Loci and candidate gene identification for soybean resistance to Phytophthora root rot race 1 in combination with association and linkage mapping

Molecular Breeding - Northern corn leaf blight (NCLB) is one of the main diseases of maize, which greatly reduces production and causes millions of dollars in losses worldwide annually....     

Expression of Umbelopsis ramanniana DGAT2A in seed increases oil in soybean

Oilseeds are the main source of lipids used in both food and biofuels. The growing demand for vegetable oil has focused research toward increasing the amount of this valuable component in oilseed crops. Globally, soybean (Glycine max) is one of the most important oilseed crops grown, contributing about 30% of the vegetable oil used for food, feed, and industrial applications. Breeding efforts in soy have shown that multiple loci contribute to the final content of oil and protein stored in seeds. Genetically, the levels of these two storage products appear to be inversely correlated with an increase in oil coming at the expense of protein and vice versa. One way to overcome the linkage between oil and protein is to introduce a transgene that can specifically modulate one pathway without disrupting the other. We describe the first, to our knowledge, transgenic soy crop with increased oil that shows no major impact on protein content or yield. This was achieved by expressing a codon-optimized version of a diacylglycerol acyltransferase 2A from the soil fungus Umbelopsis (formerly Mortierella) ramanniana in soybean seed during development, resulting in an absolute increase in oil of 1.5% (by weight) in the mature seed.     

Genome-wide association study and linkage analysis on resistance to rice black-streaked dwarf virus disease

Molecular Breeding - Wheat is one of the most important staple food crops in many parts of the world. Nitrogen (N) is often considered to be the most important mineral nutrient element for crop...     

A rice GDSL esterase/lipase protein (GELP) is required for anther and pollen development

Molecular Breeding - Gibberella ear rot (GER) caused by Fusarium graminearum (teleomorph Gibberella zeae), is one of the most devastating diseases in maize that not only severely reduces grain...     

Identification of quantitative trait loci for Fusarium head blight (FHB) resistance in the cross between wheat landrace N553 and elite cultivar Yangmai 13

Molecular Breeding - Maize is a heterosis-utilizing crop species, and the application of maize hybrids has significantly improved total maize yields worldwide. Breeding pure lines is the most...     

Functional study and elite haplotype identification of soybean phosphate starvation response transcription factors GmPHR14 and GmPHR32

Molecular Breeding - Global climate change leads to the concurrence of a number of abiotic stresses including moisture stress (drought, waterlogging), temperature stress (heat, cold), and salinity...     

Molecular mapping of Verticillium wilt resistance QTL clustered on chromosomes D7 and D9 in upland cotton

Verticillium wilt is a destructive disease with international consequences for cotton production. Breeding broad-spectrum resistant cultivars is considered to be one of the most effective means for reducing crop losses. A resistant cotton cultivar, 60182, was crossed with a susceptible cultivar, Jun-mian 1, to identify markers for Verticillium resistance genes and validate the mode of its inheritance. Genetic segregation analysis for Verticillium wilt resistance was evaluated based upon infected leaf percentage in the seedling stage using major gene-polygene mixed inheritance models and joint analysis of P₁, P₂, F₁, B₁, B₂ and F₂ populations obtained from the cultivar cross. We found that resis-tance of upland cotton cultivar 60182 to isolates BP2, VD8 and T9, and their isoconcentration mixture was controlled by two major genes with additive-dominance-epistatic effects, and the inheritance of the major gene was dominant. Furthermore, a genetic linkage map was constructed using F₂ segregating population and resistance phenotypic data were obtained using F_2︰3 families inoculated with different isolates and detected in different developmental stages. The genetic linkage map with 139 loci was comprised of 31 linkage groups covering 1165 cM, with an average distance of 8.38 cM between two markers, or 25.89% of the cotton genome length. From 60182, we found 4 QTL on chromosome D7 and 4 QTL on D9 for BP2, 5 QTL on D7 and 9 QTL on D9 for VD8, 4 QTL on D7 and 5 QTL on D9 for T9 and 3 QTL on D7 and 7 QTL on D7 for mixed pathogens. The QTL mapping results revealed that QTL clusters with high contribution rates were screened simultaneously on chromosomes D9 and D7 by multiple interval mapping (CIM), whether from resistance phenotypic data from different developmental stages or for different isolates. The result is consistent with the genetic model of two major genes in 60182 and suggests broad-spectrum resistance to both defoliating isolates of V. dahliae and nondefoliating iso-lates. The markers associated with resistance QTL may facilitate the use of Verticillium wilt resistance genes in improving breeding programs for cotton.     

Reproduction and survival of suricates (Suricata suricatta) in the southern Kalahari

In most respects, the demography of Kalahari suricates (Suricata suricatta) resembles that of other social mongooses. Average group size varies from four to nine, and groups typically include several mature females, of which one is responsible for the majority of breeding attempts. Breeding females show a postpartum oestrus; gestation is around 60 days; litter size is three to five pups at emergence and females rarely breed before the age of 24 months. In contrast, annual survival rates (0.20 for pups and 0.43 for animals over one year old) are lower than those recorded in other species. Breeding frequency is related to rainfall and breeding can cease altogether when rainfall is unusually low. In a year when this occurred, group size eroded rapidly and over 60% of groups became extinct. Total numbers were slow to recover during the following year because emigration by females was infrequent and new groups did not form in vacant ranges created by the extinction of groups. High rates of group extinction have been found in other cooperative breeders and may occur because breeding success and survival show inverse density dependence.     

Future area expansion outweighs increasing drought risk for soybean in Europe

The European Union is highly dependent on soybean imports from overseas to meet its protein demands. Individual Member States have been quick to declare self-sufficiency targets for plant-based proteins, but detailed strategies are still lacking. Rising global temperatures have painted an image of a bright future for soybean production in Europe, but emerging climatic risks such as drought have so far not been included in any of those outlooks. Here, we present simulations of future soybean production and the most prominent risk factors across Europe using an ensemble of climate and soybean growth models. Projections suggest a substantial increase in potential soybean production area and productivity in Central Europe, while southern European production would become increasingly dependent on supplementary irrigation. Average productivity would rise by 8.3% (RCP 4.5) to 8.7% (RCP 8.5) as a result of improved growing conditions (plant physiology benefiting from rising temperature and CO₂ levels) and farmers adapting to them by using cultivars with longer phenological cycles. Suitable production area would rise by 31.4% (RCP 4.5) to 37.7% (RCP 8.5) by the mid-century, contributing considerably more than productivity increase to the production potential for closing the protein gap in Europe. While wet conditions at harvest and incidental cold spells are the current key challenges for extending soybean production, the models and climate data analysis anticipate that drought and heat will become the dominant limitations in the future. Breeding for heat-tolerant and water-efficient genotypes is needed to further improve soybean adaptation to changing climatic conditions.     

小麦子粒铁、锌元素含量的研究进展

目前,铁、锌元素营养失衡已严重影响人类健康,而小麦作为人们的主要食物,其子粒中铁、锌元素含量普遍较低。因此,通过小麦育种策略提高铁、锌元素含量则被认为是最经济有效的手段,这也引起了国内外学者的广泛关注。本文概述了小麦子粒铁、锌元素含量的遗传差异、影响因素以及分子机理的研究现状,并展望了提高小麦子粒铁、锌元素含量的研究前景及途径。     

The consistency and stability of abundance-occupancy relationships in large-scale population dynamics

1. Abundance-occupancy relationships comprise some of the most general and well-explored patterns in macro-ecology. The theory governing these relationships predicts that species will exhibit a positive interspecific and intraspecific relationship between regional occupancy and local abundance. Abundance-occupancy relationships have important implications in using distributional surveys, such as atlases, to understand and document large-scale population dynamics and the consequences of environmental change. A basic need for interpreting such data bases is a better understanding of whether changes in regional occupancy reflect changes in local abundance across species of varying life-history characteristics. 2. Our objective was to test the predictions of the abundance-occupancy rule using two independent data sets, the New York State Breeding Bird Atlas and the North American Breeding Bird Survey. The New York State Breeding Bird Atlas consists of 5332 25-km(2) survey blocks and is one of the first atlases in the USA to be completed for two time periods (1980-85 and 2000-05). The North American Breeding Survey is a large-scale annual survey intended to document the relative abundance and population change of songbirds throughout the USA. 3. We found that regional occupancy was positively correlated with relative abundance across 98 (beta = 0.60 +/- 0.11 SE, P < 0.001, R(2) = 0.60) and 85 species (beta = 0.67 +/- 0.06 SE, P < 0.001, R(2) = 0.57) in two separate time periods. This relationship proved stable over time and was notably consistent between breeding habitat groups and migratory guilds. 4. Between 1980 and 2005, changes in regional occupancy were highly correlated with long-term abundance trend estimates for 75 species (beta = 5.73 +/- 0.24 SE, P < 0.001, R(2) = 0.88). Over a 20-year period, woodland and resident birds showed an increase in occupancy while grassland species showed the greatest decline; these patterns were mirrored by changes in local abundance. 5. Although exceptions existed, we found most changes in occupancy parallel changes in local abundance. These findings support the basic predictions of the abundance-occupancy rule and demonstrate its consistency and stability in species and groups of varying life-history characteristics.     

Cellular associations and the differential spermiogram: making sense of stallion spermatozoal morphology

Morphologic assessment of spermatozoa is one of the most objective measures in a Breeding Soundness Examination of a stallion. There are different systems for morphologic assessment of spermatozoa. The objectives of this article are to review spermatogenesis, describe clinical sample preparation, discuss previous methods of morphologic classification and explain the use of a differential spermiogram. The advantages of the differential spermiogram method of analysis are discussed, along with its use in delineating intrinsic and extrinsic disturbances in spermatogenesis. Case examples of specific cellular associations and their diagnostic relevance are discussed.     

Root-specific expression of rice OsHMA3 reduces shoot cadmium accumulation in transgenic tobacco

Molecular Breeding - Apple mildew, caused by the fungus Podosphaera leucotricha, is an ongoing problem for apple growers in most world production regions. To manage apple foliar mildew with less...     

Genomic regions associated with chocolate spot (Botrytis fabae Sard.) resistance in faba bean (Vicia faba L.)

Molecular Breeding - Maize (Zea mays L.) is the most important food crop in the world, with significant acreage and production across the globe. However, it is affected by low temperatures...     

Potentials toward genetic engineering of drought-tolerant soybean

Soybean (Glycine max) is one of the most important crops in legume family. Soybean and soybean-based products are also considered as popular food for human and animal husbandry. With its high oil content, soybean has become a potential resource for the production of renewable fuel. However, soybean is considered one of the most drought-sensitive crops, with approximately 40% reduction of the yield in the worst years. Recent research progresses in elucidation of biochemical, morphological and physiological responses as well as molecular mechanisms of plant adaptation to drought stress in model plants have provided a solid foundation for translational genomics of soybean toward drought tolerance. In this review, we will summarize the recent advances in development of drought-tolerant soybean cultivars by gene transfer.     

Breeding without Breeding

We developed a deterministic model to optimize DNA fingerprinting effort in the presence of gene flow during the application of Breeding without Breeding. The method considers trait??s heritability, level of gene flow, selection differential, and the proportion of progeny test subjected to fingerprinting (truncation). All the model??s variables individually or in concert proved important; however, the trait??s heritability magnitude played the most important role in minimizing the selection of contaminated individuals and it could be used as a surrogate to traits with low heritability.     

BREEDING BIOLOGY AND BEHAVIOUR OF THE QUAIL FINCH ORTYGOSPIZA ATRICOLUS

Summary

Nuttall, R.J. 1992. Breeding biology and behaviour of the Quail Finch Ortygospiza atricollis. Ostrich 63:110-117.

During a study of the breeding biology of the Quail Finch Ortygospiza atricollis, observations of nest-building, egg-laying, incubation and nestling periods, and nestling development in a grassland near Pietermaritzburg, South Africa were supplemented with observations of breeding behaviour in captivity. Mean clutch size was 4,5 and eggs were laid at intervals of approximately one day. Incubation began after the third or fourth egg was laid. An incubation period of 15–16 days and an estimated nestling period of 18–19 days was recorded. Incubation and brooding are shared by both sexes. Breeding success was low (26,7% ?28,6%), with most losses resulting from predation during either the egg-laying or incubation stages.     

Spatial structuring and dispersal in a high density population of the California vole Microtus californicus

Space use patterns of California voles are described from intensive live-trapping data obtained during the late breeding season in a peak density year. Operational sex ratios were strongly female biased. Breeding males had mutually exclusive home ranges that overlapped the home ranges of one to several females. The average male home range was larger than the average female home range and tended to encompass female home ranges in their entirety. Breeding females had home ranges that often overlapped extensively with the home ranges of other breeding females. The degree of overlap, however, tended to be either very high or very low, indicating that groups of females may act territorially among themselves. Family groups that may include members of sequential litters formed at high density. Males on experimental removal grids had larger home ranges than males on the high density grids and some became wanderers while most females had home ranges comparable to those on the high density grids.
Dispersers onto low density grids were not a random sample of the high density population; large breeding adults and small juveniles were under-represented. No sex differences in dispersal were noted. Immigration into the high density populations was probably negligible.     

A Review of Size at Maturity in Male Tanner (Chionoecetes bairdi) and King (Paralithodes camtschaticus) Crabs and the Methods Used to Determine Maturity

This paper reviews existing studies on the size of sexual maturityfor male Tanner or snow crab (Chionoecetes bairdi), a brachyuran,and the anomuran red king crab (Paralithodes camtschaticus).In this report the term sexual maturity is denned as the abilityto reproduce. A variety of indirect and direct methods thathave been used to determine maturity are reviewed. Examiningthe vas deferens for the presence of spermatophores was usefulin determining the size at which males first become mature.Breeding experiments in the laboratory demonstrated that mostmales, from both species, that produced spermatophores couldbreed with soft-shelled mates. Males of both species can breedat smaller sizes than do females. Morphometric techniques basedon reproductive tract weights and chela morphometry overestimatedthe sizes at which males mature in both species. Previous experimentsfor Tanner crab, which have internal fertilization, suggestsmall mature males can fertilize two to five females. Breedingexperiments showed recently matured red king crab do not appearto be able to fertilize more than one female per breeding season,while males nearing harvestable size can fertilize more thanone female. Breeding experiments and in situ observations of grasping pairsappear to be the most feasible methods for identifying malesize at maturity for these species. The value of morphometricestimations for determining when males mature is questionable.     

Breeding performance and timing of breeding of inland and coastal breeding Cormorants Phalacrocorax carbo in England and Wales

Capsule Breeding performance was higher at inland colonies than on the coast due to higher nestling survival during late development.

Aims To compare breeding performance of inland and coastal breeding Cormorants in England and Wales and to provide breeding performance data for Cormorants for future demographic studies.

Methods Breeding performance and timing of breeding was monitored at six inland and four coastal colonies during 1997 and 1998. We compare clutch and brood size and egg and nestling survival.

Results Breeding performance was higher at inland colonies because of higher nestling survival during the later stages of nestling development, from 15–56 days.

Conclusions Greater and earlier food availability at inland colonies, resulting in earlier and more protracted breeding is the most probable explanation for differences in breeding performance. A more protracted breeding season would reduce competition for food and enhance breeding performance, which may be especially apparent during late chick development when energy demands are greatest.