Characterizing genetic diversity based on evaluations involving germination and seed vigor, is a fundamental stage in starting the development of a cultivation system for Calotropis procera. Thus, this study aimed to estimate genetic diversity among 35 C. procera genotypes based on germination and vigor of seeds stored for 1 year. The genotypes, which originated from areas in Paraíba (Brazil), where they occur naturally, were collected and stored in March 2014. In order to evaluate the physiological potential of the seeds, two experiments were conducted between March and April 2015. The first involved a propagation test conducted in a germination chamber, while the second involved an emergence test in washed sand, performed in polyethylene trays in a screened environment under uncontrolled conditions. In both experiments, an entirely randomized design was used, with four repetitions of 25 seeds per genotype. The characteristics evaluated were germination, average daily germination, daily germination speed, the speed of germination index, the plantlet vigor index, emergence, the speed of emergence index, total length, and total dry mass. The results showed that genetic variability exists among the C. procera genotypes for variables involving germination and vigor of seeds stored for 1 year. Also, emergence, total dry plantlet mass, and germination characteristics contribute most to the genetic divergence among C. procera genotypes.

Characterizing genetic diversity based on evaluations involving germination and seed vigor, is a fundamental stage in starting the development of a cultivation system for Calotropis procera. Thus, this study aimed to estimate genetic diversity among 35 C. procera genotypes based on germination and vigor of seeds stored for 1 year. The genotypes, which originated from areas in Paraíba (Brazil), where they occur naturally, were collected and stored in March 2014. In order to evaluate the physiological potential of the seeds, two experiments were conducted between March and April 2015. The first involved a propagation test conducted in a germination chamber, while the second involved an emergence test in washed sand, performed in polyethylene trays in a screened environment under uncontrolled conditions. In both experiments, an entirely randomized design was used, with four repetitions of 25 seeds per genotype. The characteristics evaluated were germination, average daily germination, daily germination speed, the speed of germination index, the plantlet vigor index, emergence, the speed of emergence index, total length, and total dry mass. The results showed that genetic variability exists among the C. procera genotypes for variables involving germination and vigor of seeds stored for 1 year. Also, emergence, total dry plantlet mass, and germination characteristics contribute most to the genetic divergence among C. procera genotypes. | A caracterização da diversidade genética, com base na avaliação da germinação e do vigor de sementes, é uma etapa fundamental para dar inicio ao desenvolvimento do sistema de cultivo de C. procera. Dessa maneira, objetivou-se estimar a divergência genética em genótipos de C. procera baseada na germinação e no vigor de sementes armazenadas por doze meses. Foram utilizados 35 genótipos, oriundos de áreas de ocorrência natural na Paraíba, coletados e armazenados em março de 2014. Para a avaliação do potencial fisiológico das sementes, foram realizados dois experimentos entre março e abril de 2015. O primeiro constou de um ensaio de germinação conduzido em câmara de germinação, enquanto o segundo, de um ensaio de emergência em areia lavada, realizado em bandejas de polietileno no interior de ambiente de telado em condições não controladas. Em ambos os experimentos foi utilizado o delineamento inteiramente casualizado com quatro repetições de 25 sementes por genótipo. As características avaliadas foram germinação, a germinação média diária, a velocidade diária de germinação, o índice de velocidade de germinação, o tempo médio de germinação, o índice de vigor de plântulas, a emergência, o índice de velocidade de emergência, o comprimento total e a fitomassa seca total. Entre os genótipos de C. procera existe variabilidade genética para variáveis de germinação e vigor de sementes armazenadas por um ano. As características de emergência, fitomassa seca total de plântula e germinação são as que mais contribuem para a divergência genética em genótipos de C. procera.

The objective of this research was to evaluate combinations of cultivars of coriander and arugula in two croppings with cultivars of carrot in a strip-intercropping system. The study was conducted from November 2014 to March 2015. The experimental design was a randomized complete block in a 2 x 2 x 2 + 2 factorial scheme, with four replications. The treatments consisted of the combination of two cultivars of coriander (Verdão and Português) with two cultivars of carrot (Brasília and Esplanada) and two cultivars of arugula (Cultivada and Folha Larga) in a strip-intercropping system plus two additional treatments, where the first represents the cultivars in monocropping and the second the cultivation types (monocropping and intercropping). The characteristics evaluated in the coriander and arugula were green mass yield and shoot dry mass. The following were evaluated in carrot: shoot dry mass, dry mass of roots, total and commercial productivity, and classified productivity of roots. In the intercropping system, the agronomic indices of land equivalent ratio, productive efficiency index, and score of the canonical variable were evaluated. The economic efficiency indicators determined were gross and net income, rate of return, profit margin, monetary advantage, and modified monetary advantage. There was no significant interaction among the cultivars of coriander, carrot, and arugula for coriander and arugula green mass yields, and for total and commercial productivities of carrot roots. The best polyculture was of that involved in the cultivars ―Português,‖ ―Esplanada,‖ and ―Cultivada‖.

The objective of this research was to evaluate combinations of cultivars of coriander and arugula in two croppings with cultivars of carrot in a strip-intercropping system. The study was conducted from November 2014 to March 2015. The experimental design was a randomized complete block in a 2 x 2 x 2 + 2 factorial scheme, with four replications. The treatments consisted of the combination of two cultivars of coriander (Verdão and Português) with two cultivars of carrot (Brasília and Esplanada) and two cultivars of arugula (Cultivada and Folha Larga) in a strip-intercropping system plus two additional treatments, where the first represents the cultivars in monocropping and the second the cultivation types (monocropping and intercropping). The characteristics evaluated in the coriander and arugula were green mass yield and shoot dry mass. The following were evaluated in carrot: shoot dry mass, dry mass of roots, total and commercial productivity, and classified productivity of roots. In the intercropping system, the agronomic indices of land equivalent ratio, productive efficiency index, and score of the canonical variable were evaluated. The economic efficiency indicators determined were gross and net income, rate of return, profit margin, monetary advantage, and modified monetary advantage. There was no significant interaction among the cultivars of coriander, carrot, and arugula for coriander and arugula green mass yields, and for total and commercial productivities of carrot roots. The best polyculture was of that involved in the cultivars “Português,” “Esplanada,” and “Cultivada”. | O objetivo desta pesquisa foi avaliar combinações de cultivares de coentro e rúcula em bicultivo com cultivares de cenoura em sistema consorciado de faixas. O estudo foi desenvolvido de novembro de 2014 a março de 2015. O delineamento experimental utilizado foi o de blocos ao acaso, em esquema fatorial 2 x 2 x 2 + 2, com quatro repetições. Os tratamentos consistiram da combinação de duas cultivares de coentro (Verdão e Português), com duas cultivares de cenoura (Brasília e Esplanada) e duas cultivares de rúcula (Cultivada e Folha Larga) em sistema de consórcio em faixas, mais dois tratamentos adicionais, onde o primeiro representa as cultivares em monocultivo e o segundo os tipos de cultivo (monocultivo e consórcio). As características avaliadas no coentro e na rúcula foram: rendimento de massa verde e massa seca da parte aérea. Na cenoura foram avaliados: massa seca da parte aérea, massa seca de raízes, produtividade total e comercial e produtividade classificada de raízes. No sistema de consórcio, foram avaliados os índices agronômicos: índice de uso eficiente de terra, índice de eficiência produtiva e pontuação da variável canônica. Os indicadores de eficiência econômica determinados foram: lucro bruto e líquido, taxa de retorno, margem de lucro, vantagem monetária e vantagem monetária corrigida. Não houve interação significativa entre as cultivares de coentro, cenoura e rúcula nos rendimentos de massa verde de coentro e de rúcula e nas produtividades total e comercial de raízes de cenoura. A melhor policultura foi a que envolveu a cultivar “Português”, “Esplanada” e “Cultivada”.

In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT) and no-tillage system (NTS) at low and high nitrogen (N) fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops sunhemp (Crotalaria juncea and C. spectabilis), velvet bean (Mucuna aterrima), jackbean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Japanese radish (Raphanus sativus), cowpea (Vigna unguiculata) and a fallow field. In the subplots were the tillage systems (CT or NTS). The nitrogen fertilization levels in the sub-subplots were (10 kg N ha-1 and 45 kg N ha-1). All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level.

In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT) and no-tillage system (NTS) at low and high nitrogen (N) fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops [sunhemp (Crotalaria juncea and C. spectabilis), velvet bean (Mucuna aterrima), jackbean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Japanese radish (Raphanus sativus), cowpea (Vigna unguiculata)] and a fallow field. In the subplots were the tillage systems (CT or NTS). The nitrogen fertilization levels in the sub-subplots were (10 kg N ha-1 and 45 kg N ha-1). All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level. | O uso de plantas de cobertura pode alterar atributos do solo e afetar significativamente a nutrição das plantas e produtividade do arroz cultivado em planícies inundáveis. Este trabalho teve como objetivo determinar atributos do solo, nutrição de plantas e produtividade do arroz irrigado tropical em planícies irrigáveis por inundação após o cultivo de plantas de cobertura, no preparo convencional do solo (PC) ou sistema plantio direto (SPD) em baixa e alta adubação com N. O delineamento experimental foi em blocos casualizados, no esquema de parcelas sub-subdivdidas, com quatro repetições. Nas parcelas estavam as coberturas vegetais [Crotalaria juncea, C. spectabilis, mucuna preta (Mucuna aterrina), feijão de porco (Canavalia ensiformis), feijão guandu (Cajanus cajan), nabo forrageiro (Raphanus sativus), feijão caupi (Vigna unguiculata) e pousio], nas subparcelas o sistema de preparo do solo (PC ou SPD) e nas sub-subparcelas a adubação nitrogenada (10 e 45 kg ha-1 N). As plantas de cobertura, com exceção do nabo forrageiro, proporcionam incrementos nos teores de N total e nitrato no solo. C. juncea, C. spectabilis, mucuna preta e feijão caupi proporcionam incrementos nos teores de amônio no solo. O SPD proporciona maiores teores de N total e amônio do que o PC. No âmbito geral, as plantas de cobertura proporcionaram maiores teores de nutrientes nas plantas de arroz no SPD do que no PC. As plantas de cobertura também proporcionaram maior produtividade do arroz em relação ao tratamento pousio. O rendimento do arroz é maior em SPD do que PC, e superior com alto nível de adubação nitrogenada.

The aim of this study was to evaluate physiological quality in seeds of sweet sorghum grown under semi-arid conditions, and to determine the age of physiological maturity of the seeds as a function of the foliar application of potassium silicate. The experiment was carried out at the Curu Valley Experimental Farm, in Pentecoste in the state of Ceará, during the rainy seasons of 2014 and 2015. The BRS 506 and BRS 511 varieties were used, under foliar fertilisation with potassium silicate at doses of 500, 1000 and 1500 mL.ha -1, in addition to the control lots (with no application); harvesting was at four periods, 30, 37, 44 and 51 days after full bloom (DAB). The percentage and speed of germination were evaluated, together with the accelerated ageing test and seedling growth. The seeds presented greater than 90% germination from 37 DAB, reaching high seedling vigour at 51 DAB. Foliar fertilisation with potassium silicate under the conditions of the experiment resulted in an increase in the physiological quality of the seeds. The BRS 506 and BRS 511 cultivars displayed the highest physiological quality between 49 and 53 DAF.

The aim of this study was to evaluate physiological quality in seeds of sweet sorghum grown under semi-arid conditions, and to determine the age of physiological maturity of the seeds as a function of the foliar application of potassium silicate. The experiment was carried out at the Curu Valley Experimental Farm, in Pentecoste in the state of Ceará, during the rainy seasons of 2014 and 2015. The BRS 506 and BRS 511 varieties were used, under foliar fertilisation with potassium silicate at doses of 500, 1000 and 1500 mL.ha-1, in addition to the control lots (with no application); harvesting was at four periods, 30, 37, 44 and 51 days after full bloom (DAB). The percentage and speed of germination were evaluated, together with the accelerated ageing test and seedling growth. The seeds presented greater than 90% germination from 37 DAB, reaching high seedling vigour at 51 DAB. Foliar fertilisation with potassium silicate under the conditions of the experiment resulted in an increase in the physiological quality of the seeds. The BRS 506 and BRS 511 cultivars displayed the highest physiological quality between 49 and 53 DAF. | O objetivo deste trabalho foi avaliar a qualidade fisiológica das sementes de sorgo sacarino cultivado em condição semiárida, procurando-se determinar a época de maturidade fisiológica das sementes em função da aplicação foliar com silicato de potássio. O experimento foi conduzido na Fazenda Experimental Vale do Curu, Pentecoste – CE no período de chuvas dos anos de 2014 e 2015. Utilizaram-se as variedades BRS 506 e BRS 511 sob adubação foliar com silicato de potássio nas doses 500; 1000 e 1500 mL.ha-1, além das parcelas controle (sem aplicação) e com colheita realizada em quatro épocas (30, 37, 44 e 51 dias após a plena floração (DAF)). Foram avaliados as porcentagens e velocidade de germinação, o teste de envelhecimento acelerado e o crescimento de plântulas. As sementes obtiveram germinação acima de 90% a partir dos 37 dias DAF, atingindo alto vigor de plântulas aos 51 dias APF. A adubação foliar com silicato de potássio nas condições aplicadas promoveu acréscimo na qualidade fisiológica das sementes. As cultivares BRS 506 e BRS 511 apresentam o máximo de qualidade fisiológica entre 49 e 53 dias DAF.