Increasing global agricultural production by reducing ozone damages via methane emission controls and ozone‐resistant cultivar selection

Meeting the projected 50% increase in global grain demand by 2030 without further environmental degradation poses a major challenge for agricultural production. Because surface ozone (O₃) has a significant negative impact on crop yields, one way to increase future production is to reduce O₃‐induced agricultural losses. We present two strategies whereby O₃ damage to crops may be reduced. We first examine the potential benefits of an O₃ mitigation strategy motivated by climate change goals: gradual emission reductions of methane (CH₄), an important greenhouse gas and tropospheric O₃ precursor that has not yet been targeted for O₃ pollution abatement. Our second strategy focuses on adapting crops to O₃ exposure by selecting cultivars with demonstrated O₃ resistance. We find that the CH₄ reductions considered would increase global production of soybean, maize, and wheat by 23–102 Mt in 2030 – the equivalent of a ~2–8% increase in year 2000 production worth $3.5–15 billion worldwide (USD₂₀₀₀), increasing the cost effectiveness of this CH₄ mitigation policy. Choosing crop varieties with O₃ resistance (relative to median‐sensitivity cultivars) could improve global agricultural production in 2030 by over 140 Mt, the equivalent of a 12% increase in 2000 production worth ~$22 billion. Benefits are dominated by improvements for wheat in South Asia, where O₃‐induced crop losses would otherwise be severe. Combining the two strategies generates benefits that are less than fully additive, given the nature of O₃ effects on crops. Our results demonstrate the significant potential to sustainably improve global agricultural production by decreasing O₃‐induced reductions in crop yields.     

Management of the late blight (Phytophthora infestans) disease of potato in the southern hills of India

Late blight of potato is considered to be the most devastating problem causing severe yield losses in potato worldwide. Among the different management strategies, the use of resistant cultivars is the most viable option, but the non‐availability of enough quantity of quality seed materials of resistant cultivars forces the farmers to grow susceptible cultivars with proper fungicide scheduling. Therefore, in the present study, chemical control using fungicide has been attempted with newer molecules in the susceptible cultivar along with a resistant cultivar as a positive control. All the tested fungicides were found safe, and no phytotoxicity was observed with any chemical at the applied rate. In resistant cultivar, no late blight was appeared in both the years, whereas maximum AUDPC was observed in the untreated control (276.3) and minimum (41.7) in mancozeb‐cymoxanil + mancozeb based scheduling which was found on par with chlorothalonil‐famoxadone + cymoxanil (51.3) and chlorothalonil‐ametoctradin + dimethomorph (53.5) based scheduling. Among the treatments, resistant cultivar, Kufri Girdhari followed by chlorothalonil‐ametoctradin + dimethomorph and mancozeb‐cymoxanil + mancozeb based fungicidal scheduling were proven as the best treatments for both the crop seasons resulting in the highest yield parameters. The disease severity showed a strong negative correlation with the tuber yield of potatoes in both the years. Based on overall observations including BC ratio, it can be concluded that, wherever seed material of resistant cultivar is available farmers should grow the same or else with susceptible cultivars the fungicidal scheduling based on mancozeb‐cymoxanil + mancozeb or chlorothalonil‐ametoctradin + dimethomorph can be followed to obtain the maximum returns with effective management of late blight at the southern hills of India.     

Effects of elevated ozone concentration on yield of four Chinese cultivars of winter wheat under fully open‐air field conditions

Four modern cultivars of winter wheat (Triticum aestivum L.) were grown under elevated ozone concentration (E‐O₃) in fully open‐air field conditions in China for three consecutive growth seasons from 2007 to 2009. Results indicated that a mean 25% enhancement above the ambient ozone concentration (A‐O₃, 45.7 p.p.b.) significantly reduced the grain yield by 20% with significant variation in the range from 10% to 35% among the combinations of cultivar and season. The varietal difference in the yield response to E‐O₃ became nonsignificant when the anova was done by omitting one cultivar which showed unstable response to E‐O₃ among the seasons. The reduction of individual grain mass accounted mostly for the yield loss by E‐O₃, and showed significant difference between the cultivars. The response of relative yield to E‐O₃ was not significantly different from those reported in China, Europe and India on the basis of experiments in open‐top chambers. Our results thus confirmed the rising threat of surface O₃ on wheat production worldwide in the near future. Various countermeasures are urgently needed against the crop losses due to O₃ such as mitigation of the increase in surface O₃ with stricter pollution control, and enhancement of the wheat tolerance against O₃ by breeding and management.     

梨品种资源果实轮纹病抗性的评价

采用田间人工接种的方法,2009-2010年连续两年对保存于国家梨种质资源更新圃的182个品种进行果实轮纹病抗性评价。结果表明：砂梨、白梨、秋子梨、种间杂交梨、西洋梨和新疆梨的两年平均发病率分别为6.15%、7.20%、7.43%、12.66%、17.00%、18.93%,梨品种间对轮纹病抗性存在差异,不同条件下多数品种轮纹病发病率有差异。依据两年平均发病率进行抗性评价分级,72个品种为高抗、63个品种为抗、25个品种为中抗、14个品种为低抗、8个品种为不抗。     

13. Lake Saloio (Nazaré, western Portugal)

The possible impact of altitude and the related microclimatic conditions on the total production of fruiting branches, inflorescences, flowers and pollen grains of olive trees Olea europaea was analysed. A total of 90 Picual cultivar trees, the most extensive olive cultivar in the Iberian Peninsula, were studied for a three-year period (2007–2009). The study shows that production of flowers and pollen grains in a cultivar of the olive tree varies according to the microclimate. Our study also indicates that the olive trees frequently can have up to half a million flowers per tree. Moreover, the total flower production differs between years and study areas. In the Picual cultivar, the average production of pollen grains per anther is usually more than 60?000 grains. The total production of pollen per tree is around 72?000 million on average. The most favourable microclimatic conditions for reproduction in olive trees are found in years and olive growing areas with low temperature and high precipitation records during the months prior to flowering of the olive trees. We hypothesise that olive trees tend to increase their pollen production rate as altitude increases, which can be interpreted as a reproductive strategy to ensure fertilisation.     

Stripe rust analysis of D-genome synthetic wheats (2n = 6x = 42, AABBDD) and their molecular diversity

Stripe or yellow rust caused by Puccinia striiformis f. sp. tritici is a threat to many of the existing cultivars of Pakistan. Many attempts are being made to evolve new varieties resistant to stripe rust to reduce the losses caused by this disease. For this purpose, novel genes are needed to incorporate into the existing cultivars. These genes are found in the wild progenitors of wheat that are D-genome donors to wheat. As a result of extensive research, wheat synthetic hexaploids have been developed. These synthetics have resistances against biotic as well as abiotic stresses including the yellow rust. A group of such synthetics has been identified which seems resistant to this destructive disease. This group was tested under field conditions to identify resistance against stripe rust. The same population was analysed at molecular level to explore the genetic diversity for rust resistance. Genetic diversity among 34 selected synthetic hexaploid wheats was studied by random amplified polymorphic DNA (RAPD) analysis. A set of 12 RAPD primers was applied, and the level of polymorphism was found to be 46.67%. The coefficients in the range of 71–100% were detected by genetic similarity matrix based on Nei and Li's index. These coefficients were used for constructing a dendrogram using unweighted pair group of arithmetic means. Synthetic hexaploid line 34 was found to exhibit maximum genetic distances among the 34 selected lines. The same accession also showed excellent phenotypic characters with above average grain weight. These synthetic hexaploids carrying genetic potential for stripe rust resistance and morphological traits should be useful for improvement of existing wheat cultivars.     

The GmCLC1 protein from soybean functions as a chloride ion transporter

Soil salinization is a global issue that hampers agricultural production. Chloride is one of the prominent anions on saline land that cause toxicity to the plant. We previously identified the GmCLC1 gene from soybean (Glycine max) that encodes a putative tonoplast-localized chloride transporter. In this study, using electrophysiological analysis, we demonstrated the chloride transport function of GmCLC1. Interestingly, this chloride transport activity is pH dependent, suggesting that GmCLC1 is probably a chloride/proton antiporter. When the cDNA of GmCLC1 was expressed in tobacco BY-2 cells under the control of a constitutive promoter, the protective effect against salinity stress in transgenic tobacco BY-2 cells was also found to be pH sensitive. In the native host soybean, the expression of GmCLC1 gene is regulated by pH. All these findings support the notion that the function of GmCLC1 is regulated by pH.     

Unexpected hybridization reveals the utility of genetics in native plant restoration

Native plant materials (NPMs) are increasingly utilized during the restoration of disturbed plant communities. Here, we analyze next‐generation genetic sequencing data for Hilaria jamesii, a dominant graminoid across drylands of the southwestern United States, and document that the species' only commercially‐available NPM, “Viva,” is a hybrid between H. jamesii and its sister species, Hilaria mutica. In fact, hybrids between these species are common where they geographically overlap. Furthermore, we show that the “Viva” hybrid has successfully been moved beyond the hybrid zone and into the core range of H. jamesii. The potential ramifications of introducing novel genetic material into H. jamesii are discussed, as well as the utility of genetic analyses to protect species' natural patterns of genetic diversity and help managers make informed decisions regarding the development and deployment of NPMs.     

Effect of perennial ryegrass (Lolium perenne L.) cultivars on the milk yield of grazing dairy cows

The objective of this experiment was to investigate the effect of four perennial ryegrass cultivars: Bealey, Astonenergy, Spelga and AberMagic on the milk yield and milk composition of grazing dairy cows. Two 4 × 4 latin square experiments were completed, one during the reproductive and the other during the vegetative growth phase of the cultivars. Thirty-two Holstein–Friesian dairy cows were divided into four groups, with each group assigned 17 days on each cultivar during both experiments. Within each observation period, milk yield and milk composition, sward morphology and pasture chemical composition were measured. During the reproductive growth phase, organic matter digestibility (OMD) was greater for Bealey and Astonenergy (P < 0.001; +1.6%). AberMagic contained a higher stem proportion (P < 0.01; +0.06) and a longer sheath height (P < 0.001; +1.9 cm). Consequently, cows grazing AberMagic recorded a lower milk yield (P < 0.001; −1.5 kg/day) and a lower milk solids yield (P < 0.001; −0.13 kg/day). During the vegetative growth phase, OMD was greater (P < 0.001; +1.1%) for Bealey, whereas the differences between the cultivars in terms of sward structure were smaller and did not appear to influence animal performance. As a result, cows grazing Bealey recorded a higher milk yield (P < 0.001; +0.9 kg/day) and a higher milk solids yield (P < 0.01; +0.08 kg/day). It was concluded that grass cultivar did influence milk yield due to variations in sward structure and chemical composition.