Australian Journal of Crop Science   AJCS

NOVEMBER 2020 | 14(11):2020 | 10.21475/ajcs.20.14.11


Production and quality of watermelon grown under seaweed extract

Antonio Francisco de Mendonça Júnior*, Ana Paula Medeiros dos Santos Rodrigues, Rui Sales Jr., Andréia Mitsa Paiva Negreiros, Marcos Oliveira Bettini, Esdras de Oliveira França Júnior, Álvaro Carlos Gonçalves Neto, Ranoel José de Sousa Gonçalves, Kevison Rômulo da Silva França


Rural Federal University of Pernambuco (UFRPE), Brazil
Rural Federal University of Semiarid (UFERSA), Brazil
Acadian Seaplant, Brazil
Federal University of Campina Grande (UFCG), Brazil


Abstract
The use of biofertilizers with macroalgae base has become a viable alternative to conventionally used synthetic fertilizers. Among the advantages of using these extracts is the increase in productivity and improvements in the agronomic performance of the crop. Its use is allowed in organic agriculture as it is a natural product. The objective of this research was to evaluate the influence of the seaweed extract, Ascophyllum nodosum (L.) to the productive development and quality of watermelon plants. A randomized block design with 6 treatments and 4 replications was applied. The treatments comprised of full or divided doses (total of 3.0 ml L-1) of seaweed extract (T1: producer standard; T2: (1.0 – 1.0 – 1.0 mL L-1) applied 2 - 16 - 30 days after transplanting (d.a.t.); T3: (1.5 - 1.5 ml L-1) 2 - 30 (d.a.t.); T4: (1.0 – 1.0 – 1.0 mL L-1) 16 - 30 - 44 (d.a.t.); T5: (1.5 - 1.5 mL L-1) 16 - 30 (d.a.t.) T6: (3.0 mL L-1) 2 (d.a.t.). 100 mL of the prepared solution was used for each experiment. The application of Acadian® improved the yield of water melon in the order of 12.69 to 27.76% and at different periods of the crop cycle.

Pages 1701-1706 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p1407
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Screening of sweetpotato germplasm collections for sweetpotato weevil (Cylas spp.) resistance in Tanzania

Filson Kagimbo, Hussein Shimelis*, Julia Sibiya

African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences; College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
Tumbi Agricultural Research Institute, P.O. BOX 306, Tabora, Tanzania

Abstract
Weevil damage caused by sweetpotato weevil (Cylas spp.) is a major constraint to sweetpotato production in Tanzania due to a lack of improved varieties with durable resistance. The objective of this study was to screen sweetpotato germplasm collections for weevil resistance and to select the best parents to be used in resistance breeding. Field studies involving 96 sweetpotato genotypes were conducted at two weevil hotspot sites in Western Tanzania using a 12 x 8 lattice design with three replications at each site. Data collected included yield and yield related traits, weevil reaction and weevil damage score. The tested genotypes differed significantly (P < 0.01) for sweetpotato storage root number, root weight, root infestation and root damage score. Weevil infestation on storage roots significantly (P ≤0.05) correlated with total root number (r = 0.38) and weevil damage score (r = 0.79). Marketable root weight and total root weight were significantly correlated with infested root weight each with r = 0.45. The study identified nine sweetpotato genotypes expressing resistance and 10 genotypes with moderate resistance to weevil. Five genotypes including Magunhwa, Chuchu ya Nesi, Rugomoka, Tumauma and New Kawogo were selected with weevil resistance and desirable yield and yield-related traits. These genotypes can be used in future weevil resistance breeding programs of sweetpotato in Western Tanzania or related agro-ecologies.

Pages 1707-1714 | Full Text PDF| Supplementary Data PDF | doi: 10.21475/ajcs.20.14.11.p1603
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Effect of different LED lights spectrum on the in vitro germination of gac seed (Momordica cochinchinensis)

Chew Hong Lim, Toh Sin Guan, Eyu Chan Hong, Yeow Lit Chow, Chew Bee Lynn, Sreeramanan Subramaniam*

School of Biological Sciences, Universiti Sains Malaysia, Georgetown, 11800 Penang, Malaysia
Centre for Chemical Biology, Universiti Sains Malaysia, 11900 Bayan Lepas, Penang, Malaysia
School of Bioprocess Engineering, Universiti Malaysia Perlis (UNIMAP), 02600 Arau, Perlis, Malaysia


Abstract
Momordica cochinchinensis, also known as gac, is an indigenous fruit that can commonly found in Southeast Asia. Studies had shown that M. cochinchinensis contained a higher level of carotenoids, β-carotene, and lycopene compared to other vegetables and fruits. The present study was conducted to study the effect of light conditions on gac seeds germination and effect of light-emitting diode (LED) spectra (violet, blue, green, and red) on shoot, root, and leaf formation from germinated gac seeds. A total of 60 surface sterilised uncoated gac seeds were cultured in MS media where half of them exposed to sunlight while another half kept in the enclosed cupboard. Germinated seeds were then transferred to new MS media which contained 1 mg/L of BAP and cultured under different LED lights. Gac seeds germinated well in 12 hours light treatment at the rate of 75% after one week while dark treated seeds did not germinate at all. The green LED light spectrum was the most effective for the production of the highest mean number of shoots at 4.75 ± 0.63. On the other hand, the violet LED was the most effective spectrum in producing the highest number of roots, which was 7.50 ± 0.58. Meanwhile green LED produced the highest root length of 6.25 ± 0.25 cm. Besides, green LED treatment also able to induce the highest number of leaves, which was 10.21 ± 1.89. Lateral shoot and tendrils were developed on blue LED spectrum treated seed. In conclusion, light facilitates gac seed germination while the green LED light induced better characteristics of gac plant.

Pages 1715-1722 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p1693
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Morphological, physiological and molecular responses of Indonesian cassava to drought stress

Sholeh Avivi*, Bella Rhea Lavifa Sanjaya, Shinjiro Ogita, Sri Hartatik, Sigit Soeparjono

Graduate Program of Biotechnology, University of Jember, Jember, East Java, Indonesia
The Center of Excellence on Crop Industrial Biotechnology (PUI-PT BioTIn), University of Jember, Jember, East Java, Indonesia
Faculty of Agriculture, University of Jember, Jember, East Java, Indonesia
Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Shobara, Nanatsuka, Japan


Abstract
In Indonesia, the investigations of drought-tolerant cassava by characterizing the morphological, physiological, and molecular responses have not carried out. This research was aimed to characterize the morphological, physiological, and molecular features of 10 Indonesian cassava varieties (Adira 1, Malang 1, Cimanggu, Kaspro, Ketan, Litbang UK-2, Malang 4, Malang 6, UJ-3, and UJ-5) under drought stress. After 30 days planting, drought stress was applied by stop wattering the plant for 15 days. The plant height, root system, and wilting were measured as morphological responses of cassava. In physiological responses, the percentage of opening stomata, chlorophyll, and hydrogen peroxide (H2O2) content were also investigated. Gene expression of MeGBF3 and MeMSD used to analyze the candidate drought-tolerant genotypes. Some parameters revealed the drought stress inhibits the growth of cassava. Some genotypes could not survive because the excessive content of H2O2 would be toxic to plant cells and disturb the plant growth. The up-regulated gene expressions of MeGBF3 and MeMSD has correlations with morphological and physiological responses of cassava to drought stress. Adira 1 and Kaspro are thought as drought-tolerant genotypes due to the morphological, physiological, and molecular responses.

Pages 1723-1727 | Full Text PDF| Supplementary Data PDF| doi: 10.21475/ajcs.20.14.11.p1961
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Reference standards for soils cultivated with Urochloa brizantha and its use in nutritional diagnosis

André Cayô Cavalcanti, Fábio Luiz Partelli*, Ivoney Gontijo, Julien Chiquieri, Heder Braun

Federal University of Espírito Santo, Center of North Espírito Santo (UFES-CEUNES), Departament Plant and Biology Science, São Mateus, Espírito Santo State, Brazil
State University of Maranhão, Departament Plant Science and Pathology, Graduate Program in Agroecology, Campus Universitário Paulo VI, s/n, Tirirical, São Luís, São Luís, Maranhão State, Brazil
Fellow of Productivity in Research, CNPq, Brazil


Abstract
The Diagnosis and Recommendation Integrated System (DRIS) is a tool to assess the nutritional state of plants. Due to the decrease of soil fertility in pasture areas and little information about fertilization recommendations, the nutritional reference norms for soil and sufficiency range can be useful tools to help future fertilization. Norms DRIS has been proved efficient as a method for nutritional diagnosis in several crops. However, there are a lack of information on the use of DRIS and sufficiency range for Latosols and Acrisols cultivated with Urochloa brizantha. Thus, the objective of the present study was to establish reference nutritional norms using sufficiency ranges and DRIS norms for Latosols and Acrisols cultivated with Urochloa brizantha and their use in nutritional diagnosis. Soils samples from 20 Urochloa brizantha pastures sites of the North of Espírito Santo State were used to establish the reference norms, and a further 85 soils samples were randomly collected for diagnosis analysis, in order to characterize nutritional condition of pastures. DRIS norms and sufficiency ranges were established for Latosols and Acrisols cultivated with U. brizantha pastures. The differences found between soil norms for other Brazilian regions allow us to infer that the norms should be used only in the conditions in which they were developed. Our results suggest that using DRIS norms and sufficiency ranges developed on the basis of soil analysis revealed deficiency of P, B, Cu, and Zn in more than 40% of the pastures cultivated with U. brizantha and 47% of the areas needed liming.

Pages 1728-1735 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.2323
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Production and photosynthetic pigments of bell peppers all big (Capsicum annuum L.) subjected to fertilization with biochar and nitrogen

André Alisson Rodrigues da Silva*, Lucia Helena Garófalo Chaves Antônio Ramos Cavalcante, Washington Benevenuto de Lima, Luan Dantas de Oliveira, Benedito Ferreira Bonifácio, Robson Fabio Alves de Souza, Ronaldo do Nascimento

Federal University of Campina Grande, Academic Unit of Agricultural Engineering, Campina Grande, 58.109-970, Paraíba, Brazil

Abstract
The Northeastern semi-arid region provides favorable conditions for bell pepper cultivation, but most often the low availability of soil nutrients to plants constitutes a limiting factor to production. In this context, the present study aimed to evaluate the production and photosynthetic pigments of bell pepper subjected to increasing levels of fertilization with biochar and nitrogen. The experiment was conducted in pots (Citropote®) under greenhouse conditions. Treatments were arranged in a completely randomized design, in 4 x 4 factorial scheme, relative to four doses of biochar (0; 7; 14 and 21 m3 ha-1) and four doses of nitrogen (0; 40; 80 and 120 kg ha-1), with three replicates. Fertilization with 70 kg ha-1 of nitrogen and 14 m3 ha-1 of biochar promotes highest yield of bell pepper in terms of number of fruits and fruit fresh weight per plant. The highest contents of photosynthetic pigments were obtained in plants fertilized with 70 kg ha-1 of nitrogen associated with 10 m3 ha-1 of biochar. Biochar doses above 15.54 m3 ha-1 negatively affect the longitudinal diameter of bell pepper fruits. The recommendation of 120 kg ha-1 of nitrogen and 20 m3 ha-1 of biochar reduces bell pepper production and photosynthetic pigments.

Pages 1736-1741 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2410
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Phytoregulators and stem subdivision in the production of young forage palms (Opuntia ficus-indica and Nopalea cochellinifera)

Wellington Silva Gomes, Samy Pimenta, Poliana Soares da Cruz Mascarenhas, Luciana Cardoso Nogueira Londe, Arles Matheus Pickler de Barros do Vale, Suzane Ariadna de Souza, Hélida Chisthine de Freitas Monteiro, Bruno Rafael Alves Rodrigues, Luciano de Souza Vespoli, Osmer Balam

State University of Montes Claros (UNIMONTES) – Department of Agricutural Sciences, Janaúba – Minas Gerais, Brazil
Agricultural Research Company of Minas Gerais (EPAMIG), Nova Porteirinha- Minas Gerais, Brazil
The College of Wooster, Department of Spanish, Wooster, Ohio, USA


Abstract
The propagation of plants through stem subdivision and the incorporation of phytoregulators can be a viable and efficient technique in the large-scale production of young forage palm at a lower cost. This study was conducted in order to evaluate the influence of stem subdivision and phytoregulators on the production of young forage palms under greenhouse conditions. Three experiments (I, II and III) were performed. Experiments I and II consisted of young palm of the Miúda genotype, formed from fragmented stems submitted to solutions containing gradually increasing concentrations of benzylaminopurine (0,0; 0,5; 1,0 e 1,5 mg. L-1) and kinetin (0,0; 0,25; 0,5 e 0,75 mg. L-1) combined with naphthaleneacetic acid (1,5 mg. L-1). An additional control without the use of phytoregulators was also included. These treatments were distributed in a randomized block design (RBD), in a factorial scheme with the additional plot: 4 x 4 + 1. In experiment III, different sized fractions of four forage palm genotypes were tested: Gigante, Orelha de elefante, IPA Sertânia, and Miúda. For this test, the experimental design was RBD, with twelve treatments, distributed in five blocks with five plants per plot. There was no influence of phytoregulators on the characteristics evaluated in experiments I and II. Significant differences were found. However, for the variables length, width, and thickness of sprouts among treatments in experiment III. Therefore, the application of phytoregulators in young forage palms at the dosages used is not recommended. For the Gigante, Orelha de Elefante and Miúda genotypes, the fractional stem size recommended is 5x3 cm whereas for IPA Sertânia, the size recommended is 4x2 cm.

Pages 1742-1747 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2469
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Effect of water salinity and potassium doses on physiological traits and growth of ‘Embrapa 51’ precocious dwarf cashew (Anacardium occidentale L.) rootstock

Geovani Soares de Lima, Jailson Batista da Silva, Lauriane Almeida dos Anjos Soares, Reginaldo Gomes Nobre, Hans Raj Gheyi, Genilson Lima Diniz, Pedro Dantas Fernandes, Jussara Silva Dantas, Vera Lúcia Antunes de Lima

Federal University of Campina Grande, Academic Unit of Agrarian Sciences, Pombal, 58.840-000, Paraíba, Brazil
Federal Rural University of the Semi-arid Region, Department of Science and Technology, Caraúbas, 59.780-000, Rio Grande do Norte, Brazil
Federal University of Recôncavo of Bahia, Nucleus of Soil and Water Engineering, Cruz das Almas, 44.380-000, Bahia, Brazil
Federal University of Campina Grande, Academic Unit of Agricultural Engineering, Campina Grande, 58.109-970, Paraíba, Brazil

Abstract
In the semiarid regions, plants are constantly exposed to different conditions of abiotic stresses due to the occurrence of excess salts in both soil and water. Thus, it is extremely important to identify an alternative capable of minimizing the effects of salt stress on plants as a way to ensure the expansion of irrigated areas. In this context, this study aimed to evaluate the chloroplast pigments, photochemical efficiency and growth of ‘Embrapa 51’ precocious dwarf cashew as a function of irrigation with saline water and potassium fertilization in the rootstock formation stage. The study was conducted under greenhouse conditions in the municipality of Pombal, PB, Brazil, using a randomized block design in a 5 x 2 factorial scheme, corresponding to five levels of irrigation water electrical conductivity - ECw (0.4; 1.2; 2.0; 2.8 and 3.6 dS m-1) and two doses of potassium fertilization - KD (100 and 150% of the recommendation corresponding to 150 and 225 g K2O kg-1 soil), with two plants per plot and three replicates. Water salinity from 0.4 induced reductions in chlorophyll a and b synthesis, maximum and variable fluorescence and growth in sexually propagated precocious dwarf cashew seedlings and increases in carotenoid content and initial chlorophyll fluorescence. The quantum efficiency of photosystem II in cashew plants was decreased sharply with the increment in water salinity levels, standing out as indicative of damage to the photosystem II reaction centres. 'Embrapa 51' precocious dwarf cashew plants can be classified as sensitive to water salinity above 0.4 dS m-1. Potassium doses of 100 and 150% of the recommendation did not alleviate the effects of salt stress during the precocious dwarf cashew rootstock production phase.

Pages 1748-1755 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2471
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Effects of liming on the growth and nutrient concentrations of pitaya species in acidic soils

Letícia Alves Carvalho Reis, Maria do Céu Monteiro Cruz*, Enilson de Barros Silva, Josimara Mendes Rabelo, Cintia Maria Teixeira Fialho

Department of Agronomy at the Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, Minas Gerais, Brazil
Department of Plant Agriculture at the University of Guelph, Guelph, Ontario, Canada
Department of Agronomy at the Federal Technological University of Paraná, Santa Helena, Paraná, Brazil


Abstract
With the increasing demand for pitaya orchard management information to achieve high productivity and commercial quality fruits, liming practice is fundamental since most Brazilian soils are acidic. This study aims to assess lime requirements of Typic Quartzipisamment and Haplorthox soils to calculate tolerated aluminum saturation, desired base saturation, calcium and magnesium requirements to cultivate two pitaya species; Hylocereus undatus and Hylocereus polyrhizus. Two independent experiments were conducted in a greenhouse, organized in a 2 x 4 factorial scheme. Treatments were distributed in randomized blocks with five replications. Treatments of the first experiment corresponded to H. undatus and H. polyrhizus and four lime requirements, 0; 0.8; 1.2 and 1.7 t ha-1 cultivated in Typic Quartzipisamment. Treatments of the second experiment corresponded to H. undatus and H. polyrhizus and four lime requirements, 0; 1.3; 2.0 and 2.8 t ha-1 cultivated in Haplorthox. Shoot and root dry matter, chemical soil attributes and shoot nutrient concentrations were measured. Regression equations were adjusted for each variable, according to the lime requirements of both soils providing the highest dry matter yield in both pitaya species. H. undatus and H. polyrhizus cultivated in Typic Quartzipisamment produced more dry matter when the aluminum saturation was between 13% and 16%, base saturation 70% and the calcium and magnesium requirement 2.5 cmolcdm-3. H. undatus and H. polyrhizus cultivated in Haplorthox produced more dry matter when the aluminum saturation was between 1% and 4%, base saturation between 55% and 70%, and calcium and magnesium requirement 3.0 cmolcdm-3.

Pages 1756-1763 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2509
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Assessment of inoculation techniques for screening sugarcane resistance to red stripe disease caused by Acidovorax avenae subsp. avenae

Romina Priscila Bertani, Constanza María Joya, Diego Daniel Henriquez, Claudia Funes, Victoria González, María Francisca Perera*, María Inés Cuenya, Atilio Pedro Castagnaro

Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. William Cross 3150, Las Talitas, Tucumán, R. Argentina, T4101XAC.
Estación Experimental Agroindustrial Obispo Colombres (EEAOC), Av. William Cross 3150, Las Talitas, Tucumán, R. Argentina, T4101XAC.

Abstract
The red stripe disease caused by Acidovorax avenae subsp. avenae in sugarcane, has become a quite relevant issue in Argentina because of its high incidence in the sugarcane growing area. The resistance of host plants is the most promising method for controlling the disease. In that sense, the Estación Experimental Agroindustrial Obispo Colombres (EEAOC) has a Sugarcane Breeding Program, which generates new varieties with higher productivity and good sanitary behavior. The lack of an effective screening technique to select resistant sugarcane genotypes limits the cultivar selection process. To develop a practical and affordable method for achieving the expression of the red stripe disease, three available inoculation techniques were evaluated under controlled conditions over two sugarcane varieties, with a previously adjustment of soil composition and nutrition and relative humidity. They consisted in (i) scrubbing the leaf surface with a cotton ball soaked in the suspension of A. avenae subsp. avenae; and spraying inoculum under two conditions: (ii) leaves pre-treated with a refined sand scarification and (iii) leaves with no scarification. Fifteen plants were inoculated per cultivar and treatment according to a randomized protocol with three replicates and the severity of the disease was evaluated on a scale of 1- 9 according to the International Society of Sugarcane Technologists. The spray inoculation using a bacterial suspension of A. avenae subsp. avenae without abrasives was also field tested. These results contribute to sugarcane breeding programs, providing a tool to assess the resistance to red stripe of their materials, overcoming the lack of bacterial pressure or favorable conditions for the disease.

Pages 1764-1771 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2517
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Soil chemical and microbiological attributes under integrated production system in Oxisol of degraded pasture

Nayara Christina Almeida Araújo, Leidivan Almeida Frazão, Igor Costa de Freitas, Evander Alves Ferreira*, Daniela Aparecida Freitas, Marcia Vitória Santos, Demerson Arruda Sanglard, Luiz Arnaldo Fernandes

Instituto de Ciências Agrárias, Universidade Federal de Minas Gerais, Campus Regional de Montes Claros (ICA), Av. Universitária 1000, Montes Claros, MG, CEP: 39400-090, Brasil
Universidade Federal dos Vales do Jequitinhonha e Mucuri, Campus JK, Rod. MGT 367 km 583, Diamantina, MG, CEP: 39100-000, Brasil


Abstract
The objective of this study was to evaluate the chemical attributes and quality of an Oxisol after one year of conversion of degraded pasture into integrated production system. The evaluated treatments were degraded pasture (PAST-Control); Eucalyptus, clone Urograndis 144 (Eucalyptus grandis x E. urophylla hybrid) intercropped with cor and marandu grass (Brachiaria brizantha) (integration crop-livestock-forest system - ICLFS-M); with maize and perennial horse gram (Macrotyloma axillare) (ICLFS-HG); and with maize, java and marandu grass (ICLFS-M+J); Monoculture of marandu grass (MAR) and perennial horse gram (HG); and marandu grass intercropped with Java/ perennial horse gram (H+M). Soil samples were collected in July/2015 and January/2016 in 0-5, 5-10, 10-20 and 20-30 cm soil depth layers. The soil attributes such as pH, organic matter, phosphorus, sum of bases, effective and potential cation exchange capacity and base saturation were evaluated. The implantation of ICLFS system contributed to increase of soil organic matter, sum of bases, effective and potential cation exchange capacity and soil base saturation. The soil biological activity was increased in the rainy season, and the soil microbial carbon increased in ICLFS-HG+M, ICLFS- HG, ICLFS-M and HG+M when compared to monocultures and PAST. Integrated production systems provide improved in soil quality even with a short time implementation.

Pages 1772-1778 | Ful Text PDF| 10.21475/ajcs.20.14.11.p2535
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Effects of saline stress and temperature on germination and seed vigor of Luffa operculata L. Cogn.

Paulo Costa Araújo, Paulo Alexandre Fernandes Rodrigues de Melo, Edna Ursulino Alves, Antônio Pereira dos Anjos Neto, Aderson Costa Araujo Neto, José Ribamar Gusmão de Araújo, Janaina Marques Mondego, Aline Priscilla Gomes da Silva, Joyce Naiara da Silva, Maria Luiza de Souza Medeiros

Universidade Federal da Paraíba, Centro de Ciências Agrárias, Programa de Pós-Graduação em Agronomia, CP 58051-900, São Luís, MA, Brazil.
Universidade Estadual do Maranhão, Centro de Ciências Agrárias, Programa de Pós-Graduação em Agroecologia, CP 65.055-098, São Luís, MA, Brazil.
Michigan State University, Department of Horticulture, East Lansing, MI 48824, United States
Universidade Federal da Paraíba-UFPB, Brazil


Abstract
Luffa operculata (L.) is a native Brazilian biome plant used for the treatment of respiratory diseases. Although Brazil’s flora comprises 67% of the world’s plants, only 8% of Brazilian plant species are studied each year. The studies indicate that climate change in tropical biomes intensifies the increase in salinized areas by about 10% per year for several reasons, including high temperatures, low rainfall and high evapotranspiration rates, due to surface water scarcity. Therefore, the aim of the present study was to evaluate the germination behavior and vigor of L. operculata seeds submitted to saline stress at different temperatures. To simulate salt stress conditions, sodium chloride was applied at 0.0; 3.0; 6.0; 9.0 and 12.0 dS m-1, at 25, 30, 35, 20-30 °C, with treatments distributed in a 5 x 4 factorial scheme (five levels of osmotic potential and four temperatures), using four replications. The seeds were then evaluated concerning water content, germination tests, first counts, germination speed index and seedling root and shoot lengths. At 30 and 35 °C, the seed germination and vigor of L. operculata were less affected up to an osmotic potential of 9.0 dS m-1, where it is considered a moderate salinity tolerance. At 35 ºC, the germination uniformity was reduced to 98 and 93% by applying the 6 and 9 dS m-1 solutions, respectively. For the same temperature, the germination velocity remained 6.09 (IVG) until the saline potential of 9.0 dS m-1.

Pages 1779-1785 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2544
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Induction and evaluation of tetraploid plants of Eucalyptus urophylla clones

Luciana Coelho de Moura, Aloisio Xavier, Lyderson Facio Viccini, Diego Silva Batista*, Elyabe Monteiro de Matos, Ricardo Gallo, Brígida Maria dos Reis Teixeira, Wagner Campos Otoni

Faculdade de Engenharia Florestal, Universidade Federal do Mato Grosso, Cuiabá, MT, 78085-100, Brazil
Departamento de Engenharia Florestal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
Departamento de Biologia, Laborátorio de Genética e Biotecnologia, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil
Departamento de Agricultura, Universidade Federal da Paraíba, Campus III, Bananeiras, Paraíba, Brazil
Departamento de Ciência Florestal, Universidade Federal Rural de Pernambuco, Recife, PE, 52171-900, Brazil
CMPC, Rua São Geraldo, 1680, Bairro Ermo, CEP 92703-470, Guaíba, RS, Brasil
Laboratório de Cultura de Tecidos/BIOAGRO, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. P.H. Rolfs, s/n, 36570-900 Viçosa, MG, Brazil


Abstract
Eucalyptus urophylla is an important species of the genus Eucalyptus that is used across the world, especially in Brazil. It is used for pulp and paper production, and charcoal production for iron and steel industry, thus making the development of biotechnological approaches essential for the breeding programs of this species. The polyploidy induction is one such approach that may introduce phenotypic characteristics of interest to the market and industry. This is the first study that shows the production, evaluation, and development of tetraploids (4x = 44) from a clone of E. urophylla. For this, the shoot apical meristems were cultured for elongation using in vitro conditions for 15 with 5 or 10 µM colchicine, trifluralin, or oryzalin. Following this, every 30 days, the elongated plantlets were transferred to JADS medium for multiplication using tufts as explants. Thereafter, four tufts containing six to eight buds each were inoculated in flasks followed by six subcultures and were then transferred to the greenhouse for acclimatization. The experiment was performed in a completely randomized design in a factorial scheme (3x2+1: antimitotic substance x concentrations + control), with 12 replicates. Analysis of nuclear DNA content and chromosome counting by flow cytometry, photosynthetic pigment quantification, stomatal size and density, survival, and rooting were performed for 110 days after acclimatization. Data were submitted for analysis of variance followed by Scott & Knott’s test (P ≤ 0.05). As a result, we observed that the oryzalin and trifluralin treatments were efficient in the induction of tetraploid plants, while colchicine proved to be ineffective. Also, trifluralin treatment at 5 µM provided a higher polyploidy induction (18.2% tetraploids) in comparison to the others. Diploid plants displayed 1.41 pg of nuclear DNA content with 22 chromosomes, while tetraploid plants showed 2.86 pg with 44 chromosomes. In conclusion, the tetraploid plants, as compared to the diploids (control), were found to show higher chlorophyll content, larger but fewer stomata, and lower rooting and survival, which can be mitigated nonetheless through silvicultural techniques. This study shall bring new perspectives for the breeding programs of E. urophylla.

Pages 1786-1793 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2564
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Effects of aquaponic system on growth and nutrients content and sustainable production of sprouts in urban area

Nianzhen Li, Litian Zhang*, Jia Li, Kuan Yan, Yu Wang, Bingwen Wang, Shuangjiang Li, Wanhai Zhou, Kailin Wang, Wen Li, Caijuan Xia, Yulian Yan, Yue Li, Feng Qin, Jian Chen

College of Sichuan Tea, Yibin University, Yibin 644000, Sichuan, China
College of Agriculture and Animal Husbandry, Qinghai University, Xining 810016, Qinghai, China


Abstract
An aquaponic system in urban area was designed and combined fish culture with sprouts production in a closed-loop system that mimics the ecology of the nature. In order to quantify the nutrients content of sprouts grown under different conditions, we conducted a factorial experiment with 3 types of growth conditions, routine cultivation (RC), circulating water supplement cultivation (CWSC) and aquaponic system cultivation (ASC), then produce sprouts (soybean sprouts, mung bean sprouts, pea sprouts and radish sprouts) under these conditions. The results showed that each sprout under ASC condition, height, weight (10 sprouts), vitamin C content, protein content and soluble sugar content were significantly higher than those under RC condition and CWSC condition. Each sprout showed significant difference in height, weight (10 sprouts), vitamin C content and soluble sugar content. The presence of Carassius auratus auratus can significantly promote the growth of sprouts in aquaponic system, and increase nutrients content. Therefore, aquaponic system can be promoted vigorously in urban areas.

Pages 1794-1799 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2674
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Resistance of popcorn hybrid (Zea mays) to multiple diseases and correlation between leaf disease intensity and agronomic traits

Juliana Saltires Santos*, Marcelo Vivas, Yure Pequeno de Souza, Antonio Teixeira do Amaral Júnior, Rafael Nunes de Almeida, Julio Cesar Gradice Saluci, Gabrielle Sousa Mafra, Fabio Tomaz de Oliveira, Shahid Khan, Janieli Maganha Silva Vivas

Universidade Estadual do Norte Fluminense Darcy Ribeiro/UENF, Laboratório de Melhoramento Genético Vegetal/LMGV, Av. Alberto Lamego, 2000, Parque Califórnia, 28013-602, Campos dos Goytacazes, RJ, Brazil

Abstract
Grain yield and popcorn quality losses have become more common due to attacks by pathogens responsible for leaf diseases. Genetic resistance is the main control measure, as it is applicable in large areas and uses reduced costs and less environmental impact, compared to chemical control. In this context, the purpose was to select popcorn hybrids that meet resistance to Exserohilum turcicum, Bipolaris maydis, and Puccinia polysora and to have high levels of popping expansion and grain yield. We took into account two growing seasons (summer harvest - October 2014 to January 2015 - and winter harvest- April to July 2015). Twenty-eight hybrids from the complete diallel cross scheme were evaluated, among eight inbred lines (P8, P1, L55, L61, L70, L76, L77 and L88). For this purpose, we used a randomized block design with four replicates in two growing seasons. The traits investigated were the incidence of P. polysora (IPP), B. maydis (IBM), and E. turcicum (IET); severity of P. polysora (SPP), B. maydis (SBM), and E. turcicum (SET); grain yield (GY); and popping expansion (PE). Data from the experiments were submitted to the principal component analysis (PCA) through the R software. Results showed that the traits IET and IPP in the summer harvest, and IET and SET, in the winter harvest, were the most significant in the select of hybrids. The P8 x L76 and L70 x P8 hybrids were selected for summer harvest and the L77 x L61 hybrid, for winter harvest.

Pages 1800-1809 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2743
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Desorption isotherms and thermodynamic properties of Solanum gilo

Samuel Gonçalves Ferreira dos Santos*, Jefferson Kran Sarti, Cassio da Silva Kran, Hellismar Wakson da Silva, Renato Souza Rodovalho, Luís Sérgio Rodrigues Vale, Daniel Pereira da Silva, João César Reis Alves, Daniel Emanuel Cabral de Oliveira, Ivano Alessandro Devilla

Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
Instituto Federal Goiano, Ceres, Goiás, Brazil
Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil
Instituto Federal Goiano, Iporá, Goiás, Brazil
Universidade Estadual de Goiás, Anápolis, Goiás, Brazil


Abstract
Solanum gilo is a plant belonging to the family Solanaceae with a probable origin in Africa. It was introduced to Brazil by workers. The fruit is cultivated by small producers in Brazil and it is a source of food for the low-income population. Its seeds are harvested with high moisture contents, and the drying process is necessary. Sorption isotherms consist of the relation between water activity (aw) and moisture content of an agricultural product at a constant temperature. This information contributes to the drying process, thus favoring an increased longevity of agricultural products, such as seeds. This research aims to determine the desorption isotherms of Solanum gilo seeds and calculate their thermodynamic properties (enthalpy, entropy and Gibbs free energy). Sorption experiments were performed by the gravimetric static method using saline solutions. Several mathematical models were fitted to the experimental data, and the selection of the best model was performed by statistical criteria. Equilibrium moisture contents were obtained at 10, 20 and 30°C and at water activities between 0.111 and 0.985 (decimal). The modified Oswin model best represents moisture desorption isotherms of Solanum gilo seeds under the studied conditions. The energy required for the process was 0.22-555.68 kJ kg-1. The latent heat of vaporization (L), the enthalpy (Qst), the entropy (ΔS) and the Gibbs free energy (ΔG) increased with the reduction of the equilibrium moisture content of seeds. The theory of isokinetics is valid for the desorption process.

Pages 1810-1816 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2187
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Morphophysiological traits of soybean leaflets and their relationship with crop agronomic performance

Carlos André Bahry*, Ângela Aparecida Carleso, Anelise Tessari Perboni, Françoá Santos Dal Prá, Gelson Geraldo, Leandro André Petkowicz, Leocádio Ceresoli, Américo Wagner Junior, José Abramo Marchese


Universidade Tecnológica Federal do Paraná (UTFPR), Câmpus Dois Vizinhos, Estrada para Boa Esperança, Km 04, Dois Vizinhos, Paraná, Brazil. 85.660-000
Universidade Tecnológica Federal do Paraná (UTFPR), Câmpus Pato Branco, Via do Conhecimento, Km 01, Pato Branco, Paraná, Brazil. 85503-390


Abstract
Soybean genotypes have distinct morphophysiological traits, which may influence the crop agronomic performance. The aim of this work was to evaluate the productive parameters of three contrasting soybean genotypes for leaf morphophysiological traits. The experiment was carried out at in a typical Distroferric Red Latosol, located at latitude 25º41'52" S and longitude 53º03'94" W; in the 2015/16 (CY1) and 2016/17 (CY2) seasons. The genotypes tested were: BS 2601 RR® (lanceolate and smaller leaflets); NS 6006 IPRO® (triangular and intermediate leaflets) and homozygous lineage CI 21 IPRO® (oval and larger leaflets). The gas exchange, chlorophyll index, leaf area, leaflet length and width, and petiolulus length were evaluated when plants of each genotype were at the beginning of flowering. At harvest, the variables analyzed were: first pod insertion, plant height, number of pods and grains per plant, grains per pod, mass of one thousand grains and grain yield. The design used was randomized blocks with four replicates. Photosynthesis per leaf area unit was higher in CY2, and is related to greater stomatal conductance, higher chlorophyll index, lower transpiration and lower leaf area of plants. The lanceolate leaf cultivar showed higher grain yield due to the higher number of grains and the greater mass of these grains in the two crop years. In addition, it was the one that obtained lower leaf area and lower transpiration. The cultivar NS 6006 presented greater productive stability, but this trait does not confer greater productive potential.

Pages 1817-1825 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2360
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Fruit and seed biometry of Carpotroche brasiliensis (RB) A. Gray (Achariaceae), a tropical tree with great potential to provide natural forest products

Thâmara M. Lima*, Elizabeth S. Amaral, Fernanda A. Gaiotto, Letícia dos Anjos, Ândrea Carla Dalmolin, Alesandro Souza Santos, Marcelo S. Mielke

Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado km 16, Ilhéus, BA, Brazil
Departamento de Biologia, Universidade Federal de Lavras, Av. Central, s/n - Campus Universitário, Lavras, MG, Brazil
Centro de Formação em Ciências e Tecnologias Agroflrestais, Universidade Federal do Sul da Bahia Br 415 Km 22 Ceplac, Ilhéus, BA, Brazil


Abstract
Carpotroche brasiliensis (RB) A. Gray (Achariaceae) is a native tree species of the Brazilian Atlantic Forest with great potential provide natural forest products in agroforestry systems. The oil of its seeds contains medicinal and cosmetic properties, and the fruits are appreciated by wild animals. In this study, we analyzed the biometry of fruits and seeds collected from naturally-grown trees in agroforestry systems on small farms in southern Bahia, Brazil. Fresh fruit mass (FFM), fruit length (FL), fruit diameter (FD), number of seeds per fruit (NSF), total fresh seed mass per fruit (FSMF), total dry mass of seeds per fruit (DMSF), and mass of 1,000 seeds (MTS) were collected from 66 fruits of 18 trees on six rural properties. Seed length (SL) and seed diameter (SD) were also evaluated for 5335 seeds. From this sample universe, 697 seeds represented an adequate sample size to measure these dimensions with statistical precision. The fruits analyzed in this study had uniform values for most of the biometric variables among the sites. The average values of NSF, FFM, and MTS were approximately 88 seeds, 0.5 kg, and 1.3 kg, respectively. Seeds of C. brasiliensis obtained from freshly-harvested fruits had high water content, with an average of more than 45%. Strongly significant correlations between FFM and FD and between FMSF and DMSF indicate the possibility of developing simple procedures to estimate seed production for commercial purposes from field evaluations.

Pages 1826-1833 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2596
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The 4R management for nitrogen fertilization in tropical forage: A review

Carolina Marques Costa*, Ana Beatriz Graciano da Costa, Gustavo de Farias Theodoro, Gelson dos Santos Difante, Antonio Leandro Chaves Gurgel, Juliana Caroline Santos Santana, Francisco Carlos Camargo, Emizael Menezes de Almeida

Federal University of Mato Grosso do Sul, Faculty of Veterinary Medicine and Zootechnics, Av. Senador Filinto Müler, 2443, Campo Grande - MS, 79074-460, Brazil

Abstract
Most of the tropical soils that are intended for pastures are degraded or are at a certain stage of degradation. In this context, the use of nitrogen fertilization increases the quantity as well as the quality of the fodder produced and also accelerates growth, tillering, leaf production, and consequently, expansion of the aerial region and the root system. The present review of the literature aims to determine how the control of the source, location, time, and the application of a right dose of nitrogen fertilizer influences and benefits the entire ecosystem in tropical pastures with the correct use of 4R management, along with increasing the forage yields in these areas. The results showed that in tropical pastures, the recommended N dose varies with the cultivar used and the expected forage production and ranges from 50 to 500 kg N ha–1 year–1, irrespective of division in grazing cycles, with distribution in the entire pasture area.

Pages 1834-1837 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2646
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Evaluation of nitrogen fertilization for planting corn in a yellow latosol under no-tillage system

Luana Paula Freire Souza, Manoel Tavares Paula*, Carlos Alberto Costa Veloso, Eduardo Jorge Maklouf Carvalho, Arystides Resende Silva, Altem Nascimento Pontes, Marcelo José Raiol Souza, Claudia Viana Urbinati, Henriqueta da Conceição Brito Nunes, Pedro Henrique Oliveira Simões

Center for Natural Sciences and Technology, University of the State of Pará, Belém-Pará-Brazil
Soil Analysis Laboratory, Embrapa Eastern Amazon, Belém-PA-Brazil
Department of Forest Sciences, Federal Rural University of Amazon, Belém-Pará-Brazil


Abstract
The objective of this work was to evaluate the efficiency of nitrogen fertilization in relation to the population of corn plants in a yellow latosol under no-tillage system. The experimental design was a randomized block with three replications, in a 4 x 4 factorial scheme, corresponding to four levels of N (0, 60, kg haˉ¹ 120 and 180) and four planting densities (45,000; 55,000; 65,000 and 75,000 plants haˉ¹). 48 soil samples were collected to determine chemical soil attributes (pH, OM, K, Ca, Na, Mg and Al) and 48 leaf samples to determine macronutrients in the leaf (N, P, K, Na, Ca and Mg). The data were submitted to comparison of means by the Scott-Knott test. The corn yield increased linearly up to the dose of 180 kg haˉ¹ N. Higher productivity was observed with the combination of 120 and 180 N (kg haˉ¹) with the density of 75,000 plants ha-1. There was an increase in the N content in the leaves with increasing doses of N in the soil.

Pages 1838-1843 | Full Text PDF| doi: 10.21475/ajcs.20.14.11.p2891