Breeding potential of maize composite Isanao VF1 in small spacing in the second growing season

The purpose of this study was to verify the breeding potential of the maize composite Isanao VF1 in the second growing season. One hundred and fifty half-sib progenies were evaluated of spacing of 0.45 m, densities of 57,778 and 80,000 plants ha(-1), in a randomized block design with three replications. Gains of 16.0 and 19.2% were estimated for grain Yield, H. I and 10.5% for prolificacy and 12.3 and 12.9% for ear height, respectively, at 57,778 and 80,000 plants ha(-1). The heritabilities for plant height, ear height and grain yield were 65.2 and 61.3%, 64.3 and 66.9% and 53.5 and 63.3%, respectively, confirming the potential for breeding at both densities. The absence of progeny by density interaction indicates that no further selection programs are necessary. The occurrence of segregation for modifier genes for height suggests stabilizing selection based on ear height.

A genomic assisted breeding program for cassava to improve nutritional quality and industrial traits of storage root

A mandioca é cultivada como "mandioca mansa" para consumo in natura e "mandioca para indústria" como fonte de amidos e farinhas. Raças locais foram utilizadas para descoberta de "mutações espontâneas" e desenvolvimento de abordagem evolutiva e de melhoramento para estudos de função gênica. Recursos de Genômica e Proteômica foram obtidos. Análises de expressão gênica por blot de RNA e microarranjos foram desenvolvidos para identificação de expressão diferencial. "Mandioca açucarada" foi identificada, sendo relacionada com falta de expressão do gene da BEI e de uma mutação "nonsence" na sequência do gene GBSSI causando a formação do amido serose. "Mandioca avermelhada" apresentou falta de expressão do gene CasLYB, e a "amarela" uma regulação de repressão do gene CasHYb. Análise Proteômica do complexo carotenóide-proteína, juntamente com a análise de expressão de gene da CAP4, revelaram uma dupla fita de cDNA associada ao elevado acúmulo de carotenóide. Sequenciamento do gene da GBSSI identificou 22 haplótipos e grande diversidade de nucleotídios. Populações segregantes de cruzamentos de fenótipos bioquímicos diferenciados com cultivares elites dos Cerrados foram obtidas.

Contribution and perspectives of quantitative genetics to plant breeding in Brazil

The purpose of this article is to show how quantitative genetics has contributed to the huge genetic progress obtained in plant breeding in Brazil in the last forty years. The information obtained through quantitative genetics has given Brazilian breeders the possibility of responding to innumerable questions in their work in a much more informative way, such as the use or not of hybrid cultivars, which segregating population to use, which breeding method to employ, alternatives for improving the efficiency of selection programs, and how to handle the data of progeny and/or cultivars evaluations to identify the most stable ones and thus improve recommendations.

Contribution of graduate programs in plant breeding to the education of plant breeders in Brazil

The success of agribusiness in Brazil in recent decades is unquestionable. Although the country has always had favorable conditions for agriculture (land, water and climate), this success has only come about recently, due to scientific research, which has resulted in considerable increases in yield and in improvement of product quality, as well as making the occupation of new agricultural frontiers possible. A decisive factor for development of agriculture in the country was the creation of EMBRAPA in 1973, which, in a few years, led to considerable demand for researchers with training in graduate programs. Among them are plant breeders, who came to exercise their activity throughout the country and in all ecosystems. The training of plant breeders was only possible because, as from the middle of the 1960s, the country began a wide-ranging education program, with the creation of several graduate programs in genetics and plant breeding.

Pattern analysis of the diversity of morphological plant attributes and herbage yield in a world collection of white clover (Trifolium repens L.) germplasm characterised in a summer moisture stress environment of Australia

Information on the variation available for different plant attributes has enabled germplasm collections to be effectively utilised in plant breeding. A world sourced collection of white clover germplasm has been developed at the White Clover Resource Centre at Glen Innes, New South Wales. This collection of 439 accessions was characterised under field conditions as a preliminary study of the genotypic variation for morphological attributes; stolon density, stolon branching, number of nodes. number of rooted nodes, stolon thickness, internode length, leaf length, plant height and plant spread, together with seasonal herbage yield. Characterisation was conducted on different batches of germplasm (subsets of accessions taken from the complete collection) over a period of five years. Inclusion of two check cultivars, Haifa and Huia, in each batch enabled adjustment of the characterisation data for year effects and attribute-by-year interaction effects. The component of variance for seasonal herbage yield among batches was large relative to that for accessions. Accession-by-experiment and accession-by-season interactions for herbage yield were not detected. Accession mean repeatability for herbage yield across seasons was intermediate (0.453). The components of genotypic variance among accessions for all attributes, except plant height, were larger than their respective standard errors. The estimates of accession mean repeatability for the attributes ranged from low (0.277 for plant height) to intermediate (0.544 for internode length). Multivariate techniques of clustering and ordination were used to investigate the diversity present among the accessions in the collection. Both cluster analysis and principal component analysis suggested that seven groups of accessions existed. It was also proposed from the pattern analysis results that accessions from a group characterised by large leaves, tall plants and thick stolons could be crossed with accessions from a group that had above average stolon density and stolon branching. This material could produce breeding populations to be used in recurrent selection for the development of white clover cultivars for dryland summer moisture stress environments in Australia. The germplasm collection was also found to be deficient in genotypes with high stolon density, high number of branches high number of rooted nodes and large leaves. This warrants addition of new germplasm accessions possessing these characteristics to the present germplasm collection.

Genetic Structure of Cochliobolus sativus Populations Sampled from Roots and Leaves of Barley and Wheat in North Dakota

Common root rot (CRR) and spot blotch, caused by Cochliobolus sativus (Ito and Kurib.) Drechsl. ex Dast., are important diseases of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) worldwide. However, the population biology of C. sativus is still poorly understood. In this study, the genetic structure of three C. sativus populations, consisting of isolates sampled respectively from barley leaves (BL), barley roots (BR) and wheat roots (WR) in North Dakota, was analysed with amplified fragment length polymorphism (AFLP) markers. A total of 127 AFLP loci were generated among 208 C. sativus isolates analysed with three primer combinations. Gene diversity (H = 0.277-0.335) were high in all three populations. Genetic variation among C. sativus individuals within population accounted for 74%, whereas 26% of the genetic variation was explained among populations. Genetic differentiation was high (empty set PT = 0.261, corrected G ''(st)= 0.39), whereas gene flow (Nm) ranged from 1.27 to 1.56 among the three populations analysed. The multilocus linkage disequilibrium (LD) ((r) over bard = 0.0760.117) was moderate in C. sativus populations. Cluster analyses indicate that C. sativus populations differentiated according to the hosts (barley and wheat) and tissues (root and leaf) although generalists also exist in North Dakota. Crop breeding may benefit from combining genes for resistance against both specialists and generalists of C. sativus.

Genetic Structure of Cochliobolus sativus Populations Sampled from Roots and Leaves of Barley and Wheat in North Dakota

Common root rot (CRR) and spot blotch, caused by Cochliobolus sativus (Ito and Kurib.) Drechsl. ex Dast., are important diseases of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) worldwide. However, the population biology of C. sativus is still poorly understood. In this study, the genetic structure of three C. sativus populations, consisting of isolates sampled respectively from barley leaves (BL), barley roots (BR) and wheat roots (WR) in North Dakota, was analysed with amplified fragment length polymorphism (AFLP) markers. A total of 127 AFLP loci were generated among 208 C. sativus isolates analysed with three primer combinations. Gene diversity (H = 0.277-0.335) were high in all three populations. Genetic variation among C. sativus individuals within population accounted for 74%, whereas 26% of the genetic variation was explained among populations. Genetic differentiation was high (empty set PT = 0.261, corrected G ''(st)= 0.39), whereas gene flow (Nm) ranged from 1.27 to 1.56 among the three populations analysed. The multilocus linkage disequilibrium (LD) ((r) over bard = 0.0760.117) was moderate in C. sativus populations. Cluster analyses indicate that C. sativus populations differentiated according to the hosts (barley and wheat) and tissues (root and leaf) although generalists also exist in North Dakota. Crop breeding may benefit from combining genes for resistance against both specialists and generalists of C. sativus.

中国青藏高原青稞抗穗发芽资源评价与α-淀粉酶基因的克隆及表达

穗发芽（PHS，preharvest sprouting）是影响禾本科作物生产的重要的灾害之一。收获时期如遇潮湿天气容易导致穗发芽发生。发生穗发芽的种子内部水解酶（主要是α-淀粉酶）活性急剧升高，胚乳贮藏物质开始降解，造成作物产量和品质严重降低。因此，选育低穗发芽风险的品种是当前作物育种工作中面临的重要任务。 青稞(Hordeum vulgare ssp. vulgare)主要分布于青藏高原，自古以来就是青藏高原人民的主要粮食。近年来，由于青稞丰富的营养成分和特有的保健品质、在燃料工业中的潜力以及在啤酒酿造工业中的利用前景，在发达国家日趋受到重视，掀起综合研究利用的热潮。我国拥有占全世界2/3 以上的青稞资源，具有发展青稞产业的得天独厚的条件。然而，由于青稞收获期间恰逢青藏高原雨季来临，常有穗发芽灾害发生，使青稞生产损失巨大。目前对青稞穗发芽研究很少，适用于育种的穗发芽抗性材料相对缺乏，不能很好的满足青稞穗发芽抗性育种的需要。本研究以青藏高原青稞为材料，对其穗发芽抗性的评价指标和体系进行构建，同时筛选青稞抗穗发芽品种并对其抗性进行评价，还利用分子生物学手段对青稞穗发芽抗性的分子机理进行了初步探讨。主要研究结果如下： 1. 本试验以来自于我国青藏高原地区的青稞为材料，对休眠性测定的温度范围进行探讨，并对各种穗发芽抗性测定方法的对青稞的适用性进行评测。通过探讨温度对13 个不同基因型的青稞籽粒发芽和休眠性表达的影响，对筛选青稞抗穗发芽资源的温度条件进行探索，并初步分析了其休眠性表达的机理。在10，15，20，25，30℃的黑暗条件下，选用新收获的13 个青稞品种为材料进行籽粒发芽实验，以发芽指数（GI）评价其休眠性。结果发现，不同品种对温度敏感性不同，其中温度不敏感品种，在各温度条件下均表现很低的休眠性；而温度敏感品种，其休眠性表达受低温抑制，受高温诱导。15℃至25℃是进行青稞休眠性鉴定的较适宜的温度范围。通过对供试材料发芽后的α-淀粉酶活性，发现温度对青稞种子的休眠性表达的影响至少在一定程度上表现在对α-淀粉酶活性的调控上。随后，对分别在马尔康和成都进行种植的34 份青稞穗发芽指数（SI），穗发芽率（SR），籽粒发芽指数（GI）和α-淀粉酶活性（AA）进行了测定和分析，发现它们均受基因型×栽培地点的极显著影响，且四个参数之间具有一定相关性。GI 参数由于其变异系数较低，在不同栽培地点稳定性好，且操作简便，是较可靠和理想的穗发芽评价参数。SI 参数可作为辅助，区别籽粒休眠性相似的材料（基因型）或全面评价材料（基因型）的穗发芽抗性特征。AA 参数稳定性较差，并且检测方法复杂，因此不建议在育种及大量材料筛选和评价时使用。此外，青稞穗发芽抗性受环境影响较大，评价时应考虑到尽可能多的抗性影响因素及其在不同栽培条件下的变异。 2. 对来自青藏高原的青稞穗发芽抗性特征及其与其它农艺性状间的关系进行研究。通过测定穗发芽指数（SI）、籽粒发芽指数（GI）和α-淀粉酶活性（AA），表明113 份青稞材料的穗发芽抗性具有显著差异。SI、GI 和AA 参数的变幅分别为1.00~8.86、0.01~0.97 和0.00~2.76，其均值分别为4.72、0.63 和1.22。根据SI 参数，六个基因型，包括‘XQ9-5’，‘XQ33-9’，‘XQ37-5’，‘XQ42-9’，‘XQ45-7’和‘JCL’被鉴定为抗性品种。综合SI、GI 和AA 参数，可以发现青稞的穗发芽抗性机制包含颖壳等穗部结构的抗性和种子自身的抗性（即种子休眠性），且供试材料中未发现较强的胚休眠品种，除‘XQ45-7’外，所有品种在发芽第四天均能检测出α-淀粉酶活性。穗部结构和种子休眠的抗性机制因基因型不同而不同，在穗发芽抗性中可单独作用或共同作用。农家品种和西藏群体分别比栽培品种和四川群体的穗发芽抗性强，而在不同籽粒颜色的青稞中未发现明显差异。相关性检验发现，青稞的穗发芽抗性，主要是种子休眠性，与百粒重、开花期、成熟期、穗长、芒长和剑叶长呈显著负相关关系，与株高相关性不显著。农艺性状可以作为穗发芽抗性材料选育中的辅助指标。本试验为青稞穗发芽抗性育种研究提供了必要的理论基础和可供使用的亲本材料。 3. α-淀粉酶是由多基因家族编码的蛋白质，在植物种子萌发时高度表达，与植物种子的萌发能力密切相关。在大麦种子发芽时，高等电点α-淀粉酶的活性远大于低等电点的α-淀粉酶。为了研究不同穗发芽抗性青稞品种中编码高等电点α-淀粉酶Amy1 基因结构与抗性间的关系，我们以筛选得到的抗性品种‘XQ32-5’（TR1）、‘XQ37-5’（TR2）、‘XQ45-7’（TR3），易感品种‘97-15’（TS1）、‘9657’（TS2）以及强休眠大麦品种‘SAMSON’（SAM）为材料，对其Amy1 基因的编码区序列进行克隆和结构分析，并对它们推导的氨基酸序列进行比较。结果显示，青稞Amy1 基因具有三个外显子、两个内含子，编码区中有13 个核苷酸变异位点，均位于2、3 号外显子，2 个变异位点位于2 号外显子。SAM 和TS1 分别在2 号外显子相应位置有5 个相同的碱基(GAACT)的插入片段。相应α-淀粉酶氨基酸序列推导发现，所有核苷酸变异中有8 个导致相应氨基酸残基的改变，其余位点为同义突变。青稞Amy1 基因编码区序列品种间相似度高达99%以上，部分序列变异可能与其穗发芽抗性有关。随后，我们又通过SYBR Green 荧光定量技术对该基因在不同发芽时间（1d~7d）的相对表达水平进行了差异性检测。结果发现，7 天内不能检测到SAM 的Amy1 基因表达，5 个青稞品种间的Amy1 基因的相对表达量均随着发芽时间延长而上升，但上升方式有所不同。弱抗品种该基因表达更早，转录本增加速率更大，且在4~5 天可达到平台期。发芽7 天中，抗性品种总转录水平明显低于易感品种。本研究结果表明，青稞Amy1 基因的转录水平是与其穗发芽抗性高度相关。 我国青藏高原青稞，尤其是农家品种的穗发芽抗性具有丰富的变异，蕴藏着穗发芽抗性育种的宝贵资源。本研究为青稞穗发芽抗性育种建立了合理抗性评价体系，筛选出可供育种使用的特殊材料，阐明了农艺性状可辅助穗发芽抗性育种，同时还对穗发芽抗性与α-淀粉酶基因的结构和表达关系进行分析，为青稞穗发芽抗性资源筛选奠定了基础。 Preharvest sprouting (PHS) is a serious problem in crop production. It often takes place when encountering damp, cold conditions at harvest time and results in the decrease of grain quality and great loss of yield by triggering the synthesis of endosperm degrading enzymes (mostly the α-amylase). Therefore, PHS is regarded as an important criterion for crop breeding. In order to minimize the risk of PHS, resistant genotypes are highly required. Hulless barley (Hordeum vulgare ssp. vulgare) is the staple food crop in Qinghai-Tibetan Plateau from of old, where is one of the origin and genetic diversity centers of hulless barley. Recently, interest in hulless barley has been sparked throughout the world due to the demonstrations of its great potential in health food industry and fuel alcohol production. Indeed, hulless barley can also be utilized to produce good quality malt if the appropriate malting conditions are used. In China, overcast and rainy conditions often occur at maturity of hulless barley and cause an adverse on its production and application. PHS resistant genotypes, therefore, are highly required for the hulless barley breeding programs. However, few investigations have been made so far on this issue. The objectives of this study were: 1) to assessment of methods used in testing preharvest sprouting resistance in hulless barley; 2) to evaluate the variability and characteristics of PHS resistance of hulless barley from Qinghai-Tibet Plateau in China; 3) to select potential parents for PHS resistance breeding; 4) to primarily study on the molecular mechanism of PHS resistance of hulless barley. Our results are as followed: 1. We investigated the temperature effects on seed germination and seed dormancy expression of hulless barley, discussed appropriate temperature range for screening of PHS resistant varieties, and analyzed the mechanism of seed dormancy expression of hulless barley. The dormancy level of 13 hulless barley were evaluated by GI (germination index) values calculating by seed germination tests at temperature of 10，15，20，25，30℃ in darkness. There were great differences in temperature sensitivity among these accessions. The insensitive accessions showed low dormancy at any temperature while the dormancy expression of sensitive accessions could be restrained by low temperature and induced by high temperature. The temperature range of 15℃ to 25℃ was workable for estimating of dormancy level of hulless barley according to our data. Analysis of α-amylase activity showed that the temperature effects on seed germination and the expression of seed dormancy be achieved probable via regulating of α-amylase activity. Furthermore, we evaluated the differences in sprouting index (SI), sprouting rate (SR), germination index (GI) and α-amylase activity (AA) between Maerkang and Chengdu among 34 accessions of hulless barley from Qinghai-Tibetan Plateau in China. These PHS sprouting parameters were significantly affected by accession×location, and they had correlation between each other. GI was the most reliable parameter because of its low CV value, good repeatability and simple operation. SI could assist in differentiating between accessions of similar dormancy or overall evaluation of the resistance. AA was bad in repeatability and had relatively complex testing method, therefore, not appropriate for breeding and evaluation and screening of PHS resistant materials. Besides, since PHS resistance of hulless barley was greatly influenced by its growth environment, possibly much influencing factors and variations between cultivated conditions should be considered. 2. In this study, large variation was found among 113 genotypes of hulless barley (Hordeum vulgare ssp.vulgare) from Qinghai-Tibetan Plateau in China, based on the sprouting index (SI), germination index (GI) and α-amylase activity (AA) which derived from sprouting test of intact spikes, germination test of threshed seeds and determination of α-amylase activity, respectively. The range of SI, GI and AA was 1.00~8.86, 0.01~0.97 and 0.00~2.76，the mean was 4.72, 0.63 and 1.22 espectively. Six resistant genotypes, including ‘XQ9-5’, ‘XQ33-9’, ‘XQ37-5’, ‘XQ42-9’, ‘XQ45-7’ and ‘JCL’, were identified based on SI. Integrating the three parameters, it was clear that both hulls and seeds involved in PHS resistance in intact spikes of hulless barley and there was no long-existent embryo dormancy found among the test genotypes. All the genotypes, except ‘XQ45-7’, had detectable α-amylase activity on the 4th day after germination. There was PHS resistance imposed by the hull and seed per se and the two factors can act together or independent of each other. Besides, landraces or Tibet hulless barley had a wider variation and relatively more PHS resistance when compared with cultivars or Sichuan hulless barley. No significant difference was found among hulless barley of different seed colors. The correlation analysis showed PHS resistance was negatively related to hundred grain weight, days to flowering, days to maturity, spike length, awn length and flag length but not related to plant height. This study provides essential information and several donor parents for breeding of resistance to PHS. 3. Alpha-amylase isozymes are encoded by a family of multigenes. They highly express in germinating seeds and is closely related to seed germination ability. In barley germinating seeds, the activity of high pI α-amylase is much higher than low pI α-amylase. The aim of this study was to determine the relationship between preharvest sprouting resistance of hulless barley and the gene structure of Amy1 gene which encodes high pI α-amylase. The coding region and cDNA of Amy1 gene of three resistant accessions, including ‘XQ32-5’ (TR1), ‘XQ37-5’ (TR2), ‘XQ45-7’ (TR3), two susceptible accessions ‘97-15’ (TS1), ‘9657’ (TS2) and one highly dormant barley accession ‘SAMSON’ (SAM) was cloned. Analysis of their DNA sequences revealed there were three exons and two introns in Amy1 gene. Thirteen variable sites were in exon2 and exon3, 2 variable sites were in intron2. SAM and TS1 had a GAACT insert segment in the same site in intron2. Only 8 variable sites caused the change of amino acid residues. There were 99% of similarity between the tested hulless barley and some of the variable sites might be related with preharvest sprouting resistance. Then, we investigated the expression level of Amy1 gene in the 7-day germination test. Results of quantitative real-time PCR indicated that the relative expression trends of Amy1 gene were the same but had significant differences in the increase fashion between hulless barleys and no detectable expression was found in SAM. Susceptible accessions had earlier expression and faster increase and reached the maximum on day 4 ~ day 5. Besides, total transcripts level was found lower in resistant accessions than susceptible accessions. This study indicated that α-amylase activity was highly related to the transcription level of Amy1 gene which not correlated to missense mutation sites. In conclusion, hulless barley, especially the landraces from Qinghai-Tibetan Plateau in China possesses high degree of variation in PHS performance, which indicates the potential of Tibetan hulless barley as a good source for breeding of resistance to PHS. This study provides several donor parents for breeding of resistance to PHS. Our results also demonstrate that agronomic traits may be used as assistants for PHS resistance selection in hulless barley. Besides, analysis of high pI α-amylase coding gene Amy1 revealed the relative high expression of was Amy1 one of the mainly reason of different PHS resistance level in hulless barley.

黄土高原地区农田土壤水分高效调控技术

分析黄土高原节水农业的必要性 ,总结出黄土高原农业调水技术主要有 7大类 :培肥地力以肥调水 ,轮作倒茬调水 ,间隙休闲调水 ,抗旱育种调水 ,节水灌溉调水 ,径流农业调水 ,化学技术调水 ;指出在干旱、半干旱的黄土高原地区 ,利用农业调水技术是粮食增产增收的有效措施和必然趋势

Reaping the benefits: science and the sustainable intensification of global agriculture

Food security is one of this century’s key global challenges. By 2050 the world will require increased crop production in order to feed its predicted 9 billion people. This must be done in the face of changing consumption patterns, the impacts of climate change and the growing scarcity of water and land. Crop production methods will also have to sustain the environment, preserve natural resources and support livelihoods of farmers and rural populations around the world. There is a pressing need for the ‘sustainable intensifi cation’ of global agriculture in which yields are increased without adverse environmental impact and without the cultivation of more land. Addressing the need to secure a food supply for the whole world requires an urgent international effort with a clear sense of long-term challenges and possibilities. Biological science, especially publicly funded science, must play a vital role in the sustainable intensifi cation of food crop production. The UK has a responsibility and the capacity to take a leading role in providing a range of scientifi c solutions to mitigate potential food shortages. This will require signifi cant funding of cross-disciplinary science for food security. The constraints on food crop production are well understood, but differ widely across regions. The availability of water and good soils are major limiting factors. Signifi cant losses in crop yields occur due to pests, diseases and weed competition. The effects of climate change will further exacerbate the stresses on crop plants, potentially leading to dramatic yield reductions. Maintaining and enhancing the diversity of crop genetic resources is vital to facilitate crop breeding and thereby enhance the resilience of food crop production. Addressing these constraints requires technologies and approaches that are underpinned by good science. Some of these technologies build on existing knowledge, while others are completely radical approaches, drawing on genomics and high-throughput analysis. Novel research methods have the potential to contribute to food crop production through both genetic improvement of crops and new crop and soil management practices. Genetic improvements to crops can occur through breeding or genetic modifi cation to introduce a range of desirable traits. The application of genetic methods has the potential to refi ne existing crops and provide incremental improvements. These methods also have the potential to introduce radical and highly signifi cant improvements to crops by increasing photosynthetic effi ciency, reducing the need for nitrogen or other fertilisers and unlocking some of the unrealised potential of crop genomes. The science of crop management and agricultural practice also needs to be given particular emphasis as part of a food security grand challenge. These approaches can address key constraints in existing crop varieties and can be applied widely. Current approaches to maximising production within agricultural systems are unsustainable; new methodologies that utilise all elements of the agricultural system are needed, including better soil management and enhancement and exploitation of populations of benefi cial soil microbes. Agronomy, soil science and agroecology—the relevant sciences—have been neglected in recent years. Past debates about the use of new technologies for agriculture have tended to adopt an either/or approach, emphasising the merits of particular agricultural systems or technological approaches and the downsides of others. This has been seen most obviously with respect to genetically modifi ed (GM) crops, the use of pesticides and the arguments for and against organic modes of production. These debates have failed to acknowledge that there is no technological panacea for the global challenge of sustainable and secure global food production. There will always be trade-offs and local complexities. This report considers both new crop varieties and appropriate agroecological crop and soil management practices and adopts an inclusive approach. No techniques or technologies should be ruled out. Global agriculture demands a diversity of approaches, specific to crops, localities, cultures and other circumstances. Such diversity demands that the breadth of relevant scientific enquiry is equally diverse, and that science needs to be combined with social, economic and political perspectives. In addition to supporting high-quality science, the UK needs to maintain and build its capacity to innovate, in collaboration with international and national research centres. UK scientists and agronomists have in the past played a leading role in disciplines relevant to agriculture, but training in agricultural sciences and related topics has recently suffered from a lack of policy attention and support. Agricultural extension services, connecting farmers with new innovations, have been similarly neglected in the UK and elsewhere. There is a major need to review the support for and provision of extension services, particularly in developing countries. The governance of innovation for agriculture needs to maximise opportunities for increasing production, while at the same time protecting societies, economies and the environment from negative side effects. Regulatory systems need to improve their assessment of benefits. Horizon scanning will ensure proactive consideration of technological options by governments. Assessment of benefi ts, risks and uncertainties should be seen broadly, and should include the wider impacts of new technologies and practices on economies and societies. Public and stakeholder dialogue—with NGOs, scientists and farmers in particular—needs to be a part of all governance frameworks.

Half-sib progenies evaluation in velvet grass

O capim-lanudo (Holcus lanatus L.) possui grande potencial de utilização como pastagem de inverno nas regiões subtropicais, devido a seu bom estabelecimento, persistência, produção, resistência ao frio, palatabilidade e capacidade de afilhamento. O objetivo deste trabalho foi estimar a variabilidade genética e a herdabilidade de caracteres agronômicos e identificar progênies superiores. Foram avaliadas 60 progênies de meios-irmãos, para altura (NH) e diâmetro da planta na fase vegetativa, duração do ciclo vegetativo (ciclo), altura final (FH) e número de afilhos. Houve diferença entre progênies para todos os caracteres. As estimativas de herdabilidade foram de 38%, 32%, 92%, 57% e 64% para NH, diâmetro, ciclo, FH e afilhos, respectivamente. O maior ganho genético estimado foi de 30,77 % para o número de afilhos. Existe variabilidade para todos os caracteres e são esperados ganhos na seleção entre progênies.

Validation of microsatellite markers for assisted selection of soybean genotypes resistant to powdery mildew

Powdery mildew is one of the most serious diseases of soybean and is found in all producing countries. The purpose of this study was to validate microsatellite markers previously identified as associated with resistance to powdery mildew in soybean. The study was conducted in two F, parent populations with contrasting resistance to powdery mildew, In the analysis 10 SSR primers were used for the populations. and tour polymorphic markers were identified for cross I (MGBR95-20937 x IAC-Foscarin 31) and three for cross 2 (MGBR-46 x Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48). The Chi-square analysis of the phenotypic evaluation confirmed the expected segregation (3: 1) of a dominant gene related to resistance. The polymorphic markers also segregated as expected (1:2:1). The markers Sat 366 and Sat 393 in the crosses 1 and 2. respectively, located at 9.41 and 12.45 cM from the gene. were considered promising for marker-assisted selection for resistance to powdery mildew in soybean. at a selection efficiency of 92.7% and 60.3% respectively.

Severity of banana leaf spot in an intercropping system in two cycles of banana Prata Ana

Prata Ana is the most planted banana cultivar in northern Minas Gerais, Brazil. It is however susceptible to several pathogens. This study was carried out to evaluate the disease severity of banana leaf spot in the Prata Ana cv. in the first and second cycle under six different planting systems. The randomized block experimental design was used with six treatments and four replications. lit an evaluation of the severity of banana leaf spot, no disease symptoms were found on Thap Maeo and Caipira. The evolution curve of the disease indicated seasonal effects in the first and second cycles. The severity, of banana leaf spot was highest soon after the regional rainy period from November to March. A comparison of the means of the evaluations indicated a reduction in disease severity from the first to the second cycle.

Inbreeding depression in castor bean (Ricinus communis L.) progenies

O objetivo do trabalho foi investigar a depressão endogâmica (DE) na mamoneira, espécie de reprodução sexuada mista. de uma população derivada da cultivar Guarani, amostraram-se 60 plantas-mãe. de cada uma foram obtidos três tipos de progênies: de autofecundação (AU), de cruzamentos obrigatórios (CR) e de polinização livre (PL). A produtividade de grãos das progênies for avaliada por meio de experimentos em blocos incompletos em dois locais. Houve forte interação de progênies x locais o que levou a obter estimativas dentro de cada local. Verificou-se ampla variação na depressão endogâmica, com médias de 6,7% e 13,4%, comparando-se as progênies AU com as PL. Verificou-se que a população tem alto potencial para selecionar linhagens promissoras. Foi baixa a freqüência de plantas-mãe gerando progênies com alta capacidade geral de combinação e baixa depressão endogâmica, simultaneamente. Seleção recorrente aumentará a ocorrência de genitoras associando essas duas propriedades, necessárias para obtenção de variedades sintéticas superiores.