritability, frequency, and degree of transgressive variation in spikelet productivity traits of F2 naked oat hybrids allowed the identification of a considerable number of transgressive forms, in which productivity elements vary widely, indicating successful selection work in creating promising high-yielding breeding material

Variability and heterosis of seed vigour traits in hybrid rice (Oryza sativa L.)

The cultivars with high seed vigor are desirable for farmers to establish optimum plant stand under sub-optimal field conditions. The basic physiological processes are required to understand the hybrid vigor phenomenon, particularly for seed vigor and associated characteristics. Limited information on seed vigor in rice hybrids and their parental lines in relation to physical, physiological and biochemical characters are available. Three released rice hybrids and their respective female (A), maintainer (B) and restorer/male (R) lines were assessed for physical, physiological and biochemical traits related to seed vigor. Significant differences were found among the three rice hybrids and its parental lines for 100 seed weight, weight of kernel, husk, endosperm and embryo. Germination percentage, seed vigor index-I and seed vigor index-II were highly significant among female and male lines and hybrids in fresh seed because of potential heterosis in hybrids. Higher activity of reactive oxygen species (ROS) scavenging enzymes such as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) in hybrids was estimated as compared to that of their parental lines. The study showed the presence of the genetic variability, phenotypic, genotypic and environmental coefficient of variation, heritability, genetic advance and heterosis for seed vigor traits in three rice hybrids and its parental lines. A favorable combination of seed vigor traits would be useful to develop desired variety and hybrids with superior seed vigour for realizing higher grain yield and better adaptability in any condition.

Study of Genetic Variability for Yield and Yield Attributes and Bran Oil Content in Maintainer Lines of Rice (Oryza sativa L.)

The present investigation was carried out during kharif, 2016 (June to October) at Regional Agricultural Research Station, Jagtial, Telangana, India to study the phenotypic coefficient of variation and genotypic coefficient of variation, heritability (bs), and genetic advance (GA) for yield contributing characters of 40 maintainer lines of rice. The experiment was designed in RBD replicated twice. Analysis of variance revealed significant differences among rice lines for 15 quantitative traits. The phenotypic coefficient of variation (PCV) value was higher than the genotypic coefficient of variation (GCV), indicating a negligible environmental influence in the phenotypic expression of traits. The PCV and GCV values were highest for the grains panicle-1 and moderate for bran oil percentage, indicating that these two characteristics have a higher variability within and between populations than other characteristics. All of the characters had high heritability. The range of bran oil content in the 40 maintainer lines used to assess the range of bran oil content was from 11.87% in line B11 to 19.35% in line JMS17B.The genetic advancewas greatest for number of grains panicle-1 (87.86%) and modest for bran oil %. The high and moderate estimations of genetic advance show that traits such as the number of tillers plant-1, test weight, L/B ratio, plant height, bran oil percentage, kernal breadth, grain yield plant-1 and kernal length were selected. The genetic advance obtained from the high and moderate estimates indicate that the selection for these characters can be used to improve the yield of the crop.

THE INFLUENCE OF THE FATHER'S GENETYPE ON THE PRODUCTIVITY OF COWS AND THE PROBABILITY OF THEIR MASTITIS UNDER DIFFERENT HOUSING

Introduction. The purpose of the study was to determine the influence of genetic factors on the productivity of cows and the probability of their disease with mastitis under different housing technologies.
 Materials and methods of research. The work was carried out according to the data of two breeding plants for the breeding of the Ukrainian black and white dairy breed with free and stall housing. The data of more than 16,000 milk samples over the past six years were analyzed. Heritability of the average indicators of the quantity and quality of milk of cows according to the data of control milkings, yield for 305 days of lactation and the number of cases of diagnosis of mastitis using correlation analysis. Variability of milk quality of cows was monitored depending on the technology of housing. The research determined the influence of breeding bulls and their line on milk yield and milk quality indicators. To determine the influence of these factors, dispersion analysis was used. Processing of the obtained data was carried out according to basic statistical techniques using computer programs.
 Research results. According to the research results, it was established that the variability of daily milk yield during free housing was higher by 6.1%, fat content by 7% compared to stall housing, and protein content, the number of somatic cells and their evaluation was lower. The strength of the influence of housing on the parameters of daily milk yield was: on the daily yield – 1.8%, on the fat content – 22.8%, on the protein content – 0.8%, on the number of somatic cells – 1.6%, on their evaluation – 4.1%, on the reliability of cows for 305 days of lactation – 4.1%, on milk fat output – 13.6%, on milk protein output – 6.3%, on the frequency of mastitis diagnosis – 4.5%. The coefficients of heritability of daily milk yield under stall housing were 2.2 times higher, fat content – 3.5 times, protein content – 1.8 times, number of somatic cells – 2.7 times, estimates of the number of somatic cells – 2 times, milk yield for 305 days of lactation – 2.4 times, the amount of milk protein – 1.6 times, and the number of cases of mastitis diagnosis – 1.7 times. The influence of bulls on indicators of the quantity and quality of cow milk was significantly higher than on daily milk yield. The strength of the influence of this factor on indicators of daily milk yield during free housing was: the milk yield – 5.5%, the fat content – 2.5%, the protein content – 2.7%, the number of somatic cells – 2.5%, the estimation of the number of somatic cells – 2.8%, and for stall housing – 4.3%, 6.7%, 6.7%, 2.9%, 7.3%, respectively. The strength of the influence on productivity indicators per lactation was as follows: for free housing on milk yield – 13.4%, on the amount of milk fat – 20.1%, on the amount of milk protein – 13.5% and on the number of cases of mastitis diagnosis – 12.7%, and for stall housing 19.1%, 13.6%, 18.0% and 35.2%, respectively (Р < 0.001). The influence of the factor "bull" was higher than the "bull line" factor on indicators of physical and chemical properties of milk and the frequency of cases diagnosis of mastitis in their daughters.
 Conclusions. The housing technology has a significant impact on the productive indicators of dairy cows, their variability and heredity. For free housing of cows, the genetic conditioning of indicators of productivity and milk quality of cows, the probability of their mastitis disease was lower in comparison with stall housing.

Genetic Variability of Coffee (Coffea arabica L.) Germplasm in Biennial Bearing and Its Influence on Selection Efficiency

Arabica coffee is a perennial cash crop and highly affected by biennial bearing which disturbs farmers’ annual income and world’s coffee industries. Developing nonbiennial bearing variety is prominent in addition to applying field management practices. This study was conducted from 2012 to 2020 in southwestern Ethiopia at Tepi and Gera to test the extent of genetic variability among Arabic coffee germplasm in biennial bearing and understand the influences of bienniality on advanced selection. The pooled analysis of variance revealed handiness of genetic variability in yield and biennial bearing. The moderate genotypic coefficient of variation (10–20%), heritability (30–50%), and high genetic advance as percentage of the mean (>20%) were manifested in yield and biennial bearing. Response to selection and selection efficiency were negatively affected by biennial bearing. Early selection excluded 30–40% of the top high yielders from advanced selection. Selection at four harvesting seasons revealed 90% and more selection efficiency. Thus, one has to be conscious of the alternate bearing nature of lines during advanced selection. Both T43/11 and T51/11 were among the top high yielders and showed low biennial bearing at Gera and Tepi. T33/11, T49/11, T55/11, and T61/11 showed very low biennial bearing at both locations. These are promising lines and could be recommended for further biennial bearing improvement breeding programs.

Recent Advances in Crop Improvement of Chilli (Capsicum annuum L.) for High Fruit Yield and Quality

Capsicum annuum L. is an indispensable spice cum vegetable crop cultivated worldwide for its edible fruit. The current research is majorly focused on the development of improved chilli varieties to achieve high fruit yield and quality to meet the rapidly growing market demands. Therefore, the screening of the chilli landraces and local cultivars for the genetic variation would provide best parents for the chilli crop improvement. Most of the recent chilli breeding programmes involve the assessment of genetic variation among the genotypes by the estimation of important genetic variation parameters such as phenotypic and genotypic coefficients of variation, heritability and genetic advance, gene flow, and cluster analysis. Correlation and path coefficient analysis was also applied to evaluate the progeny to understand the association between desired traits. The popular DNA-based molecular marker system, simple sequence repeat, is predominantly applied to understand the genetic variation as well as to select the desired progeny. In this current review, we discussed such recent research reports on chilli crop improvement for high fruit yield and quality, highlighted the recent major achievements and provided the important information for the chilli breeders. We hope this current review would shed light on recent developments in chilli crop improvement and help chilli breeders for their future breeding programmes.

Analisi dell'ereditabilità delle proprietà contrattili: osservazioni su gemelli monozigoti campioni nazionali di atletica giovanile

Heritability estimates for various traits were previously obtained in large-scale twin studies as well as in genomic analyses, which have been used more frequently recently. The potential for heritability in studies of twin athletes has never been observed for tensiomyography (TMG)-derived contractile properties. Accordingly, the aim of this study was to investigate the hereditary capabilities (HC) of lower-limb contractile properties using a twin case study design performed on a pair of monozygotic (MZ) track and field youth champions from Croatia. The results showed high HC values for contraction time, time delay, and contraction velocity, which measure the absolute (Tc, Td) and relative (Vc) velocity of the lower limb muscles. Very high HC values of the listed contractile properties indicate a strong influence of heritability on selected, mainly velocity-related properties, whereas Td-variable related to the peripheral nervous system is the most affected. Second, the muscle morphology of vastus lateralis, vastus medialis, and rectus femoris also appears to be subject to a strong heritable influence. In conclusion, the HC estimates presented, together with the heritability coefficients, can be used as guidelines for talent identification processes, especially when combined with TMG, a suitable non-invasive alternative for estimating lower-limb contractile properties in adolescent athletes.

Analysis of genetic divergence, principal component, correlation and path coefficient for quantitative traits of Gerbera (Gerbera jamesonii) in the north eastern region, India

AbstractGerbera is an important commercial flower crop in the world. Augmenting the genetic diversity is desirable for further improvement in Gerbera breeding programme. Thirty-seven (37) Gerbera accessions were evaluated and analysed for genetic variability, heritability, correlation and path coefficient analysis using yield and quality traits. Results showed that phenotypic coefficients were higher than genotypic coefficients of variation for all the characters. All the traits, except stalk and flower diameter, had high heritability (>60%) and genetic advance (>20%). Based on cluster analysis, the 37 accessions were grouped into seven clusters. Cluster I consists of the maximum number of genotypes (22), while clusters IV–VII are monogenotypic with unique traits. Cluster analysis (D2) showed wider genetic diversity within and between the clusters. The first four principal components (Eigenvalue >1) contributed 72.3% of the total variation. The number of leaves, number of flowers and flower stalk length contributed the most to genetic divergence. Flower yield showed a significant positive genotypic correlation with the number of leaves and suckers. The path analysis (genotypic) revealed that number of suckers, flower stalk diameter and flower stalk length contribute major positive direct effects on number of flowers. Therefore, the wide genetic variability existing in the germplasm may facilitate improvement in gerbera crops. Superior lines (RCGH-12, -22, -114, -117) with higher yield (>23 flowers/plant) and vase life (>5 days) could be promoted for commercial production under open field conditions. While RCGH 28 has a dwarf flower stalk that can be promoted for pots and decoration purposes.

Re-sequencing and morphological data revealed the genetics of stone shell and kernel traits in apricot.

Kernel-using apricot (Prunus armeniaca L.) is an economically important fruit tree species in arid areas owing to its hardiness and cold and drought tolerance. However, little is known about its genetic background and trait inheritances. In the present study, we first evaluated the population structure of 339 apricot accessions and the genetic diversity of kernel-using apricots using whole genome re-sequencing. Second, the phenotypic data of 222 accessions were investigated for two consecutive seasons (2019 and 2020) for 19 traits, including kernel and stone shell traits and the pistil abortion rate of flowers. Heritability and correlation coefficient of traits were also estimated. The stone shell length (94.46%) showed the highest heritability, followed by the length/width ratio (92.01%) and length/thickness ratio (92.00%) of the stone shell, whereas breaking force of the nut (17.08%) exhibited a very low heritability. A genome-wide association study (GWAS) using general linear model and generalized linear mixed model revealed 122 quantitative trait loci (QTLs). The QTLs of the kernel and stone shell traits were unevenly assigned on the eight chromosomes. Out of the 1,614 candidate genes identified in the 13 consistently reliable QTLs found using the two GWAS methods and/or in the two seasons, 1,021 were annotated. The sweet kernel trait was assigned to chromosome 5 of the genome, similar to the almond, and a new locus was also mapped at 17.34-17.51 Mb on chromosome 3, including 20 candidate genes. The loci and genes identified here will be of significant use in molecular breeding efforts, and the candidate genes could play essential roles in exploring the mechanisms of genetic regulation.

Productivity of cows depending on the type of mating and genotype of sires

At breeding enterprises, the number of sires of Holstein breed homozygous for the genotype of the ЕАВ-locus is increasing, and there is a tendency for inbreeding coefficients to increase in populations of this breed. The dairy productivity of fi rst-calf heifers obtained from heterozygous and homozygous sires, as well as the change in indicators per generation with intra-line mating and line crosses were studied. It was found that in terms of the total yield of milk fat and protein for 305 days of lactation in the line Wes Back Ideal 1013415, the fi rst-calf heifers obtained from intra-line mating and line crossing exceeded the cows their mothers by 21,4 kg, and in the whole group of fi rst-calf heifers of homozygous sires this indicator was 51,0 kg higher against the average of fi rst-calf heifers of heterozygous sires. At the same time, for the cow-mothers of these groups, the corresponding diff erence was negative: –31,6 and –64,7 kg. Similar data were revealed for another main line Refl ection Sovereign 198998. When mating heterozygous sires according to the variants of line crosses, the milk yield was 227 kg higher (p < 0,05), but the mass fat fraction in milk decreased by 0,06 – 0,08 abs.% (p < 0,01). However, the levels of manifestation of traits among fi rst-calf heifers in comparison with cow-mothers with intra-line mating increased by groups of homozygous sires in milk yield by 32,5 %, mass fat fraction by 17,6 % and mass protein fraction by 25,0 %. The correlation coefficients «mother – daughter» for milk yield, mass fat fraction and mass protein fraction were relatively higher in the group of homozygous sires, whose heritability coeffi cient in one of the farms for milk yield was higher by 0,495, mass fat fraction by 0,305; mass protein fraction by –0,110, and in the other, respectively, by 0,026; 0,161; 0,121. The conclusion is made about a higher prepotency of heterozygous sires with improving mating.

Genetic variability, heritability, genetic advance, association between fruit yield and yield components of okra (Abelmoschus esculentus L. Moench) accessions grown in two different years

Abstract Genetic improvement of okra for yield is significant because of the nutritional, economic and health benefits inherent in it and to overcome the low genetic potential of the existing varieties and environmental factors which are the major constraints to okra yield. Therefore, this study was carried out to understand the genetic nature of yield, its association with yield components on which selection can be made and to determine the effect of different years on genetic gain. The experiment involved the evaluation of twenty okra accessions in the rainy seasons of year 2019 and 2020 in a randomised complete block design. Data were collected on fourteen characters and analysed. Genotype × Year was highly significant for all the analysed characters. High heritability and high genetic advance as percent of mean were recorded for most of the characters in both years indicating that these traits were less influenced by the environment and presence of additive gene action. Genotypic coefficient of variation, heritability and genetic advance were observed to be higher for some traits in 2019 but lower for those traits in 2020. Pod yield had positive correlation with only plant height at 50% flowering, pod length, number of seeds per pods and peduncle length in both years 2019 and 2020 while the remaining were negatively correlated with pod yield in both years except petiole length and number of pods per plant. Therefore, selection based on these traits could be highly rewarding and may not be considered based on different years.

Evaluation of Genetic Diversity of Wheat (Triticum aestivum) Lines Under Terminal Heat Stress in the Hisar Environment

Various environmental stresses affect plant development and growth globally and restrict agricultural output and productivity. Wheat plants are negatively impacted by terminal heat stress, which lowers productivity. The correlation between grain yield and other qualities may determine the plant material's ability to minimize the effects of heat stress on yield, and a trait variance aids in the identification of attractive genotypes in a breeding program. To accomplish this, the genetic variability, heritability, correlation and path coefficient analyses of 64 bread wheat genotypes were conducted. As a result, all 15 morpho-physiological traits revealed highly significant genotypic variations. Total chlorophyll content and main spike weight were both higher than 42% and 16%, respectively, for the genotypic coefficient of variation and the phenotypic coefficient of variation. The grain yield per plot indicated a significant and positive correlation with spike length, spike weight, number of grains per spike, number of spikelets per spike, 1000-grain weight, biological yield per plot, grain growth rate, total chlorophyll content and number of productive tillers per meter. As a result, five genotypes, P13833, P13828, P13031, P13723, and P13726, had higher yields and should be utilized as parents in breeding programs. The results revealed that the selection of key physiological and morphological characteristics associated with grain production significantly raises wheat productivity in situations like heat stress.

Genetic Variance, Heritability And Correlation in Some Traits of Bread Wheat (triticum Aestivum L.) under Different Nitrogen Levels

Twelve genotypes of bread wheat, with four levels of nitrogen (0, 75, 150, 225 kg N ha-1). were grown in split block design with three replication in growing season (2021), correlation, phenotypic and genotypic coefficient of variation, heritability and genetic advance were estimated for (days of 75% flowering, plant height, grain filling, grain yield, number of spike/plant, spike length, grain weight, flag leaf area, biomes, protein and harvest index. Highly significant and positive correlation found between grain yield and grain weight, harvest index and protein.  While significantly 5% with plant height. Broad sense heritability was found to be low for the all studied traits followed by moderate to low values of genetic advance as percent for studied traits

Variability, heritability and genetic advance in sugarcane ( Saccharum spp. hybrid) genotypes

The study was carried out with the aim of estimating variability, heritability, and genetic advance for 196 sugarcane genotypes. Results of the analysis of variance identified a very highly significant variation among the genotypes in all the traits evaluated. Except for stalk length and single cane weight, all of the traits’ lowest and highest mean values were present within the genotypes from fuzz, indicating the wide ranges of variability within the genotypes. Except for single cane weight, the highest mean values for all the traits were seen within the genotypes of fuzz, implying greater genetic potential for the genotypes of fuzz for these traits. The number of sprouted buds, number of tillers, and cane yield had high genotypic and phenotypic coefficients of variation, heritability, and genetic advance as a percentage of the mean. This indicates the presence of high levels of heritable genetic variations for these traits, implying that these traits could be improved through phenotypic selection. The number of stalks, plant height, stalk length, internode length, stalk diameter, single cane weight, brix, and purity had high to moderate heritability with moderate to low genetic advance as percentages of the means. This indicates that the phenotypic expression of these traits is highly influenced by non-genetic factors. Thus, it could be difficult to directly improve these traits via phenotypic selection; instead, efforts should be directed toward better management practices. This study presents the first evidence for the existence of variability in the newly introduced sugarcane genotypes that should be exploited.

The interaction between the milk production, milk components with a low frequency of analysis and factors affecting the milk composition in dual-purpose Simmental cows

The aim of this study was to improve the understanding of the contribution of components typically found in milk, but which are not often included in analyses, to the nutritional status of dairy cows. This was undertaken by analysing the amount and composition of milk produced by Simmental dairy cows, a dual-purpose breed farmed in the Czech Republic. Apart from the more frequently analysed group of components in milk, a less frequently analysed group of components were also investigated. This group, typically, consists of the following components: urea, casein, citric acid, beta hydroxy butyrate (BHB) ketones and free fatty acids. The average content of urea, casein and citric acid in milk is 25.75 mg/100 ml, 2.96%, 0.15%, respectively. The influence of environmental factors on these indicators was evaluated, as well as the degree of hereditary establishment. These less frequently analysed components (indicators), as well as the more frequently analysed components of milk, are subject to several external influences, especially the influence of the breeder, the year and the season of calving. The content of these components varied significantly statistically during the lactation period and also in the order of lactation. The influence of a cow’s individuality and the degree of additive genetic background are evident, with estimated heritability coefficients ranging from 0.04 for the BHB ketone content to higher values, e.g., 0.28 for citric acid or 0.31 for the lactose content in milk. The relationships between the components of milk and the daily milk yield were also evaluated, and statistically significant negative correlations were found between the content of casein and the daily milk yield (–0.47) and between the lactose content and the number of somatic cells (–0.37).

Genetic variability studies in field pea (Pisum sativum L.) for yield and associated characters

The prime and foremost objective of the study was to estimate the genetic variability for yield and its associated characteristics among the 23 genotypes of field pea and also to engender information regarding genetic parameters like range, mean, phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic advance as a percentage over means for the18 traits under consideration. It was disclosed from the results of the analysis of variance that there exists a difference among the 23 genotypes for all the 18 traits under consideration. The trait including primary branches per plant, secondary branches per plant, plant height, swelling capacity, swelling index, biological yield per plant, and seed yield recorded high amounts of GCV and PCV. High heritability combined with high genetic advance was documented for the trait’s plant height and seeds per plant, whereas high heritability coupled with low genetic advance, was recorded for the trait’s days to fifty % flowering, days to maturity, primary branches per plant, secondary branches per plant, pod length, 100 seed weight, percent disease incidence and seed yield per plant. The existing variability identified can be further exploited in crop improvement of field pea

Variability Study in Ethiopian Sesame (Sesamum indicum L.) Genotypes at Western Oromia

The study was conducted to evaluate genetic variability and trait association of yield and yield related traits in 5x5 simple lattice design during 2019 main cropping season. The analysis of variance showed highly significant differences (P<0.01) among the genotypes for all quantitative traits except days to maturity and biomass yield per hectare. Days to flowering, plant height and capsule length showed low Phenotypic and Genotypic Coefficient of Variations and genetic advance percent mean. Branches per plant showed medium Phenotypic and Genotypic Coefficient of Variations, heritability and genetic advance percent mean. Capsule per plant, seed yield per plant and seed yield per hectare showed moderate Phenotypic and Genotypic Coefficient of Variations and high heritability with genetic advance percent mean. Biomass yield per plant and harvest index showed high Phenotypic and Genotypic Coefficient of Variations, heritability and genetic advance percent mean. Both phenotypic and genotypic correlation coefficient analyses showed positive and significant association of seed yield with seed yield per plant and harvest index. Generally, this study painted the presence of significant genetic variation among tested sesame genotypes and the possibility to get genetic progresses in the succeeding breeding generations.

Intensity of egg laying dynamics by butterflies in the first day of the caterpillar’s life’s period and their relationship with the silkworm selection characteristics

The research is devoted to the study of the genetic parameters of a less studied trait - the intensity of egg laying on the first day of female silkworm butterflies. Based on genetic experiments conducted in promising lines Line 27 and Line 28, it was found that the variability of this trait is Cv = 15,0-15,3%, and the heritability coefficient h2 = 0,321-0,340. Also, for the first time, a close positive correlation was established between the intensity of egg laying on the first day and the leading reproductive signs. A close positive correlation (rp = 0,432-0,692) was found between the growth rate of caterpillars and their productivity reflected in the yield of cocoons. At the same time, it was found that fast-growing caterpillars are less susceptible to diseases.

CHARACTERIZATION AND GENETIC ANALYSIS OF THE SELECTED RICE MUTANT POPULATIONS

The development of mutant populations, followed by their characterization, offers a significant opportunity to isolate genotypes and genes with desired traits of interest. This paper assessed the agronomic performance, genetic variability, and yield-related characteristics of 22 M3 generation mutants (gamma ray-irradiated) of rice derived from a promising local rice genotype (Fatema dhan). The seeds of the selected mutants, the original parent, and three cultivars were grown in a randomized complete block design at the research farm of the Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh. Few mutants exhibited superior quantitative phenotypic traits compared with parental genotypes and check varieties. Mutant lines 1 and 83 required minimum days to reach maturity, and mutant lines 9, 17, and 80 exhibited significantly higher yield per plant than the parent and check varieties. Heritability analysis and genetic parameters revealed that genetic components mostly controlled all observed traits, with a minor influence on the environment. The higher phenotypic and genotypic coefficient of variation, heritability, and genetic gain confirmed possible rice yield improvement through phenotypic selection. The traits, including days to first flowering and maturity, plant height, and panicle length, showed a significant positive correlation with yield. The principal component analysis revealed that the first two components explained 69% of the total variation between genotypes. Thus, the promising mutant lines (1, 9, 17, 80, and 83) isolated in this study can serve for the development of high-yielding and early-maturing rice varieties.

Genetic gains for obtaining improved progenies of oil palm in Colombia

The success of breeding programs depends on the available genetic variability and the adequate selection of parents to produce seeds that generate added value to the developed cultivars that solve limiting problems of the crops. The determination of genetic gain is a powerful tool to advance the selection of outstanding progenitors that are subsequently used to obtain improved cultivars for traits of interest. With the main objective of calculating the genetic gain in different cycles, this research evaluated the yield, vegetative parameters, and oil production components in two oil palm populations identified as C0-Monterrey and C1-Vizcaina. The analysis was carried out using the analysis of variance. Genetic variation and heritability coefficients for all the evaluated traits were also calculated to obtain the components of phenotypic, genotypic, and environmental variation. Genetic gains (Δg) were more representative in the yield traits of fresh fruit bunches, with 19%, for the number of bunches per plant, with a Δg of 18.7%, and for the oil to bunch with a Δg of 6%. Low environmental influences were observed in the phenotypic variation for the different traits evaluated. Finally, high heritability values were observed for genetic traits such as height increase, with 93%, and average bunch weight, with 85%. The development of new progenies using elite dura-type female parents derived from these evaluated populations, with excellent yields of fresh fruit, bunch components, and slow growth, will be the future of oil palm cultivation. In the meantime, progeny trials must focus on improving the ability to select outstanding parents for the best DxP progenies.