Component Of Genetic Variability Research Articles

Characterization of high-yielding aman rice genotypes through genetic and agronomic analysis

ABSTRACT Rice (Oryza sativa L.) holds immense global significance, serving as a staple food crop that sustains billions of people and supports livelihoods across diverse cultures and economies, including Bangladesh. For food security in Bangladesh, there is a significant demand for high-yielding Aman rice varieties. We assessed genetic variability of 16 Aman rice genotypes, including 11 promising Aman lines and 5 established Aman cultivars in Bangladesh, with the aim of identifying high-yielding genotypes through a three-year field experiment. The examined genotypes displayed notable variations in both yield and agronomic traits contributing to yield, as evidenced by their greater range of coefficients of variance and genetic variability components. Traits such as effective tillers per hill (ET), filled grains per panicle (FG), plant height (PH) at 80 days after transplanting, and panicle length (PL) demonstrated notable correlations with grain yield (GY) throughout the three-year evaluation. Moreover, the higher broad-sense heritability (H 2) observed in ET, FG, PH, and PL traits suggested a substantial influence of genetic factors on the variability of the Aman rice genotypes. Principal component analysis based biplot and heatmap analyses revealed that the advanced lines BU acc4 and BU acc5 had higher harvest index and relatively greater GY compared to the other Aman rice varieties. These promising Aman lines could prove to be valuable materials for future multi-location yield trials or ongoing and forthcoming breeding programs aimed at enhancing high-yielding Aman rice cultivars.

Exploring Variability in Rifampicin Plasma Exposure and Development of Anti-Tuberculosis Drug-Induced Liver Injury among Patients with Pulmonary Tuberculosis from the Pharmacogenetic Perspective.

Genetic polymorphisms can exert a considerable impact on drug pharmacokinetics (PK) and the development of adverse drug reactions (ADR). However, the effect of genetic polymorphisms on the anti-tuberculosis (anti-TB) drug, and particularly rifampicin (RIF), exposure or anti-TB drug-induced liver injury (DILI) remains uncertain. Here, we evaluated the relationship between single nucleotide polymorphisms (SNPs) detected in the RIF pharmacogenes (AADAC, SLCO1B1, SLCO1B3, ABCB1, and NR1I2) and RIF PK parameters, as well as anti-TB treatment-associated DILI. In total, the study enrolled 46 patients with drug-susceptible pulmonary TB. The RIF plasma concentration was measured using the LC-MS/MS method in the blood samples collected pre-dose and 2 and 6 h post-dose, whilst the DILI status was established using the results from blood biochemical analysis performed before and 10-12 days after treatment onset. The genotyping was conducted using a targeted NGS approach. After adjustment for confounders, the patients carrying the rs3732357 GA/AA genotype of the NR1I2 gene were found to have significantly lower RIF plasma AUC0-6 h in comparison to those with GG genotype, while the difference in RIF plasma Cmax was insignificant. None of the analyzed SNPs was related to DILI. Hence, we are the first to report NR1I2 intronic SNP rs3732357 as the genetic component of variability in RIF exposure. Regarding anti-TB treatment-associated DILI, the other preexisting factors promoting this ADR should be considered.

Studies on Components of Genetic Variability in Indian Mustard (Brassica juncea (L.) Czern and Coss.) Genotypes across Five Locations in Northern Karnataka

Indian mustard is one of the prominent edible oil yielding crops cultivated in India, with oil content ranging from 37 to 48%. An experiment was conducted to evaluate the variability in eight promising genotypes of Indian mustard along with two checks, Dodda Sasive and NRCHB-101, laid in RCBD with three replications at five different locations across Karnataka. The observations were recorded for 12 biometric traits of mustard, including seed yield and oil content and analyzed using a combined ANOVA. Biometric tools like heritability and genetic advance are crucial components of genetic variability that serve to assess variation in the available germplasm and assist in the selection of a desirable genotype. The traits, number of secondary branches and racemes per plant have registered a high genotypic coefficient of variance as well as a high genetic advance as a percent of the mean indicating the possibility of rapid improvement. A minimal influence of the environment was noticed in the expression of 8 traits out of 12 that exhibited high heritability in a broad sense. Among all the traits, only seed yield exhibited a high genetic advance coupled with moderate heritability, which signifies that seed yield is governed by additive gene effects. The genotypes that exhibited superior performance with respect to yield across all the locations were TM-210, TM-136 and KMR (E) 16-11.

Quantification of Diverse Local Germplasm of Pumpkin Through Genetic Variability Components in Garhwal Region of Uttarakhand

An experiment was conducted at Horticultural Research Center, Department of Horticulture, H.N.B Garhwal University, Srinagar (Garhwal), Uttarakhand, India, during summer season 2019, to study “Quantification of diverse local germplasm of Pumpkin through genetic variability components in Garhwal regions of Uttarakhand”. Experimental material for the study consisted of 25 genotypes. The experiment was conducted using a Randomized Block Design with three replications. The genotypes have been collected from different regions of Uttarakhand and other parts of India. Observations were recorded on 23 economic traits. Each of the traits under study, genetic variability analysis revealed that the phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were nearly identical. Highest coefficient of variability both at phenotypic and genotypic level was observed for yield per vine (50.48% and 50.33%) and lowest for days to 1st fruit harvest (5.49% and 5.49%). Maximum heritability was found in number of seeds per fruit (100%) and moderate was found for number of ridges per fruit (40.10%). Highest genetic advance was observed for number of seeds per fruit (79.26) and lowest for rind thickness (0.15mm). In terms of percentages above the mean, vine length, number of primary branches/vine, number of nodes upto first male flower and female flower, number of fruits / vine, percent of fruits setting, average fruit weight and yield/vine all demonstrated high genetic advance. In order to continue crop development programs for pumpkin in the Garhwal Region of Uttarakhand, factors like vine length, percent of fruit setting, average fruit weight, and yield per vine could be taken into consideration through selection.

Avaliação pós-comercialização de um produto trocável similar ao anastrozol em pacientes brasileiras com câncer de mama

Several formulations of the aromatase inhibitor anastrozole are available in Brazil. We carried out a postmarketing surveillance of the anastrozole (test) formulation in current use at the Brazilian National Cancer Institute (INCA), by comparing anastrozole through plasma concentrations obtained with the test versus the reference formulation. Thirty-three postmenopausal breast cancer patients participated in an open label, bracketed protocol, comprising 3 successive phases of 8-10 days each. The test formulation was used in phases 1 and 3 and the reference formulation in phase 2. Blood samples were collected in the last 2 days of each phase for LC-MS/MS quantification of anastrozole concentration in plasma. Through anastrozole concentrations ranged between 17.4-86.9ng/ml across the three phases, with median (interquartile ranges) values of 43.7 (37.2-52.7), 41.3 (30.9-50.7) and 43.3 (33.9-55.8) ng/ml in phases 1, 2 and 3, respectively. ANOVA detected no statistically significant difference in anastrozole plasma concentrations across the three phases, consistent with switchability between the reference and test formulations. The genetic component (rGC) of through anastrozole plasma concentrations, estimated using the repeated drug administration procedure across the three phases, was 0.94, suggesting an important component of genetic variability in anastrozole pharmacokinetics.

Comparative investigation of the genetic components of Withania somnifera L. yield and quality traits using multivariate and associations analysis in the Deccan plateau region

The vital herb ashwagandha was farmed for commercial purposes in India. This study aimed to estimate the nature and amount of genetic variation in the 20 attributes in the 29 genotypes of ashwagandha in order to understand the correlations and character contributions to dry root weight/plant and alkaloid content with the selection of potential parents for ashwagandha crop improvement. Twenty-nine ashwagandha genotypes were assessed using a range of genetic metrics, including analysis of variance (ANOVA), genetic variability components, correlation, principal component analysis (PCA), and Mahalanobis D2. The ANOVA confirms a large amount of variability in the genotypes/varieties under study. Out of twenty the four traits, namely fresh leaf weight per plant (X8), dry leaf weight per plant (X9), seed yield per plant (X13), and dry root weight per plant (X16)—indicates the presence of additive gene action in the current study were highly heritable and had a high genetic advance mean value. Starch estimation, main root length, and root diameter were found to be positively and significantly correlated with dry root production per plant and total alkaloid content. The principle component analysis (PCA) results showed that the first four PCA accounted for the bulk (79.56%) of the differences. All genotypes are divided into four clusters based on the distances between and within clusters. Based on the findings mentioned above, it is recommended that genotypes from clusters IV (Poshita, CIMAP-Chetak), cluster II (AKAS-10, AKAS-11, NMITLI-101, and NMITLI-118), and cluster I (AKAS-02, IC-286632, and CIMAP Pratap) be chosen for a different hybridization program. Based on the multidisciplinary investigation, some of the genotypes with desired qualities have been found. They can be employed in upcoming breeding programs to increase alkaloid content and dry root yield.

Understanding natural genetic variation for grain phytic acid content and functional marker development for phytic acid-related genes in rice

BackgroundThe nutritional value of rice can be improved by developing varieties with optimum levels of grain phytic acid (PA). Artificial low-PA mutants with impaired PA biosynthesis have been developed in rice through induced mutagenesis. However, low-PA mutant stocks with drastically reduced grain PA content have poor breeding potential, and their use in rice breeding is restricted due to their detrimental pleiotropic effects, which include decreased seed viability, low grain weight, and low seed yield. Therefore, it is necessary to take advantage of the natural variation in grain PA content in order to reduce the PA content to an ideal level without compromising the crop's agronomic performance. Natural genetic diversity in grain PA content has not been thoroughly examined among elite genetic stocks. Additionally, given grain PA content as a quantitative trait driven by polygenes, DNA marker-assisted selection may be required for manipulation of such a trait; however, informative DNA markers for PA content have not yet been identified in rice. Here we investigated and dissected natural genetic variation and genetic variability components for grain PA content in rice varieties cultivated in Eastern and North-Eastern India during the last 50 years. We developed novel gene-based markers for the low-PA-related candidate genes in rice germplasm, and their allelic diversity and association with natural variation in grain PA content were studied.ResultsA wide (0.3-2.8%), significant variation for grain PA content, with decade-wise and ecology-wise differences, was observed among rice varieties. Significant genotype x environment interaction suggested polygenic inheritance. The novel candidate gene-based markers detected 43 alleles in the rice varieties. The new markers were found highly informative as indicated by PIC values (0.11–0.65; average: 0.34) and coverage of total diversity. Marker alleles developed from two putative transporter genes viz., SPDT and OsPT8 were significantly associated with grain PA variation assayed on the panel. A 201 bp allele at the 3’ UTR of SPDT gene was negatively associated with grain PA content and explained 7.84% of the phenotypic variation. A rare allele in the coding sequence of OsPT8 gene was positively associated with grain PA content which explained phenotypic variation of 18.49%.ConclusionNatural variation in grain PA content is substantial and is mostly controlled by genetic factors. The unique DNA markers linked with PA content have significant potential as genomic resources for the development of low-PA rice varieties through genomics-assisted breeding procedures.

Genetic polymorphism in populations of voles and shrews from the Kronotsky Reserve (Kamchatka Peninsula, Russia)

We studied genetic polymorphism of four mammal species Myodes rutilus, Myodes rufocanus, Sorex isodon, from four localities, the Valley of Geysers, Uzon volcanic caldera, the Death Valley, and the Shore of Kuril Lake. In total, 172 individuals were genotyped using the inter-simple sequence repeat technique. We observed the lowest polymorphism in shrews S. caecutiens. In this species, 68.8 % of bands were polymorphic, and Nei’s genetic diversity (h) was 0.27, while these values in S. isodon were 81.3 % and 0.29, respectively. Populations of M. rufocanus were the most polymorphic among the studied species (P = 91.4, h = 0.34). Polymorphism in M. rutilus from Kamchatka (P = 87.2, h = 0.29) was similar to that from Western Siberia. In addition, we found a high genetic differentiation of rodent populations. The interpopulation component of genetic variability was about 30–40 % (GST = 0.31 in M. rutilus and 0.39 in M. rufocanus). Gene flow among populations of M. rutilus from Kamchatka was two times lower than that of populations of the species from taiga ecosystems in Siberia. Key words: Myodes, Sorex, Differentiation of populations, Genetic variability, ISSR markers, Kamchatka Peninsula

Genetic polymorphism in populations of voles and shrews from the Kronotsky Reserve (Kamchatka Peninsula, Russia)

We studied genetic polymorphism of four mammal species Myodes rutilus, Myodes rufocanus, Sorex isodon, from four localities, the Valley of Geysers, Uzon volcanic caldera, the Death Valley, and the Shore of Kuril Lake. In total, 172 individuals were genotyped using the inter-simple sequence repeat technique. We observed the lowest polymorphism in shrews S. caecutiens. In this species, 68.8 % of bands were polymorphic, and Nei’s genetic diversity (h) was 0.27, while these values in S. isodon were 81.3 % and 0.29, respectively. Populations of M. rufocanus were the most polymorphic among the studied species (P = 91.4, h = 0.34). Polymorphism in M. rutilus from Kamchatka (P = 87.2, h = 0.29) was similar to that from Western Siberia. In addition, we found a high genetic differentiation of rodent populations. The interpopulation component of genetic variability was about 30–40 % (GST = 0.31 in M. rutilus and 0.39 in M. rufocanus). Gene flow among populations of M. rutilus from Kamchatka was two times lower than that of populations of the species from taiga ecosystems in Siberia. Key words: Myodes, Sorex, Differentiation of populations, Genetic variability, ISSR markers, Kamchatka Peninsula

Studies on genetic variability components and character association of french bean (Phaseolus vulgaris L.) for growth, yield and quality attributes under the Gangetic alluvial plains of West Bengal

Twelve genotypes of bush type french bean were evaluated to study the genetic variability, correlation and path analysis for twenty- three yield and yield contributing parameters. Significant differences were observed among all the genotypes. Both GCV and PCV corresponded closely for all the characters which indicate low environmental influence. Higher phenotypic and genotypic co-efficient of variability were observed for leaf fresh weight, leaf dry weight, pod weight, ascorbic acid, total chlorophyll, reducing sugar, total sugar and pod protein. Characters like primary branches/plant (no.), leaf fresh weight (g), leaf dry weight (g), flowers/Inflorescence (no.), pod set/Inflorescence (no.), pods/plant (no.), pod girth (cm), pod weight (g), ascorbic acid (mg/100g), total chlorophyll (mg/100g), reducing sugar (%), total sugar (%), pod protein (mg/100g) and green pod yield/plant (g) exhibited high heritability coupled with high genetic advance as percent over mean indicating the presence of additive gene action and thus selection based on phenotypic performance may prove useful. Pod weight and pods/plant exhibited high positive significant correlation with green pod yield/plant as well as high positive direct effect on green pod yield/plant. Hence, these traits can be directly considered for yield improvement programme in french bean.

Agro morphological Characterization and Evaluation of Okra [Abelmoschus esculentus (L.) Moench] Genotypes for Yield and Other Variability Components at Melkassa, Central Ethiopia

Okra [Abelmoschus esculentus (L).Moench] is one of indigenous and endemic genetic resource of Ethiopia as well as Benishangul Gumuz, but only few studies were carried out to assess its diversity and performance throughout the country and specifically no research conducted to assess diversity of okra within regional state. Therefore, this study was conducted with the objective of assess the genetic divergence and estimate the genetic variability components in okra genotypes collected from regional state. A total of 36 genotypes were evaluated of which 33okra genotypes were collected from different areas of Benishangul Gumuz Regional State, 3(three) checks, of 2 introduced and 1(one) released were evaluated for 27 quantitative traits at MARC in year 2018/19 using simple lattice design (6x6). The results from analysis of variance revealed that the presence of significant variation for all quantitative traits except 3 traits. Moreover, the variation of genotypes for fruit yield per hectare ranged from 9.44 to 32.88ton/ha-1 with mean 19.59ton/ha-1 for genotypes 29620 and 29618, respectively. Most of genotypes had high mean performance as compared to checks for majority of traits. The genotypic (GCV) and phenotypic (PCV) coefficient of variation showed within range of 6.3 to 54.19% and 9.19 to 55.51%, respectively. Heritability in broad sense (H2) and genetic advance as percent of mean (GAM) had ranged from 43.46 to 97.34% and 9.16 to 109.14%, respectively. The variability components (GCV, PCV, H2 and GAM) were high for all traits except few traits like days to 90% maturity, hundred seed weight low in PCV and GCV. Number of ridge and hundred seed weight showed moderate H2 whereas days to 90% maturity, number of ridge and percentage of mucilage content had moderate GAM and low for hundred seed weight. The result observed in this study was the presence of a wide genetic variation among genotypes collected from Benishangul Gumuz Regional State.

Selection criteria for genetic improvement of sugar snaps (Pisum sativum var. saccharatum) based on components of genetic variability

The present investigation was conducted on newly generated material of sugar snaps comprising of 29 advanced breeding lines (F7) developed from 4 interspecific crosses at HP Agricultural University, Palampur along with 7 lines collected from different institutes in randomized complete block design over three replications during winter 2016-17. The phenotypic (PCV) and genotypic (GCV) coefficients of variation were high for straw yield/plant while branches/ plant, internodal length, pods/plant, dry pod weight and seed yield/plant showed high PCV with moderate GCV. High heritability and genetic advance was recorded for internodal length, plant height, straw yield/plant, dry pod weight and seed yield/plant, indicating additive gene effect for their inheritance. Seed yield/plant was positively associated with pod length, seeds/pod, protein content of seed, straw yield/ and 100-seed weight both at phenotypic and genotypic levels. Harvest index and straw yield contributed maximum via their direct and indirect contributions towards totalassociation of these traits with seed yield while, nodes/ plant, internodal length, 100-seed weight and seeds/pod also contributed to some extent. Therefore, these traits would be of great significance for achieving enhanced performance of genotypes for seed yield.

Post-marketing assessment of generic tamoxifen in Brazilian breast cancer patients.

Generic formulations of tamoxifen are commonly prescribed to oestrogen receptor-positive breast cancer patients at the Brazilian National Cancer Institute (INCA). We carried out a post-marketing surveillance of the generic tamoxifen formulation in current use at INCA, by comparing plasma concentrations of the parent drug and metabolites obtained with the generic vs the reference formulation. Thirty patients participated in an open-label, bracketed protocol, comprising 3 successive phases of 30-32days each: the generic formulation was used in phases 1 and 3 and the reference formulation in phase 2. Two blood samples were collected in the last 4days of each phase, for LC-MS/MS quantification of tamoxifen and metabolites in plasma. The median plasma concentrations (ng/mL) for the reference formulation were as follows: tamoxifen, 135.0 (CI 95% 114.2-155.8); endoxifen, 35.3 (30.0-40.8); and 4-hydroxytamoxifen, 4.8 (4.2-5.4). The endoxifen/tamoxifen plasma concentration ratio was 0.27 (0.21-0.25). ANOVA detected no statistically significant difference in plasma concentrations of tamoxifen, metabolites or the endoxifen/tamoxifen ratio among the three phases. The genetic component (rGC) of the CYP2D6-mediated conversion of tamoxifen into endoxifen, estimated using the repeated drug administration procedure across the three phases, was 0.87, pointing to an important component of genetic variability. In conclusion, this first post-marketing surveillance trial of oncologic generic drugs carried out in Brazilian patients verified the switchability between the reference and the generic tamoxifen formulation currently used at our institution. The adopted bracketed protocol adds confidence to this conclusion and may serve as a frame for future trials of post-marketing assessment of other generic drug products.

English

Inbred line development requires information on the nature and magnitude of genetic variability and transmissibility of desired trait in source populations. In this study, the level of genetic variability, heritability and genetic advance of thirteen agronomic and fresh yield traits among twelve shrunken-2 super-sweet corn populations were evaluated. Field experiments were conducted for two years in Ibadan, Nigeria using a randomised complete block design with three replicates. Estimates of genetic variability components, broad-sense heritability and genetic advance were computed for each trait. All the traits exhibited significant genotypic differences. Genotypic variance was significant for number of marketable cobs, yield of cobs, number of cobs, number of kernel rows, husk cover, ear height and days to anthesis, while environmental variance was significant for all the traits. Phenotypic coefficients of variation were higher than the corresponding genotypic coefficients of variation for all traits. Broad-sense heritability ranged from 22.2% for anthesis-silking interval to 85.1% for husk cover. The genetic advance was high (32.7%) for husk cover, medium (12.0%) for yield of cobs and low for other traits. Genetic variability was present among the shrunken-2 super-sweet corn populations. Opportunities abound for further improvement of the populations and extraction of lines for hybrid seed production. Key words: Broad-sense heritability, genotypic coefficient of variation, husk cover score, sweet corn, yield of marketable cobs. &nbsp

Estimates of genetic variability among the backcross populations involving UMI1200 and UMI1230 maize inbreds

A knowledge of genetic variability parameters, heritability and genetic advance of the traits is essential in a breeding programme to select and advance a right individual from a population. The aim of this study was to estimate the genetic variability among the backcross (BC1F1, BC2F1) and selfed (BC2F2) population derived from two independent crosses of maize inbreds (UMI 1200 × VQL1 and UMI 1230 × VQL1) and select the efficient individual. Fourteen morphological traits were used to estimate the genetic variability components. The populations exhibited high PCV than the corresponding GCV for all the traits. Yield and its attributes like cob length and girth, number of kernel rows/ cob, number of kernels/ row and 100 grain weight revealed high heritability with high genetic advance as percent of mean in BC2F2 generations of both the crosses. Hence these traits indicated the presence of additive gene action and selection would be effective.

Abstract LB-162: Common genetic variants within TEP1 gene (14q11.2 locus) and TK1 gene (17q25.3 locus) are associated with the risk of colorectal tumors in Latinos

Abstract Introduction: Around 63 common risk variants have been associated with colorectal cancer (CRC) through genome-wide association studies (GWAS) in European and Asian populations; these variants, together with the high penetrance genes responsible for 5% of the cases, do not completely explain the CRC heritability estimated at ~ 35%. Objective: To discover new common variants associated with the risk of colorectal tumors, taking advantage of the high level of admixture in Latino populations. Materials and methods: We performed a candidate gene association (CG) and GWAS analyses, in a multicenter case-control study that included 313 cases of CRC, 200 cases of adenomatous polyps (AP) and 506 controls from six Colombian cities. The role of these common variants was assessed by basic SNP association analyses (X2) and logistic regressions adjusted for age, sex and ancestry proportions. Selected SNPs were genotyped by TaqMan in additional samples. Results: European ancestry was associated with the risk of AP while African ancestry was associated with the risk of both, AP and CCR, (P ≤ 0.01). In the adjusted logistic regression analyses of the CG study, we found that the minor allele (A) of the SNP 14q11.2:rs1760898 (C>A) was associated with the risk of CRC (OR 0.48; 95% CI 0.33-0.69; UNADJ P = 6.8 x 10-5; 100,000 Pperm = 0.03). This association persisted in the adjusted logistic regressions analyses with additional samples genotyped by TaqMan (P = 0.03). In the basic SNP association analyses (X2) of the GWAS study, we found that the minor allele (A) of the SNP 17q25.3:rs1065768 (G>A) was associated with the risk of AP (OR 0.35; 95% CI 0.24 -0.51; UNADJ P = 3.4 x 10-8; Bonferroni corrected P = 0.02). This association persisted after including additional samples genotyped by TaqMan, both, in the basic SNP analysis (P = 1.7 x 10-7) and in the adjusted logistic regressions analysis (P = 9.7 x 10-5). Moreover, the association remained when other variables were also included in the model, such as the first 10 major principal components of genetic variability, ancestry proportions along chromosome 17 and locus-specific ancestry (P = 1.7 x 10-4). Conclusions: The SNP rs1760898 (TEP1, Telomerase Associated Protein 1 gene) confers a change of Asparagine (Asn) to Lysine (Lys) within the RNA binding domain, TROVE. This change could affect the activity of telomerase enzyme that has an important role in cancer development. The SNP rs1065768 (3'UTR TK1, Thymidine kinase 1 gene) could affect mRNA stability and protein production of TK1, which is essential in DNA synthesis. Although, functional analyses are required to confirm their potential role in colorectal tumorogenesis, our findings help increase our understanding about the biological basis for the development of colorectal tumors, as well as will contribute to the overall knowledge on the heritability of CRC. Citation Format: María Carolina Sanabria-Salas, Konrad Rawlik, Albert Tenesa, Adriana Umaña-Pérez, Martha Lucía Serrano-López, Myriam Sánchez de Gómez, Jovanny Zabaleta, Gustavo Hernández-Suárez. Common genetic variants within TEP1 gene (14q11.2 locus) and TK1 gene (17q25.3 locus) are associated with the risk of colorectal tumors in Latinos [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-162. doi:10.1158/1538-7445.AM2017-LB-162

Genetic variability for root traits in carrot (Daucuscarota L.) evaluated under tropical condition

A study was conducted to evaluate the diverse carrot genotypes under tropical conditions for their genetic variability parameters during summer season 2015 at Haveli farm of UHS Bagalkot which represents the tropical region of Karnataka. Analysis of variance revealed significant variation among the genotypes for most of the characters. The range of variation and the genetic variability components such as genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) high for all the traits studied indicating the existence of variation for all the characters studied. Higher heritability was recorded by shoulder length and shoulder width and all the other characters showed low to moderate heritability indicating the influence of environment on these traits. The present investigation provides useful information about the genetic variation available in carrot for the root traits, which helps to plan a suitable strategy for the crop improvement of carrot to tropical region.

Serotonin transporter gene 5-HTTLPR VNTR allele frequency distribution in Africa and Eurasia

The S allele frequencies of serotonin transporter gene 5-HTTLPR, which is associated with a number of psychiatric disorders, were found for 21 populations of Eurasia and Africa. The principal components of genetic variability (PC1 and PC2) based on the published frequencies for 68 alleles at five STR loci of CODIS, which are supposed to be neutral, were calculated for the same populations. The S allele frequency is correlated to PC2 (R = 0.820, p < 0.0001); this means that the correlation corresponds to the general genetic variability in the studied populations. The correlation between the STR allele frequency and Hofstede’s individualism-collectivism dimension index for 4 of the 68 studied alleles is even higher than the correlation of the S allele frequency. Our findings do not support the hypothesis (Chiao and Blizinsky, 2010) on the culture-gene coevolution of the S allele frequency and the level of collectivism.

Evaluation of Genetic Variation in Local and Introduced Desert Banana (&lt;i&gt;Musa&lt;/i&gt; sp.) Genotypes for Morpho-physicochemical Traits

Knowledge of nature and magnitude of variation existing in available plant breeding materials is of great importance for successful selection of varieties for yield and other desirable traits. Therefore, this study was conducted to evaluate the genetic variation among 4 local and 11 introduced desert banana (Musa sp.) genotypes. The genotypes were planted at Dire Dawa, Eastern Ethiopia in randomized complete block design with five replications. Genetic variability components analyses were conducted considering 20 morpho-physicochemical traits. The results showed the presence of significant differences among genotypes for all traits. Phenotypic and genotypic coefficient of variations ranged from 8.95 to 52.63% and 7.2 to 48.16%, respectively, with low magnitude of differences and moderate to high for most of the traits. Heritability (H2) and genetic gain (GA) values were ranged from 14.69 to 98 and 7.4 to 81.45%, respectively, and both H2 and GA values were high and moderate for 16 traits. Fruit yield showed strong genotypic and phenotypic correlations with all growth traits and yield components with higher magnitude of genotypic correlation coefficients. Euclidean distance ranged from 2.36 to 7.6 which distinctly grouped genotypes into two clusters and five sub-groups. Moreover, the local clones were more distant each other and with introduced genotypes and performed better than introduced genotypes for most of the traits including fruit yield. The study revealed the presence of genetic variation among local and introduced genotypes and most of the traits were controlled more of by genetic factors. This suggested the importance of exploiting genetic variability of local banana clones as equal to introduction and evaluation of exotic genotypes and the higher chance of increasing fruit yield through indirect selection for growth traits and yield components.

Genetic variability of cassava progenies developed through introgression of cassava mosaic disease resistance into Ghanaian landraces

Availability of genetic diversity is important in selecting suitable cultivars for crop improvement. Progenies of crosses between 19 farmer-preferred cassava landraces and Cassava Mosaic Disease (CMD)-resistant cultivar TME 11 were evaluated and compared with their maternal parents to assess their genetic variability and genetic gains based on CMD tolerance, some growth variables and root yield. The combined analysis of variance for the traits showed significant genotypic differences amongst the progenies and the parents. Apart from a few instances, the differences in replications and years were also significant. Genetic variability components showed high heritability ranging from 92.3 to 99.6% and moderately high genetic gains of 54.1 to 99.6% for the parental cultivars. Apart from canopy spread and plant height, heritability and genetic gains of the progenies were slightly lower than the parents indicating high variability within families of the progenies. The phenotypic coefficient of variation was slightly greater than genotypic coefficient of variation indicating minimal influence of environment on the genotypes. For most of the characters evaluated, the mean performance of the progenies was higher than their corresponding parental lines. Although the genotypes differed significantly (P < 0.001) for all traits evaluated, cultivars such as Afebankye, Bosome nsia, Cedi bankye, 262 Debor, Kwadaso 25, Nkaakom 57 and Sisipe were found to constitute a pool of germplasm with adequate variability. The negative correlation between CMD incidence and other traits evaluated showed significant progress made in the breeding program.