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The major drawback to the implementation of genomic selection in a breeding program lies in long-term decrease in additive genetic variance, which is a trade-off for rapid genetic improvement in short term. Balancing increase in genetic gain with retention of additive genetic variance necessitates careful optimization of this trade-off. In this study, we proposed an integrated index selection approach within the genomic inferred cross-selection (GCS) framework to maximize genetic gain across multiple traits. With this method, we identified optimal crosses that simultaneously maximize progeny performance and maintain genetic variance for multiple traits. Using a stochastic simulated recurrent breeding program over a 40-years period, we evaluated different GCS methods along with other factors, such as the number of parents, crosses, and progeny per cross, that influence genetic gain in a pulse crop breeding program. Across all breeding scenarios, the posterior mean variance consistently enhances genetic gain when compared to other methods, such as the usefulness criterion, optimal haploid value, mean genomic estimated breeding value, and mean index selection value of the superior parents. In addition, we provide a detailed strategy to optimize the number of parents, crosses, and progeny per cross that can potentially maximize short- and long-term genetic gain in a public breeding program. [ABSTRACT FROM AUTHOR]

Sustaining crop production and food security are threatened by a burgeoning world population and adverse environmental conditions. Traditional breeding methods for vegetable crops are time-consuming, laborious, and untargeted, often taking several years to develop new and improved varieties. The challenges faced by a long breeding cycle need to be overcome. The speed breeding (SB) approach is broadly employed in crop breeding, which greatly shortens breeding cycles and facilities plant growth to obtain new, better-adapted crop varieties as quickly as possible. Potential opportunities are offered by SB in plant factories, where optimal photoperiod, light quality, light intensity, temperature, CO2 concentration, and nutrients are precisely manipulated to enhance the growth of horticultural vegetable crops, holding promise to surmount the long-standing problem of lengthy crop breeding cycles. Additionally, integrated with other breeding technologies, such as genome editing, genomic selection, and highthroughput genotyping, SB in plant factories has emerged as a smart and promising platform to hasten generation turnover and enhance the efficiency of breeding in vegetable crops. This review considers the pivotal opportunities and challenges of SB in plant factories, aiming to accelerate plant generation turnover and improve vegetable crops with precision and efficiency. [ABSTRACT FROM AUTHOR]

Understanding the relationship between nest site features and the breeding biology of wetland birds is crucial, as these ecosystems are significantly threatened. Particularly, studies assessing Neotropical bird breeding success are sparse. During three consecutive breeding seasons (2016–2019), we monitored 66 nests of the black-backed water tyrant Fluvicola albiventer in central Argentina. We described basic nesting parameters and analysed the relationship between breeding parameters (nest survival, clutch, and brood size), nest site features, and nest morphometry. Breeding season lasted from early September to the end of January, with a peak in October and November. Nests were placed 136.81 ± 60.44 cm above the ground or water. Clutch size was 2.70 ± 0.47 eggs (n = 30 nests), and brood size was 2.11 ± 0.60 chicks (n = 10 nests). We found a positive relationship between external nest width and both clutch and brood size. Conversely, there was a negative relationship between nest concealment and brood size. Daily nest survival rate (DSR) was 0.92, and the cumulative probability of nest survival in a 28 day nesting cycle was 9%. We found a positive influence of external nest width on DSR. We also found a negative relationship between nest concealment and DSR. The low success probability found in this species raises uncertainties about the future of its populations. Moreover, the availability of suitable nesting sites may be affected by wetland degradation. This study could provide valuable insights into the consequences of wetland loss and design strategies for wetlands conservation. [ABSTRACT FROM AUTHOR]

Forest tree breeding is new and more difficult, time-consuming, and expensive than crop breeding. Forest trees breed every 20–40 years. Genomic and molecular biology advances have revolutionized plant breeding based on phenotypes. Molecular markers make genotype selection possible. Marker-assisted breeding can speed up breeding, however, it is not effective for selecting complicated features in forest trees. The genomic estimated breeding value of an individual can be determined using this unique genomic selection method, which studies all impacts of quantitative trait loci using a large number of genetic markers across the genome. This method should improve forest trees better than conventional breeding. This article reviews genomic selection's current advancements in forest tree improvement and discusses genotyping and phenotyping methods. We also evaluate genomic prediction algorithms and stress the importance of cost–benefit analysis before genomic selection. This technique of forest breeding can be improved by boosting species diversity, favorable traits, and epigenetic variation. [ABSTRACT FROM AUTHOR]

Despite the economic and social importance, high-yielding cassava cultivars are only released after extensive research, mainly due to the low multiplication rate. This study aimed to assess the impact of using smaller-sized seed cuttings treated with agrochemicals (8MP) compared to the conventional planting size (16 cm) on genetic parameters, agronomic performance, and the ranking of cassava clones based on yield and growth attributes. The evaluation was carried out in clonal evaluation trial (CET), preliminary yield trial (PYT), and uniform yield trials (UYT). Additionally, a new selection scheme for cassava breeding programs was proposed. A total of 169 clones were evaluated, including 154 improved clones at different stages of selection and 15 local varieties used as checks. Field trials were conducted using both sizes of propagative material (8MP and 16 cm) in each phase of the breeding program. The data were analyzed using mixed models, considering the random effects of genotype and genotype-environment interaction (G×E) to determine variances and heritabilities. Bland-Altman concordance and correlation analysis of selection indices were employed to examine the consistency in the ranking of cassava clones using different seed cutting sizes. The distribution of variance components, heritabilities, means, and range of the 8MP and 16 cm trials in different phases of the cassava breeding program exhibited remarkable similarity, thereby enabling a comparative assessment of similar genetic effects. With a selection intensity of 30%, the concordance in clone ranking was 0.41, 0.57, and 0.85 in CET, PYT, and UYT trials, respectively, when comparing the selection based on 8MP and 16 cm trials. It is worth noting that the ranking of the top 15% remained largely unchanged. Based on the findings, proposed changes in the cassava selection scheme involve increasing the number of trials starting from the CET phase, early incorporation of G×E interaction, elimination of the PYT trial, reduction of the breeding cycle from 5 to 3 years, and a decrease in the time required for variety development from 11 to 9 years. These modifications are expected to lead to cost reduction and enhance the effectiveness of cassava breeding programs. [ABSTRACT FROM AUTHOR]

Despite the economic and social importance, high-yielding cassava cultivars are only released after extensive research, mainly due to the low multiplication rate. This study aimed to assess the impact of using smaller-sized seed cuttings treated with agrochemicals (8MP) compared to the conventional planting size (16 cm) on genetic parameters, agronomic performance, and the ranking of cassava clones based on yield and growth attributes. The evaluation was carried out in clonal evaluation trial (CET), preliminary yield trial (PYT), and uniform yield trials (UYT). Additionally, a new selection scheme for cassava breeding programs was proposed. A total of 169 clones were evaluated, including 154 improved clones at different stages of selection and 15 local varieties used as checks. Field trials were conducted using both sizes of propagative material (8MP and 16 cm) in each phase of the breeding program. The data were analyzed using mixed models, considering the random effects of genotype and genotype-environment interaction (G×E) to determine variances and heritabilities. Bland-Altman concordance and correlation analysis of selection indices were employed to examine the consistency in the ranking of cassava clones using different seed cutting sizes. The distribution of variance components, heritabilities, means, and range of the 8MP and 16 cm trials in different phases of the cassava breeding program exhibited remarkable similarity, thereby enabling a comparative assessment of similar genetic effects. With a selection intensity of 30%, the concordance in clone ranking was 0.41, 0.57, and 0.85 in CET, PYT, and UYT trials, respectively, when comparing the selection based on 8MP and 16 cm trials. It is worth noting that the ranking of the top 15% remained largely unchanged. Based on the findings, proposed changes in the cassava selection scheme involve increasing the number of trials starting from the CET phase, early incorporation of G×E interaction, elimination of the PYT trial, reduction of the breeding cycle from 5 to 3 years, and a decrease in the time required for variety development from 11 to 9 years. These modifications are expected to lead to cost reduction and enhance the effectiveness of cassava breeding programs.

Increasing selection differential and decreasing cycle time, the rate of genetic improvement can be accelerated. Creating and capturing higher genetic with higher accuracy within the shortest possible time is the prerequisite for enhancing genetic gain for any trait. Comprehensive yield testing at multilocations at early generations together with the shortest line fixation time can expedite the rapid recycling of parents in the breeding program through recurrent selection. Genomic selection is efficient in capturing high breeding value individuals taking additive genetic effects of all genes into account with and without extensive field testing, thus reducing breeding cycle time enhances genetic gain. In the Bangladesh Rice Research Institute, GS technology together with the trait-specific marker-assisted selection at the early generation of RGA-derived breeding lines showed a prediction accuracy of 0.454-0.701 with 0.989-2.623 relative efficiency over the four consecutive years of exercise. This study reports that the application of GS together with trait-specific MAS has expedited the yield improvement by 117 kg ha-1·year-1, which is around seven-fold larger than the baseline annual genetic gain and shortened the breeding cycle by around 1.5 years from the existing 4.5 years. [ABSTRACT FROM AUTHOR]

Information on breeding habits of grey crowned crane (Balearica regulorum) in Kenya is currently lacking. Investigations were therefore carried out between 2017 and 2020 to determine its nesting habits in Lake Ol' Bolossat basin including nest‐site features, number and distribution of territorial pairs, clutch size, eggs, and duration of breeding cycle. While 103 pairs were observed in the lake marshlands (mean density 5.00 pairs/km2), only 20 were found in upland wetlands. The number of pairs and densities (pairs/km2) in each of the lake's sections were as follows: north (24; 3.23), middle (47; 5.42), and south (32; 6.24). During this study, 61% (n = 63) of the lake marshland pairs attempted to breed compared to 80% (n = 16) in the upland wetlands. A mean of 2.23 eggs/clutch and a modal clutch of three eggs was recorded in 33 accessible nests. The range of influential factors in nest‐site selection were as follows: water depth (50–100 cm), vegetation height around the nest (60–90 cm), and an offshore distance of >100 m. Breeding cycle showed phenotypic plasticity in response to variations in local weather conditions. The number and density of cranes in this study area show its importance in the recovery and survival of the species, and which should subsequently be accorded effective protection. [ABSTRACT FROM AUTHOR]

Increasing selection differential and decreasing cycle time, the rate of genetic improvement can be accelerated. Creating and capturing higher genetic with higher accuracy within the shortest possible time is the prerequisite for enhancing genetic gain for any trait. Comprehensive yield testing at multi-locations at early generations together with the shortest line fixation time can expedite the rapid recycling of parents in the breeding program through recurrent selection. Genomic selection is efficient in capturing high breeding value individuals taking additive genetic effects of all genes into account with and without extensive field testing, thus reducing breeding cycle time enhances genetic gain. In the Bangladesh Rice Research Institute, GS technology together with the trait-specific marker-assisted selection at the early generation of RGA-derived breeding lines showed a prediction accuracy of 0.454–0.701 with 0.989–2.623 relative efficiency over the four consecutive years of exercise. This study reports that the application of GS together with trait-specific MAS has expedited the yield improvement by 117 kg ha−1·year−1, which is around seven-fold larger than the baseline annual genetic gain and shortened the breeding cycle by around 1.5 years from the existing 4.5 years.

The current investigation was carried out with an aim to evaluate disparity in haematological and serum biochemical parameters of healthy male and female Schizothorax labiatus with respect to its four reproductive phases, i.e. preparatory (autumn), pre-spawning (winter), spawning (spring) and spent (summer). The study indicated that significant (p < 0.05) alterations were seen in gonadosomatic index (GSI) of S. labiatus with maximum value for both sexes noted in spring while minimum value in autumn. Contrary to this, the highest value of hepatosomatic index (HSI) for both sexes was noted in the autumn season and the lowest value in spring. The haemoglobin (Hb) content, red blood corpuscle (RBC) and white blood corpuscle (WBC) counts and haematocrit amount of S. labiatus also revealed significant (p < 0.05) variations with peak values noted in summer while least values were recorded during winter. It was also observed that male fishes comprised significantly (p < 0.05) maximum level of all these parameters amongst all seasons of the year, except WBC count. Erythrocyte indices specifically mean corpuscular haemoglobin (MCH), MCH concentration (MCHC) and mean corpuscular volume (MCV) exhibited insignificant (p > 0.05) alterations between the sexes. The lowest levels (p < 0.05) of serum glucose, cholesterol and urea were recorded in the pre-spawning period, i.e. winter, while as the highest values (p < 0.05) were seen in the summer because of the cessation of reproductive activities and greater availability of food. Similar trend was also noted in the amount of total protein, albumin and globulin of the fish, although insignificant (p > 0.05) variation was observed between sexes. [ABSTRACT FROM AUTHOR]

Diurnal changes in daylength and temperature influence circadian rhythm of melatonin synthesis in the fish pineal organ. All core clock genes and clock-controlled aanat2 gene are expressed in the pineal organ of teleosts. However, there is paucity of information on the circadian rhythm of expression of clock genes and any clock-controlled gene in the pineal organ of any tropical/subtropical fish species under natural photoperiod and temperature during different phases of the annual breeding cycle and/or seasons. Therefore, we studied circadian rhythms of expression of clock genes (clock, bmal1, per1, per2, per3, cry1 and cry2) and aanat2 in the pineal organ of the catfish, Clarias gariepinus maintained under natural environmental conditions during different phases of its annual breeding cycle. All clock genes and aanat2 gene invariably exhibited prominent circadian rhythm of expression in the fish pineal organ irrespective of seasons/breeding phases. Further, acrophase, mesor and amplitude of the circadian rhythm of expression of the clock genes and aanat2 gene responded differently to different seasons. Our findings suggest that photoperiod-, temperature- and season-independent circadian rhythm of expression of clock genes and aanat2 gene in the pineal organ enable it to act as a potential master clock in the fish under natural conditions. [ABSTRACT FROM AUTHOR]

Common lilac is an important flowering shrub that accounts for ≈$20 million of sales in the U.S. nursery industry. Cultivar improvement in common lilac has been ongoing for centuries, yet little research has focused on shortening the multiple-year juvenility period for lilacs and the subsequent time required between breeding cycles. The practice of direct-sowing of immature “green” seed has been shown to reduce juvenility in some woody plants, but it has not been reported for common lilac. This study investigated the effects of seed maturity [weeks after pollination (WAP)], pregermination seed treatment (direct-sown vs. cold-stratified), and postgermination seedling chilling on the germination percentage, subsequent plant growth, and time to flower on lilac seedlings. All seedlings were derived from the female parent ‘Ludwig Spaeth’ and the male parent ‘Angel White’. Seeds harvested at 15 and 20 WAP resulted in 58% (sd ± 9.9%) and 80% (sd ± 9.0%) germination, respectively, which were similar to that of dry seed collected at 20 WAP with stratification (62% ± 4.2%). Seedlings from the green seed collected at 15 and 20 WAP were also approximately three-times taller than those of dry seed groups DS1, DS2, and DS3 after the first growing season. Over the next two growing seasons, there were no differences in seedling height across all treatments. Flowering occurred at the beginning of the fourth season and without differences among treatments. These results indicate that the collection and direct sowing of immature, green seed can be used to successfully grow lilac seedlings, but that they do not reduce the juvenility period. However, this method can provide more vegetative growth in year one to observe early vegetative traits such as leaf color, and it can provide more material for DNA extraction to support molecular research.

Sustaining crop production and food security are threatened by a burgeoning world population and adverse environmental conditions. Traditional breeding methods for vegetable crops are time-consuming, laborious, and untargeted, often taking several years to develop new and improved varieties. The challenges faced by a long breeding cycle need to be overcome. The speed breeding (SB) approach is broadly employed in crop breeding, which greatly shortens breeding cycles and facilities plant growth to obtain new, better-adapted crop varieties as quickly as possible. Potential opportunities are offered by SB in plant factories, where optimal photoperiod, light quality, light intensity, temperature, CO 2 concentration, and nutrients are precisely manipulated to enhance the growth of horticultural vegetable crops, holding promise to surmount the long-standing problem of lengthy crop breeding cycles. Additionally, integrated with other breeding technologies, such as genome editing, genomic selection, and high-throughput genotyping, SB in plant factories has emerged as a smart and promising platform to hasten generation turnover and enhance the efficiency of breeding in vegetable crops. This review considers the pivotal opportunities and challenges of SB in plant factories, aiming to accelerate plant generation turnover and improve vegetable crops with precision and efficiency., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 He, Ju, Liu, Song, Zhang, Zhang, Hu, Liu, Li and Liu.)

Double-brooding is an avian breeding strategy where birds produce at least two successful nests in a single season. Double-brooding is seen most frequently in small passerines for which the breeding season is lengthy enough that they can easily fit in multiple nesting attempts. Such a pattern of breeding is therefore less common among large birds with long incubation periods and slow offspring development. In the case of hornbills (Family Bucerotidae), double-brooding would be unexpected for not only these reasons, but also due to the fact that the females of nearly all hornbill species exhibit a synchronous moult of flight feathers immediately following clutch completion. Double-brooding would thus require not only an exceptionally long breeding season, but also that females undergo two very costly flight feather moults in a single season. Here we describe the double-brooding of 10 individual female Southern Yellow-billed Hornbills Tockus leucomelas in a single Namibian population during the 2019/2020 breeding season. Because the breeding cycle of Yellow-billed Hornbills lasts three months, double-brooding requires that conditions remain appropriate for breeding for more than half the year, a stringent requirement in a relatively arid country. Our analysis demonstrates that double-brooding is not a response to either small spring brood sizes or the disappearance of fledglings and appears not to be limited to females of above-average mass. Rather, we found that double-brooding is most common among females who initiated their spring nest early and appears to be associated with wetter-than-average years. [ABSTRACT FROM AUTHOR]

Breeding crops in a conventional way demands considerable time, space, inputs for selection, and the subsequent crossing of desirable plants. The duration of the seed-to-seed cycle is one of the crucial bottlenecks in the progress of plant research and breeding. In this context, speed breeding (SB), relying mainly on photoperiod extension, temperature control, and early seed harvest, has the potential to accelerate the rate of plant improvement. Well demonstrated in the case of long-day plants, the SB protocols are being extended to short-day plants to reduce the generation interval time. Flexibility in SB protocols allows them to align and integrate with diverse research purposes including population development, genomic selection, phenotyping, and genomic editing. In this review, we discuss the different SB methodologies and their application to hasten future plant improvement. Though SB has been extensively used in plant phenotyping and the pyramiding of multiple traits for the development of new crop varieties, certain challenges and limitations hamper its widespread application across diverse crops. However, the existing constraints can be resolved by further optimization of the SB protocols for critical food crops and their efficient integration in plant breeding pipelines.

Abstract Background Despite the critical role rice breeders play to ensure food security, there is a lack of information regarding their current socio-economic characteristics, constraints and attitudes towards technology adoption. Some key concepts like budget, experience, local ecosystems, level of education and even main breeding method have hardly been surveyed in the past. This not only clouds any policy making regarding scientists in national agricultural research programmes, it also makes it difficult to assess the needs and problems local rice breeders face around the world. Methods A global online survey was conducted reaching 189 rice breeders from 51 rice-growing countries around the world. The questionnaire was structured according to an adoption framework we proposed from the literature. We specifically investigated their attitudes to adopting an alternative breeding method called rapid generation advance (RGA) (also known as single seed descent). To provide some historical perspective, we compare our results with those reported by Hargrove (Rice breeders in Asia: a ten-country survey of their backgrounds, attitudes, and use of genetic materials, 1978), the only published survey on rice breeders. Results Overall, rice breeders are highly educated and have a long experience with their main breeding method. However, a gender gap with respect to education seems to persist. Large variation in resources (staff, land and budget) was observed with a small number of resource-rich institutes and a large number of resource-poor institutes. Most rice breeders are focused on breeding for irrigated conditions. Most breeders have a relatively high degree of risk taking and time preference towards shorter breeding cycles. The majority of breeders are aware of RGA and its benefits with more than half having observed RGA in practice. Finally, breeders are confident in the RGA technique and estimate its resource savings to be substantial. Conclusions Breeders’ willingness to adopt RGA was remarkably high. Surprisingly, adoption of RGA remains low (4% as main method). This may suggest that the benefits of using the RGA method still need to be further demonstrated in rice breeding. Our results could be useful to develop targeted extension material or interventions for implementing new technologies, which could be useful to high-level agricultural managers, international research centres and aid agencies.

The effects of photoperiod and temperature manipulation on reproductive cycles in threespine stickleback Gasterosteus aculeatus were examined. The experimental "advanced group" conditions were adjusted to simulate two reproductive seasons within a calendar year by adjusting light and temperature cycles. G. aculeatus subject to advanced conditions had two reproductive cycles per year, grew at normal rates and suffered little additional mortality. The research of many stickleback scientists would benefit from faster generation times and our methods could potentially shorten the time required to produce fish for genetic, behavioural and morphological work. [ABSTRACT FROM AUTHOR]

Common lilac is an important flowering shrub that accounts for '$20 million of sales in the U.S. nursery industry. Cultivar improvement in common lilac has been ongoing for centuries, yet little research has focused on shortening the multiple-year juvenility period for lilacs and the subsequent time required between breeding cycles. The practice of direct-sowing of immature ''green'' seed has been shown to reduce juvenility in some woody plants, but it has not been reported for common lilac. This study investigated the effects of seed maturity [weeks after pollination (WAP)], pregermination seed treatment (direct-sown vs. cold-stratified), and postgermination seedling chilling on the germination percentage, subsequent plant growth, and time to flower on lilac seedlings. All seedlings were derived from the female parent 'Ludwig Spaeth' and the male parent 'Angel White'. Seeds harvested at 15 and 20 WAP resulted in 58% (SD ± 9.9%) and 80% (SD ± 9.0%) germination, respectively, which were similar to that of dry seed collected at 20WAP with stratification (62%± 4.2%). Seedlings fromthe green seed collected at 15 and 20WAP were also approximately three-times taller than those of dry seed groups DS1, DS2, and DS3 after the first growing season. Over the next two growing seasons, there were no differences in seedling height across all treatments. Flowering occurred at the beginning of the fourth season and without differences among treatments. These results indicate that the collection and direct sowing of immature, green seed can be used to successfully grow lilac seedlings, but that they do not reduce the juvenility period. However, this method can provide more vegetative growth in year one to observe early vegetative traits such as leaf color, and it can provide more material for DNA extraction to support molecular research. [ABSTRACT FROM AUTHOR]

Understanding the breeding cycle of wildlife is essential to afford conservation strategies. This is especially important for barely studied species and urgent for those at serious risk of extinction. The Andalusian Buttonquail is an endangered endemic of the Western Mediterranean, confined to a cultivated strip in the Moroccan Atlantic coast. We performed 2 302 sampling events to determine the presence-absence and breeding of the species. The breeding season lasted for eight months, from February to October. Present in 17 different crops, breeding occurred in all but cucumber and artichoke. However, a strong preference for breeding crops was found for alfalfa, pumpkin and maize fields. Nests were 82 mm × 71.4 mm grass-lined structures built on a ground scrape. Eggs had 26.14 mm mean maximum length, 20.24 mean diameter and weighed 5.9 g. All complete clutches had four eggs and the hatching rate was 3.42. All but one of the monitored nests successfully reared at least one chick. Clutch size and hatching rate matched other Buttonquail populations and species, so causes of the decline must be found in other stages of the reproductive cycle. In this sense, additional studies are needed to reveal chick and juvenile survival. [ABSTRACT FROM AUTHOR]

Luteinising hormone (LH), follicle-stimulating hormone (FSH) and prolactin (PRL) are pituitary-derived hormones and mediate their functions through LH receptor (LHR), FSH receptor (FSHR) and PRL receptor (PRLR) respectively. This study aimed to investigate the seasonal expression patterns of LHR, FSHR and PRLR in the epididymis of the male wild ground squirrel during the breeding and non-breeding seasons. Histologically, principal cells, basal cells, cilia and mature spermatozoa were found in the lumen of caput, corpus and cauda epididymidis in the breeding season, whereas in the non-breeding season, cilia and basal cells were rarely found and the epididymidal duct was devoid of spermatozoa. Immunohistochemical results showed that LHR, FSHR and PRLR were mainly present in the filamentous cytoplasm layer of epithelial cells of the caput, corpus and cauda epididymidis and FSHR and PRLR displayed stronger staining in the breeding season than in the non-breeding season. Furthermore, the mRNA and protein levels of FSHR and PRLR in all regions of epididymis as well as the levels of LHR in the caput and cauda epididymidis were higher during the breeding season. The protein levels of FSHR, LHR and PRLR were positively correlated with epididymal weight. Together, these results suggest that LHR, FSHR and PRLR may regulate epididymal functional changes in the male wild ground squirrel during its seasonal breeding cycle. Seasonal breeders have distinct reproductive strategies, which include synchronised cycles of active and inactive epididymal function between the breeding and non-breeding seasons. The expression of pituitary-derived hormone receptors was positively correlated with morphological and histological changes in the epididymis of the wild ground squirrel. Pituitary-derived hormones may regulate the epididymal functional changes required to adapt to seasonal environmental changes. [ABSTRACT FROM AUTHOR]

The breeding cycle, breeding behavior, female attendance cycles and pup growth of Australian sea lions were studied at Kangaroo Island, South Australia, during December to May, 1986-87, April to October,1988, and November to March 1989-90. Animals were identified using paint, dye and bleach marks during each breeding season and with tags and natural scars between seasons.Females exhibited a synchronized, non-seasonal breeding cycle that is unique for pinnipeds. Data from 191 births gave 527 and 532 day intervals between the median pupping dates of the three breeding seasons. Sixteen females had a mean pupping interval of 540 ± 12.0 days (17.7 ± 0.4 months). Comparison to the timing of the breeding seasons during a previous study show a seasonal shift of 3-4 months during a 12 year period.Breeding females were non-gregarious and parturition sites were spread out in the study area. As a consequence, male territories were plastic in space and time. Tenure on territories ranged from almost continuous occupation to less than one day a week depending on whether females were present. Differential reproductive success of males was low. Males usually attended one female at a time and thus practiced serial polygyny to achieve more than one copulation. Attacks on pups by adult territorial males accounted for 19% of pup mortality during two breeding seasons.Females suckled their pups for 15-18 months until the birth of the next pup, although 23% did not give birth consecutively each breeding season, and continued to suckle their yearlings for up to 23 months. Female attendance cycles consisted of feeding trips of about two days in length and stays ashore of about 1.5 days, and did nat change over time. Feeding trips were significantly shorter during the winter months of June and July and may reflect a day length affect. Pup age or sex seemed to have no influence on attendance cycles. Male pups were significantly heavier than female pups and grew faster in 1988, but not in 1986-87. Growth rate data of older pups indicate that there was a reduction in the rate of growth at about one year of age but this was not always related to time of weaning.

Despite the economic and social importance, high-yielding cassava cultivars are only released after extensive research, mainly due to the low multiplication rate. This study aimed to assess the impact of using smaller-sized seed cuttings treated with agrochemicals (8MP) compared to the conventional planting size (16 cm) on genetic parameters, agronomic performance, and the ranking of cassava clones based on yield and growth attributes. The evaluation was carried out in clonal evaluation trial (CET), preliminary yield trial (PYT), and uniform yield trials (UYT). Additionally, a new selection scheme for cassava breeding programs was proposed. A total of 169 clones were evaluated, including 154 improved clones at different stages of selection and 15 local varieties used as checks. Field trials were conducted using both sizes of propagative material (8MP and 16 cm) in each phase of the breeding program. The data were analyzed using mixed models, considering the random effects of genotype and genotype-environment interaction (G×E) to determine variances and heritabilities. Bland-Altman concordance and correlation analysis of selection indices were employed to examine the consistency in the ranking of cassava clones using different seed cutting sizes. The distribution of variance components, heritabilities, means, and range of the 8MP and 16 cm trials in different phases of the cassava breeding program exhibited remarkable similarity, thereby enabling a comparative assessment of similar genetic effects. With a selection intensity of 30%, the concordance in clone ranking was 0.41, 0.57, and 0.85 in CET, PYT, and UYT trials, respectively, when comparing the selection based on 8MP and 16 cm trials. It is worth noting that the ranking of the top 15% remained largely unchanged. Based on the findings, proposed changes in the cassava selection scheme involve increasing the number of trials starting from the CET phase, early incorporation of G×E interaction, elimination of the PYT trial, reduction of the breeding cycle from 5 to 3 years, and a decrease in the time required for variety development from 11 to 9 years. These modifications are expected to lead to cost reduction and enhance the effectiveness of cassava breeding programs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Conceicão, Cortes, Klauser, Robinson and Oliveira.)

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We have analysed five samples from the skin of 368 Iberian ibexes from Sierra Nevada Natural Space (southern Spain) in order to characterize the age structure of theSarcoptes scabieimetapopulation affecting this host population and, particularly, to search for possible reproductive peaks of the parasite. Monthly mean mite density and number of larvae peaked in November, coinciding with the rutting season of its host, when the size of ibex mixed groups becomes larger. On the other hand, monthly number of nymphs differed significantly, reaching higher values in May (coinciding with the peak of parturitions), August and November. Our results suggest that (i) there is some extent of synchronization between the breeding cycles of both the host and the parasite and (ii) nymphs could play an important role in the mite transmission to offspring. We discuss the potential role of sexual hormones in such increase of larvae and therefore in mite numbers. [ABSTRACT FROM AUTHOR]

Differences in life histories and mating systems can influence the strength of sexual selection, leading to different degrees of sexual dimorphism among allied species. To test this premise, we compared the life history traits (including operational sex ratios) between two brachyuran crabs (Hemigrapsus takanoi Asakura & Watanabe, 2005 and H. sinensis Rathbun, 1931) that have different degrees of sexual dimorphism. In H. sinensis, both sexes have setal patches on their chelae, but patches are found only on the males of H. takanoi. Our field surveys showed that sexual dimorphism about body size (carapace width) differed between the two species, males being larger than females in H. takanoi, whereas females were slightly larger than males in H. sinensis. Ovigerous females of H. takanoi occurred from May to October, with two peaks in the abundance trend; ovigerous females of H. sinensis were found from March to June, with one peak of abundance when almost all females were ovigerous. The population density of H. takanoi in the field far exceeded that of H. sinensis. Although the operational sex ratio was highly biased toward males in both species due to the rarity of receptive females, the bias was more pronounced in H. takanoi than in H. sinensis, partly due to the longer receptive duration of H. sinensis females than that of H. takanoi females. The larger male biased operational sex ratio and higher population densities of H. takanoi (compared to H. sinensis) may explain interspecific differences in sexual dimorphism of morphological features, including the occurrence of the setal patch. [ABSTRACT FROM AUTHOR]

The reproductive biology of planktonic chaetognaths is poorly known, particularly with regard to the importance of seasonal factors such as daylength, temperature and lunar phase. We undertook semilunar plankton sampling (March 2013-March 2014) in the Hauraki Gulf, New Zealand, to survey sexual maturity of the abundant chaetognath Aidanosagitta regularis (the only chaetognath species present in sufficient numbers for reproductive study). Contrary to our expectations, breeding of A. regularis appeared unconstrained by seasonal factors, as reproductively mature individuals were available year-round. This finding has implications for embryological study of the chaetognaths. [ABSTRACT FROM AUTHOR]

Many different ecological factors affecting the size, use, and spatial configuration of home ranges have been investigated, yet the chronology of the breeding cycle has been relatively under studied. Here, we studied peregrine falcons ( Falco peregrinus) to describe variation in home range within and between breeding seasons in the Yamal peninsula, a region of the Russian Arctic with a high breeding density of peregrines. We used satellite telemetry to investigate variation in home range at different stages of the breeding cycle during three breeding seasons (2009-2011). We fitted Argos satellite transmitters to 10 breeding peregrines (nine females and one male) and two male fledglings. All breeding females showed fidelity to the region of the southwestern Yamal peninsula, but they were not necessarily faithful to their specific breeding ranges with 33 % dispersing to new ranges up to 40 km away. The population of peregrines in our study area was relatively synchronous in their breeding chronology, with clutches initiated in close synchrony in early June despite the birds arriving on their breeding ranges ca. 3 weeks earlier. The average home range size for breeding females was 98 km (95 % Maximum Convex Polygon). Over the breeding season, the home range area utilized by females increased in the late nestling period and again after the chicks fledged. Expansion of the home range coincided with changes in behavior associated with parental care, resulting in greater activity and more time spent away from the nest area when the female began hunting to provision nestlings and fledglings. [ABSTRACT FROM AUTHOR]

Association analysis is used to measure relations between markers and quantitative trait loci (QTL). Their estimation ignores genes with small effects that trigger underpinning quantitative traits. By contrast, genome-wide selection estimates marker effects across the whole genome on the target population based on a prediction model developed in the training population (TP). Whole-genome prediction models estimate all marker effects in all loci and capture small QTL effects. Here, we review several genomic selection (GS) models with respect to both the prediction accuracy and genetic gain from selection. Phenotypic selection or marker-assisted breeding protocols can be replaced by selection, based on whole-genome predictions in which phenotyping updates the model to build up the prediction accuracy. [ABSTRACT FROM AUTHOR]

The diet composition of the Grey Wagtail Motacilla cinerea of the Babor Range is followed by analysis of faecal samples (90 faeces) before and during the breeding season 2010. The Grey Wagtail's diet varies depending on the stage of the breeding cycle at the southern edge of their breeding area in North Africa (Bejaia). The diet consists predominantly of aquatic preys (51.79%), with Coleoptera being the most frequent constituent (n = 331, 45.5%). During the pre-laying period (February-March), the diet was variable (91 prey-taxa and H' = 3,36 bits) and preys of medium size (5 to 8 mm) were most common. During the incubation period (April-May), preys were mainly aquatic (60%) and larger (20 to 32 mm). At the end of the breeding season (June-July), there was a greater occurrence of terrestrial preys (31 aquatic versus 30 terrestrial taxa). [ABSTRACT FROM AUTHOR]

Despite the unique gonadal organization and reproductive strategies known for elasmobranchs very little is known about the reproductive biology of local species. The stages of spermatogenesis for the lesser guitar fish, Rhinobatus annulatus, has not been described and specifically the mechanism for sperm release from the spermatosyst was until now not known. The elongated paired testes, consisting of dome-shaped lobules, were embedded in an epigonal matrix. The lobules consisted of spherical spermatocyst, containing the spermatogenic cells arranged in concentric layers. In each spermatocyst, germ elements were in the same stage of differentiation. Discharging of sperm was found to be conveyed via a ciliated ductule system. The excurrent duct system consisted of the vasa efferentia, epididymis, vas deferens, seminal vesicle and cloaca. Seasonal reproductive activity was evident when the gonadosomatic index reached a maximum in November and a minimum in May. Ripe running males were observed from January to June. Mating took place between April and June. Sexual maturity was reached at a total body length of 580 mm and at three years of age. Knowledge of size/age at sexual maturity and seasonal reproductive activity in the local elasmobranch, Rhinobatus annulatus may prove critical to ensure effective management and conservation strategies for this species. [ABSTRACT FROM AUTHOR]

The survival for adult loggerhead sea turtles from a saturation tagging study on Bald Head Island, NC, USA, was estimated using a multistate model with unobservable states to relax assumptions that are violated when survival is estimated from multistate models and produce more accurate estimates of survival, recapture, and breeding transition probabilities. The influence of time, trap dependence, and low site fidelity to the study nesting beach on survival and recapture were examined. The best model given the data included an imprecise site-fidelity effect on survival, constrained the reproductive cycle to 4 years, and contained a time effect on recapture rates. The estimate of annual survival for adult females was of 0.85, producing the highest estimate in the literature for loggerhead sea turtles. Multistate models should be applied to other nesting beach data for sea turtles to improve survival estimates and in turn the ability to model and manage populations. [ABSTRACT FROM AUTHOR]

Abstract: While the role of corticosterone in mediating the response of birds to acute stress is well established, it has recently been proposed that a decrease in prolactin levels following stress may complement corticosterone in redirecting resources away from breeding activities and towards behaviors promoting immediate survival. Here, for the first time, we detail changes in the prolactin stress response of birds throughout the breeding cycle. We then discuss the modulation of the corticosterone and prolactin stress responses over successive stages of breeding, differing in reproductive value and parental effort. In a long-lived Procellariiform seabird, the Manx shearwater Puffinus puffinus, we found that prolactin levels decreased in response to acute stress during incubation and mid chick-rearing but increased in response to stress during late chick-rearing and in non parenting birds, a pattern similar to that previously described for mammals. The high corticosterone stress response in pre-breeders was consistent with predictions based on reproductive value, but a similar response during late chick-rearing was not. This probably reflected foraging effort and a heightened importance of the parents’ own nutritional status at this stage of the season, in advance of post-breeding migration. We also found that baseline prolactin levels were maintained at high levels during chick-rearing and were only slightly lower during late chick-rearing and in failed breeders and non-breeders. These data suggest that prolactin may play a role in nestling care long beyond the brooding phase, that this is not due to birds spending long periods away from the colony and that prolactin secretion may be necessary for nest-guarding behavior. [Copyright &y& Elsevier]

Mammalian reproductive biology is modified consistently across pinnipeds to achieve a synchronous and seasonal reproductive pattern. This synchrony relies on an embryonic diapause and ensures optimal conditions for offspring survival. Behavioral observations on Galapagos sea lions (Zalophus wollebaeki) indicate little synchrony and variable breeding seasons, making this species unique among otariids. We studied the reproductive physiology of wild female Galapagos sea lions in 2 months in contrasting seasons, March 2005 (n = 11) and August 2006 (n = 12) by examining progesterone and estrogen concentrations in serum and plasma. We provide physiological evidence for remarkably low synchrony and minor seasonality in the breeding cycle of Galapagos sea lions. Specifically, we found females in intermediate or advanced pregnancy during both seasons, as determined by high progesterone concentrations coupled with physical examination. Possible causes for this low synchrony are absence of strong photoperiodic change throughout the year, thought to regulate embryonic diapause, or adaptation to an environment with variable productivity and prey availability, or both. [ABSTRACT FROM AUTHOR]

During the late 19th and early 20th centuries, when blubber oil fuelled house lamps, the king penguin population at Macquarie Island was reduced from two very large (perhaps hundreds of thousands of birds) colonies to about 3000 birds. One colony, located on the isthmus when the island was discovered in 1810, was extinct by 1894 and it took about 100 years for king penguins to re-establish a viable breeding population there. Here we document this recovery. The first eggs laid at Gadget Gully on the isthmus were recorded in late February 1995 but in subsequent years egg laying took place earlier between November and February (this temporal discontinuity is a consequence of king penguin breeding behaviour). The first chick was hatched in April 1995 but the first fledging was not raised until the following breeding season in October 1996. The colony increased on average 66% per annum in the five years between 1995 and 2000. King penguins appear resilient to catastrophic population reductions, and as the island's population increases, it is likely that other previously abandoned breeding sites will be reoccupied. [ABSTRACT FROM AUTHOR]

Abstract: PPAR isotypes have been previously identified in the teleost brown trout (Salmo trutta f. fario) and their organ distribution pattern established. Being that the liver is a vital metabolic organ presenting expression of all isotypes and also knowing that estrogens/estrogen receptors seem to interact with PPARs, we hypothesized that the latter may very well change seasonally. So, we studied the expression of these receptors in the liver, along the annual reproductive cycle and in both genders. According to real-time RT-PCR, PPARα mRNA expression in females was significantly higher in May and lower in September than in other seasons. No significant variation was observed along the year in males. A significant difference between genders occurred in May, when PPARα expression was higher for females. PPARβ expression showed little variation along the reproductive cycle in females, but in males it was significantly higher in December than in the other seasons. No significant differences existed between genders. PPARγ was more expressed in February than in September and December, for females. As to males, it was more expressed in February than in all other seasons. No significant differences were observed between genders. The study proved our hypothesis that PPARs gene expression varies along the year. Moreover, PPARα expression in females followed the same annual variation pattern as peroxisome volumes and enzyme activities, and an inverse pattern relatively to the salmonid type annual plasma estradiol levels. The data agrees with the idea that PPARα is under estradiol modulation and that cross-talk between this receptor and the estrogen receptor possibly exists. [Copyright &y& Elsevier]

Simple Summary: Feeding our growing population is one of the primary concerns of plant breeders. Plant breeding needs to deliver a steady stream of modern cultivars in a time- and resource-efficient manner. This review discusses the speed breeding (SB) techniques which allow breeders to advance the crop generation in a shorter period of time. In addition, we highlight the current SB applications in major crops and explore ways to integrate SB with new breeding techniques for efficient and faster production of stable lines for basic and applied research. Breeding crops in a conventional way demands considerable time, space, inputs for selection, and the subsequent crossing of desirable plants. The duration of the seed-to-seed cycle is one of the crucial bottlenecks in the progress of plant research and breeding. In this context, speed breeding (SB), relying mainly on photoperiod extension, temperature control, and early seed harvest, has the potential to accelerate the rate of plant improvement. Well demonstrated in the case of long-day plants, the SB protocols are being extended to short-day plants to reduce the generation interval time. Flexibility in SB protocols allows them to align and integrate with diverse research purposes including population development, genomic selection, phenotyping, and genomic editing. In this review, we discuss the different SB methodologies and their application to hasten future plant improvement. Though SB has been extensively used in plant phenotyping and the pyramiding of multiple traits for the development of new crop varieties, certain challenges and limitations hamper its widespread application across diverse crops. However, the existing constraints can be resolved by further optimization of the SB protocols for critical food crops and their efficient integration in plant breeding pipelines. [ABSTRACT FROM AUTHOR]