Chilean Journal of Agricultural Research

Artículos

Chilean Journal of Agricultural Research

  • Sowing date as a response to ecological conditions in maize seed production
    el día diciembre 6, 2021 a las 9:34 pm

    ABSTRACT The environment protection, energy, and resources preservation are especially pronounced under present climate changes. In agriculture, these changes are recognised as drought, high temperatures, occurrence of stormy winds and hail. The aim of this study was to determine variations in seed morphology that are a result of different sowing dates in relation with agro- ecological conditions of maize (Zea mays L.) cultivation. The material used for the study encompassed three inbred lines (G1, G2, G3) sown every 10 d on five sowing dates (T1, T2, T3, T4, T5) starting from 1 April to 10 May, during 2 yr (Y1: 2018, Y2: 2019). The following physical properties of seeds were estimated: width (W), length (L), thickness (Tk), ratio of small (SF) to large fraction (LF) and grain yield (GY). The width was the highest in all three inbreeds on T4 (1.00, 1.03, 0.99 cm, respectively); T5 was the least favourable date for L (1.09, 1.12, 1.09 cm, respectively) while Tk was the lowest in G1 (0.51 cm) and G2 (0.51 cm) sown on T1. The most significant differences in the formation of physical properties occurred in seeds sown on T5 (p ≤ 0.05). The highest differences were observed in width between T5-T4 (-0.223 cm), in length between T5-T2 (-0.309 cm) and in thickness between T5-T3 (-0.129 cm). Later sowing dates favoured LF (85.2%) in comparison to SF (14.7%). Seed size variability participated with 50% in yield formation (R2 ≥ 0.5).

  • Effect of maize straw additives on the nutritional quality and bacterial communities of ensiled forage rape for animal feed
    el día diciembre 6, 2021 a las 9:34 pm

    ABSTRACT The impact of forage rape (Brassica napus L.) with maize (Zea mays L.) straw addition on the changes of nutritional quality and bacterial community was investigated by using high-throughput sequencing analysis of the 16S rRNA. The six ensilage treatments were set based on different mass ratios of forage rape (S) and maize stalk (Y): S1 (forage rape:maize stalk 10:0), S7Y3 (7:3), S6Y4 (6:4), S5Y5 (5:5), S4Y6 (4:6), and S3Y7 (3:7). The results showed that compared with S1, the DM content of S7Y3, S6Y4, S5Y5, S4Y6 and S3Y7 increased by 10.71%, 16.02%, 22.56%, 24.37% and 30.19% after the maize straw addition, respectively. Contents of crude protein (CP), ether extracts (EE) and water-soluble carbohydrate (WSC) contents in S7Y3 were significantly higher than that of other maize straw additive treatments (P < 0.05), which were 11.11% DM, 4.54% DM and 12.50% DM, respectively. On the 60th day of fermentation, the lowest pH value was found in S7Y3, which was 3.56. The V-score of each treatment were above 80. Bacterial Shannon and Chao indices were highest in S7Y3. The dominant bacterial phyla across all silage samples were Firmicutes, Proteobacteria, Cyanobacteria and Actinobacteria. The dominant genera are Lactobacillus and Weissella. Redundancy analysis (RDA) suggested that DM, CP, EE and WSC are the main factors in shaping bacterial communities. This study demonstrated that forage rape with maize straw addition can affect the nutritional quality and bacterial community of silage, and the best mixing ratio of maize straw and forage rape ensilage is 7:3.

  • Silicon induces changes in the antioxidant system of millet cultivated in drought and salinity
    el día diciembre 6, 2021 a las 9:34 pm

    ABSTRACT In recent years, benefits of silicon in plants grown under stress conditions have been reported. The objective of the research was to evaluate the response at a physiological and biochemical level of millet (Panicum miliaceum L.) to fertilization with Si under controlled stress conditions during vegetative stage, drought, salinity and the control (without stress). After stress, shoot and root length, DM content, peroxidase (POD) and catalase (CAT) activity, proline, H2O2 and Si content, seed yield and germination percentage were measured. Drought and salinity significantly decreased shoot (24%, 21%) and root (30% in drought) development, weight (36%, 29%) and seed number (30%, 21%) per plant. Application of Si significantly increased seed number (289) and seed weight (1.20 g) in the control plants, increased seed weight (0.83 g) in plants under drought and germination percentage (99%) in plants under salinity. Silicon increased 2.1 times POD activity in drought, 1.4 times in salinity and control plants; CAT activity increased 10.6 times in salinity and 1.7 times in control plants. Silicon decreased 10 times proline levels in plants under drought; in salinity and control, proline content increased 1.3 times with Si and H2O2 levels decreased in these treatments. The Si content in plants fertilized with Si under drought, salinity and control was 6%, 3.54% and 5.45% respectively. In conclusion, Si can improve plant stress tolerance by stimulating POD and CAT activity, and regulating proline levels, allowing it to improve the production and physiological seed.

  • Evaluation of pigment, antioxidant capacity and bioactive compounds in microgreens of wheat landraces and cereals
    el día diciembre 6, 2021 a las 9:34 pm

    ABSTRACT Landraces that adapt to all kinds of stress factors over thousands of years are considered a very important genetic resource. In this study, antioxidant activities, bioactive compounds, and pigment contents of microgreen in Kose and Kirik wheat landraces, which are used extensively in bread making especially in rural areas of Eastern Anatolia, and some cereals, were examined. In the study, chlorophyll (CHLdx), flavonol (FLV), anthocyanin (ANT), and N balance index (NBI) were measured in fresh material with a Dualex device. Also, total antioxidant capacity (TAC), total phenolic content (TPC), total flavonoid content (TFC), ascorbic acid (AAC) content and pigment values such as total chlorophyll (TCHL), chlorophyll a (CHLa), chlorophyll b (CHLb) and carotenoid content (CAR) were determined. It was observed that TAC capacity of wheat landraces was more than twice that of other cereals (except ‘Alparslan’) and their NBI, AAC, ANT and FLV contents were low. Kirik landrace had high TCHL, CHLa, CHLb and CAR content, while Kose landrace had low all pigment values. Besides, NBI content of barley, AAC and FLV content of oat cultivars and ANT content of wheat ‘Alparslan’ were high as a group. The CHLdx values of barley and oats were twice that of wheat. A very important and positive correlation was determined between TCHL with CHLa, CHLb, and CAR contents. Also, correlations between CHLa with CHLb and CAR, and between CHLb with CAR was important and positive. In the study, especially TAC capacities of local wheat varieties were significantly higher.

  • Stages of grassland degradation in subalpine ecosystems of the Central Caucasus, Russia
    el día diciembre 6, 2021 a las 9:34 pm

    ABSTRACT Overgrazing and grassland degradation are significant environmental problems in the mountain ecosystems of the Central Caucasus. The aim was to define the criteria for the stages of grassland degradation to provide land managers with useful guidelines on evaluating grassland status. We identified four stages of grassland degradation based on a statistical analysis of 23 vegetation and soil parameters at 126 model plots in the subalpine meadows. Main indicators of grassland degradation were grass height, coverage of forage species, coverage of grazing-resistant species, and fresh herbage yield. Grass height decreased significantly (P < 0.05) with each stage of grassland degradation from 31.4 ± 3.6 cm in untransformed grasslands to 3.3 ± 1.7 cm in severely degraded pastures. Fresh herbage yield in untransformed grasslands (120.8 ± 12.5×102 kg ha-1) was 81% higher than in highly degraded pastures. Coverage of forage species decreased in the row of grassland degradation from 72% to 34%, while coverage of grazing-resistant species increased with grazing intensity from 23% to 77%. Critical values of the integral degradation index based on these four parameters are useful for a reliable assessment of grassland status in the field.

Buscador Avanzado

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