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

An engrossing progress report by an economic and cultural geographer tackles the number one issue related to utilization of plant genetic resources today. The era of free and unencumbered access to new crop varieties appears to be passing (Koo et al. 2004). This development in intellectual property (IP) raises concerns about its implications for food production and human health. New global regulations are reshaping our cultural and natural environments. This work involves an investigation of the role that global institutions (World Trade Organization, United Nations, World Bank) play in constructing new commodities (genetic resources, cultural products, and types of specialized labor) and in modifying the market economies to which they give rise. Debates about the function of the nation state and how its sovereignty is undermined by the emergence of these new global institutions are examined. Cross-cultural analysis of alternative forms of environmental regulation illustrates the culturally embedded nature of knowledge production. Indigenous folk, social movements, and NGO’s now play key roles in contemporary geo-political conflicts. The history of the development of global regulatory institutions and regimes in the post-WWII period, their intended purposes and operational structures, are followed by theoretical debates about the ‘transboundary’ nature of environmental issues and of the need for a global approach to their control. Case studies on genetic resources and IP rights, commodification of cultural property, food safety governance, and global regulation of specialized labor markets illustrate the impact that their regulations are having in shaping local environments. Henry Shands, head of the USDA’s Genetic Resources division, suggested that DNA extraction techniques are advancing so rapidly that it is now even possible to use dried herbarium specimens as sources of replicable DNA. This development has created consternation amongst the holders of scientific and academic collections. Parry investigates why these impacts are so geographically uneven and considers what powers nation states and non-state NGOs and indigenous groups have to mediate these effects through alternative, localized, systems of regulation. Koo et al. (2004:1,297) point out that concerns over IP seem to be diverting policy attention from more fundamental negative trends, notably, the slowdown of investment in agricultural R&D worldwide, especially research targeted to poor people’s food crops. This weakens domestic capacities to conduct agricultural R&D in many poor countries, especially throughout sub-Saharan Africa. Parry’s outsider status provides her an opportunity to speak out without reprisal. It is undeniable that this subject is riddled with contradictions and qualms. All plants have genetic potential. There is a need to rank species according to the likelihood of exploitation, based on objective criteria. Gene bank collections of genetic resources must genuinely be accessible to all. Sites must be selected carefully. Access must not be denied for geopolitical reasons. Are farmer’s rights and benefits lost in bureaucratic considerations? Read Wolfgang’s (1995) report on challenges to patents on native technology from constituents of the neem tree. Who benefits under benefit sharing? The central government, or the descendants of those farmers whose efforts at crop selection and breeding over hundreds of generations, led to welladapted landraces? Suppose farmers whose successful discoveries are out of favor with the central government, their current status is problematic, or those are residents scattered in refugee camps or incarcerated as prisoners of conscience? Annoyingly, footnotes force readers to refer repeatedly to notes at the end of the volume. There are numerous typographical errors: spelling, hyphenation, superscripts, incorrect placement of information in tables, etc. Parry tackled a difficult subject with adroitness. She does not preach, but reports the facts and leaves readers to draw their own conclusions. Her compilation may irritate some; it will certainly provoke discussion. This book is essential reading for all researchers involved with plant genetic resources—including field botanists, botanical gardens, gene banks, breeders, chemists, pharmacologists, and everyone interested in using plant germplasm—because it critically assesses one of the fundamental issues of our times.

Farmers' Bounty: Locating Crop Diversity in the Contemporary World

Plant Breeding – Theory and Practice

Forty-five single-cross hybrids developed from ten inbred lines of quality protein maize through diallel mating design along with four checks viz., Pratap QPM Hybrid-1, Vivek QPM-9, HQPM-1 and HQPM-5 were evaluated in randomized block design with three replications for seventeen traits during kharif-2014, to identify the heterotic superiority of the New cross combinations over the parents and best check. Out of 45 crosses, 42 crosses over mid parent, 37 crosses over better parent and 6 crosses over standard check (HQPM-5) significantly out yielded for grain yield plant-1. Hybrid P6×P8 showed maximum per se performance for grain yield plant -1, stover yield plant-1, ear length, ear girth and tryptophan content also showed good per se performance for oil content (6.13%), starch content (69.83%), protein content (10.52%) and for lysine content (4.19%) with maximum positive significant economic heterosis (19.63%) for grain yield plant-1, over the best check HQPM-5. Hybrid P5×P8 showed highest per se performance along with maximum positive significant economic heterosis for lysine content and protein content over the best check Vivek QPM-9 and HQPM-5, respectively. Another hybrid P3×P5 and P5×P7 exhibited highest per se performance for oil content and starch content, respectively, along with maximum positive significant economic heterosis over the best check HQPM-5 and HQPM-1, respectively.

/pdf/exploitation-of-heterosis-in-single-cross-hybrids-of-quality-dr5u2mzdas.pdf

Exploitation of Heterosis in Single Cross Hybrids of Quality Protein Maize (Zea maize L.) for Yield and Quality Traits

Nine inbred lines (S5) of white maize derived from Giza -2 and IW- 469 were crossed using of half  diallel cross mating design, during spring season of 2019 at the Farm of Faculty of Agriculture, Al-Azhar University at Assiut Branch, to produce thirty six F1 crosses. The parents, crosses and tow checks i.e. SC-163 and SC-10 were evaluated during spring season of 2020 in R.C.B.D with three replications to determine combining ability, heterotic and gene action effects. Significant differences were found among parental and their crosses as well as for general combining ability (GCA) and specific combing ability (SCA) for all studied traits. The previous results indicating the importance of both additive and non-additive genetic effects for studied traits. The ratio of Σg2i/ΣS2ij was less one for all studied traits, indicate that the non-additive gene action in the inheritance of all the studied traits.  Parents P1 and P4 showed best GCA effects for grain yield/plant, while the parents P2 and P6 appeared to be the best general combiners for most of the studied traits. The crosses P1 x P8, P2 × P6 and P2 × P5 appeared to be the best mean performance, SCA and superiority percentage for most studied traits. The values of the broad sense heritability were high (>80%) for all studied traits. While, the narrow sense heritability was low for grain yield/plant (13.00%). Results indicated that some inbred lines could be used in breeding program to develop single crosses which have higher grain yield.

https://aasj.journals.ekb.eg/article_120101_61e2e2378e8bdd6d8484d5eb89930743.pdf

Combining ability and genetic parameters of some white maize (Zea mays L.) inbred lines using diallel analysis

Six extra-early quality protein maize (QPM) inbred lines from IITA were investigated using a partial diallel cross design. The objectives were to assess the hybrids and their parents for their agronomic performance. The six parents along with their hybrids (15) were evaluated using a Randomized Complete Block Design (RCBD) with three replications per site in four locations. General combining ability (GCA) and specific combining ability (SCA) effects as well as mid-parent heterosis were determined. Results of combined analysis of variance (ANOVA) revealed significant environmental effect for all the traits studied. Significant additive effect was observed for only grain yield whilst non-significant GCA and SCA effects were identified for all other traits. The GCA estimate identified parental lines P1, P3 and P5 as the high combiners for grain yield. The GCA estimates identified parental lines P1, P3 and P5 as the best combiners for grain yield. Again, P1 was the most suitable parent for increased cob length, cob diameter, number of rows per cob and reduced anthesis-silking interval; P3 for thousand-grain weight and reduced days to flowering (anthesis and silking days), and P5 for number of kernels per row, and reduced plant height and ear height. Hence, these parents may be used in hybridization programmes as donors of the superior traits indicated. The highest values for SCA and mid-parent heterosis for grain yield were observed in the crosses P1xP4, P5xP6, P1xP5 and P4xP6.

	 

	Key words: Quality protein maize (QPM), diallel, combining ability.

Combining ability and heterosis estimate of extra-early quality protein maize (QPM) single cross hybrids

Correlation coefficients and stability of grain yield were determined using 6 extra-early quality protein maize (QPM) parental inbred lines and their F1 (15) single crosses evaluated in selected ecological zones of Ghana. The objectives were; to estimate the genetic correlation between grain yield and other agronomic traits and to determine the stability of the single cross hybrids across four locations. Randomized Complete Block Design (RCBD) with three replications was used for each location. Estimates of correlation coefficients and stability analysis of grain yield was done using Genstat 9.2 and additive main effects and multiplicative interaction (AMMI) statistical model (MATMODEL 2.0). Results from phenotypic correlation of grain yield showed highly positive correlation with thousand grain weight (TGW) and number of kernels per row (NKR) across all locations suggesting that selection efficiency could be improved through indirect selection. AMMI analysis revealed non-significant genotype by environment interaction (GEI) for grain yield whilst genotypic and environmental main effects were highly significant. However, the contribution of the environment was higher which suggests that anyone of the locations used in this study can be used for subsequent evaluations in order to manage the limited resources available for the testing program.

	 

	Key words: Correlation, stability, grain yield.

B Badu-Apraku

Papers

Combining ability and heterosis estimate of extra-early quality protein maize (QPM) single cross hybrids

Genetic analysis of single cross Quality Protein Maize (QPM) hybrids