Protocolos de sincronização de ovulação utilizados em búfalas submetidas a programas de IATF: Protocols of ovulation synchronization used in buffaloes submitted to FTAI programs

O objetivo desta revisão foi de apresentar conhecimentos sobre o uso de protocolos de sincronização de cio em programas de Inseminação Artificial em Tempo Fixo (IATF) de fêmeas bubalinas (Bubalus bubalis) que garantam melhor relação de custo/benefício, a fim de fornecer informações atuais sobre a eficácia dessas tecnologias utilizadas na reprodução animal. A búfala não exterioriza os sinais clínicos do estro tão evidentemente como em bovinos, muito embora ocorram sinais significativos. Porém, a IATF permite a inseminação destas fêmeas sem a necessidade de observação de cio, promovendo menor custo com mão de obra e evita possíveis falhas de observação dos sinais do estro. É possível sincronizar a ovulação de búfalas durante todo o ano com eficiência, entretanto os hormônios utilizados nos protocolos para a sincronização, principalmente os dispositivos de progesterona (P4), correspondem a um elevado custo, inviabilizando muitas vezes a utilização do protocolo. Visando a melhoria da relação custo/benefício dos programas de IATF, já é possível a reutilização e redução do período de exposição aos implantes de P4 e a substituição de indutores de ovulação sem comprometer a eficácia dos protocolos,  tornando-as alternativas interessantes para a redução dos custos do programa de IATF. Portanto, os protocolos utilizados atualmente na sincronização de búfalas são eficazes, possibilitando o ganho genético de rebanhos bubalinos submetidos a programas de IATF com melhor custo/benefício

Growth retardants in dry bean plants: impacts on the architecture, photoassimilate partition, and their consequences on the yield

The objective of this study was to evaluate the effects of three growth retardants on the development and yield of dry bean plants. The treatments were control (water), maleic hydrazide (0.09 g a.i. L-1), ethyl-trinexapac (0.5 g a.i. L-1) and propiconazole (0.125 g a.i. L-1). Maleic hydrazide decreased the plant growth rate, resulting in the height reduction (46%). It also inhibited the twining shoot development, thus controlling the vigor excess of this genotype which has indeterminate growth. On the other hand, plants which were treated with ethyl-trinexapac and propiconazole showed the higher heights (from 25 to 52%, respectively), indicating that both compounds provide the plant growth. These compounds also increased the number of pods (48 to 52%) and grains (47 to 102%), when compared to the control. However, ethyltrinexapac and maleic hydrazide decreased 50-grain dry mass (41 to 52%), indicating changes in the photoassimilate partition among plant structures. This change was evidenced by the correlation coefficient of the biomass allocated between the shoots and grains, which was inversely proportional (r=-60.57) and highly significant (p=0.0002). It is concluded that maleic hydrazide is an efficient growth inhibitor of dry bean plants. Propiconazole and ethyl-trinexapac provide the plant growth, and also improve the main yield components. However, ethyl-trinexapac and maleic hydrazide decrease grain biomass

Are plant growth retardants a strategy to decrease lodging and increase yield of sunflower?

One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied.One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied

Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil

The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others

Pharmacological manipulation of the estrous cycle in Nellore cows: I - Effect of doses of PGF2α for luteolysis on days 5 and 7 of the estrous cycle. II - Effect of replacement of GNRH by EB, in the 5Co-Synch program, at estrus detection and distribution, at ovulation rate and pregnancy rate

O objetivo do experimento I foi avaliar a luteólise causada por três doses de PGF2&#945; (12,5; 25 e 50 mg de Dinoprost tometamina) nos dias 5 e 7 do ciclo estral. Foram utilizadas 339 vacas não lactantes da raça Nelore. Os animais foram divididos em dois grupos de acordo com a apresentação do estro, recebendo a dose de PGF2&#945; nos dias 5 e 7 do ciclo estral. Cada grupo foi subdividido em três, que receberam os seguintes tratamentos de PGF2&#945; (12,5 mg; 25 mg; 50 mg). Através da concentração de P4 foram estimadas as taxas de regressão luteal 1 e 0,5 (1 - animais com concentração de P4 abaixo de 1 ng/mL; 0,5 animais com concentração de P4 abaixo de 0,5 ng/mL). Não houve interação entre a dose de PGF2&#945; e o dia do ciclo estral. A aplicação de PGF2&#945; no dia 7 do ciclo estral apresentou maior taxa de regressão luteal 1 e 0,5 quando comparada com o dia 5 do ciclo estral (1 - 76,9 vs 37,0 % - P = 0,0001; 0,5 - 57,5 vs 21,7 %, P = 0,0001, respectivamente). A taxa de regressão luteal 1 aumentou de acordo com a dose de PGF2&#945; administrada (12,5 mg 39,0 %; 25 mg 56,9 %; 50 mg 76,5 % P <0,0001). Quando a PGF2&#945; foi administrada no dia 5 do ciclo estral a concentração média de P4 segui o padrão de luteólise parcial e foi dependente da dose de PGF2&#945;. Quando a PGF2&#945; foi aplicada no dia 7 do ciclo estral a concentração média de P4 caiu drasticamente de 0 para 24 h e não voltou a se elevar em 48 h. A concentração de P4 em 48 h após a aplicação de PGF2&#945; foi menor na dose de 50 mg (0,51 ± 0,07 ng/mL). A taxa de luteólise foi menor no dia 5 do ciclo estral comparado com o dia 7 do ciclo estral. À medida que a dose de PGF2&#945; foi aumentada, a porcentagem de regressão luteal se elevou. O objetivo do experimento II foi avaliar se a substituição das aplicações do GnRH por BE, ECP e eCG no protocolos de 5 dias de P4 causa dupla ovulação e se a utilização de 1 ou 2 mg de BE no início do protocolo influencia na taxa de ovulação dupla. Foram utilizadas 85 multíparas da raça Nelore. No dia 0 do protocolo, as vacas receberam um implante de P4 e a dose de BE segundo o tratamento pertencente (tratamento A 1 mg de BE, tratamento B 2 mg de BE). Cinco dias após, o dispositivo foi retirado e aplicou-se PGF2&#945;, ECP eCG. Houve 5,9 % de dupla ovulação. O tratamento A causou menor porcentagem folículos maiores que 8 mm no dia 7 protocolo que o tratamento B (28,7 vs 50,6 P = 0,0460). Não houve diferença significativa na taxa de ovulação dupla, no diâmetro do folículo dominante no dia 5 e no dia 7 do protocolo e na taxa de crescimento folicular entre os tratamentos A e B. O protocolo de 5 dias de P4 com BE, ECP e eCG causou uma baixa taxa de dupla ovulação. O objetivo do experimento III foi comparar o aparecimento e a frequência de estro e a taxas de ovulação e gestação entre os protocolos de 5 dias de P4 + GnRH / GnRH e de 7 dias de P4 + BE / ECP + eCG em nulíparas, primíparas e multíparas. Foram utilizadas 411 fêmeas da raça Nelore (nulíparas - n = 198; primíparas - n = 80; multíparas - n = 133). No protocolo de 7 dias de P4, os animais receberam no dia 0 um implante de P4 e BE. No dia 7, o dispositivo foi retirado e aplicou-se PGF2&#945;, ECP e eCG. No protocolo de 5 dias de P4, os animais receberam no dia 0 o implante de P4 e GnRH. No dia 5, o dispositivo foi retirado e aplicaram-se 2 doses de PGF2&#945; com intervalo de 6 h entre as doses de PGF2. Os animais que não apresentaram estro até a hora da IA receberam 100 &#956;g de GnRH no momento da IA. A taxa de prenhez utilizando o protocolo de 5 ou 7 dias de P4 variou de acordo com a categoria da fêmea (nulíparas - 41,0 vs 51,0 % - P = 0.1608; primíparas 25,6 vs 31,7 % - P = 0,5513; multíparas - 58,4 vs 32,8 % - P = 0,0041, respectivamente). A taxa de apresentação de estro no protocolo de 7 dias de P4 foi maior para todas as categorias de fêmeas quando comparado com o protocolo de 5 dias deP4. (nulíparas 95,8 vs 66,0 % - P <0,0001; primíparas 48,7 vs 0 %; multíparas - 76,9 vs 13,4 % - P <0,0001, respectivamente). A resposta ao protocolo de 5 dias com GnRH foi pior nas multíparas.The objective of the experiment I was to evaluate the luteolysis caused by three doses of PGF2&#945; (12.5, 25 and 50 mg of Dinoprost tometamina) when applied on the 5th and 7th days of the estrous cycle. Three hundred thirty-nine (339) nonlactating Nelore cows were used. The animals were divided into two groups according to the onset of estrus, and received the PGF2&#945; dose on the 5th or 7th day of the estrous cycle. Each group was divided into three subgroups, which were submitted to the treatments of PGF2&#945; with dose of 12.5 mg, 25 mg or 50 mg. Through the P4 concentration, the rates of 1 and 0.5 luteal regression were estimated (1 - animals with P4 concentration below 1 ng/mL and 0.5 - animals with P4 concentration below 0.5 ng/mL). There was no interaction between the PGF2&#945; dose and the day of the estrous cycle. The PGF2&#945; application on the 7th day of the estrous cycle had higher rates of the 1 and 0.5 luteal regression, when compared to the PGF2&#945; application on the 5th day of the estrous cycle (1 - 76.9 vs 37.0 % - P = 0.0001; 0,5 - 57.5 vs 21.7 %, P = 0.0001, respectively). The rate of 1 luteal regression increased with the PGF2&#945; dose (12.5 mg - 39.0 %; 25 mg - 56.9 %; 50 mg - 76.5 %, P < 0.0001). The average concentrations of P4, when the PGF2&#945; was administered on the 5th day of the estrous cycle, follow the partial luteolysis standard that dependent on the PGF2&#945; dose. When the PGF2&#945; is applied on 7th day of the estrous cycle, the average concentration of P4 drops dramatically from 0 to 24 h and it do not rise again in 48 h. The P4 concentration is lower in the 50 mg (0.51 ± 0.07 ng/mL), 48 h after the PGF2&#945; application. The luteolysis rate was low on the 5th day of the estrous cycle. The luteal regression percentage increased with increase of the PGF2&#945; dose. The objective of the experiment II was to evaluate whether the replacement of the GnRH applications by BE, ECP and eCG in the 5-day protocols of P4 cause double ovulation and if the use of 1 or 2 mg of BE at the beginning of the protocol influences the double ovulation rate. Eighty-five (85) multiparous Nelore cows were used. On day 0 of the protocol, the cows received a P4 implant and a dose of BE that depending on the treatment to which the cows belong (Treatment A - 1 mg of BE, treatment B - 2 mg of BE). Five days later, the device was removed and the PGF2&#945;, ECP and eCG were applied. In the experiment II, there was 6.5 % of double ovulation. There was no significant difference in the double ovulation rate, dominant follicle diameter on the 5th and 7th day of the protocols, and follicular growth rate between the treatments A and B. The 5-day protocol of P4 with BE, eCG and ECP caused a low rate of the double ovulation, and there was no difference between 1 or 2 mg of BE to synchronize the follicular development wave. The objective of the experiment III was to compare the onset and frequency of estrus and the ovulation and pregnancy rates among the protocols of 5 days of P4 with GnRH and 7 days of P4 with BE, ECP and eCG in nulliparous, primiparous and multiparous. Four hundred eleven (411) Nellore females were used (nulliparous - n = 198; primiparous - n = 80; multiparous - n = 133). In 7-day protocol of P4, the animals received an implant of P4 and BE on day 0. On day 7, the device was removed and the PGF2&#945;, ECP and eCG were applied in the cows. In 5-day protocol of P4, the animals received implants of GnRH and P4 on the day 0. On day 5, the device was removed and two doses of PGF2&#945; were applied with interval of 6 h. The animals that did not show estrus until the AI time received 100 mg of GnRH at this moment. The pregnancy rate varied according to the female category in both protocols (nulliparous - 41.0 vs 51.0 % - P = 0.1608; primiparous - 25.6 vs 31.7 % - P = 0.5513; multiparous - 58.4 vs 32.8 % - P = 0.0041, respectively). The rate estrus onset in the 5-day protocol of P4 with GnRH was lower for all female categories, when compared to the 7-day protocol (nulliparous - 95.8 vs 66.0 % - P <0.0001; primiparous 0 vs 48.7 %; multiparous - 76.9 vs 13.4 % - P <0.0001, respectively). The response in the 5-day protocol with GnRH was worse in multiparous cows

Puberty of heifers: 1 - Effect of nutrition and EPD of sire for sexual precocity on puberty in Nellore heifers; 2 - Effect of early weaning and nutrition in metabolic imprinting on puberty in Nellore and crossbreed (Angus x Nellore) heifers

O objetivo do experimento I foi avaliar a interação entre dois ganhos médios diários [GMD - fator nutricional (ganho elevado GA = 0,700 e ganho baixo GB = 0,300 Kg/dia)] e a diferença esperada da progênie (DEP para idade ao primeiro parto - fator genético) na puberdade de novilhas Nelore. Foram utilizadas 58 novilhas desmamadas com 8 meses de idade, filhas de 4 touros [2 precoces (P) e 2 tardios (T)], formando um esquema fatorial 2 x 2, no qual o fator 1 foi o GMD e o fator 2 foi a DEP do touro, constituindo assim quatro tratamentos: Touro precoce com GMD elevado (PGA), touro precoce com GMD baixo (PGB), touro tardio com GMD elevado (TGA), touro tardio com GMD baixo (TGB). Houve efeito dos tratamentos na porcentagem de novilhas púberes durante o experimento (PGA e PGB = 100%; TGA = 83% até 27 meses de idade; TGB = 38% até 3 anos de idade). As novilhas do PGA apresentaram a menor (P = 0,0001) idade na puberdade (18 &#177; 1 meses). Contudo, a nutrição atrasou a puberdade em cerca de 10 meses nas novilhas filhas de touros precoces e tardios (PGA = 18 &#177; 1 vs. PGB = 29 &#177; 1 meses; TGA = 24 &#177; 1 vs. TGB = 34 &#177; 1 meses). Assim podemos concluir que a DEP para IPP foi o fator necessário para o adiantamento da idade a puberdade. No entanto, o GMD foi um fator limitante para o aparecimento da puberdade. O objetivo do experimento II foi avaliar o efeito do imprinting metabólico dos 3 aos 7 meses de idade na puberdade em novilhas cruzadas (Angus x Nelore). Os tratamentos foram arranjados em esquema fatorial 2 x 2, no qual o fator 1 foi GMD elevado e médio dos 3 aos 7 meses de idade (fase 1) e o fator 2 foi GMD elevado e médio dos 7 meses de idade até a puberdade (fase 2). Formando os seguintes tratamentos: CAA Novilhas cruzadas submetidas ao GMD elevado nas fases 1 e 2; CAM - GMD elevado na fase 1 e GMD médio na fase 2; CMA- GMD médio na fase1 e GMD elevado na fase 2; CMM GMD médio nas fases 1 e 2. O GMD médio foi atingido pela restrição do consumo de matéria seca (CMS) no GMD médio. As novilhas dos tratamentos CAA, CAM e CMA apresentaram puberdade na mesma idade (cerca de 12 meses). As novilhas cruzadas submetidas ao GMD elevado na fase 2 foram mais pesadas (P = 0,0379) na puberdade do que novilhas submetidas ao baixo GMD. O GMD elevado dos 3 aos 7 meses de idade não impactou na puberdade das novilhas cruzadas. O objetivo e a metodologia do experimento III foram semelhantes ao experimento II, no entanto foram utilizadas novilhas Nelore (N) ao invés de cruzadas e o experimento terminou aos 19 meses de idade. O tratamento NAA (84%) induziu maior (P = 0,0145) proporção de novilhas púberes do que o NMM (23%), mas não houve diferença na taxa de puberdade entre os tratamentos NAM (60%) e NMA (50%). Além disso, o comportamento das curvas de puberdade dos tratamentos NAM e NMA foram semelhantes, sendo assim não houve efeito de imprinting metabólico nas novilhas Nelore. O GMD elevado dos 3 aos 19 meses idade aumentou a porcentagem de novilhas Nelore púberes aos 19 meses de idadeThe objective of experiment I was to evaluate the interaction between two average daily gain (ADG nutritional factor (high gain HG = 0,700 and low gain LG = 0,300 kg/day)] and expected progeny differences (EPD to age at first calving; genetic factor) on puberty attainment of Nellore heifers. Fifth eight heifers weaned at 8 months of age and daughters of 4 sires [2 precocious (P) and 2 later (L)]. A factorial design 2 x 2 was used, where the factor 1 was the ADG and the factor 2 was the EPD of sire, resulting in four treatments: Precocious sire with HG (PHG), precocious sire with LG (PLG), later sire with HG (LHG) and later sire with LG (LLG). There was effect of treatment in the percentage of pubertal heifers (PHG and PLG = 100%; LHG = 83% until 27 month of age; LLG = 38% until 3 years old). Heifers from the PHG treatment were the youngest (P = 0,0001) (18 months of age). However, the nutritional factor delayed puberty achievement by approximately 10 months the age at puberty in precocious and later heifers (PHG = 18 &#177; 1 vs. PLG = 29 &#177; 1 months; LHG = 24 &#177; 1 vs. LLG = 34 &#177; 1 months of age). The EPD to age at first calving was the main factor affecting the age at puberty. However, the ADG was limiting to puberty onset. The objective of experiment II was to evaluate the effect of metabolic imprinting from 3 to 7 months of age on puberty attainment of crossbreed heifers (Angus x Nellore). The treatments were arranged in 2 x 2 factorial design, where the factor 1 was high (H) and medium (M) ADG from 3 to 7 months of age (phase 1) and the factor 2 was high and medium ADG from 7 months of age to puberty onset (phase 2), resulting in the following treatments: CHH crossbreed heifers submitted to high ADG in both phases of experiment; CHM high ADG in phase 1 and medium ADG in phase 2; CMH medium ADG in phase 1 and high ADG in phase 2; CMM Medium ADG in both phases. The medium ADG were targeted by restricting of dry mater intake (DMI) in medium ADG. Crossbreed heifers of treatments CHH, CHM, CMH showed the same age at puberty, about 12 months. Heifers submitted to high ADG on phase 2 were heavier (P = 0,0379) at puberty than heifers submitted to low ADG. The high ADG from 3 to 7 months did not affect puberty onset in crossbreed heifers. The objective and methodology used in experiment III was the same of used in experiment II. However, Nellore heifers (N) were used instead of crossbreed heifers and the experimental period ended at 19 months of age. The NHH treatment (84%) induced higher (P = 0,0145) percentage of pubertal heifers than NMM (23%), but there was not difference in puberty rate between NHM (60%) and NMH (50%) treatments. Furthermore, the comportment of curves of puberty of treatments NHM and NMH were similar, thus there was not effect of metabolic imprinting in Nellore heifers. The high ADG from 3 to 19 months of age increased the percentage of pubertal Nellore heifers at 19 months of ag

Seaweed extract provides development and production of wheat

Agricultural crop performance can be improved with use of seaweed extracts. The aim of this study was to evaluate the effects of Ascophyllum nodosum extract on biometric, biochemical and yield parameters of the wheat. The experimental design was completely randomized with 3 treatments [control (water), seed treatment (0.1 mL of the A. nodosum extract on the 100 g of seeds) and soil irrigation (5 mL L-1 of seaweed extract, which was applied at 14th, 28th and 42nd days after sowing)] and 10 replications. Plants irrigated with A. nodosum extract showed increments in the height, dry mass of shoots and number of spikes (10.72%, 22.22% and 13.19%, respectively), however these plants had the lowest harvest index (reduction of 17.12%), when compared to the control. Seed treatment also increased plant height, but it did not change biochemical and productivity parameters. It is concluded that soil irrigation with 5 mL L-1 of A. nodosum extract provides development and positively affects production of ‘IAC 364’ wheat

Are plant growth retardants a strategy to decrease lodging and increase yield of sunflower?

One of the major disadvantages of sunflower cultivation is the increased plant height, making it prone to the lodging. The use of plant growth retardants can be an alternative strategy to reduce plant height; however, these compounds may affect productivity. The aim of this study was to evaluate the effects of plant growth retardants on sunflower development and yield. Four treatments were studied: 1- control; 2- gibberellic acid (GA) 10 mg L−1; 3- trinexapac-ethyl (TE) 5 mL L−1, and 4- maleic hidrazide (MH) 8 mL L−1. TE and MH decreased plant height (16.9 and 35.9%, respectively); however, only TE positively influenced capitulim diameter and dry mass (46.7 and 311%, when compared to control) at 60 days after planting (DAP). At 81 DAP, dry mass of capitulum did not differ among control and TE-treated plants. On the other hand, MH impaired diameter and dry mass of capitulum (92.9 and 74.7%, respectively). It can be concluded that the application of TE is a potential strategy to decrease lodging probability without affecting sunflower yield. Furthermore, although MH negatively affected sunflower development, its use on the crop cannot be excluded since other doses, frequencies and moment of application can be studied.Uma das principais desvantagens do cultivo do girassol é a elevada altura da planta, tornando-a propensa ao acamamento. Porém, o uso de retardadores de crescimento vegetal pode ser uma estratégia alternativa para diminuir o porte da planta; no entanto, estes compostos podem afetar a produtividade. O objetivo deste estudo foi avaliar os efeitos de retardadores de crescimento no desenvolvimento e na produção de girassol. Foram testados quatro tratamentos: 1- controle; 2- ácido giberélico (GA) 10 mg L−1; 3- etil-trinexapac (ET) 5 mL L−1 e 4- hidrazida maleica (HM) 8 mL L−1. ET e HM reduziram a altura das plantas (16,9 e 35,9%, respectivamente); no entanto, apenas ET influenciou positivamente o diâmetro e massa seca dos capítulos (46,7 e 311%, quando comparado com o controle) aos 60 dias após o plantio (DAP). Aos 81 DAP, a massa seca dos capítulos não diferiu entre plantas controle e tratadas com ET. Por outro lado, HM prejudicou o diâmetro e a massa seca dos capítulos (diminuição de 92,9 e 74,7%, respectivamente). Conclui-se que a aplicação de ET é uma estratégia em potencial para diminuir a probabilidade de acamamento sem impactar o rendimento do girassol. Além disso, embora MH tenha afetado negativamente o desenvolvimento do girassol, seu uso na cultura não pode ser excluído, uma vez que outras doses, frequências e momento de aplicação podem ser estudados

Núcleos de Ensino da Unesp: artigos 2007

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Núcleos de Ensino da Unesp: artigos 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq