Chilean Journal of Agricultural Research

ABSTRACT Selection of a representative sampling area for accurate and reliable yield evaluation of wheat (Triticum aestivum L.) is important for optimizing straw retention in soils and its removal as biofuel feedstock. A field experiment was conducted at four wheat fields in the North China in 2020. Wheat straw and grain yields varied from 359.2-682.8 and 338.5-640.4 g m-2, respectively, and plant height varied from 51.3-59.7 cm across all plots in the four sites. Variation in either relative deviation (RD) or standard error (SE) of straw and grain yield and plant height estimates decreased with the increase in random sampling square (RSS) (one square = approximately 1 m²) and random sampling plant (RSP) numbers, respectively. Minimum RSS numbers of 3-10 and 1-10 m2 were needed to satisfy RD less than 5% in two-third of the plots for straw and grain yield estimates, respectively. This suggests that 10 m2 could be recommended as the minimum RSS number per plot. However, the incidence frequency of RD was 63.75% and 60.00% within the RD interval of 0%-5% for straw and grain yield estimates, respectively, from the RSS number of 10 m2, indicating that yields from RSSs in field trials are prone to large variations. Therefore, it is strongly recommended to design a large plot as possible and to harvest the whole plot for estimating yields. The threshold RSP number ranged from 14-18 to satisfy RD less than 1.5% and a minimum RSP of 20 plants (including mains and tillers) per plot could be recommended for wheat field experiments.

ABSTRACT The use of agroindustrial byproducts in cattle diets, such as castor-bean (Ricinus communis L.) meal, is a more sustainable practice because it does not compete with human food and reduces the volume of organic waste deposited in the environment. The aim of this study was to examine the effect of replacing soybean (Glycine max (L.) Merr.) meal with castor-bean meal on the intake, digestibility, feeding behavior and performance of crossbred steers supplemented while on Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster ‘Marandu’ pasture. The experiment was laid out in a randomized complete design with 40 animals, which started the experiment weighing 227.1 kg, at 10 mo of age, and were divided into four treatment groups. Castor-bean meal was added to replace soybean meal at the levels of 0, 90, 180, and 280 g kg-1 in the supplement, which was supplied at the rate of 0.4% of body weight. Total DM, pasture DM and neutral detergent fiber intakes did not change (P > 0.05) with the castor-bean levels added to the supplement. Ether extract intake and digestibility decreased linearly (P < 0.05). The animals showed no differences (P > 0.05) in production performance (average daily gain), which averaged 0.65 kg d-1. Grazing, idle, and rumination times were not influenced (P > 0.05) by the treatments. Castor-bean meal can be included up to 280 g kg-1 in the total diet without changing the performance of crossbred steers finished on tropical pasture.

ABSTRACT Red ginger (Zingiber officinale var. rubrum Theilade) is one of the materials used in the functional food and biopharmaceutical industry; it has a low productivity and quality problem and is unable to meet market demand. The present study aimed to evaluate the impact of K fertilization on growth, yield, antioxidant content, and K use and response efficiency in red ginger cultivation. The study was conducted at Agro Techno Park (ATP) Jatikerto, Malang Regency, Indonesia. The field experiment was carried out in two periods, December 2019-August 2020 and January 2021-September 2021. In the first planting season, treatments included 4 K fertilizer rates (100, 200, 300, and 400 kg K ha-1), while eight treatments were applied in the second planting season (0, 60, 120, 180, 240, 300, 360, and 420 kg K ha-1). Measured variables included growth, yield, rhizome quality, and K use and response efficiency. Red ginger growth variables (height, leaf number, and tiller number per clump), yield, plant biomass, K uptake, and soil exchangeable K were strongly affected by K application rates, and the highest effect occurred at 300 kg K ha-1. In addition, the 300 kg K ha-1 rate resulted in the best rhizome morphology quality (rhizome diameter) and antioxidant content (6% to 30% higher than other treatments). Increased K fertilization decreased K use and response efficiency from 43% to 99% and decreased antioxidant content. Therefore, the study suggests that applying K fertilization at approximately 200-300 kg ha-1 improves the yield and quality of red ginger.

ABSTRACT Physical mutagenesis with 60Co is a technique used in plant breeding to induce desired phenotypic characteristics. This research objective was to evaluate physical and physiological quality and protein content of jalapeño pepper (Capsicum annuum L.) seeds from plants that were selected as tolerant to water stress, these plants were derived from seeds irradiated with 60Co at 100 Gy dose (T1P2 and T1P5 both from tolerant plants to water stress). Control seeds were significantly superior to the mutants in the variable standard germination (90.66%), standard germination with accelerated aging (57.3%), normal seedlings (95.6%), 1000 seeds weight (6.349 g), hectoliter weight (51.97 kg hL-1) and radicle dry weight (18 mg). Mutant seeds were significantly superior to control seeds in seed length and width (4.356 mm in T1P2 and 4.256 mm in T1P5 for length; 3.544 mm in T1P2 and 3.632 mm in T1P5 for width). In seed thickness tests, germinated seeds aerial part fresh and dry weight, radicle fresh weight, the two mutants seed types and the control were significantly equal. In seed storage proteins content, T1P2 treatment had a higher globulins concentration. In the prolamin fraction, the two mutant seed types were superior to control. T1P5 treatment seeds had the highest glutelins concentration. Mutant seeds showed different characteristics as compared to control in physical, physiological and plantlet parts weight components.

ABSTRACT The maize weevil (Sitophilus zeamais Motschulsky, 1855; Coleoptera, Curculionidae) is one of the most important pests associated with stored grains. It is controlled almost exclusively with synthetic insecticides. Thus, leading to problems such as pollution and resistance development. Hence an alternative is the use of natural compounds such as edible mushrooms derivates. The aim of this research was to assess, under laboratory conditions, the insecticidal and insectistatic effect of a hydroalcoholic extract of Pleurotus ostreatus (Jacq.) P. Kumm. 1871 against adults of S. zeamais. The parameters assessed were contact and fumigant toxicity, repellency, and antifeedant effect. The highest contact toxicity (57.5% mortality) was achieved with 30 mL extract L-1 solvent. No treatment showed repellent effect; the repellency index (RI) values were higher than 1, and the antifeeding activity < 30%. The fumigant effect showed a maximum of 30% mortality with the highest concentration (300 μL L-1 air). The hydroalcoholic extract of P. ostreatus exerts contact toxicity and interferes with insect reproduction or oviposition of Sitophilus zeamais.