Mapping of Quantitative Trait Loci for Exserted Stigma Rate By Using (ZS97B/MH63) Ril Population

For increasing pollination and seed set, stigma exsertion has been identified as a major component in hybrid rice. By using a recombinant inbred line (RIL) population derived from an important Indica rice cross between Zhenshan97 and Minghui63, a molecular marker-based analysis of quantitative trait loci (QTL) for stigma exsertion was performed. As a result, six prominent QTL were detected for the exserted stigma rate on chromosome 6, 2, 9, 3, 5 and 1, respectively. qSER-1-1, qSER-2-1, qSER-5-1, qSER-6-1, qSER-15-1, and qSER-18-1 explained 8.1515, 4.6657, 7.2387, 4.8997, 6.925 and 6.9291% of the total phenotypic variance, respectively. In addition, for the qSER-1-1 and qSER-2-1, the ZS97B allele increased exserted stigma rate by about 4.3484 and 3.2836%, respectively; while for qSER-5-1, qSER-6-1, qSER-15-1 and qSER-18-1, the MH63 allele increased exserted stigma rate by approx. 4.1527, 3.4243, 3.9801 and 4.0025%, respectively. Bangladesh J. Bot. 50(3): 551-556, 2021 (September)

Stability of the expression of the maize productivity parameters by AMMI models and GGE-biplot analysis

The objective of this study was to estimate genotype by locality, by year, by treatments (G×LxYxT) interaction using AMMI model, to identify maize genotypes with stable number of rows of grains performance in different growing seasons. The trials conducted with seven maize lines/genotypes, four treatments, two years and at the two locations. The results showed that the influence of genotype (G), year (Y), locality (L), and G×L, G×T, G×L×T, G×Y×T, G×Y×L×T interaction on maize number of rows of grains were significant (p<0.01). The genotype share in the total phenotypic variance for the grains number rows of was 53.50%, and the interaction was 21.15%. The results also show that the sums of the squares of the first and second major components (PC1 and PC2) constitute 100% of the sum of the squares of the interaction G×L. The first PC1 axis belongs to all 100%, which points to the significance of the genotype in the total variation and significance of the genotype for overall interaction with other observed sources of variability. The highest stability in terms of expression of the grains number of rows had the genotype L-6, followed by the genotypes L-4, L-5 and L-3. The lowest stability was demonstrated by the genotypes L-2 and L-1, which confirmed that these genotypes are not important for further selection in terms of this trait.

Rethinking heritability

Two markedly different concepts of heritability co-exist in the social and life sciences. Behavioral genetics has popularized a highly technical, quantitative concept: heritability as the proportion of genetic variance relative to the total phenotypic variance of a trait in a population. At the same time, a more common biological notion simply refers to the transmission of phenotypic traits across generations via the transmission of genes. It is argued here that the behavioral-genetic concept is of little use overall, while the common biological concept is overly narrow and implies a false view of the significance of genes in development. By appropriately expanding heritability into a general causal concept based on its role in evolution, we will arrive at a new view of development, heritability, and evolution that recognizes the importance of non-genetic inheritance and the causal parity of all determinants of phenotypic traits.

Quantitative Trait Loci Analysis of Folate Content in Dry Beans,Phaseolus vulgarisL.

Dry beans (Phaseolus vulgarisL.) contain high levels of folates, yet the level of folate may vary among different genotypes. Folates are essential vitamins and folate deficiencies may lead to a number of health problems. Among the different forms of folates, 5-methyltetrahydrofolate (5MTHF) comprises more than 80% of the total folate in dry beans. The objectives of this paper were to compare selected genotypes of dry beans for the folate content of the dry seeds and to identify quantitative trait loci (QTL) associated with the folate content in a population derived from an inter-gene-pool cross of dry beans. The folate content was examined in three large-seeded (AC Elk, Redhawk, and Taylor) and one medium-seeded (Othello) dry bean genotypes, their six F1(i.e., one-way diallel crosses), and the F2of Othello/Redhawk that were evaluated in the field in 2009. Total folate and 5MTHF contents were measured twice with one-hour time interval. The significant variation (P<0.05) in the folate content was observed among the parental genotypes, their F1progeny, and members of the F2population, ranging from 147 to 345 μg/100 g. There was a reduction in the 5MTHF and total folate contents in the second compared to the first measurement. Dark red kidney variety Redhawk consistently had the highest and pinto Othello had the lowest total folate and 5MTHF contents in both measurements. A single marker QTL analysis identified three QTL for total folate and 5MTHF contents in the first measurement and one marker for the total folate in the second measurement in the F2. These QTL had significant dominance effects and individually accounted for 7.7% to 10.5% of the total phenotypic variance. The total phenotypic variance explained by the four QTL was 18% for 5MTHF and 19% for total folate in the first measurement, but only 8% for total folate in the second measurement.

QTL detection of yield-related traits of cashew

The identification of quantitative trait loci (QTL) and marker-assisted selection with a view to breeding programs have aroused great interest, including for cashew improvement. This study identified QTL for yield-related traits: nut weight, male and hermaphrodite flowers. The traits were evaluated in 71 F1 genotypes of the cross CCP 1001 x CP 96. The methods of interval mapping and multiple QTL mapping were applied to identify QTL. Eleven QTL were detected: three for nut weight, four for male flowers and four for hermaphrodite flowers. The QTL accounted for 3.79 to 12.98 % of the total phenotypic variance and had phenotypic effects of -31.81 to 34.25 %. The potential for marker-assisted selection of the QTL hf-2f and hf-3m is great and the phenotypic effects and percentage of phenotypic variation higher than of the others.

Genetic and Environmental Influences on Finger-Sucking and Nail-Biting in Japanese Twin Children

The purpose of this study was to clarify the genetic contribution to finger-sucking and nail- biting in childhood using the largest databases available on Japanese twins. The subjects were 1131 pairs of 12-year-old twin children, consisting of 1057 males and 1205 females. All data were gathered by maternal questionnaire, and responses to the questionnaire were checked in the medical interview. The prevalence of finger-sucking between 0 to 2 years was 40% in males and 43% in females (p = .0053). The prevalence of nail-biting up until the age of 12 years was 28% in males and 26% in females (nonsignificant). Concordance rates and polychoric correlations were all higher in monozygotic pairs than in dizygotic pairs, irrespective of the sex combination. Univariate and bivariate genetic analyses using structural equation modeling was performed. The results showed that the proportion of total phenotypic variance attributable to genetic influences was 66% in males and 50% in females for finger-sucking, and 50% in both males and females for nail-biting. A co-occurrence of finger-sucking and nail-biting was observed in 17.7% of males (tetrachoric correlation: r = .40) and 15.7% of females (r = .32), which was attributed partly to common genetic or environmental factors. The proportion of total shared variance explained by genetic factors was 67%.

Genetic and Environmental Influences on Stuttering and Tics in Japanese Twin Children

The purpose of this study was to clarify the genetic contribution to stuttering and tics in childhood using the largest databases of Japanese twins. The subjects were 1896 pairs of twin children consisting of 1849 males and 1943 females with a mean age of 11.6 years (3 years to 15 years). All data were gathered by questionnaire. The prevalence of stuttering was 6.7% in males and 3.6% in females (p < .0001). The prevalence of tics was 6.8% in males and 4.1% in females (p = .0021). Concordance rates and polychoric correlations were all higher in monozygotic pairs than in dizygotic pairs irrespective of sex combination. Structural equation modeling showed that the proportion of total phenotypic variance attributable to genetic influences was 80% in males and 85% in females for stuttering, and 28% in males and 29% in females for tics. Moreover, co-occurrence between stuttering and tics was observed in 0.8% of males (tetrachoric correlation: r = .18) and 0.5% of females (r = .31), which was attributed partly (nearly 10% of total genetic variance of each trait) to the common genetic factors, with genetic correlation of r = .32.

Molecular mapping of seed aliphatic glucosinolates in Brassica juncea

An RFLP genomic map with 316 loci was used to study the inheritance of aliphatic glucosinolates in Brassica juncea using doubled-haploid (DH) populations developed from a cross between RLM-514, an agronomically superior non-canola quality B. juncea (high erucic acid and high glucosinolates), and an agronomically poor canola quality B. juncea breeding line. Two QTLs (GSL-A2a and GSL-A2b) associated with 3-butenyl were consistent across years and locations, and explained 75% of the phenotypic variance in the population. Three QTLs (GSL-A2a, GSL-F, GSL-B3) affected 2-propenyl and explained 78% of the phenotypic variance in the population. For total aliphatic glucosinolates, five QTLs explained 30% to 45% of the total phenotypic variance in the population in different environments. Several QTLs (GSL-A7 and GSL-A3) were highly inconsistent in different environments. Major QTLs (GSL-A2a and GSL-A2b) associated with individual glucosinolates were non-significant for total aliphatic glucosinolates. A marker-assisted selection strategy based on QTLs associated with individual glucosinolates rather than total aliphatic glucosinolates is proposed for B. juncea.Key words: Brassica juncea, aliphatic glucosinolate, 2-propenyl, 3-butenyl, RFLP genome map, QTLs, marker-assisted selection.

Non-parametric interval mapping in half-sib designs: use of midranks to account for ties

In QTL analysis of non-normally distributed phenotypes, non-parametric approaches have been proposed as an alternative to the use of parametric tests on mathematically transformed data. The non-parametric interval mapping test uses random ranking to deal with ties. Another approach is to assign to each tied individual the average of the tied ranks (midranks). This approach is implemented and compared to the random ranking approach in terms of statistical power and accuracy of the QTL position. Non-normal phenotypes such as bacteria counts showing high numbers of zeros are simulated (0–80% zeros). We show that, for low proportions of zeros, the power estimates are similar but, for high proportions of zeros, the midrank approach is superior to the random ranking approach. For example, with a QTL accounting for 8% of the total phenotypic variance, a gain from 8% to 11% of power can be obtained. Furthermore, the accuracy of the estimated QTL location is increased when using midranks. Therefore, if non-parametric interval mapping is chosen, the midrank approach should be preferred. This test might be especially relevant for the analysis of disease resistance phenotypes such as those observed when mapping QTLs for resistance to infectious diseases.

Genetic and phenotypic variability of cherry plum (Prunus cerasifera Ehrh) pomological characteristics

Cherry plum (Prunus cerasifera Ehrh) is one of the most widely spread fruit species in our country. The fruits are mostly used for brandy production and the seed is used for rootstock production in fruit culture. As cherry plum is resistant to plant diseases and pests, chemical protection is not required. Concerning that, cherry plum is reach and cheap source for the production of healthy food. The objective of this research was the analysis of genetic and phenotypic variability, as well as study on correlation of pomological traits of 49 cherry plum genotypes selected from the native population in Serbia. It was measured mat the highest genetic variance in total phenotypic variance was for the fruit height and total sugar content. The lowest genetic variance in total phenotypic variance was for the length of the stalk and dry matter content. The highest genetic variance coefficient (CVg = 22.93%) was calculated for the total acid content although the lowest value of genetic and phenotypic variance was for the fruit width (CVg = 0.69%; CVf = 0.80%). The highest coefficient of phenotypic and genetic correlation was calculated between the weight and height of the fruit. Native population of cherry plum in Serbia and Montenegro is specific because of the extensive variability of the forms which is highly important for the selection of raw material in breeding process.