So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

A reviewer for the Journal of the Royal Statistical Society of England comments \"This is the first book covering in one volume all important topics in genetical statistics.\" Written to provide basic probability ideas in terms of genetic situations, since the theory of genetics is a probability theory; to give a definitive treatment of applications of these ideas to genetic theory; and to describe statistical methods appropriate to the data models that are developed.

An Introduction to Genetic Statistics

The chromosomes have held the interest of geneticists since 19th century, when it was revealed that chromosomes were the vehicles of heredity material from generations to generations. The genetic material in all species is located in these specific structures termed chromosomes. Each species possess a distinguishing karyotype poised of a definite number of individual chromosomes having constant shape and size. The cytogenetic characterization will, therefore, provide the genomic array of the genetic material. Study of chromosomes by karyotyping is gaining importance. Microsatellite based data has helped in assessment of diversity it can be a valuable tool in biodiversity analysis. The use of microsatellite markers in the non-coding regions of genomic DNA and their polymorphism is visualized. The techniques of Cytogenetics and more recently of molecular genetics, have been used widely to characterize and explore the basis of their heredity. New methodologies are emerging, in particular those of molecular genetics and Cytogenetics.

Evaluation of genetic diversity

Marketing underutilized crops: the case of the African garden egg (Solanum ethiopicum) in Ghana

The aromatic rice represents a smaller but independent rice collection, the quality of which is considered to be highly acceptable. Farmers are interested in growing aromatic rice due to high premium market price. The prime objective of this study was to enhance genetic improvement of aromatic rice. Combining ability analysis (GCA and SCA) and gene action are studied in a set of 7 × 7 half-diallel crosses. Twenty-one hybrids along with their seven parents were assessed in randomized complete block design. Different quantitative characters were used to estimate the magnitude of heterosis. GCA and SCA significance for all traits revealed the importance of both additive and nonadditive genetic components. Several genes determine quantitative traits, with each gene having very little impacts and being easily influenced by environmental factors. Pusa Basmati-1 and Govindobhog were the best combiners among the seven parents. In terms of per se performance, heterosis, and SCA effects on seed yield per plant and important yield qualities, the crosses BM-24 Deharadun Pahari, Baskota × Tulaipanji, and Pusa Basmati-1 × Tulaipanji may be of interest. Because of its interconnected processing properties, ANN can play a critical role in this experiment. As a result, the current study was carried out to collect data and validate it using an artificial neural network (ANN) on the combining ability, gene action, and heterosis involved in the expression of diverse fragrant rice features. Using ANN, the validation of the result was done and it was found that the overall efficiency was approximately 99%.

/pdf/understanding-gene-action-combining-ability-and-heterosis-to-18tqzjjf.pdf

Understanding Gene Action, Combining Ability, and Heterosis to Identify Superior Aromatic Rice Hybrids Using Artificial Neural Network

Salinity is a major abiotic constrain faced by farmers in most rice cultivating areas of the world and improving grain yield in rice is the most important breeding objective. Twenty seven hybrids were generated in a line x tester mating design and were evaluated with their parents in a Randomized Complete Block Design at the Fadama site of the Federal University of Agriculture, Abeokuta (FUNAAB) during the 2014/2015 and 2015/2016 cropping season. Analysis of variance revealed a highly significant difference (P<0.01) among testers and lines for all traits except panicle length and a number of effective tillers per plant, respectively. Variances of Specific Combining Ability (SCA) were higher in magnitude than the corresponding General Combining Ability (GCA). The lines FARO 60 (P 7 ), OG300315 (P 10 ), NERICA L53 (P 4 ) including a tester ITA 212 (P 1 ) were the best general combiners for yield per plant. POKKALI (P 3 ) was the best general combiner for reduced vegetative growth and ITA 212 (P 1 ) and ITA 222 (P 2 ) were the best general combiners for plant height. The best specific combiner for yield per plant was P 1 x P 4 . P 3 x P 11 was the best specific combiner for reduced duration characters and P 2 x P 7 was the best specific combiner for plant height.  Estimates of narrow sense heritability (0.00 – 0.03) for all the traits under study were low which indicated preponderance of non-additive gene action governing these traits. Therefore, inter-mating among selected segregants followed by recombination breeding in an advanced generation might be advocated for improvement of the studied traits under salinity.

/pdf/combining-ability-analysis-and-gene-action-for-yield-and-2wvgs17uxs.pdf

Combining ability analysis and gene action for yield and yield related traits in rice (Oryza sativa L.) under saline conditions

Grain Amaranths are important nutritional vegetables in the world for their grains and leaves. Twelve grain Amaranth accessions were evaluated for their performances using randomized complete block design with 3 replications for 2 years to measure variability and group the accessions. Analysis of Variance and accessions performances revealed significant variability among the grain Amaranths. Phenotypic variances were higher in magnitude than genotypic variance for all the traits studied. High genetic advance was obtained for all the characters except 1000 grain weight (23.61). The genotypic coefficients of variations were lower than the phenotypic coefficient of variations. Heritability ranged from 41.08% for grain yield/plot to 62.18% for plant height at flowering. Grain yield was positive and highly significantly correlated with 1000 grain weight, leaf area but significantly correlated with leaf length and leaf width. The PCA revealed four main components of variations representing 78.06% of the total variability among the 12 grain amaranth accessions. The PCA identified all the 12 traits as strongly correlated with the three principal components. PC1 is well-correlated with Plant height at flowering, Stem girth, Number of leaves, Plant height at maturity, leaf width, leaf length, leaf area and Petiole length. The bi-plot analysis classified the accession NG/AA/03/11/010, NGB 01259, and NGB 0127 as having good leaf yield and desired leaf traits, Accession NHGB/09/108, NG/AO/08/04 and NGB 01261 were grouped as better grain yield with good yield attributes, while accession NGB 01234, NHGB 09/09 and NHAC3 are good dual purpose accessions having good grain and leaf yield.

https://ejar.journals.ekb.eg/article_174732_427b02cae71b4c9f5a17c7160c6cb19f.pdf

Traits selection criteria for genetic improvement of grain and leafy Amaranth (Amaranthus spp) using Principal Component Analysis

The rising demand for maize (Zea mays L.) in West and Central Africa (WCA) requires the availability of economical, adaptable, and high-yielding hybrids in the sub-region. The screening of maize hy...

Performance of three-way maize hybrids across different agro-ecologies

African eggplant is an important fruit and leafy vegetable in Africa. Heterosis over mid and better parents was estimated in eight crosses of eggplant involving eight pure lines in a field experiment in 2012 and 2013 cropping seasons. The experiment was laid out using a randomized complete block design with three replications. Collected data was subjected to analysis of variance and significant differences were further subjected to Duncan Multiple Range Test. The aim of this study was to identify superior hybrids that can be advanced in the eggplant breeding program for improved yield and related traits. Significant variation was observed among all traits measured for the parents and hybrids. The highest fruit number was observed in NHS10-40 and in NHS 10-71 x NHS 10-40 among the parents and hybrids respectively. The highest heterosis was recorded in the cross between NHS10-71 x NHS10-40.

/pdf/estimation-of-heterosis-of-yield-and-yield-related-traits-in-380g9a1dur.pdf

Justina B.O. Porbeni

Papers

Combining ability analysis and gene action for yield and yield related traits in rice (Oryza sativa L.) under saline conditions

Traits selection criteria for genetic improvement of grain and leafy Amaranth (Amaranthus spp) using Principal Component Analysis

Performance of three-way maize hybrids across different agro-ecologies

Estimation of Heterosis of Yield and Yield-Related Traits in the African Eggplant (Solanum Aethiopicum) Hybrids