Irrigation is a major factor on sugarcane yield, especially on semi-arid regions. Genetic degenerated varieties, presenting low yield and quality, are still being planted on semi-arid regions. This study objective was to evaluate the agronomic performance of six sugarcane varieties, IAC86-2480, RB76-5418, RB83-5486, RB85-5536, SP80-1816 and SP80-1842, under different irrigation depths. Height, number of culms, culm`s diameter and yield were evaluated 11 months after planting. The experiment was conducted in Brazil, on the semi-arid region of Minas Gerais state, Jaíba city, at the experimental farm Mocambinho (FEMO). The experiment was designed on a randomized complete block design (RCBD), on a subdivided parcels scheme (6 x 5), being the six varieties used on the parcels and sub-parcels composed by five irrigation depths, with four repetitions. The varieties SP80-1842 and IAC86-2480 presented, on the highest irrigation depth, the highest height and number of culms, respectively. The varieties IAC86-2480 and RB83-5486 presented, on the lowest irrigation depth, the lowest results to culms diameter. The varieties SP80-1842 and SP80-1816 presented higher yields with 1351 mm depth. On a general manner, the varieties SP80-1842 and SP80-1816 presented the best agronomical performance, within the evaluated varieties, to semi-arid conditions. The 1351 mm depth presented the best results, regarding sugarcane production, on the studied conditions.
The objective of this study was evaluating the production of arugula fertilized with wood ash, organomineral fertilizer (wood ash + mineral fertilizer) and mineral fertilizer in function of the base saturation levels in Oxisol. The experiment was performed in a greenhouse using the completely randomized experimental design with eight treatments, as follows: T1 - wood ash at 50% of BS; T2 - wood ash at 80% of BS; T3 - wood ash + mineral fertilizers at 50% of BS; T4 - wood ash + mineral fertilizers at 80% of BS; T5 - mineral fertilizers at 50% of BS; T6 - mineral fertilizers at 80% of BS; T7 - control (limed for 50% of BS) and T8 - control (limed for 80% of BS) and four replications. The experimental units consisted of a 2 dm3soil pot. pH of the soil 30 days after incubation with limestone and wood ash was evaluated for all treatments. At 30 days after emergence of plants the chlorophyll index, fresh and dry mass of shoot, dry mass of root and evapotranspiration of the arugula were evaluated. The highest values of pH of the soil were observed in the treatments at 80% of BS. Generally, the higher of shoot fresh and dry mass were obtained by application of mineral and wood ash combined with mineral fertilizers (organomineral fertilizer). The higher of root dry mass was obtained by minerally fertilized plots at 80% of BS. Compared to wood ash fertilized plots only, the minerally fertilized plots followed by the wood ash and mineral treated plot provided the highest of chlorophyll index, shoot fresh and dry mass and root dry mass of the arugula plants. For the mineral or organomineral fertilizer, arugula could be grown at a base saturation of 80% and 50%, respectively.
Genotyping of crop plants, especially pigeon pea is very strategic in the global quest for crops that will be suitable for the precarious climate change as it provides genotypes for introgression. 22 pigeon pea accessions obtained from IITA germplasm were evaluated for genetic diversity. Genomic DNA was extracted using SDS protocol from young leaves of each accession and quantification was done. 12 RAPD primers were used for PCR DNA amplification and bands were visualized under UV light using ethidium bromide. Data analyses were computed using power marker version 3.25 and GenAlex 6.41 software. Results obtained revealed that the polymorphic information content ranged from 0.6458-0.9436 while percentage polymorphism ranged from 71.4-100. Average percentage polymorphism was 88.6%. UPGMA- based cluster generated two major clusters with 12 and 10 accessions, respectively. Principal coordinates (PCoA) contributed 20.75% to the total diversity. Though showing two clusters, it was not population-dependent. AMOVA result gave 0.00% to variation among the population while variation within population was 100%. Additionally, genetic diversity parameters such as heterozygosity, mean Nei unbiased genetic distance, genetic identity were 0.015, 0.006 and 0.994, respectively. However, Shannon’s information index, diversity and unbiased diversity were 1.858±0.02, 0.648±0.005 and 0.503±0.005. Pigeon pea accessions used in this present study revealed very narrow genetic diversity suggesting that they came from one population. The little variability observed may have been contributed by the accession TCc CITA 3. The implication of the results taking together is that further genotyping should be carried out using other DNA markers before explicit conclusion can be made.
Aims: Objectives were to evaluate the effects of timed irrigations on plant biomass and seed-cotton production, plant leaf area, whole-plant transpiration, and transpiration per unit leaf area.
Study Design: A complete randomized design with four replications.
Place and Duration of Study: Study was conducted in the Drought Tolerance Laboratory at the Texas A&M AgriLife Research and Extension Center near Corpus Christi, TX during the 2014 and 2015 growing seasons.
Methodology: One plant per pot of the cultivar Phytogen 375 was grown in the greenhouse; pots were irrigated during nighttime with 0.5 L of a modified Hoagland’s nutrient solution to prevent pot weight changes affecting the calculations of hourly daytime transpiration. A computerized system developed to convert whole-plant transpiration from changes in pot weight included an algorithm to remove nighttime weight data “noise” related to pot weight data collection when excess water drainage occurs, that otherwise would affect hourly and daily whole-plant transpiration calculations.
Results: The full irrigation treatments applied during different phenological stages had significant impact on production of biomass, leaf area, and seed-cotton, as well as whole-plant transpiration and transpiration per unit leaf area. Seed-cotton production per plant increased 49% in 2015 when irrigation was applied during MH-FB and FB-MB, but not when applied late during MB-OB. These effects could not be confirmed in 2014, although not significant numerical differences due to experimental data variation were pointing to comparable effects.
Conclusion: The slope of the linear regression of seed-cotton on cumulative whole-plant transpiration (CWPT), which represents the overall impact of irrigation on plant seed-cotton production regardless of their timing, showed that seed-cotton per plant increased 1.063 and 0.554 g per L of CWPT increase in 2014 and 2015, respectively. This difference illustrates the effect of environmental conditions affecting the overall response of plant seed-cotton production to irrigation.
The incorrect use of herbicides can cause the contamination of soil and aquatic ecosystems. In this study, we evaluated the contamination of surface water samples from the northern state of São Paulo, Brazil. Samples were collected from rain, streams and lakes in three seasons in different agricultural areas. Liquid chromatography coupled with high performance mass spectrometry was used to analyze water contamination by the following herbicides: ametryn, amicarbazone, clomazone, diclosulam, diuron, hexazinone, imazapic, imazapyr, isoxaflutole, s-metolachlor, sulfentrazone, sulfometuron-methyl and tebuthiuron. According to the method, the limits of quantification were 3.13 μg L-1 for diuron and 0.391 μg L-1 for the other herbicides. It was observed that 82% of all the samples contained at least one herbicide, and clomazone was the most common product. The highest quantized values were found for streams: s-metolachlor (10.2 hg L-1), diuron (7.65 and 5.49 μg L-1) and hexazinone (4.3 μg L-1). The results indicate that surface water from the north of São Paulo contains residual herbicides in quantifiable levels.