Gesso aplicado na superfície do solo no desenvolvimento do arroz de terras altas sob plantio direto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fusarium species responsible for mycotoxin production in wheat crop: involvement in food safety

Fusarium Head Blight (FHB) is a worldwide cereal disease responsible of significant yield reduction, inferior grain quality, and mycotoxin accumulation. Fusarium graminearum and F. culmorum are the prevalent causal agents. FHB has been endemic in Italy since 1995, while there are no records about its presence in Syria. Forty-eight and forty-six wheat kernel samples were collected from different localities and analyzed for fungal presence and mycotoxin contamination. Fusarium strains were identified morphologically but the molecular confirmation was performed only for some species. Further differentiation of the chemotypes for trichothecene synthesis by F. graminearum and F. culmorum strains was conducted by PCR assays. Fusarium spp. were present in 62.5% of Syrian samples. 3Acetyl-Deoxynivalenol and nivalenol chemotypes were found in F. culmorum whilst all F. graminearum strains belonged to NIV chemotype. Italian samples were infected with Fusarium spp for 67.4%. 15Ac-DON was the prevalent chemotype in F. graminearum, while 3Ac-DON chemotype was detected in F. culmorum. The 60 Syrian Fusarium strains tested for mycotoxin production by HPLC-MS/MS have shown the prevalence of zearalenone while the emerging mycotoxins were almost absent. The analysis of the different Syrian and Italian samples of wheat kernels for their mycotoxin content showed that Syrian kernels were mainly contaminated with storage mycotoxins, aflatoxins and ochratoxin whilst Italian grains with mainly Fusarium mycotoxins. The aggressiveness of several Syrian F. culmorum isolates was estimated using three different assays: floret inoculation in growth chamber, ear inoculation in the field and a validated new Petri-dish test. The study of the behaviour of different Syrian wheat cultivars, grown under different conditions, has revealed that Jory is a FHB Syrian tolerant cultivar. This is the first study in Syria on Fusarium spp. associated to FHB, Fusarium mycotoxin producers and grain quality.

Caratterizzazione bio-molecolar e ruolo di specie di Fusarium associate alla Fusariosi della spiga su frumento duro

La Fusariosi della spiga (FDS) è una fitopatia diffusa a livello mondiale che colpisce le colture cerealicole, tra cui il frumento duro, ed è in grado di causare gravi danni di tipo qualitativo ed economico. Le specie fungine responsabili appartengono al genere Fusarium, tra cui F. graminearum, F. culmorum e più recentemente F. poae. La conseguenza più rilevante riguarda la contaminazione della granella da micotossine, molecole prodotte dai miceti, considerate dalla comunità scientifica ad alto rischio per la salute dell’uomo e animali. L’eziologia è molto complessa, dal momento che su una stessa spiga di frumento possono coesistere più specie fungine che contribuiscono ad influenzare i quantitativi di micotossine prodotte. Lo scopo della ricerca è incentrato sulla caratterizzazione di ceppi di F. poae, in termini di potenziale patogeno e aggressività. Tramite l’allestimento di un saggio di inoculazione in vitro “Petri-dish” è stato possibile attribuire un indice di aggressività a ciascun isolato fungino, basato su parametri quali AUHPC e AUDPC standard, insieme ad altre variabili come la riduzione della lunghezza del coleottile e del tasso di germinazione. Il saggio è stato esteso anche a F. culmorum, per valutare la riproducibilità del test su altre specie fungine. Il test in vitro offre diversi vantaggi, tra cui affidabilità e rapidità di esecuzione ed è quindi adatto allo screening di ceppi patogeni da utilizzare in successive sperimentazioni. Gli stessi ceppi di F. poae, provenienti da una prova di inoculazione artificiale in serra su piante di frumento duro, sono stati caratterizzati dal punto di vista bio-molecolare. Poichè lo studio della fusariosi della spiga richiede la determinazione quantitativa della biomassa dei patogeni nei tessuti della pianta-ospite, anche in assenza di sintomi, il protocollo di Real-Time PCR con chimica SYBR® Green I qui sviluppato, ha dimostrato essere un buon compromesso tra attendibilità, rapidità e costi complessivi della metodica.

Testadores para a seleção de linhagens de milho-doce

O milho-doce é um tipo especial de milho, de alto valor nutricional que acumula polissacarídeos solúveis de caráter adocicado no endosperma. O consumo deste vegetal está crescendo no Brasil. Sendo esse um dos maiores países produtores de milho do mundo, há também um enorme potencial de produção de milho-doce. Atualmente, existem 53 cultivares de milho-doce registradas no país, mas apenas uma predomina nas lavouras desta cultura. Nota-se uma demanda por novas cultivares de milho-doce adaptadas às condições tropicais, com altas produtividades e excelente qualidade dos grãos. Há também uma escassez de informações sobre a avaliação e obtenção de cultivares de milho-doce. Os objetivos deste trabalho compreenderam: (i) verificação da viabilidade da utilização de um testador com elevado nível de endogamia e mais selecionado, em relação aos testadores com menores níveis de endogamia e menos selecionados, para obtenção de testcrosses; (ii) verificação do progresso realizado nas médias dos testcrosses; (iii) estimação das correlações entre a produtividade de espigas e os componentes de produção; (iv) aplicação de um índice de seleção para caracterizar e selecionar os melhores testcrosses e (v) verificação da variância genética disponível após a seleção e autofecundação. Foram avaliadas duas populações de milho-doce, em que uma é testadora da outra. Os três tipos de testadores utilizados foram obtidos a partir de uma mistura de linhagens selecionadas da geração anterior, sendo assim eles possuíam duas etapas de seleção e três níveis de endogamia. Visando a seleção de linhagens, 176 testcrosses foram avaliados em duas épocas de plantio, em delineamento casualizado em blocos com três repetições. Foram avaliados os caracteres dias para florescimento masculino(FM), altura das plantas(AP), número de espigas comerciais(EC), produtividade das espigas comerciais(PE), comprimento das espigas(CE), diâmetro das espigas(DE) e enchimento de ponta(EP). Foram observadas diferenças significativas entre as médias dos testcrosses nas análises de variância individuais e conjuntas. As interações entre testcrosses e testadores, nas análises individuais, não apresentaram diferenças significativas, indicando que não houve mudança no ordenamento dos testcrosses quando se utilizaram diferentes testadores. Para a mesma interação, nas análises conjuntas foram estimadas as correlações de Spearman, que se mostraram, na grande maioria, significativas, ou seja, foi detectada correlação entre o ranqueamento dos testcrosses. Para todos os caracteres avaliados, os testcrosses exibiram médias iguais ou superiores à melhor testemunha. Não houve evidências claras da diminuição da variância genética dos testcrosses quando foram utilizados testadores mais endogâmicos e mais selecionados. O testador com endogamia equivalente à das linhagens testadas e mais selecionado mostrou-se tão eficiente quanto os testadores com endogamia menor e menos selecionado. Foram observados valores consideráveis para os progressos realizados nas médias dos testcrosses, na maioria superiores a 1%, quando a seleção se deu nos testadores e nas linhagens, destacando que a utilização de testadores selecionados maximiza as médias dos testcrosses. Observaram-se correlações genéticas positivas (rG≥0,556) entre a produtividade de espigas comerciais e os caracteres EC, CE, DE e EP. O índice utilizado classificou os testcrosses em relação a todos os caracteres avaliados simultaneamente e permitiu a seleção dos melhores.

The effect of timing and severity of water deficit on growth, development, yield accumulation and nitrogen fixation of mungbean

Mungbean (Vigna radiata L.), as a dryland grain legume, is exposed to varying timing and severity of water deficit, which results in variability in grain yield, nitrogen accumulation and grain quality. In this field study, mungbean crops were exposed to varying timing and severity of water deficit in order to examine: (1) contribution of the second flush of pods to final grain yield with variable timing of relief from water deficit, (2) the sensitivity to water deficit of the accumulation of biomass and nitrogen (N) and its partitioning to grain, and (3) how the timing of water deficit affects the pattern of harvest index (HI) increase through pod filling. The results showed that the contribution of the second flush to final yield is highly variable (1-56%) and can be considerable, especially where mid-season stress is relieved at early pod filling. The capacity to produce a second flush of pods did not compensate fully for yield reduction due to water stress. Relief from mid-season stress also resulted in continued leaf production, N-2 fixation and vegetative biomass accumulation during pod filling. Despite the wide variation in the degree of change in vegetative biomass and N during pod filling, there were strong relationships between grain yield and net-above-ground biomass at maturity, and grain N and above-ground N at maturity. Only in the extreme situations were HI and nitrogen HI affected noticeably. In those treatments where there was a large second flush of pods, there was a pronounced biphasic pattern to pod number production, with HI also progressing through two distinct phases of increase separated by a plateau. The proportion of grain yield contributed to by biomass produced before pod filling varied from 0 to 61% with the contribution greatest under terminal water deficit. There was a larger effect of water deficit on N accumulation, and hence N-2 fixation, than on biomass accumulation. The study confirmed the applicability of a number of long-standing physiological concepts to the analysis of the effect of water deficit on mungbean, but also highlighted the difficulty of accounting for timing effects of water deficit where second flushes of pods alter canopy development, biomass and yield accumulation, and N dynamics. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.

Molecular Breeding for Rainfed Lowland Rice in the Mekong Region

In the past 20 years, the rice-breeding program in Thailand had little success in developing new cultivars to replace Kao Dawk Mali 105 (KDML105) and Kao Khor 6 (RD6) for the tainted lowland rice environments. The main reason for the poor adoption of new cultivars by farmers is the susceptibility to diseases and unacceptable grain qualities. The conventional breeding program also takes at least 15 years from initial crossing to the release of new cultivars. A new breeding strategy can be established to shorten the period for cultivar improvement by using marker-assisted selection (MAS), rapid generations advance (RGA), and early generation testing in multi-locations for grain yield and qualities. Four generation of MAS backcross breeding were conducted to transfer genes and QTL for bacterial blight resistance (BLB), submergence tolerance (SUB), brown plant hopper resistance (BPH) and blast resistance (BL) into KDML105. Selected backcross lines, introgressed with target gene/QTL, were tolerant to SUB and resistant to BLB, BPH and BL. The agronomic performance and grain quality of these lines were as good as or better than KDML105.

Breeding Rice for Drought-Prone Environments

A large portion of the world’s poor farm in rainfed systems where the water supply is unpredictable and droughts are common. In Asia, about 50% of all the rice land is rainfed and, although rice yields in irrigated systems have doubled and tripled over the past 30 years, only modest gains have occurred in rainfed rice systems. In part, this is because of the difficulty in improving rice varieties for environments that are heterogeneous and variable, and in part because there has been little effort to breed rice for drought tolerance. Information available for other cereals (for example, maize, Bänziger et al 2000) and for wheat and the limited or circumstantial evidence available for rice indicate that we can now breed varieties that have improved yield under drought and produce high yields in the good seasons. This manual aims to help plant breeders develop such varieties. While the manual focuses on drought tolerance, this must be integrated with the mainstream breeding program that also deals with agronomic adaptation, grain quality, and pest and disease resistance. Mackill et al (1996) have written a guide to the overall improvement of rice for rainfed conditions. This manual should be seen as an amplification of and updating of the section on drought tolerance in that book. Because final proof of many approaches for breeding drought-tolerant rice is not yet available, and because some aspects may not work in all environments and germplasm, we recommend that you use this manual with caution. Test the suggested approaches and only implement them on a large scale if they are effective and realistic for your own situation

Molecular breeding for rainfed lowland rice in the Mekong Region

In the past 20 years, the rice-breeding program in Thailand had little success in developing new cultivars to replace Kao Dawk Mali 105 (KDML105) and Kao Khor 6 (RD6). Main reason is a poor adoption of new cultivars by farmers due to poor adaptation of new cultivars to the rainfed environments, susceptibility to diseases and insect pests and unacceptable grain qualities. The conventional breeding program also takes at least 15 years for releasing new cultivars. New breeding strategy can be established to shorten period for cultivar improvement by using marker-assisted selection (MAS), rapid generations advance (RGA), early generation testing in multi-locations for grain yield and qualities. Four generation of MAS backcross breeding were conducted to transfer gene and QTL for bacterial blight resistance (BLB), submergence tolerance (SUB), brown planthopper resistance (BPH) and blast resistance (BL) into KDML105. Selected backcross lines, introgressed with target gene/QTL, were tolerant to SUB and resistant to BLB, BPH and BL. The agronomic performance and grain quality of these lines were as good as or better than KDML105.

Produtividade e qualidade de grãos de híbridos de canola cultivados em diferentes épocas no sudoeste do Paraná

Canola is the third most important oilseed in global agribusiness. Used in several market segments, its cultivation in Brazil began in the 70s The growth of canola cultivation aimed at producing beans intended for oil extraction can provide high economic efficiency of farms, the choice of the time correct for sowing is essential for this purpose is achieved. Objective of this study was to evaluate the performance of canola hybrids (Hyola 61, Hyola 76, Hyola 411, 433 and Hyola Hyola 571) evaluated in six sowing dates started on 09/03 (1 time) 06/04 (2 times ), 04/05 (3 times), 01/06 (4 times), 29/06 (5 times) and 26/07 (6 times). The experiments were conducted at the Experimental Station of the Federal Technological University of Paraná - UTFPR, Campus Dois Vizinhos. The field experiment was arranged in a randomized block design with split plots in three replications in two years (2013 and 2014 crop). Evaluated the agronomic characteristics as the number of days between emergence and flowering, number of days duration of flowering, number of days between emergency and physiological maturity, average plant height, plant lodging, grain yield, weight a thousand grains, crude protein content in grain and ether extract in the grains. There were significant differences between the effects of the six sowing dates in all variables, including hybrids and years. The study was able to show that it is possible to grow canola in the Southwest of Paraná. Being the first times more responsive sowing and Hyola 411 and Hyola 433 hybrid proved the most suitable among the variables observed.

Competitive ability of cultivated rice against weedy rice biotypes – A review

Weedy rice has been identified as a threat to rice production worldwide. Its phenotypic and genotypic diversity and its potential to compete against rice in all development stages from germination to maturity have resulted in a loss of rice yield and grain quality, which is remarkably high in directseeded rice cultivation. Weedy rice dormancy varies, it has a higher germination rate, and tolerates deeper germination depth compared to rice cultivars. Interactions of weedy rice with cultivars often reflect early vigor, more tillering, nutrient utilization ability for shoot development with respect to rice cultivars even though the latter also show an improvement in shoot development under competition. An exponential relationship has been reported between cultivated rice loss and weedy rice density: this is true for all rice cultivars. The degree of loss is dependent on the competitive ability of the rice cultivar being studied, and each weedy rice biotype also interacts differently. Hence, the need for a comprehensive study of the biology of various weedy rice variants. Difficulties arise in the management of weedy rice due to its physiological, anatomical, and morphological similarities to cultivated rice. The manipulation of the environment to improve cultivated rice production and suppress the emergence of weedy rice variants is important in the management of weedy rice, as well as other cultural practices and use of pesticides. The development of herbicide-resistant rice cultivars is necessary to totally eliminate the weedy rice variants. This review provides information on the competitive ability of weedy rice against rice cultivars; this information is essential to create management options to control weedy rice.

SUSCEPTIBILITY TO BRUCHIDS AMONG COMMON BEANS IN UGANDA

The bean bruchids, Acanthoscelides obtectus Say and Zabrotes subfasciatus Boheman (Coleoptera: Bruchidae), are cosmopolitan pests of stored dry common beans ( Phaseolus vulgaris L. ), causing damage through reduction of grain quality and seed germination. Biological resistance to these bruchids was definitively established in non-cultivated bean accessions, and has been introgressed into a range of drybean market classes. However, existing resistance to bruchids in Uganda’s common bean germplasm has not been systematically studied. In this study, 45 bean genotypes from the National Bean-Breeding Programme (25 genotypes) and agroecologically diverse bean growing areas in Uganda (20 genotypes), were evaluated for postharvest bruchid resistance. None of the evaluated bean genotypes expressed resistance to either bruchid species, with all the 45 bean genotypes supporting bruchid development, reproduction and feeding. All genotypes were severely damaged by bruchids feeding, resulting in significant (P<0.05) reduction of seed germination. Reduction in seed germination was related to the number of emergence holes and seed size; small bean seeds damaged by up to 2 bruchid emergence holes had a 7.1% reduction in germination, while large bean seeds with a similar number of emergence holes showed a 25% reduction in germination. Whereas this study further confirms bruchids as important storage pests of beans causing direct loss through consumption of the seed and indirect loss through viability deterioration, the resistance to bruchids in the evaluated range of Uganda’s dry bean germplasm is inadequate for direct exploitation in a breeding programme.

Infestação de insetos-praga de grãos de soja armazenados colhidos na safra 2014/15.

2016

Determinação dos defeitos dos grãos de soja colhidos na safra 2014/15 pela classificação comercial.

2016

Determinação da qualidade física dos grãos de soja colhidos na safra 2014/15.

2016

Effects of row spacing and nitrogen topdressing fertilization on the yield of upland rice in a no-tillage system.

This study aimed to evaluate the effect of row spacing and nitrogen topdressing fertilization of two materials (genotype 07SEQCL441 CL and cultivar BRS Esmeralda) on the plant height, yield components, grain yield, and quality of an upland rice crop grown in a no-tillage system. Trials were conducted for two growing seasons under field conditions in a 3 x 4 factorial, randomized, complete block design, with four replications. For each material, treatments consisted of the combination of row spacing (0.225, 0.35, and 0.45 m) with nitrogen (N) applied as topdressing (0, 50, 100, and 150 kg ha-1). The lowest row spacing (0.225 m) for genotypes 07SEQCL441 CL and BRS Esmeralda provided a higher number of tillers, number of panicles m-2, and grain yield of rice. Increasing rates of N in the topdressing improved the rice grain yield for both cultivars, but for 07SEQCL441 CL, the grain yield was positively affected only to applications up to 50 kg N ha-1. Row spacing and N rates did not affect the rice grain quality. Therefore, these results indicate that the narrowest row spacing used (0.225 m) with N fertilization as topdressing increased the rice grain yield most in the no-tillage system.