Toward pollen sterility in German chamomile (Matricaria chamomilla)–Conventional breeding approaches of cytoplasmic/genic male sterility and chemical emasculation

Pollen sterility (PS) in mother lines is crucial for hybrid crossings in plant breeding. 21 di- (2x) and tetraploid (4x) accessions of the hermaphroditic chamomile were screened for spontaneous, thermic or gametocide induced PS. Two crossing trials with the diploid accessions 'Bona' (BON) and 'Hungary 2' (HUN2) should specify maternally inherited cytoplasmic male sterility (CMS). Progeny thereof showed increased PS. BON as mother (BH) entailed means of 30 and 22% PS, versus 8% and 20% after reciprocal crossings. Backcrosses of BH with HUN2 in paternal and maternal direction revealed increasing mean PS (24% and 32%), without verification of CMS. A split plot design of 100 individuals treated with four chemical gametocides analyzed PS, seed set, germination rate and whole plant damage. Tri-iodobenzoic acid caused the highest PS (43%). Progeny of two plants (2x, 4x) with degenerated anthers without pollen, showed 100% PS either in tetraploid F₁ and F₂ (4% and 11%) or in diploid F₂ and F₃ (26% and 23%). High temperature (30/28°C day/night) decreased the male fertility to some extent.     

Is there a need for a radical reorganization of publishing the results of plant breeding research?

In this article a survey is given of motives for publishing on plant breeding research. The spate of publications should be welcomed.There is no need for a radical reorganization of publishing the results. It is a utopia to include all publications in one international journal. However, as concerns documentation in the field of plant breeding, it is advisable to adhere to one international journal (Plant Breeding Abstracts).     

Genetics of fertility restoration of ‘Wild Abortive’ cytoplasmic male sterility in rice,Oryza sativa L.

Summary Genetics of fertility restoration in six varieties and breeding lines of rice was studied in Wild Abortive cytoplasmic genetic male sterility system using cytoplasmic male sterile lines V 20 A and IR 54752 A. Fertility evaluation of the plants in F₂ and testcross populations of the crosses of V 20 A with PR 103, PR 106 and PAU 502-94-1, and IR 54752 A with PAU 1124-36-1 and PAU 1126-1-1 revealed that fertility restoration in PR 103, PR 106, PAU 502-94-1, PAU 1124-36-1 and PAU 1126-1-1 was controlled by two independently segregating dominant genes. The two genes appeared to have additive effects; one of them being stronger than the other in imparting fertility restoration. Data on spikelet fertility of the plants in F₂ and testcross populations of V 20 A/UPR 82-1-1 cross showed that fertility restoration in UPR 82-1-1 was controlled by two independently segregating dominant genes which exhibited recessive epistatic interaction.

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Did continued separate maintenance breeding of ‘Zephyr’ barley result in sub-cultivars?

Summary It was investigated whether separate maintenance breeding during 12 years of three stocks of Zephyr barley had an effect on the yielding ability and other characteristics. Trials carried out on two sites and over two years showed that the stocks were still morphologically identical and produced the same yield. Apparently the long lasting separate maintenace of the three stocks had no effect on the genetical composition for morphology and yielding ability. Zemir, the French stock of Zephyr headed two days earlier.     

Does post‐anthesis heat stress affect plant phenology,physiology, grain yield and protein content of durum wheat in a semi‐arid Mediterranean environment?

Increasing air temperature due to changing climate is projected to decrease the length of the growing season, hasten vegetative development and maturation, and ultimately affect yield of many C3 crops. Previous multilocation trials highlighted strong relationships between thermal trends in the interval “beginning of flowering‐end of grain filling” and grain yield, and protein content in durum wheat (Triticum turgidum subsp. durum (Desf.) Husn.). With the aim to confirm these relationships, nine durum wheat genotypes, including old (Capeiti 8, Senatore Cappelli and Trinakria) and modern (Amedeo, Arcangelo, Mongibello, Simeto, and Svevo) varieties and a Sicilian landrace (Russello) were grown at three different sites representing a climate gradient in Sicily, Italy. Moreover, the effect of post‐anthesis heat stress on these durum wheats was further investigated in two contrasting environments: open‐field (control—C) and greenhouse heat stress (HS). HS shortened the interval “beginning‐end of flowering” of 1.5 days across genotypes, and the “end of flowering‐beginning of grain filling” and maturation of 4.9 days, with a range of 1 day in Arcangelo to 11 days in Cappelli. Advances in main phenophases significantly decreased kernel weight (KW) and grain yield (GY), whereas grain protein content (PC) increased. As expected, a negative relationship was observed between GY and PC, while positive relationships were found for GY and grain‐filling duration (GFD), and GY and KW. Genotypes responded differently to heat stress, as evidenced by the net photosynthesis, transpiration rate, instantaneous water use efficiency and dry matter accumulation in kernels. Genotypes were ranked according to the heat susceptibility index (HSI): Amedeo, Arcangelo, Capeiti 8, Svevo and Trinakria resulted heat‐tolerant. These varieties were characterized by an early trigger of dry matter accumulation in kernels under HS (Amedeo, Arcangelo and Trinakria), or showed similar length of the GFD (Capeiti 8) between environments. The multilocation trial confirmed a negative relationship between maximum temperatures and grain yield, and a positive relationship between minimum temperatures and protein content during grain–filling periods. Research focusing on agronomic strategies, phenology and breeding for tolerance to heat stress is of strategic importance to cope with the detrimental effect of global warming in semi‐arid climates.     

Genetic research in a public–private research consortium: prospects for indirect use of Elite breeding germplasm in academic research

The creation of a public–private research partnership between plant breeding industry and academia can be beneficial for all parties involved. Academic partners benefit from the material contributions by industry and a practically relevant research focus, while industry benefits from increased insights and methodology tailored to a relevant set of data. However, plant breeding industry is highly competitive and there are obvious limits to the data and material partners are willing and able to share. This will usually include current and historic released cultivated materials, but will very often not include the elite germplasm used in-house to create new cultivars. Especially for crops where hybrid cultivars dominate the market, parental lines of hybrid cultivars are considered core assets that are never provided to outside parties. However, this limitation often does not apply to DNA or genetic fingerprints of these parental lines. We developed a procedure to take advantage of elite breeding materials for the creation of new promising research populations, through indirect selection of parents. The procedure starts with the identification of a number of traits for further study based on the presence of marker-trait associations and a priori knowledge within the participating companies about promising traits for quality improvement. Next, regression-based multi-QTL models are fitted to hybrid cultivar data to identify QTLs. Fingerprint data of parental lines of a limited number of specific hybrids are then used to predict parental phenotypes using the multi-QTL model fitted on hybrid data. The specific hybrids spanned the whole of the sensory space adequately. Finally, a choice of parental lines is made based on the QTL model predictions and new promising line combinations are identified. Breeding industry is then asked to create and provide progeny of these line combinations for further research. This approach will be illustrated with a case study in tomato.     

A new inequality? Privatisation,urban bias,migration and medical tourism

Access to health care in developing countries, the main destinations of medical tourists, is notoriously uneven, and often becoming more so. Medical tourism, urban bias and privatisation have combined to exacerbate this trend. This is exemplified in both Thailand and India, where regional areas have been disadvantaged by the migration of health-care workers to hospitals focusing on medical tourism, neo-liberal national financial provision for medical tourism (and related tourism campaigns) and evidence of trickle-down gains is lacking. Medical tourism challenges rather than complements local health care providers, distorts national health care systems, and raises critical national economic, ethical and social questions.     

Can conventional breeding programmes provide onion varieties that are suitable for organic farming in the Netherlands?

Main stream commercial onion breeders do not select varieties for organic farming, but solely for conventional farming. Seed companies consider the organic market too small to justify investments in breeding for this sector. In order to study if their varieties also suit organic farmers’ needs we interviewed four Dutch commercial onion breeders on their breeding programme and selection criteria and compared the outcome with a variety profile composed of the priority traits of Dutch organic farmers. Breeders gave priority to the same storage and bulb quality traits that are demanded by organic farmers, because organic onions are exported to conventional supermarkets that apply the same quality standards to organic and conventional onions. However, organic farmers also need varieties that perform well in the field. Breeders give low priority to field selection. Furthermore, three of the four seed companies only breed hybrids. The cytoplasmic male sterility system used to produce these hybrids does not comply with organic principles. We conclude that at present breeders can provide varieties that meet organic farmers’ demands for storability and quality traits, but they should give higher priority to field selection to also improve required field traits. The latter will only occur, if in future the organic seed market will grow. If the organic sector wants varieties developed according to its own principles, it should either set up its own onion breeding programme or seek alliances with breeding companies that are prepared to harmonize their breeding methodology with the organic principles.     

Changes in the concept of genotype × environment interactions to fit agriculture diversification and decentralized participatory plant breeding: pluridisciplinary point of view

The standardization of environments (E) encouraged by modern society and by the productivist model of agriculture has resulted in the standardization of genotypes (G) thereby reducing G × E interaction. New societal values call for the diversification of agriculture to fit contrasted environments. This process can be depicted by four models defined by two axes, one socio-economic (individual logics versus collective governance), and the other agro-ecological (reductionist versus systemic approaches). These models differ in (i) their objectives (from improvement in yield to the empowerment of farmers), (ii) their specific expectations with respect to genotypes (from inherited genetic resources to varieties that represent genetic, ethical and social progress), (iii) their specific representations of the environment (E) (from a simple interaction between the bio-physical environment (B) and the crop management (C), to a complex interaction including the competences of the actors (A), outlets (O), regulations (R), society (S)), (iv) their particular relations between G and E (from G × E to G × B × C × A under evolving constraints represented by R × O × S). Taking this diversity into account changes the way plant improvement is considered. Thus, depending on the model, the order, interest and status of the five classic stages of plant improvement (setting objectives, creating variability, selecting, evaluating and disseminating) may be called into question. Between the existing analytical model (Model I) and a holistic model (Model IV) which remains to be developed, lies the challenge of ensuring the sustainability, efficiency and acceptability of plant breeding and resulting innovations. From a simple “statistical parameter” that we, as plant breeders, attempt to reduce, the G × E interaction is becoming an “objective” that we try to predict and valorize. Structuring the different components of E, G and G × E, enables us to extend the basic concept of representivity to both the cultivation conditions and the relational socio-economic positions of the actors involved.

Rachis brittleness in a hybrid–parent barley (Hordeum vulgare) breeding germplasm with different combinations at the non-brittle rachis genes

Two dominant, closely linked and complementary genes, Btr1 and Btr2, control rachis brittleness in barley. Recessive mutations in any of these genes turn the fragile rachis (brittle) into a tough rachis phenotype (non-brittle). The cross of parents with alternative mutations in the btr genes leads to a brittle F₁ hybrid that presents grain retention problems. We evaluated rachis fragility through a mechanical test and under natural conditions, in F₁ crosses with different compositions at the btr genes. Brittleness was significantly higher in Btr1btr1Btr2btr2 crosses compared to hybrids and inbred parents carrying one of the mutations (btr1btr1Btr2Btr2/Btr1Btr1btr2btr2). This fact could jeopardize the efficient harvest of hybrids bearing alternative mutations, reducing the choice of possible crosses for hybrid barley breeding and hindering the exploitation of potential heterotic patterns. Furthermore, non-brittle hybrids showed higher brittleness than inbreds, suggesting the presence of other dominant factors affecting the trait. In conclusion, this work encourages a deeper study of the genetic control of the rachis brittleness trait and urges the consideration of rachis tenacity as a target for hybrid barley breeding.     

Recent Trends in Nonmetropolitan Migration: Toward a New Turnaround?

An attempt is made to review migration trends in the United States over the past 30 years. The emphasis is on changes in migration patterns between metropolitan and nonmetropolitan areas. "Annual net migration estimates are examined, considering the changing metropolitan-nonmetropolitan differential, and differences across geographic and functional county types in nonmetropolitan areas. Some differences stand out across the 24-year period, but the most notable finding is the widespread nature of the turnaround, the reversal, and the current recovery. There are differences between the present and the 1970s, but a trend toward greater retention and/or acquisition of people in rural and small town areas is clear."     

Towards new regionalism? Case study of changing regional governance in the Yangtze River Delta

This paper draws on a series of interviews with urban planners and government officials to examine the changing regional governance in the Yangtze River Delta. It finds that integration and collaboration are emerging and the growing economic benefits of intercity cooperation serves as a driver for local government to change from hostile competition to collaboration. Nevertheless, regional governance is far from established. Instead, regional transformations reflect the local politics of economic devolution and urban entrepreneurialism. Currently, there is no formal regional institution or coalition and the regional agenda is economic oriented and project based. Policies are formulated by individual cities rather than through multilateral negotiation between cities. The primary motive underlying the initiatives for cooperation is regional economic competitiveness rather than regional integration. Hence, the paper argues that emerging collaboration is far from being a substantial departure from inter‐jurisdiction competition in the earlier phase of regional governance.     

The introduction of oil palm in Northeast Thailand: A new cash crop for smallholders?

As part of the Thai Government's objective to increase energy security through biodiesel, oil palm was introduced to Northeast Thailand in 2005. Nong Khai Province was selected as a pilot project because of its suitable environmental conditions. This study assesses the acceptance of policy interventions and socio‐economic conditions by adopters and non‐adopters. We found that total farmland size was significantly higher among oil palm producers than among non‐producers. Nevertheless, the area under oil palm cultivation did not increase in accordance with land size in the way rubber did. Oil palm and non‐oil palm farmers had almost equal amounts of rice area thereby providing household food security. Oil palm did not replace food crops. Farmers investing in oil palm tend to base their livelihood around on‐farm production, whereas non‐adopters tend to diversify with off‐farm income sources. Oil palm was found to be one component of a diversified farming system and an additional income source, albeit not the primary one. In conclusion, oil palm was a crop that had been tried by (wealthier) farmers with sufficient capital, and an aim to further diversify on‐farm household income. Oil palm is certainly not (yet) contributing substantially to household income in Thailand's Northeast.     

Rapid identification of a major effect QTL conferring adult plant resistance to stripe rust in wheat cultivar Yaco“S”

Stripe rust is a devastating disease in common wheat (Triticum aestivum) worldwide. Growing cultivars with adult-plant resistance (APR) is an environmental friendly approach that provides long-term protection to wheat from this disease. Wheat cultivar Yaco“S” showed a high level of APR to stripe rust in the field from 2008 to 2014. The objective of this study was to detect the major quantitative trait loci (QTL) for APR to stripe rust in Yaco“S”. One hundred and eighty-four F_2:3 lines were developed from a cross between Yaco“S” and susceptible cultivar Mingxian169. Illumina 90K and 660K single nucleotide polymorphism (SNP) chips were implemented to bulked pools and their parents to identify SNPs associated with the major QTL. A high-density linkage map was constructed using simple sequence repeat (SSR) and SNP markers. Inclusive composite interval mapping detected a major effect QTL Qyryac.nwafu-2BS conferring stable resistance to stripe rust in all tested environments. Qyryac.nwafu-2BS were mapped to a 1.3 cm interval and explained 17.3–51.9% of the phenotypic variation. Compared with stripe rust resistance genes previously mapped to chromosome 2B, Qyryac.nwafu-2BS is likely a new APR gene to stripe rust. Combining SNP iSelect assay and kompetitive allele specific PCR technology, we found that the APR gene could be rapidly and accurately mapped and it is useful for improving stripe rust resistance in wheat breeding.     

Tagging of four fertility restorer loci for wild abortive—cytoplasmic male sterility system in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) using microsatellite markers

Tagging of restorer genes for wild abortive (WA) CMS source by studying a 222 individual plants from a F₂ population of a cross between IR58025A × IR42686R. The restorer line IR42686R that was used in this study had been previously derived through random mating composite population (RMCP) involving 12 parents facilitated by IR36 genetic male sterility. Four Rf genes were tagged to simple sequence repeats (SSR) markers on chromosomes 1, 7, 10, 12 by recessive class analysis. The recombination frequency between a positive marker and Rf locus was calculated using maximum likelihood estimator assuming that all the 46 extremely sterile individual plants were homozygous at the targeted Rf locus. The recombination frequency between the marker and the restorer trait were converted to genetic distances using Kosambi function. A new Rf locus designated as Rf7 on chromosome 12 was found to be linked to RM7003 at a genetic distance of 13.3 cM (LOD 6.12). We report here first, a new molecular marker (RM 6344) linked to Rf4 locus on chromosome 7 that was previously mapped by trisomic analysis. RM443 and RM315 were flanking the Rf3 gene at a genetic distance of 4.4 (LOD 10.29) and 20.7 cM (LOD 3.98) on chromosome 1, respectively. The Rf6 was flanked on both side with SSR markers RM258 and RM591 at a genetic distance of 4.4 (LOD 10.29) and 23.3 cM (LOD 3.39) located on chromosome 10. The random mating composite population is an excellent breeding approach to develop superior restorer lines and for pyramiding different Rf genes of different CMS systems. Rf genes tagged with closely linked SSR markers would be facilitating marker assisted selection (MAS) in hybrid rice breeding program by reducing time and workload for identifying potential restorers. L. Bazrkar and A. J. Ali equally contributed to this work.     

Can additional N fertiliser ameliorate the elevated CO2‐induced depression in grain and tissue N concentrations of wheat on a high soil N background?

Elevated CO₂ stimulates crop yields but leads to lower tissue and grain nitrogen concentrations [N], raising concerns about grain quality in cereals. To test whether N fertiliser application above optimum growth requirements can alleviate the decline in tissue [N], wheat was grown in a Free Air CO₂ Enrichment facility in a low‐rainfall cropping system on high soil N. Crops were grown with and without addition of 50–60 kg N/ha in 12 growing environments created by supplemental irrigation and two sowing dates over 3 years. Elevated CO₂ increased yield and biomass (on average by 25%) and decreased biomass [N] (3%–9%) and grain [N] (5%). Nitrogen uptake was greater (20%) in crops grown under elevated CO₂. Additional N supply had no effect on yield and biomass, confirming high soil N. Small increases in [N] with N addition were insufficient to offset declines in grain [N] under elevated CO₂. Instead, N application increased the [N] in straw and decreased N harvest index. The results suggest that conventional addition of N does not mitigate grain [N] depression under elevated CO₂, and lend support to hypotheses that link decreases in crop [N] with biochemical limitations rather than N supply.     

Will breeding for nitrogen use efficient crops lead to nitrogen use efficient cropping systems?: a simulation study of G×E×M interactions

The benefits of improving nitrogen use efficiency (NUE) in crops are typically studied through the performance of the individual crop. However, in order to increase yields in a sustainable way, improving NUE of the cropping systems must be the aim. We did a model simulation study to investigate how improvement of NUE traits of individual crops affects the succeeding crops and the NUE of the crop rotation. Based on experimental results parameterization was altered for different types of improved NUE in the EU-Rotate_N model, e.g. through higher N harvest index, reduced litter loss or improved root depth penetration rate. The different ways of improving NUE have different effects on the cropping system, affecting either N uptake, the ability of the crop to hold on to N already taken up, or the fraction of crop N being harvested. Due to the different modes of action, the model simulations show that these changes in NUE traits will also have different effects on N leaching loss and on N availability and N loss in the following years. Simulations also show that the effect of genotypes with improved NUE depend on environment and crop management. This is true for the improved crop itself and when its effect is analyzed for the whole cropping system. The environmental conditions, crop choices and management will all affect the fate of the N left in the soil, and whether this will contribute mainly to leaching loss or be used for production in later crops. As an example, increasing pre-crop fertilization was shown to affect the leaching after the following oilseed rape crop with up to 50 kg N ha^?1 taken up before it was lost to the environment when pre-crop fertilization as well as root depth penetration rate was high. All in all, the simulations illustrate the concept of NUE as the result of interactions between genotype, environment and crop management (G×E×M).