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The aim of this study was to estimate the effects of crossbreeding on milk production and milk components in crossbred Tsigai, Lacaune, and Improved Wallachian sheep used to create a synthetic Slovak dairy sheep population. The local breeds Tsigai and Improved Wallachian were crossed with the high-yielding breed Lacaune to increase milk yield. The effects of crossbreeding were evaluated based on breed and heterosis effects. The database used consisted of 23 018 lactations from 15 888 ewes. The effects of crossbreeding on milk production and fat and protein content were estimated using the restricted maximum likelihood method in REMLF90. Fixed effects on milk yield were also studied. In ewes with a 100% heterosis effect (ewes from purebred parents of different breeds), the heterosis effect increased milk production by 11.642 kg, milk fat production by 0.772 kg, and protein production by 0.565 kg per milking period. The effect of the Tsigai breed on milk production was -21.98 kg compared to Lacaune, while for the Improved Wallachian breed, the value was -38.58 kg. The Tsigai direct breed effect reduced fat production by 1.56 kg and protein production by 1.34 kg. The Improved Wallachian direct breed effect was -2.71 kg for fat production and -2.27 kg for protein production.

The aim of this study was to estimate the effects of crossbreeding on milk production and milk components in crossbred Tsigai, Lacaune, and Improved Wallachian sheep used to create a synthetic Slovak dairy sheep population. The local breeds Tsigai and Improved Wallachian were crossed with the high-yielding breed Lacaune to increase milk yield. The effects of crossbreeding were evaluated based on breed and heterosis effects. The database used consisted of 23 018 lactations from 15 888 ewes. The effects of crossbreeding on milk production and fat and protein content were estimated using the restricted maximum likelihood method in REMLF90. Fixed effects on milk yield were also studied. In ewes with a 100% heterosis effect (ewes from purebred parents of different breeds), the heterosis effect increased milk production by 11.642 kg, milk fat production by 0.772 kg, and protein production by 0.565 kg per milking period. The effect of the Tsigai breed on milk production was -21.98 kg compared to Lacaune, while for the Improved Wallachian breed, the value was -38.58 kg. The Tsigai direct breed effect reduced fat production by 1.56 kg and protein production by 1.34 kg. The Improved Wallachian direct breed effect was -2.71 kg for fat production and -2.27 kg for protein production. [ABSTRACT FROM AUTHOR]

The object of the research was the study of the influence of the breed of pigs and methods of their breeding on the reproductive functions of sows. Manifestation of various forms of the effect of hybrid power during direct and reverse crossing of animals of these breeds, as well as the tightness and directionality of correlative relationships were studied. No significant difference was found in most parameters of reproductive capacity between Large White and Landrace sows of Irish origin for purebred breeding and crossing, except for individual piglet weight at weaning. The weight of one piglet at weaning was probably higher in purebred litters of the Landrace breed compared to other investigated genotypes. We found that the heterosis caused the advantages of crossbred litters over purebred litters in most traits of reproductive performance. But despite this, the mass of weaned piglets had an intermediate form of inheritance. It was established that there was a strong positive correlation between fertility indicators and litter weight of piglets at birth, as well as between the number of piglets in the nest at weaning and the weight of the litter of piglets at weaning, similarly as between the weight of the litter of piglets at birth and the number of piglets in the nest at weaning and the weight of the litter of piglets at weaning. A strong positive correlation was found between indicators of the number of piglets in the nest at weaning and their weight during this period, as well as between the individual weight of the piglet at weaning and the weight of the nest of piglets at the time of weaning. Between multifertility and the average weight of one piglet at weaning, an inverse moderate relationship was found, as well as between the indicator of survival of piglets before weaning and survival of piglets at the time of weaning. As a result of the research, it can be asserted that there is a medium-strength correlation between the weight of the litter of piglets at birth and their weight at weaning. [ABSTRACT FROM AUTHOR]

Safflower (Carthamus tinctorius L.) is an important source of edible oil and bioenergy with its high quality oil in its seeds. In this research, seed mixtures were made in advanced generation safflower lines to benefit from both the natural heterosis effect and the advantages of multi-line varieties. Three safflower lines (BAY-ER 2, BAY-ER 5 and BAY-ER 15) with similar phenological characteristics, but different seed and oil yields were used. Pure, double (1/2 + 1/2) and triple (1/3 + 1/3 + 1/3) seed mixture ratios were grown under open pollination condition. The partial hybrid seeds were planted in randomized block experimental design with three replicates in the following year to evaluate the the agricultural and quality characteristics. Statistically significant differences were found between pure lines and mixtures in terms of plant height, number of branches, number of heads, 1000 grain weight, seed hull ratio, oil ratio, seed yield and oil yield. Double and triple seed mixtures showed higher yield performance than pure lines, and high mixing efficiency was obtained as 50.7% from BAY-ER 2 + BAYER 15 and 44.0% from BAY-ER 5+ BAY-ER 15 binary mixtures. All the mixtures gave higher seed yield and oil ratio than their pure lines. Linoleic acid ratios in the lines and oleic acid ratios in the mixtures were found to be slightly higher. As a result, it has been understood that agricultural performance can be increased with different ratios of seed mixtures of a certain number of pure lines in safflower. [ABSTRACT FROM AUTHOR]

Hybrid advantage, described as the superiority of hybrids in some traits over their parents and termed the "heterosis effect," is widely documented in the case of reciprocal crosses of parental species (i.e., hybrids representing the F1 generation). In fish, high survival, fast growth and better health status have been widely documented in F1 hybrids. Nonetheless, the effects of interspecific hybridization on vigour, physiology and immunity‐related traits in fish are largely unknown, especially concerning native systems of coexisting parental and hybrid genomes in the same habitat. The present study examined the potential physiological and immune aspects of hybrid heterosis by comparing condition status (measured especially by indexes), haematological profile, glucose concentration and selected parameters of non‐specific and specific immunity between the evolutionarily divergent non‐congeneric cyprinoid species Abramis brama and Rutilus rutilus and their hybrids representing the F1 generation, all of them caught in nature. Clear differences were documented for vigour‐related, physiological and immune parameters between the two divergent species. Hybrids generally tended to express intermediate characters of the measured traits, likely generated by the evolutionary divergence of the hybridizing species; nonetheless, for some traits, hybrids exhibited a character that was more similar to one parental species than to the other. This was interpreted as the heterozygote advantage for F1 hybrids. It is suggested that a maternally inherited genetic background may potentially influence the expression of some branches of non‐specific immunity or other aspects related to the fish health status. [ABSTRACT FROM AUTHOR]

The research was carried out at the Surkhandarya Scientific Experimental Station of the Vegetable-Melon Plant and Potato Research Institute in 2013-2015.mThe aim of the research was to evaluate F1 hybrids and their parental forms by early maturity and to identify the most promising combinations in the conditions of southern Uzbekistan. The studies are devoted to the selection of the parental forms of tomato of different maturation period and the creation on their basis of F1 tomato hybrids and their evaluation on a set of economically valuable traits, primarily on early maturity. The total yield was highest for Dar Zavolzhye, Chelnok, Persey, Utro-2, Slava Moldova, Gruntoviy Gribovskiy 1180, Lyana (51.4-64.4 t/ha) and F1 hybrids: Ion-N x Persey, Novichok x Persey, Dar Zavolzhye x Slava Moldovy, VIR-100 x Perseus, Gruntoviy Gribovsky 1180 x Liyana, Lyana x Persey, Novichok x Slava Moldova, (76,2-90,8 t/ha). High early yield properties are distinguished in the samples of Ion-N, Lyana, Gruntovy Gribovsky 1180, Utro -2, VIR-100, Dar Zavolzhye (21.7-30.5 t/ha) and hybrid combinations Ion-N x Persey, Novichok x Persey, VIR-100 x Persey, Dar Zavolzhye x Slava Moldovy, Gruntoviy Gribovsky 1180 x Lyana, Lyana x Ion-N, the productivity of which for the first three harvest is 25.8-34.2 t/ha. The high effect of heterosis on the overall yield was noted in combinations of Novichok x Persey, Ion-N x Persey, VIR-100 x Persey, Argo x Slava Moldovy, Lyana x Persey, Dar Zavolzhye x Slava Moldovy, Novichok x Slava Moldovy. The above hybrids exceeded the most productive parent by 21.6-33.6 t / ha. The effect of heterosis was 39.6-64.0%. A high effect of heterosis (from 107.5 to 161.2%) on early yield was noted in combinations of Novichok x Persey, Ion-N x Persey, Dar Zavolzhye x Slava Moldovy, Dar Zavolzhye x Novichok, Lyana x Ion-N. Ion-N, VIR-100, Argo, Lyana, and the Slava Moldovy are distinguished according to this important indicator of the maturity of ripening. Only three combinations of Ion-H x Persey, Ion-N x VIR-100, Lyana x IonN, with the maturity of fruit ripening 43-54%.

The experiment was conducted at the level of a pilot farm located in eastern Algeria under a humid bioclimatic stage, during two successive crop years. The study focused on a F1 generation of barley (Hordeum vulgare L.) consisting of twelve hybrids from a complete diallel cross between the two locals varieties (Saida and Tichedrett) and two other introduced varieties (Nadawa and Fouara). The aim was to determine the value of parental genotypes as genitors and to analyze their descendants, while evaluating the phenotypic variability of ten quantitative variables. Analysis of the variance revealed a significant difference for the whole of parameters studied in the parents as in their descendants. Additive and non-additive effects are involved in the genetic control of the analyzed variables. The Hayman model (1954) seems acceptable for five variables on ten variables studied for which additive effects are more important than dominance effects. The analysis of the heterosis effect was significant for the characters tested. For the productivity of the plant, eight hybrids on twelve have expressed a positive heterosis compared to the mid- parent, six combinations on twelve have registered a positive heterosis compared to the over-batter parent and compared to the best variety with an overall heterosis of 17.53%. [ABSTRACT FROM AUTHOR]

In recent years Sorghum x Sudangrass hybrids are becoming a promising forage crop for production of green mass especially in conditions of extreme drought during vegetation. The results from tests for productivity heterosis in Sorghum x Sudangrass hybrids in the period 2015-2016 are presented. The registered heterosis effects towards pollinators and the standard varieties enables the selection of hybrids with high green mass yield potential. Perspective hybrids have been selected with proven higher green and dry mass productivity than the standard commercial varieties. [ABSTRACT FROM AUTHOR]

Two-year study was conducted for the production of green and dry mass from three swaths in brooming phase. F1 sorghum × sudangrass hybrids of two selected sudangrass pollinators with eight MS lines of grain sorghum of the breeding program of Agricultural Institute – Shumen were tested. The pollinator SVE is an elite origin – a typical Sudan grass, while SZE is a stabilized population after hybridization with sweet sorghum. In brooming stage the majority of tested sorghum x sudangrass hybrids have higher productivity of green and dry mass than standard varieties. No matter the unfavorable conditions during the vegetation in the period of study the highest heterosis effect in the productivity have been realized by the hybrids SC × SVE and S13 × SZE. [ABSTRACT FROM AUTHOR]

In Argentina, susceptibility of the sunflower crop to Sclerotinia sclerotiorum capitulum attacks can cause significant yield losses. We reported earlier two hybrids among a series obtained from crosses between inbred lines following a factorial mating design that had a sufficient level of resistance to be adapted to the main Argentina sunflower growing area. Results concerning the per se behavior of the parental lines involved in these crosses and the combining ability and heterosis effects of such parental genotypes are presented in this article. The lines showed different responses to white rot incidence and relative incubation period. There were significant effects for general and specific combining ability and also for midparent heterosis, for the two variables evaluated. Preponderance of additive gene effects on genetic control white rot resistance level was shown. The development of sunflower inbred lines to be used as parents in the production of hybrids for areas requiring moderately resistant hybrids is an important phase in breeding programs. To optimize the use of resources and time, our results suggest that testing general combining ability at early generations of selfing followed by testing of hybrids may be considered as an adequate strategy in breeding for white rot resistance. [ABSTRACT FROM AUTHOR]

Non additive genetic component that is the base of a quantitative character has no predictability, this is the reason for which the present paper is proposing to appreciate the special combmatory capacity for total gain and average daily gain recorded the finishing period (30-80 days), in a specific crossing scheme combining three rabbit breeds common in Timis County breeders New Zealand White, Large Chinchilla and Californian. The data obtained, were statistically analyzed and demonstrates a good special combinative capacity for these characters, reason for which the crossing scheme is recommended for pmducing of meat individuals destined for slaughterhouses. This scheme provides an exploitation of the high fervency of the heterozygote at maternal forms and at the final hybrids. [ABSTRACT FROM AUTHOR]

Non additive genetic component that is the base of a quantitative character has no predictability, this is the reason for which the present paper is proposing to appreciate the special combinatory capacity for average nests weight and average body mass of the descendants at the age of 21 days, in a specific crossing scheme combining three rabbit breeds common in Timis County breeders New Zealand White, Large Chinchilla and Californian. The data obtained, statistic presented confirm a good special combinative capacity for this character, reason for which the crossing scheme is recommended for producing meat individuals destined for slaughterhouses. This scheme provides an exploitation of the high frequency of the heterozygote at maternal forms and at the final hybrids. [ABSTRACT FROM AUTHOR]

Depending on the extent of evolutionary divergence among parent taxa, hybrids may suffer from a breakdown of coadapted genes or may conversely exhibit vigour due to the heterosis effect, which confers advantages to increased genetic diversity. That last mechanism could explain the success of hybrids when hybridization zones are large and long lasting, such as in the water frog hybridization complex. In this hybridogenetic system, hybrid individuals exhibit full heterozygosity that makes it possible to investigate in situ the impact of hybridization. We have compared parasite intensity between hybrid Rana esculenta and parental R. lessonae individuals at the tadpole stage in two populations inhabiting contrasted habitats. We estimated intensity of Gyrinicola sp. (Nematoda) in the gut, Echinostome metacercariae in the kidneys and Haplometra cylindracea in the body cavity (both species belong to Trematoda). Despite high sampling effort, no variation in parasite intensity was detected between taxa, except a possible higher tolerance to H. cylindracea in hybrid tadpoles. The low effect of hybridization suggests efficient gene co-adaptation between the two genomes that could result from hemiclonal selection. Variation in infection intensity among ponds could support the Red Queen hypothesis. [ABSTRACT FROM AUTHOR]

In a temperate climate the survival of carp larvae is limited by the pronounced cooling that usually occurs in the period of early stages of larval development, i.e. during the late spring. On the basis of previously obtained results it was assumed that years favourable for the survival of juvenile carp occur when the water temperature in the pond decreases from about 20 °C to about 14 °C more than 10 days after pond stocking. The unfavourable years are those with a temperature decrease occurring earlier. In a shallow nursery pond the cooling causes severe temperature drops that can create lethal conditions for the carp larvae. The frequent temperature decreases encouraged the seeking of carp strains and crossbreeds resistant to such changes. Polish, Hungarian, and French strains and also crossbreeds between them were considered. Under favourable thermal conditions the crossbreeds and strains showed distinctly higher average survival (p = 0.086). In each year the survival rate of the crossbreeds was higher (p = 0.013) although there was a pronounced variability in the survival rate of all breeds and crosses. [ABSTRACT FROM AUTHOR]