Agronomic performance of canola hybrids cultivated in a low altitude region in Southern Brazil

The area occupied by crops has expanded in recent years in the central region of Rio Grande do Sul, Brazil and the search for alternative winter crops to integrate the productive system is relevant given the idleness of the areas at this time and the lower risk of frost losses that occur in most grain-producing regions. In this sense, the objective of this research was to evaluate the agronomic performance of eight canola hybrids (Hyola 61, Hyola 50, Hyola 433, Hyola 571CL, Hyola 575CL, Diamond, ALHT B4, and ALHT M6), cultivated in low altitude areas, in the Central region of Rio Grande do Sul (RS). The experiment was conducted in 2017, in Santa Maria, RS, using a randomized block design with four replicates. Canola hybrids show variability regarding the morphological components and grain production. The environmental condition and low altitude of the region of Santa Maria do not compromise the productive potential of the canola crop, obtaining grain productivity superior to the state and national averages. Therefore, canola crop can be inserted in the central region of Rio Grande do Sul if adequate agronomic management is performed. The cultivars Hyola 50, Hyola 571CL, Hyola 433, Hyola 575CL, Diamond, and Hyola 61 present the highest grain productivity

Correlation and path analysis in wheat cultivars in the initial period of development

The cultivation of soybeans in the central region of the state of Rio Grande do Sul, has increased the interest of farmers for winter crops in the region. However, information related to crop development in a low-latitude environment is limited and necessary to improve crop management. The objectives of this article were to evaluate the linear relation between traits of spring wheat cultivars in the initial period of development in a low-altitude site. The experiments were conducted in two years in Santa Maria - RS. The experimental design used was randomized blocks, with ten wheat cultivars. The evaluations were carried out at the end of the tillering, where 300 plants were selected per year, obtaining a total sample number of 600 plants. After selecting, the character’s plant height (PH), the number of leaves of the main stem (NLMS), the number of leaves per plant (NLP), the number of tillers (NT), and the dry matter (DM) were measured. Pearson’s correlation coefficient matrices were estimated, and the path analysis of the main variable DM was performed as a function of PH, NLMS, NLP, NT, and DM. The cultivars TBIO Mestre and TBIO Sinuelo have a higher number of tillers. The NLP has a greater direct effect on DM, in field conditions it is recommended to count the NT, as it has a direct relationship with DM and NLP, associated with this, the character is fast to count and has agronomic value for the wheat crop. In a low-altitude cultivation site, the number of tillers depends on cultivation and environmental conditions. The cultivars TBIO Mestre and TBIO Sinuelo have high tillering capacity. Based on linear relationships, through the non-destructive selection of wheat plants with a greater number of leaves per plant and a greater number of tillers, plants with a higher dry matter mass are indirectly selected. However, the number of tillers is recommended because it is quick to measure.

Densidade agronômica ótima de milho em ambientes subtropicais

The objective of this work was to determine the agronomic optimal plant density (AOPD) for corn (Zea mays) in environments with a high, medium, and low grain yield, as well as to define which yield component is the most sensitive to variations in plant density. On-farm experiments were conducted in the municipalities of Júlio de Castilhos, in the 2018/2019 growing season, and of Entre-Ijuís, Jóia, Agudo, and Júlio de Castilhos, in the 2019/2020 growing season, in the state of Rio Grande do Sul, Brazil. The production environments were classified as having a low ( 16 Mg ha-1) grain yield. Júlio de Castilhos was identified as a site of high yield; Jóia and Entre-Ijuís, as of medium yield; and Agudo, as of low yield. The AOPDs ranged from 60,000 to 140,000 plants per hectare in the different production environments. The AOPD was of 110,300 to 116,200 plants per hectare for the high-yield environment, 101,000 plants per hectare for the medium-yield environment, and 60,000 plants per hectare for the low-yield environment. The number of grains per row is the yield component that is the most sensitive to variations in plant density in all production environments.O objetivo deste trabalho foi determinar a densidade agronômica ótima de plantas (DAOP) para o milho (Zea mays), em ambientes de alta, média e baixa produtividade de grãos, bem como definir qual componente da produtividade é mais sensível às variações de densidade de plantas. Experimentos em fazenda foram conduzidos nos municípios de Júlio de Castilhos, na safra de 2018/2019, e de Entre-Ijuís, Jóia, Agudo e Júlio de Castilhos, na safra de 2019/2020, no estado do Rio Grande do Sul, Brasil. Os ambientes de produção foram classificados como de baixa ( 16 Mg ha-1) produtividade. Júlio de Castilhos foi identificado como ambiente de alta produtividade; Jóia e Entre-Ijuís, como de média produtividade; e Agudo, como de baixa produtividade. As DAOPs variaram de 60.000 a 140.000 plantas por hectare nos diferentes ambientes de produção. A DAOP foi de 110.300 a 116.200 plantas por hectare para o ambiente de alta produtividade, de 101.000 plantas por hectare para o ambiente de média produtividade e de 60.000 plantas por hectare para o ambiente de baixa produtividade. O número de grãos por fileira é o componente de rendimento mais sensível às variações de densidade de plantas, em todos os ambientes de produção

Modification of canola cultivation conditions in a waterlogging-susceptible subtropical environment

Waterlogging directly interferes with the production capacity of agricultural crops in response to the morphophysiological changes caused to plants. Since the cultivation of poorly drained soils is traditionally avoided, this study aimed to evaluate the possibility of expanding canola cultivation into waterlogged soils using soil surface drainage and different row spacings in lowland areas of Rio Grande do Sul, Brazil. Treatments consisted of the presence and absence of surface drains at 0.25 m depth and row spacings of 0.17, 0.34, 0.51, and 0.68 m arranged in two-factorial randomized blocks with four replications, in 2018 and 2019. In this study, growth traits, yield components, and the final grain yield of canola were evaluated. The increase in lateral branching in canola plants was found to be directly related to waterlogging and negatively affected yield. The use of drains positively impacted the number of pods per plant, seeds per pod, the 1,000 seeds weight, and grain yield. The more intense waterlogging conditions in 2018 resulted in the highest grain yield and superior production traits were obtained with row spacings between 0.41 and 0.48 m. In the absence of waterlogging, the 0.17 m row spacing was more productive. Canola cultivation can occur in waterlogged soils in the presence of surface drainage and at row spacings ranging from 0.40 to 0.50 m

Filocrono e número de folhas da canola em diferentes condições ambientais

The objective of this work was to determine the number of leaves and phyllochron of canola genotypes, in response to thermal variations associated with sowing dates. Two experiments were conducted in a randomized block design, with a factorial arrangement of genotype by sowing date (5x2, in 2009, and 2x3 in 2010), and four replicates. The number of leaves on the main stem and first branch was determined threefold a week. Phyllochron was estimated by the inverse of the slope between the thermal time and the number of leaves, at the rosette stage and at stem elongation. The number of leaves on the main stem ranged from 11.5 to 16.4; this number was on average 70% lower in the first segment. The number of leaves on the main stem was higher in early sowing, and the opposite occurred in the first segment. The phyllochron was higher in the rosette stage, and values ranged from 21.4 to 52.9 degree‑days per leaf, according to genotypes and sowing dates. Late sowing dates increased the phyllochron. Early genotypes have lower number of leaves and phyllochron than medium and late genotypes, and the variability between them increase in late sowings.O objetivo deste trabalho foi determinar o número de folhas e o filocrono de genótipos de canola, em resposta a variações térmicas associadas com datas de semeadura. Foram realizados dois experimentos, em delineamento de blocos ao acaso, com arranjo fatorial de genótipos por datas de semeadura (5x2, em 2009, e 2x3 em 2010) e quatro repetições. O número de folhas do caule principal e do primeiro ramo foi determinado três vezes por semana. O filocrono foi estimado pelo inverso do coeficiente angular entre a soma térmica e o número de folhas, para os subperíodos da roseta e do alongamento do caule. O número de folhas no caule variou de 11,5 a 16,4; nos ramos, este número foi, em média, 70% menor. O número de folhas no caule foi maior em semeaduras precoces, e o inverso ocorreu no ramo. O filocrono foi maior no subperíodo da roseta e variou entre 21,4 e 52,9 graus‑dia por folha conforme o genótipo e a data de semeadura. Semeaduras tardias aumentaram o filocrono. Genótipos de ciclo precoce apresentam número de folhas e filocrono menores que genótipos de ciclo médio ou longo, e a variabilidade entre os genótipos acentua-se em semeaduras tardias

Bioclimatic parameters and responses of canola to the physical environment

Embora a expansão do cultivo da canola seja expressiva, no Sul do Brasil, poucos são os estudos envolvendo a fenologia e o crescimento das plantas, visando ampliar conhecimentos relativos à elaboração do rendimento de grãos, em resposta ao ambiente físico. Assim, este trabalho teve por objetivo avaliar a fenologia e o crescimento da canola, visando ajustar parâmetros bioclimáticos e avaliar respostas da cultura às variações do ambiente físico. Experimentos de campo foram conduzidos em 2009, 2010 e 2011, com diferentes genótipos de canola semeados de abril a julho, em delineamento de blocos ao acaso. Foram avaliadas as seguintes variáveis: datas dos principais estádios fenológicos, índice de área foliar, matéria seca de hastes, folhas, flores, síliquas e grãos, componentes e rendimento de grãos e parâmetros de interceptação de radiação fotossinteticamente ativa (RFA). A partir de dados meteorológicos, foram calculados balanços hídricos climatológicos e necessidade térmica da cultura (graus-dia), para cada ano e data de semeadura. A necessidade térmica variou durante o ciclo e subperíodos da cultura, em função de genótipos e datas de semeadura. A canola apresentou menor índice de área foliar quando semeada em abril e maio, porém, a longevidade do índice de área foliar foi maior do que em semeaduras de junho e julho. Hastes, flores e síliquas interceptaram a maior parte da radiação solar fotossinteticamente ativa após a ocorrência do máximo índice de área foliar. O coeficiente de extinção da cultura para RFA foi de 0,98. A eficiência de uso da radiação fotossinteticamente ativa variou de 1,9 a 2,8 g MJ-1, sendo mais elevada nos ambientes com baixos excessos hídricos, nos quais a cultura também expressou seus maiores rendimentos de grãos. O acúmulo de biomassa da parte aérea das plantas, ao longo do ciclo, não foi limitante à elaboração do rendimento de grãos. O híbrido Hyola 61 apresentou rendimento de grãos superior e mais estável, em diferentes ambientes, do que o Hyola 432. Semeaduras mais precoces, em abril e maio, apresentam maior potencial rendimento de grãos que as tardias, realizadas em junho e julho.Although the expansion of rapeseed crops is expressive in Southern Brazil, there are few studies on phenology and growth of plants, aiming to amplify knowledge on the elaboration of the grain yield, in response to the physical environment. This study aimed to evaluate the phenology and growth of rapeseed plants, aiming to adjust bioclimatic parameters and to evaluate crop responses to variations in the physical environment. Field experiments were conducted in 2009, 2010 and 2011, with different genotypes of rapeseeds sown from April to July, in a randomized complete blocks design. The following variables were evaluated: dates of the main phenological stages, leaf area index, dry matter of stems, leaves, flowers, seedpods and grains, grain yield and its components, and interception parameters of photosynthetically active radiation (PAR). From daily meteorological data, climate water balances and thermal requirements of the crop (degree-days) were calculated, for each year and sowing date. The thermal requirements varied during the crop cycle and sub-periods for different genotypes and sowing dates. The lower leaf area index occurred when the crop was sown in April and May, but the longevity of the leaf area index was higher than in the latest sowing dates (June and July). Most of the incident photosynthetically active radiation was intercepted by stems, flowers and seedpods, after the occurrence of the maximum leaf area index. The extinction coefficient of the crop for RFA was 0.98. The use efficiency of photosynthetically active radiation ranged from 1.9 to 2.8 g MJ-1, being higher in environments with low water excesses, in which the crop also expressed the highest grain yields. The accumulation of aboveground biomass of plants, throughout the crop cycle, did not limit the grain yields. The hybrid Hyola 61 had higher and more stable grain yields than the Hyola 432, for different environments. The earliest sowing dates, in April and May, promoted the greatest grain yield, compared to the latest ones, held in June and July