Genetic parameters controlling the inheritance of glaucousness and yield traits in bread wheat

Wheat breeders frequently use generation mean analysis to obtain information on the type of gene action involved in inheriting a trait to choose the helpful breeding procedure for trait improvement. The present study was carried out to study the inter-allelic and intra-allelic gene action and inheritance of glaucousness, earliness and yield traits in a bread wheat cross between divergent parents in glaucousness and yield traits; namely Mut-2 (P1) and Sakha 93 (P2). The experimental material included six populations, i.e. P1, P2, F1, F2, BC1, and BC2 for this wheat cross. A randomized complete block design with three replications was used, and a six parameters model was applied. Additive effects were generally more critical than dominance for all studied traits, except for plant height (PH) and grain yield/plant (GYPP). The duplicate epistasis was observed in spike length; SL, spikes/plant; SPP and days to heading; DTH. All six types of allelic and non-allelic interaction effects controlled SL, GYPP, DTH and glaucousness. All three types of epistasis, i.e. additive x additive, additive x dominance, and dominance x dominance, are essential in determining the inheritance of four traits (SL, GYPP, DTH and glaucousness). Dominance × dominance effects were higher in magnitude than additive × dominance and additive × additive in most traits. The average degree of dominance was minor than unity in six traits (glaucousness, grains/spike, spike weight, days to maturity, 100-grain weight and SL), indicating partial dominance and selection for these traits might be more effective in early generations. Meanwhile, the remaining traits (PH, SPP, GYPP and DTH) had a degree of dominance more than unity, indicating that overdominance gene effects control such traits and it is preferable to postpone selection to later generations. The highest values of narrow-sense heritability and genetic advance were recorded by glaucousness trait followed by SL and SPP, indicating that selection in segregating generations would be more effective than other traits.

Genetic studies of different agronomic, quality and yield contributing traits in Gossypium hirsutum L.

An experiment of 4 × 4 diallel was carried out to study the gene action of different yield and yield contributing traits of four advanced cotton cultivars using Mather and Jinks approach. Significant variation was present for all the characters (P< 0.01). The data on recorded parameters revealed that most of the traits were fully or partially fit for genetic interpretation. Additive gene action (D) was significant and pre-dominant for all the characters while seeds per locule showed dominance effect of H1& H2, and it was confirmed by the value of degree of dominance (H1/D 0.5). The value of H2/4H1 and h2 (measures the direction of dominance) demonstrated asymmetrical division of dominant genes for all traits, except ginning out turn (G.O.T) percentage and fiber length, in parental material. All the studied traits showed high value of narrow sense heritability (h2NS), however seeds per locule possessed low heritability. The genetic analysis revealed that all the characters could be improved by progeny and pedigree selection, whereas hybrid dynamism could be exploited in the trait like seeds per locule.

Agrarian structure of the Rostov region: level of development and governance mechanisms

Purpose. The article is dedicated to the analysis of the level of development of the agrarian structure, the research of problems and constraints of the functioning of various forms of management in order to identify and study the mechanisms of management of the agricultural sector. Methods. In the course of the scientific research, such methods as monographic, econometric, analytical, abstract-logical, as well as the method of monitoring studies were used. Results. Studies have shown that the Russian agricultural industry is represented by various forms of agricultural management: representatives of large and small agribusiness with a constant increase in the degree of dominance of large agribusiness. However, for some regions, due to the specifics of national, cultural and historical characteristics, the dominance of small agribusiness in the production of agricultural products is characteristic. One of these regions is the Rostov region, where the share of farming and households accounts for 55.4 % of the region's agricultural production. This, in turn, allows us to conclude that it is impractical to shift the emphasis of state regulation and support towards one of the forms of agricultural management. Scientific novelty. Some mechanisms and tools for managing the agrarian structure are proposed to provide for the improvement of the institutional environment and the creation of equal conditions for the development of both small and large agribusiness, as well as taking into account the strengths and weaknesses of the development of each form of agricultural management. In order to determine the most effective and efficient tools and mechanisms for managing the agricultural sector of the economy in relation to a specific region, the implementation of which will activate the potential of both the entire industry and individual agricultural structures, it is proposed to analyze the level of development of the agricultural structure of the region.

Ecological and philosophical aspects of the pre-professional and professional training of agro-industrial complex specialists

Annotation. The article dedicated to substantiation necessity for serious ecologically oriented pre-professional professional training for future specialists agro-industrial complex of the country based on a holistic and systematic approaches. The vital importance of preservation natural wealth is attributable to the global environmental crisis closely related to the crisis of the spirituality of humanity. The purpose of our study was in the identification the degree of dominance of such a universal human value as “nature” using the express methods “Dominant”. The processing of the results showed that the overwhelming majority of respondents do not see and do not understand the importance of nature in ensuring the life and health of each person and humanity as a whole. This confirms the authors’ idea of the need for reviewing the curriculum and programs with the aim of strengthening their environmental component for the formation a high level of environmental culture of future specialists in the agro-industrial complex, because in their professional activities they are directly related to the use of the natural resources of our country.

Divergent phenotypic plasticity of a convergent Mendelian trait in Drosophila

In Drosophila, comparisons of the thermal plasticity of pigmentation across serially homologous abdominal segments have been conducted in two species, namely Drosophila melanogaster and D. kikkawai. Pigmentation variation has different genetic architecture in the two species, being oligogenic in the former and monogenic in the later. Here, we analyze the thermal plasticity of abdominal pigmentation in a third species, D. erecta, which is phylogenetically close to D. melanogaster but like D. kikkawai has a monogenic basis for pigmentation variation. However, the underlying locus differs between D. erecta and D. kikkawai, being the X-linked melanin-synthesis gene tan in the former and the autosomal transcription factor pdm3 in the later. We found that in spite of a low overall plasticity in monogenic species compared to D. melanogaster, the two monogenic species showed divergent plasticity patterns in respect to the response to temperature and to the degree of dominance in heterozygotes. Those results provide new insights on the dependence of the degree of plasticity on the genetic architecture as well as on the extent of phenotypic convergence.

Optimization of BSA-seq experiment for QTL mapping

Deep sequencing-based bulked segregant analysis (BSA-seq) has become a popular approach for quantitative trait loci (QTL) mapping in recent years. Effective statistical methods for BSA-seq have been developed, but how to design a suitable experiment for BSA-seq remains unclear. In this paper, we show in theory how the major experimental factors (including population size, pool proportion, pool balance, and generation) and the intrinsic factors of a QTL (including heritability and degree of dominance) affect the power of QTL detection and the precision of QTL mapping in BSA-seq. Increasing population size can improve the power and precision, depending on the QTL heritability. The best proportion of each pool in the population is around 0.25. So, 0.25 is generally applicable in BSA-seq. Small pool proportion can greatly reduce the power and precision. Imbalance of pool pair in size also causes decrease of the power and precision. Additive effect is more important than dominance effect for QTL mapping. Increasing the generation of filial population produced by selfing can significantly increase the power and precision, especially from F2 to F3. These findings enable researchers to optimize the experimental design for BSA-seq. A web-based program named BSA-seq Design Tool is available at http://124.71.74.135/BSA-seqDesignTool/ and https://github.com/huanglikun/BSA-seqDesignTool.

Overdominant and partially dominant mutations drive short-term adaptation in diploid yeast

Identification of adaptive targets in experimental evolution typically relies on extensive replication and allele reconstructions. An alternative approach is to directly assay all mutations in an evolved clone by generating pools of segregants that contain random combinations of the evolved mutations. Here, we apply this method to 6 clones isolated from 4 diploid populations that were clonally evolved for 2,000 generations in rich glucose medium. Each clone contains ~20-25 mutations relative to the ancestor. We derived intermediate genotypes between the founder and the evolved clones by bulk mating sporulated cultures of each evolved clone to a barcoded haploid version of the founder. We competed the barcoded segregants en masse and quantified the fitness of each barcode. We estimated average fitness effects of evolved mutations using barcode fitness and whole genome sequencing for a subset of segregants or time-course whole population whole genome sequencing. In contrast to our previous work in haploid populations, we find that diploids carry fewer evolved mutations with a detectable fitness effect (6%), contributing a modest fitness advantage (up to 5.4%). In agreement with theoretical expectations, reconstruction experiments show that all adaptive mutations manifest some degree of dominance over the ancestral allele, and most are overdominant. Competition assays under conditions that deviated from the evolutionary environment show that adaptive mutations are often pleiotropic.

Heterosis effect in hybrids of parthenocarpic cucumber in the open field

Представлены результаты исследования проявления гипотетического и истинного гетерозиса у гибридов партенокарпического огурца по основным компонентам урожайности в условиях открытого грунта Москвы. Согласно полученным данным, у гибридов F1 Кайман и Хоббит отмечены высокие положительные эффекты гетерозиса по скороспелости (MPH=20,1…28,8%; HPH=10,4…14,2%), урожайности (MPH=24,7…44,4%; HPH=14,9…34,5%), числу плодов с растения (MPH=14,3…22,6%; HPH=11,1…18,8%) и средней массе плода (MPH=7,7…18,2%; HPH=3,7…13,0%). Невысокие отрицательные показатели эффекта гетерозиса отмечались по раннеспелости от всходов до цветения (MPH= –3,7…-8,8%; HPH= –7,1…-10,3%) и от всходов до плодоношения (MPH= –3,9…-4,0%; HPH= –5,1…-7,7%). При оценке на устойчивость к ложной мучнистой росе на естественном инфекционном фоне F1 Хоббит и его инбредные родительские линии оказались восприимчивыми как в начале, так и в конце плодоношения (6...9 балла поражения). Однако при оценке в начале поражения ЛМР небольшой отрицательный гетерозисный эффект по степени поражаемости (MPH= –7,7%; HPH= –14,3%) обеспечивает меньшую восприимчивость гибрида Хоббит по сравнению с родительскими линиями. Растения F1 гибрида Кайман меньше поражались пероноспорозом по сравнению с родительскими линиями и F1Хоббит как в начале (MPH= –11,1%; HPH= –20,0%), так и в конце вегетационного периода (MPH= –6,7%; HPH= –12,5%), что указывает на его большую устойчивость к ложной мучнистой росе. Значение степени доминантности в пределах 1< hp < +∞ указывает на наличие положительного сверхдоминирования в наследовании таких компонентов урожайности как: число плодов с растения (hp=4,0…6,0), скороспелость (hp=1,3), и урожайность (hp=2,3…5,0). Отрицательное сверхдоминирование –1< hp < -∞, наблюдалось по раннеспелости (hp= –2,0…-6,0) и поражаемости пероноспорозом (hp= –2,0). Значения гетерозиса по всем признакам были весьма значимыми как по отношению к среднему значению у родительских линий, так и значению признака у родительской линии с более высоким показателем. Очевидно, что наличие гибридной силы по основным компонентам урожайности у партенокарпического огурца может с большой вероятностью обеспечить создание гетерозисных гибридов для открытого грунта. The paper presents the results of a study of hypothetical and true heterosis in hybrids of parthenocarpic cucumber by the main components of yield in open ground conditions in Moscow. According to the data obtained, F1 Cayman and Hobbit had high positive effects of heterosis in early yield (MPH=20.1…28.8%; HPH=10.4…14.2%), yield (MPH=24.7…44.4%; HPH=14.9…34.5%), the number of fruits from the plant (MPH=14.3…22.6%; HPH=11.1…18.8%) and average fruit weight (MPH=7.7…18.2%; HPH=3.7…13.0%). Low negative indicators of the heterosis effect were observed for earliness from germination to flowering (MPH= –3.7…-8.8%; HPH= –7.1…-10.3%) and from germination to fruiting (MPH= –3.9…-4.0%; HPH= –5.1…-7.7%). When evaluating for resistance to peronosporosis on a natural infectious background, F1 Hobbit and its inbred parental lines were susceptible both at the beginning and at the end of fruiting (6..9 points of defeat). However, when assessing at the beginning of the lesion of peronosporosis, there is a small negative heterosis effect in terms of the degree of lesion (MPH= –7.7%; HPH= –14.3%) provides a lower susceptibility of the Hobbit hybrid compared to the parent lines. Plants of the F1hybrid Cayman were less affected by peronosporosis compared to the parent lines and F1 Hobbit both at the beginning (MPH= –11.1%; HPH= –20.0%) and at the end of the growing season (MPH= –6.7%; HPH= –12.5%), which indicates its greater resistance to peronosporosis. The value of the degree of dominance within 1 < hp < +∞ indicates the presence of a positive overdominance in the inheritance of such yield components as: the number of fruits from the plant (hp=4.0…6.0), early yield (hp=1.3) and yield (hp=2.3…5.0). A negative overdominance –1 < hp < – ∞ was observed for earliness (hp= –2.0…-6.0) and infection with peronosporosis (hp= –2.0). The values of heterosis for all characters were very significant both in relation to the average value of the parent lines, and in terms of the value of the trait in the parent line with a higher indicator. It is obvious that the presence of heterosis for the main components of yield in parthenocarpic cucumber, most likely, can ensure the breeding of heterotic hybrids for open ground.

Использование мутантных генов томата при селекции на гетерозис

The article presents the results on the use of lines of carriers of mutant marker genes in crossings to obtain heterotic F1 hybrids. The degree of dominance of the main traits of determining productivity (the duration of the growing season, the average number of flowers on inflorescences, the number of fruits and the mass of the fruit), depending on the characteristics of the initial parental forms, is shown. Combina-tions of hybrids with a high effect of heterosis in all studied features are isolated.

Гетерозис у кукурузы: к вопросу о преобладающем типе внутрилокусных взаимодействий

Heterosis in maize: toward prevalence type of intralocus interactions. In the biometrical genetic analysis of maize productivity, performed according to the North Caroline III design, unbiased estimates were used to calculate the average degree of dominance, in which, on average, the effect of linkage was eliminated. The hybrids Rf7×Ku123, MK01×A619 were studied, and unbiased estimates were calculated for four more hybrids according to the literature data. For genes controlling productivity, unbiased estimates of the average degree of dominance ranged from 0.65 to 0.87 for different hybrids. The result indicates that the heterosis effect in maize is more likely to be caused by dominant interactions than over-dominant ones.