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Current Publisher: MDPI (10.3390)
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Proceedings, Volume 36; doi:10.3390/proceedings2019036150
Sclerotinia Blight, caused by ascomycete fungal pathogen S. minor (Jagger), is a serious soil-borne disease of peanut crops within the South Burnett area in Queensland, Australia. The pathogen can infect root, stem and foliage tissues, forming characteristic fluffy white mycelial growth on stems leading to tissue wilting and necrosis. The disease can cause significant yield reductions and, in some cases, complete crop losses in peanut production. Outbreaks occur in cooler weather (under 18 °C) with high humidity levels (above 95%) as the higher humidity levels promote germination of sclerotia (Smith 2003, Maas, Dashiell et al. 2006). Therefore, knowledge of inoculum levels prior to sowing could enhance cropping systems through enhanced capacity to predict outbreaks. The South Australia Research and Development Institute (SARDI) offers a new soil test for Sclerotinia sp., called PreDictaB, available for farmers to asses inoculum levels pre-planting as a crop risk assessment tool. This project validated the accuracy of the PreDictaB test for Sclerotinia inoculum levels in the South Burnett soils, while gathering paddock and weather data to identify key characteristics linked to high risk of Sclerotinia Blight incidence to be transposed in a pre-season risk matrix model. Results demonstrated a close positive relationship between the level of Sclerotinia in the soil pre-planting and the paddock disease severity observed at harvest. The significance of the results for future research into potential management strategies is discussed. This new test has the potential to reduce the impact and presence of Sclerotinia in the field within the South Burnett region.
Proceedings, Volume 36; doi:10.3390/proceedings2019036151
In soybean cropping, sulfonylurea (SU) herbicides are a potentially useful alternative to glyphosate-based herbicides. Normally, soybeans are susceptible to SU herbicides, but two unlinked non-GMO genes (ALS1 and ALS2), have been identified that confer SU tolerance. In this project, we explored the effectiveness of these genes in Australian soybean genetic backgrounds. Four lines, carrying both ALS1 and ALS2, were derived by backcrossing different Australian genotypes to a SU-tolerance donor line ‘W4-4’ and then using molecular markers, plants homozygous for both ALS genes were selected. The W4-4 donor and the four derived lines were evaluated in a hydroponic system at increments up to 4× the recommended field rate of metsulfuron-methyl. The ALS genes provided high levels of tolerance, with evidence of some minor interaction with the genetic background. To further test whether there was an effect of background, the five lines were crossed together in a half-diallel mating design and the resulting ten F2 populations were screened hydroponically for tolerance to metsulfuron-methyl herbicide at 4× the recommended field rate. Analyses of seedling dry weight of the five parental lines and their F2 progeny in response to the herbicide, identified differences among the crosses. These results indicated that the development of commercial varieties with maximum herbicide tolerance requires incorporation of both ALS genes, and if combined with selection in segregating populations in the presence of SU herbicide may capture additional tolerance from background genes of minor effect.
Proceedings, Volume 36; doi:10.3390/proceedings2019036147
Rice is the predominant crop during wet season (July–December) and majority of land remain fallow during dry season (January–June) in the coastal saline region of West Bengal, India. Sustainable cropping system intensification in this salt affected region needs improved package of practices which conserve soil moisture, facilitate early crop establishment, ensures profitability and has positive effect on soil health. To achieve these objectives in a rice-based cropping system, we evaluated seven treatments for potato crop during the dry season viz. T1: ridge sowing (control), T2: Zero tillage (ZT) sowing with 9 t ha−1 paddy straw mulching (PSM), T3: T2 + foliar spray of nutrients, T4: ZT sowing with 12 t ha−1 PSM, T5: T4 + foliar spray of nutrients, T6: ZT sowing with 15 t ha−1 PSM, T7: T6 + foliar spray of nutrients in randomized block design with five replications. This study was conducted during 2016-2019 in the Gosaba island of the Indian Sundarbans. Cost of cultivation of potato reduced by about 27% due to ZT sowing (₹ 81,287 ha−1) compared to ridge sowing (₹ 1,11,260 ha−1). Tuber yield, net return and irrigation water productivity was significantly increased in T5, T6 and T7 over other treatments. There was reduction in soil salinity (ECe reduced from 5 to 3 dS m−1), bulk density (from 1.49 to 1.44 Mg m−3), irrigation water use (less 20 cm), conservation of soil moisture (4–8%), and increase in organic carbon (0.39 to 0.44%) due to ZT sowing with PSM. Rice-ZT potato-green gram cropping system was the most profitable one with highest net return (₹ 1,71,752 ha−1), however, the benefit-cost ratio was highest (2.33) with Rice-ZT potato cropping system.
Proceedings, Volume 36; doi:10.3390/proceedings2019036148
Genetic diversity is an essential part of successful crop development and can be evaluated by different methods, e.g. the Coefficient of Parentage (COP). This coefficient is established on pedigree data. This method can determine the variation among genotypes without the influence of environment effects as would be the case for field data. This study measured genetic diversity among 317 wheat cultivars from a population generated by the speed breeding technique. Using pedigree data, we determined the associations between parents and individuals, and then used the pattern analysis techniques of principal component analysis and clustering. The results enabled an appropriate graphical representation of wheat cultivars. This information is useful for selecting future parents in breeding programs. This demonstrates that using COP is a viable way to evaluate diversity among genotypes, especially in inbred populations.
Proceedings, Volume 36; doi:10.3390/proceedings2019036149
: Pigeonpea (Cajanus cajan (L) Millspaugh) is extensively grown in tropical subtropical and warmer equatorial regions of the world and ranks 6th in the global legume production (6.8MT; 2017). It is consumed by billions of people as a major source of protein in developing countries. Despite the increasing demand the crop is facing severe yield losses (2.4 billion US$/Annum) due to the insect pest Helicoverpa.armigera (68% globally). As this pest is polyphagous was exposed to several pesticides and gained strong resistance, it necessities a strong need for identifying host plant resistance towards this pest. Australia is the second hub with 15 out of 32 Cajanus species next to Asia. This is the pilot study exploring the potential of Australian Cajanus species as wild were proven sources for potential trait information in many other crops. My study firstly characterized the Australasian wild species and their derivatives for phenotypic variation and secondly tested for their resistance to Helicoverpa armigera. My research also demonstrated a very high levels of resistance to Helicoverpa armigera in some of the Australian wild species and their derivatives, compared to cultivated species. This research also revealed a high levels of total phenolic compounds in the wild species and a significant negative correlation of total phenols with the pest survival. We were successful in identifying the major phenolic compound in resistant species. Exploring the role of that specific compound related to host plant resistance and identifying the genetic markers associated with phytochemicals triggering the pest resistance is underway.
Proceedings, Volume 36; doi:10.3390/proceedings2019036144
Farmers are being encouraged to represent the conjunctive use of fresh water (FW) and saline water (SW) irrigation for the future agriculture in the coastal saline prone areas of Bangladesh where the scarcity of FW. Therefore, the effects of fresh and saline water irrigation for maize was performed on the crop performances, water use, water productivity (WP), soil salinity and scope for maize cultivation in coastal areas. The experiment was carried out at farmers’ field at two locations with six irrigation treatments and replicated thrice during 2016–2017 and 2017–2018. Results showed that the effect of FW (0.5 ≤ salinity ≤ 1.5 dS/m) at early growth stages and SW (1.5 ≤ salinity ≤ 5 dS/m) at later growth stages had insignificant difference compared to the treatment of FW irrigation. Yield slightly increased with increased number of irrigations but there was no significant differences among the treatment. WP significantly affected by irrigation frequency in both locations, decreasing greatly with increasing amount. The more changes in soil water occurred at upper layer than lower depth of soil profiles. The highest changes soil salinity (ECe) occurred at mid-February of the crop growing season compared to the beginning and later growth stages of maize in 60 cm soil profiles. The technique of fresh and saline water irrigation at different growth stages of maize in coastal regions could be an alternative irrigation scheduled and method for increasing yield and WP through establishment of maize compared to no crops at fallow lands during rabi (dry) season in the salt affected areas of Bangladesh.
Proceedings, Volume 36; doi:10.3390/proceedings2019036145
Three constraints affect the growth of crops in the Rabi (dry) season in southern Bangladesh: these are the clay nature of the soils which decreases the infiltration of water, the conserving of soil moisture with the increasingly dry conditions and the accumulation of salts on the soil surface through capillary from saline groundwater. Field experiments were conducted in the salt-affected areas of southern Bangladesh. The objectives of the study were to: (i) evaluate the effect of straw and irrigation frequency on crop growth and yield in maize and sunflower, and (ii) determine the combined effect of straw and irrigation frequency on the salinity, osmotic potential and moisture of soils. The experiment was carried out in farmers’ fields with eight treatments and was replicated three times during the dry (rabi) season of 2018–2019. There were two rice straw treatments (with or without straw), and 4 irrigation frequencies (at intervals of 5–7,10–12,15–17 or 20–25 days). Maize and sunflower seeds were sown by dibbling in no-tilled systems. The results showed that rice straw significantly affected the crop growth and yield, increasing the yield of maize and sunflower by 22% and 4.3% compared to treatments of without residue. The irrigation treatments also significantly affected crop yields. There was no interaction between straw levels and irrigation. The causes of these effects appeared to be improved water relations: rice straw and more frequent irrigations both reduced the salinity and osmotic potential of soils compared with treatments without straw while the soil moisture was greater in rice straw treatments and increased with the increased soil layers. We conclude that straw mulching and irrigation management practice could be used in coastal saline of heavy soils to reduce soil salinity, osmotic potentials thereby increasing crop yields in no-tilled systems.
Proceedings, Volume 36; doi:10.3390/proceedings2019036146
Due to seasonal dry-season salt accumulation in the coastal saline zone (CSZ) of West Bengal, India, the cultivation of winter crops (following summer rice) is rare. To address this issue, field experiments were conducted over two years (2016–18) in the CSZ to study the feasibility of cropping system intensification through incorporating grass pea into the dominant rice-fallow rotation. The experiment was conducted in strip plot design with two factors namely, Factor A: Six dates of rice sowing (at one-week intervals—2nd week of June to 3rd week of July) and Factor B: Two land situations (Medium-upland and Medium-lowland). The experiment was simulated using APSIM (Agricultural Production Systems sIMulator) utilizing the APSIM-SWIM water balance module to understand the mechanisms of seasonal soil salinity dynamics and the associated crop responses. The results suggest that irrespective of land situation, early sown rice (2nd week of June) produces higher dry matter and yield compared to late sown crops. This early rice sowing also facilitated better subsequent grass pea performance, by avoiding the worst of the salinity build-up and drought stress later in the winter. The model performed well in simulating the observed rice and grass pea yields (R2 = 0.97 with low bias (slope, α = 0.93, intercept, β = 149 kg ha−1), RMSE = 558 kg ha−1). It may be concluded that ASPIM-SWIM is an effective tool to understand, assess and predict the complex bio-physical mechanisms of ground water and soil salinity dynamics in rice-pulse-based cropping systems of CSZ of West Bengal.
Proceedings, Volume 36; doi:10.3390/proceedings2019036143
Current production of oats for grain in Queensland is minor due to unsuitable varieties bred for different climates, and high disease pressure from leaf and stem rust late in the growing season. A range of grain oat breeding lines developed by the Federal University of Rio Grande do Sul in Porto Alegre, Brazil, was screened for leaf rust resistance and subsequently identified as potential grain oat cultivars for sub-tropical Queensland. The evaluation of these grain oat lines from Brazil may provide an opportunity to re-establish oats as a winter grain crop in central and southern Qld and northern NSW. Two replicated trials were established near Toowoomba in Qld and Grafton in NSW to assess grain yield and agronomic characteristics. These trials showed significant differences in grain yield within the set of Brazilian grain oat lines, compared with the Australian cultivars, showing the potential for selection of higher yielding lines. The Brazilian line coded UFRGS037031-3 was the highest yielding line in both high yielding conditions at Grafton and moisture stressed conditions at Wellcamp, and should be the focus of any further evaluation. The Brazilian grain oat lines have very strong resistance to leaf rust compared with Australian cultivars. Further research is needed to determine the potential demand for grain oats as a feed grain in Queensland and to determine the profitability of grain oats to farmers as an alternative winter cereal.
Proceedings, Volume 36; doi:10.3390/proceedings2019036141
Land-use type is known to affect levels of soil organic carbon (SOC). However, the degree to which SOC is affected by land-use type over the short—(<10-years) and long—(≥10-years) term remains relatively uncertain. Moreover, there is limited data on the distribution of SOC across particulate (POC), humus (HOC) and resistant (ROC) fractions, and the responses of these fractions to land-use. Using mid-infrared spectroscopy (MIR) coupled with partial least squares regression (PLSR) algorithms generated from the Australian Soil Carbon Research Program (SCaRP), soil organic carbon (TOC, POC, HOC and ROC) was estimated across 280 paired samples across Australia’s Northern Grains Regions. Our analysis covered five land-use types: remnant native vegetation, long-term pasture (≥10-years), short-term pasture (<10-years), short-term cropping (<10-years) and long-term cropping (≥10-years). All land-use types except long-term pasture generated significant declines across all SOC fractions compared with native vegetation. Long-term cropping resulted in the greatest declines, with an average decrease of 6.25 g TOC/kg soil relative to native vegetation. Long-term cropping also reduced POC (−0.71 g/kg) and HOC (−3.19 g/kg) below that of short-term cropping. In addition, the ROC fraction responded to land-use type, with native vegetation and long-term pasture maintaining greater ROC compared with other land-use types. The results demonstrate substantial reductions across all SOC fractions with long-term cropping. The ability of long-term pastures to maintain levels of SOC similar to that of native vegetation indicates the importance of limiting soil disturbance and maintaining more continuous living plant cover within cropping systems.