Climate change impacts and potential benefits of drought and heat tolerance in chickpea in South Asia and East Africa

Using CROPGRO-Chickpea model (revised version), we investigated the impacts of climate change on the productivity of chickpea (Cicer arietinum L.) at selected sites in South Asia (Hisar, Indore and Nandhyal in India and Zaloke in Myanmar) and East Africa (Debre Zeit in Ethiopia, Kabete in Kenya and Ukiriguru in Tanzania). We also investigated the potential benefits of incorporating drought and heat tolerance traits in chickpea using the chickpea model and the virtual cultivars approach. As compared to the baseline climate, the climate change by 2050 (including CO₂) increased the yield of chickpea by 17% both at Hisar and Indore, 18% at Zaloke, 25% at Debre Zeit and 18% at Kabete; whereas the yields decreased by 16% at Nandhyal and 7% at Ukiriguru. The yield benefit due to increased CO₂ by 2050 ranged from 7 to 20% across sites as compared to the yields under current atmospheric CO₂ concentration; while the changes in temperature and rainfall had either positive or negative impact on yield at the sites. Yield potential traits (maximum leaf photosynthesis rate, partitioning of daily growth to pods and seed-filling duration each increased by 10%) increased the yield of virtual cultivars up to 12%. Yield benefit due to drought tolerance across sites was up to 22% under both baseline and climate change scenarios. Heat tolerance increased the yield of chickpea up to 9% at Hisar and Indore under baseline climate, and up to 13% at Hisar, Indore, Nandhyal and Ukiriguru under climate change. At other sites (Zaloke, Debre Zeit and Kabete) the incorporation of heat tolerance under climate change had no beneficial effect on yield. Considering varied crop responses to each plant trait across sites, this study was useful in prioritizing the plant traits for location-specific breeding of chickpea cultivars for higher yields under climate change at the selected sites in South Asia and East Africa.     

Nitrogen‐, water‐ and radiation‐use efficiencies affected by sugarcane breeding in Argentina

This study aimed to identify whether and how sugarcane (Saccharum spp.) breeding in Argentina modified nitrogen‐use efficiency (NUE), water‐use efficiency (WUE) and radiation‐use efficiency (RUE). Thirteen varieties were grown in two consecutive seasons. Trends in different traits were estimated by fitting the data to linear or bilinear regression models. There was a linear increase in NUE and WUE with the year of release throughout the 70‐year span, whereas water use was not modified by sugarcane breeding. There was a positive and strong (r > 0.90; P < 0.01) association between NUE and WUE and between sugar yield and NUE or WUE. Although RUE was not modified by sugarcane breeding, the amount of radiation intercepted by the crop increased with the year of release. Modern varieties had a higher maximum interception and needed fewer days to reach maximum interception than old varieties. This study suggests that applying ecophysiological knowledge would be instrumental in sugarcane breeding programmes in order to develop varieties with high resource‐use efficiency and capable to adapt to global climate change.     

沧源蔗区土壤养分现状研究

为了解甘蔗产区土壤养分状况,并根据养分丰缺情况进行合理科学的施肥,最终实现甘蔗高产高糖,对云南省临沧市沧源蔗区采集的185份土壤样品进行养分测定,结果表明：沧源蔗区土壤大部分呈微酸性,53.51%土壤样品的pH在5.5~6.5;有机质含量平均为2.74%;全氮含量极低,75.14%的土壤样品小于0.050%,平均为0.042%;碱解氮含量中等,平均为101.43 mg/kg;全磷含量低,平均为0.082%;有效磷含量低,平均为6.33 mg/kg;全钾含量低,52.97%的土壤样品含量在1.01%~1.50%,平均为1.403%;速效钾含量中等,平均为146.32 mg/kg;微量元素有效锌缺乏,79.75%的含量低于1.5 mg/kg;有效锰、有效铁和有效铜93%以上的土壤样品都高于临界值,铜、铁和锰不缺乏。根据土壤养分分析结果,在沧源蔗区建议有机肥结合速效氮磷钾复合肥施用,有利于甘蔗的高产高糖。     

气候变化对长江中下游稻区水稻产量的影响

选择长江中下游平原作为研究区域,按照政府间气候变化专业委员会(IPCC)排放情景特别报告(SRES)中的A2和B2方案,将基于区域气候模式PRECIS构建的气候变化情景文件与水稻生长模型ORYZA2000结合,模拟基准时段(1961—1990)气候(Baseline)和2021—2050时段A2、B2情景下的水稻产量,分析未来气候变化对长江中下游水稻产量的影响。构建两种影响评估方法,重点分析增温和大气CO2肥效作用对水稻产量的影响。结果表明,不考虑CO2肥效作用时,随着温度升高,水稻生育期缩短,产量下降。A2情景下水稻生育期平均缩短4.5d,产量减少15.2%;B2情景下平均缩短3.4d,产量减少15%。其中,减产达到20%以上的区域集中在安徽中南部、湖北东南部和湖南东部地区。当考虑CO2肥效作用后,A2情景下水稻平均产量减少5.1%,B2情景平均减少5.8%。减产区域缩小且幅度降低,江西和浙江部分地区则呈现一定程度增产,但增幅10%。大气CO2肥效作用一定程度上可提高水稻产量,使晚稻在增温的不利影响下仍呈现不同程度的增产态势,但对单季稻和早稻的增产贡献仍不足以抵消升温的负面影响。另外,大气CO2肥效作用可有利于提高未来气候变化下水稻的稳产性。     

福建省基于自适应调整的水稻生产对未来气候变化的响应

将福建省划分为3 个稻区, 共选取17 个样点和9 个代表性品种开展气候变化影响评价研究。首先, 根据IPCC排放情景特别报告(SRES)中的A2、B2、A1B 三种方案和区域气候模式(PRECIS), 生成了研究区域两个时段(1961-1990 年, 2021-2050 年)的气候变化情景; 然后, 采用经验证的CERES-Rice 模型, 模拟分析了福建省各稻区在未来不同气候变化情景下可能的稻作制度、品种搭配及水稻播期, 并认为这是水稻生产自适应调整后的结果; 接着, 以调整后的稻作制度、品种搭配及水稻播期作为CERES-Rice 模型新的输入, 在3 种气候变化情景下再次进行模拟试验, 最后得出未来经过自适应调整后的水稻产量、稳产性以及全省水稻总产的变化。结果表明: 在A2、B2、A1B 三种气候变化情景下, 闽东南双季稻区的早稻模拟产量经自适应调整后, 较之不考虑这种调整依次提高了15.9%、18.0%和19.2%, 后季稻依次提高了9.2%、7.4%和7.4%; 闽西北双季稻区的早稻模拟产量依次提高了21.2%、20.5%和18.9%, 后季稻依次提高了14.7%、14.8%和7.2%。考虑自适应调整后, 闽西北山地单季稻区的水稻模拟产量在A2、B2、A1B 情景下, 较之不考虑这种调整依次增产4.9%、5.0%和2.9%, 其中长汀在A2 与B2 情景下可改种双季稻。在综合考虑水稻生产自适应调整后, 福建省水稻模拟总产表现为增产, 在A2、B2 与A1B 情景下较之当前依次增加5.9%、5.2%和5.1%。因此,在气候变化影响评价研究中, 将水稻生产的自适应能力考虑在内, 不仅科学合理, 而且可以得到较为乐观的结论。     

Contributions of cultivars,management and climate change to winter wheat yield in the North China Plain in the past three decades

The detailed field experiment data from 1980 to 2009 at four stations in the North China Plain (NCP), together with a crop simulation model, were used to disentangle the relative contributions of cultivars renewal, fertilization management and climate change to winter wheat yield, as well as the relative impacts of different climate variables on winter wheat yield, in the past three decades. We found that during 1980–2009 cultivars renewal contributed to yield increase by 12.2–22.6%; fertilization management contributed to yield increase by 2.1–3.6%; and climate change contributed to yield generally by −3.0–3.0%, however by −15.0% for rainfed wheat in southern part of the NCP. Modern cultivars and agronomic management played dominant roles in yield increase in the past three decades, nevertheless the estimated impacts of climate change on yield accounted for as large as −23.8–25.0% of observed yield trends. During the study period, increase in temperature increased winter wheat yield by 3.0–6.0% in northern part of the NCP, however reduced rainfed winter wheat yield by 9.0–12.0% in southern part of the NCP. Decrease in solar radiation reduced wheat yield by 3.0–12.0% across the stations. The impact of precipitation change on winter wheat yield was slight because there were no pronounced trends in precipitation. Our findings highlight that modern cultivars and agronomic management contributed dominantly to yield increase in the past three decades, nevertheless the impacts of climate change were large enough in some areas to affect a significant portion of observed yield trends in the NCP.     

Response of Mung Bean (Vigna radiata (L.) R. Wilczek) to an Increasing Natural Temperature Gradient under Different Crop Management Systems

Increasing temperatures pose a significant threat to crop production in the tropics. A field experiment was conducted with mung bean at three locations in Sri Lanka representing an increasing temperature gradient (24.4–30.1 °C) during two consecutive seasons to (i) determine the response of mung bean to increasing temperature and (ii) test a selected set of crop management practices aimed at decreasing essential inputs such as water, synthetic pesticides and inorganic nitrogen fertilizer. The control treatment (T₁) consisted of standard crop management including irrigation, chemical crop protection and inorganic fertilizer application. Adaptation system 1 (T₂) included mulching with rice straw at 8 t ha^?1 with 30 % less irrigation and crop protection and nutrient management as in T₁. Adaptation system 2 (T₃) included crop protection using a pretested integrated pest management package with water and nutrient management as in T₂. In adaptation system 3 (T₄), 25 % of the crop's nitrogen requirement was given as organic manure (compost) at 0.8 t ha^?1 while 75 % was given as inorganic fertilizer with water management and crop protection as in T₃. Durations of both pre‐ and post‐flowering phases were reduced with increasing temperature. In the warmer (25.4–30.1 °C) yala season, seed yield (Y) of T₁ decreased with increasing temperature at 366 kg ha^?1 °C^?1. However, in maha season, Y did not show a significant relationship across the narrower temperature gradient from 24.4 to 25.8 °C. Pooling the data from both seasons showed a second‐order polynomial response with an optimum temperature of 26.5 °C. In addition to shortened durations, reduced crop growth rates and reduced pod numbers per plant were responsible for yield reductions at higher temperatures. In yala, yields of all adaptation systems at all locations were on par with yields of the respective controls. Furthermore, yala yields of T₂ and T₃ were less sensitive than T₁ to increasing temperatures (265 and 288 kg ha^?1 °C^?1). In maha, T₃ and T₄ had greater yields than the control at the relatively cooler site while having lower yields than the control at the warmer site. Maha yields of T₂ were on par with the control at both temperature regimes. While demonstrating the significant temperature sensitivity of mung bean yields, results of the present work showed that components of the tested adaptation systems could be promoted among smallholder farmers in Asia, especially in view of their long‐term environmental benefits and contributions to sustainable agriculture in a warmer and drier future climate.     

Global warming likely reduces crop yield and water availability of the dryland cropping systems in the U.S. Central Great Plains

We investigated the impact of GCM-projected climate change on dryland crop rotations of wheat-fallow and wheat-corn-fallow in the Central Great Plains (Akron in Colorado, USA) using the CERES 4.0 crop modules in RZWQM2. The climate change scenarios for CO₂, temperature, and precipitation were produced by 22 GCM projections for Colorado based on the A1B scenario. The climate change for years 2050 and 2075 was super-imposed on measured 30-year-baseline climate data (1989–2008). For all the cropping rotations and projection years, simulated yields of wheat and corn decreased significantly (P < 0.05) with increasing temperatures. The yield declines due to the elevated temperatures should be attributable to the shortening of crop maturity duration and concurrent decreases in soil water and evapotranspiration. The model was also projected to decrease crop yields for the combined climate change scenarios of CO₂, temperature, and precipitation in the dryland cropping rotations.     

Potassium and Silicon Improve Yield and Juice Quality in Sugarcane (Saccharum officinarum L.) under Salt Stress

Soil salinity is a major abiotic stress which adversely affects the yield and juice quality in sugarcane. However, the mineral nutrient status of plant plays a crucial role in increasing plant tolerance to salinity. We investigated the effects of K and/or Si on plant growth, yield and juice quality in two sugarcane genotypes differing in salinity tolerance. Addition of K and Si significantly (P ≤ 0.05) increased K and Si concentrations and decreased the accumulation of Na⁺ in plants under salt stress. Cane yield and yield attributes were significantly (P ≤ 0.05) higher where K and Si were added. Juice quality characteristics like Brix (% soluble solids in juice), Pol (% sucrose in juice), commercial cane sugar (CCS) and sugar recovery in both sugarcane genotypes were also significantly (P ≤ 0.05) improved with the supplementation of K and Si. For most of the growth parameters, it was found that K either alone or in combination with Si was more effective to alleviate salt stress in both sugarcane genotypes than Si alone. Moreover, the beneficial effects of K and Si were more pronounced in salt sensitive genotype than in salt tolerant genotype. The results suggested that K and Si counteracted the deleterious effects of high salinity/sodicity in sugarcane by lowering the accumulation of Na⁺ and increase in K⁺ concentration with a resultant improvement in K⁺/Na⁺ ratio which is a good indicator to assess plant tolerance to salinity.     

Effect of Formative Phase Drought on Different Classes of Shoots, Shoot Mortality, Cane Attributes, Yield and Quality of Four Sugarcane Cultivars

Field experiments were conducted at Coimbatore, India to study the effect of three levels of drought (severe, moderate and no drought) during the formative phase (60–150 days after planting; DAP) of sugarcane on the tillering, the conversion of shoots to millable canes, cane attributes and the quality of different classes of shoots in four sugarcane cultivars (Co 8021, Co 419, Co 8208 and Co 6304)_the different classes of shoots studied were: mother shoots (which emerged 0–30 DAP), early tillers (30–60 DAP), mid‐season tillers (60–150 DAP) and late tillers (150 DAP). The results indicated that drought during the formative phase reduced the total number of shoots and their conversion to millable canes at harvest. Drought also reduced the cane length, number of inter‐nodes and single cane weight of different classes of shootsand the subsequent total cane yield. Irrespective of drought treatments, Co 8021, a high‐tillering, thick‐stalked cultivar, gave the highest cane yield despiteits higher shoot mortality, while Co 8208, a low‐tillering, thin‐stalked cultivar, gave the lowest cane yield despite its lower shoot mortality. Thus a moderate level of shoot mortality is clearly necessary to obtain higher millable canes and subsequently higher cane yield. Mother shoots and early tillers together contributed most of the total number of millable canes (84.5 %) and of the total cane yield at harvest (86.2 %). The contribution of late tillers to the number of millable canes and cane yield was, however, negligible, especially in cultivars Co 6304 and Co 8208. There was a gradual reduction in stalk attributes such as cane length, number of internodes, single cane weight and commercial cane sugar percentage as the physiological age of shoots decreased. This study emphasizes the need for a cultivar with the optimal characteristics of early tillering (like Co 8021 and Co 6304) and maximum conversion to millable canes (like Co 8208) and provides information relevant to breeders making decisions on crossing programmes to produce improved cultivars for drought conditions.     

Adaptation to climate change and climate variability in European agriculture: The importance of farm level responses

Climatic conditions and hence climate change influence agriculture. Most studies that addressed the vulnerability of agriculture to climate change have focused on potential impacts without considering adaptation. When adaptation strategies are considered, socio-economic conditions and farm management are often ignored, but these strongly influence current farm performance and are likely to also influence adaptation to future changes. This study analysed the adaptation of farmers and regions in the European Union to prevailing climatic conditions, climate change and climate variability in the last decades (1990–2003) in the context of other conditions and changes. We compared (1) responses in crop yields with responses in farmers’ income, (2) responses to spatial climate variability with responses to temporal climate variability, (3) farm level responses with regional level responses and (4) potential climate impacts (based on crop models) with actual climate impacts (based on farm accountancy data). Results indicated that impacts on crop yields cannot directly be translated to impacts on farmers’ income, as farmers adapt by changing crop rotations and inputs. Secondly, the impacts of climatic conditions on spatial variability in crop yields and farmers’ income, with generally lower yields in warmer climates, is different from the impacts of temporal variability in climate, for which more heterogeneous patterns are observed across regions in Europe. Thirdly, actual impacts of climate change and variability are largely dependent on farm characteristics (e.g. intensity, size, land use), which influence management and adaptation. To accurately understand impacts and adaptation, assessments should consider responses at different levels of organization. As different farm types adapt differently, a larger diversity in farm types reduces impacts of climate variability at regional level, but certain farm types may still be vulnerable. Lastly, we observed that management and adaptation can largely reduce the potential impacts of climate change and climate variability on crop yields and farmers’ income. We conclude that for reliable projections of the impacts of climate change on agriculture, adaptation should not be seen anymore as a last step in a vulnerability assessment, but as integrated part of the models used to simulate crop yields, farmers’ income and other indicators related to agricultural performance.     

Fijian adolescents’ understanding and evaluation of climate change: Implications for enabling effective future adaptation

Pacific Island countries are particularly vulnerable to future manifestations of climate change due to high coastline‐to‐land‐area ratios, and high dependence of inhabitants on natural ecosystems. While everyone in the Pacific Islands should participate in climate change adaptation activities, it is the young people, given they are the generation likely to not only bear the burden of climate change, but to lead and live effective climate change adaptation activities and strategies specific to their region, the involvement of youth is critical. Pacific Island youths are often marginalised within traditional decision‐making hierarchies, therefore they are typically excluded from participating in meaningful discussions at community and government levels. Discussions were held with 30 adolescents aged 14–18 years in Fiji to explore knowledge and experiences regarding climate change. Participants revealed their dismay at their inability to talk to family – who they consider are not doing enough – about what they consider as appropriate responses to climate change, recommending the help of an authoritative outsider who could speak to their community leaders and family. Discussions also revealed that Fijian youth could not distinguish between changes in the climate and normal weather events, attesting to the importance of climate‐change education and awareness‐raising efforts within the Pacific Islands more generally.     

Cropping System Affects Polymer‐Coated Urea Release and Corn Yield Response in Claypan Soils

Preplant‐applied, urea‐based fertilizer management in high‐residue, no‐till (NT) corn (Zea mays L.) is challenging because of potential N loss due to cool, wet conditions in the spring and dry conditions during the summer months. Field research evaluated the effects of polymer‐coated urea (PCU) application timing, placement and cropping system on urea release for corn and determined corn yield response to PCU on claypan soils following wheat (Triticum aestivum L.) cropping systems [reduced‐till corn following wheat, no‐till corn following wheat with double‐cropped (DC) soybean [Glycine max (L.) Merr.] and no‐till corn following wheat with a frost‐seeded red clover (FSC) (Trifolium pratense L.) cover crop]. Urea release from PCU was <35 % from fall through winter (November–January) and <20 % for early preplant (February–March) applications until 1 April. By 1 August, less urea was released in some instances from surface applications of PCU following FSC or DC soybean, but release was generally greater than in the absence of soil. No‐till corn following DC soybean or FSC had yields that were 1.01–1.32 Mg ha^?1 greater when grown with PCU compared to urea at 168 kg N ha^?1. Grain yields were similar within no‐till cropping systems with PCU, anhydrous ammonia and sidedressed urea ammonium nitrate (UAN) at 168 kg N ha^?1. Farmers should recognize that high yields may not be obtained if PCU rates are reduced by 50 % (84 kg N ha^?1) in high‐residue (DC soybean or FSC), no‐till production systems. Several N sources such as PCU, anhydrous ammonia and sidedressed UAN worked similarly in high‐residue, no‐till systems, although no differences between N sources were observed in a reduced‐tillage system.     

Combined impacts of climate and nutrient fertilization on yields of pearl millet in Niger

Effects of climate variability and change on yields of pearl millet have frequently been evaluated but yield responses to combined changes in crop management and climate are not well understood. The objectives of this study were to determine the combined effects of nutrient fertilization management and climatic variability on yield of pearl millet in the Republic of Niger. Considered fertilization treatments refer to (i) no fertilization and the use of (ii) crop residues, (iii) mineral fertilizer and (iv) a combination of both. A crop simulation model (DSSAT 4.5) was evaluated by using data from field experiments reported in the literature and applied to estimate pearl millet yields for two historical periods and under projected climate change. Combination of crop residues and mineral fertilizer resulted in higher pearl millet yields compared to sole application of crop residues or fertilizer. Pearl millet yields showed a strong response to mean temperature under all fertilization practices except the combined treatment in which yields showed higher correlation to precipitation. The crop model reproduced reported yields well including the detected sensitivity of crop yields to mean temperature, but underestimated the response of yields to precipitation for the treatments in which crop residues were applied. The crop model simulated yield declines due to projected climate change by −11 to −62% depending on the scenario and time period. Future crop yields in the combined crop residues + fertilizer treatment were still larger than crop yields in the control treatment with baseline climate, underlining the importance of crop management for climate change adaptation. We conclude that nutrient fertilization and other crop yield limiting factors need to be considered when analyzing and assessing the impact of climate variability and change on crop yields.     

Radiation‐Use Efficiency,Biomass Production,and Grain Yield in Two Maize Hybrids Differing in Drought Tolerance

Drought‐tolerant (DT) maize (Zea mays L.) hybrids have potential to increase yield under drought conditions. However, little information is known about the physiological determinations of yield in DT hybrids. Our objective was to assess radiation‐use efficiency (RUE), biomass production, and yield in two hybrids differing in drought tolerance. Field experiments were conducted in 2013 and 2014 with two hybrids, P1151HR (DT hybrid) and 33D49 (conventional hybrid) under well‐watered (I₁₀₀) and drought (I₅₀) conditions. I₁₀₀ and I₅₀ refer to 100 % and 50 % evapotranspiration requirement, respectively. On average, P1151HR yielded 11–27 % greater than 33D49 at I₁₀₀ and about 40 % greater at I₅₀, At I₁₀₀, greater yield in P1151HR was due to greater biomass at physiological maturity (BM_pm) resulting from greater post‐silking biomass accumulation (BM_post). At I₅₀, both hybrids had similar BM_pm but P1151HR showed a higher harvest index and greater BM_post. RUE differed significantly (P < 0.05) between the hybrids at I₁₀₀, but not at I₅₀. At I₁₀₀, the RUE values for P1151HR and 33D49 were 4.87 and 4.28 g MJ^?1 in 2013, and 3.71 and 3.48 g MJ^?1 in 2014. At I₅₀, the mean RUE was 3.89 g MJ^?1 in 2013 and 3.16 g MJ^?1 in 2014. Results indicate that BM_post is important for maintaining high yield in DT maize.     

Drought Tolerance and Water‐Use Efficiency of Biogas Crops: A Comparison of Cup Plant,Maize and Lucerne‐Grass

The cup plant (Silphium perfoliatum L.) is discussed as an alternative energy crop for biogas production in Germany due to its ecological benefits over continuously grown maize. Moreover, a certain drought tolerance is assumed because of its intensive root growth and the dew water collection by the leaf cups, formed by fused leaf pairs. Therefore, the aim of this study was to estimate evapotranspiration (ET ), water‐use efficiency (WUE ) and the relevance of the leaf cups for the cup plant's water balance in a 2‐year field experiment. Parallel investigations were conducted for the two reference crops maize (high WUE ) and lucerne‐grass (deep and intensive rooting) under rainfed and irrigated conditions. Root system performance was assessed by measuring water depletion at various soil depths. Transpiration‐use efficiency (TUE ) was estimated using a model approach. Averaged over the 2 years, drought‐related above‐ground dry matter reduction was higher for the cup plant (33 %) than for the maize (18 %) and lucerne‐grass (14 %). The WUE of the cup plant (33 kg ha^?1 mm^?1) was significantly lower than for maize (50 kg ha^?1 mm^?1). The cup plant had a lower water uptake capacity than lucerne‐grass. Cup plant dry matter yields as high as those of maize will only be attainable at sites that are well supplied with water, be it through a large soil water reserve, groundwater connection, high rainfall or supplemental irrigation.     

Physiological and Growth Responses of Sugarcane Genotypes to Nitrogen Rate on a Sand Soil

Yields of sugarcane (a complex hybrid of Saccharum spp.) in FL, USA, are lower on sand soils than on organic (muck) soils. Nitrogen (N) supply may limit sugarcane growth and yields on these sand soils. A 2‐year pot study was conducted to determine sugarcane genotypic variation in response to N rate on a sand soil. Treatments included four N rates (0, 75, 150 and 225 kg ha^?1) and three sugarcane genotypes (CP 80‐1743, CP 01‐2390 and TCP 87‐3388). Nitrogen fertilizer was equally split and applied at about 55 and 125 days after planting (DAP) for each treatment. During the experiment, the number of nodes and length of the primary stalks and tillers were recorded. Leaf relative chlorophyll (soil plant analysis development (SPAD)) and net photosynthetic rate (Pn) were measured biweekly. All plants were harvested at 183 DAP to measure green leaf area (GLA), shoot biomass accumulation and partitioning, and fertilizer N use efficiency (NUE). Genotypes differed significantly in leaf SPAD, Pn, GLA, and shoot biomass accumulation and partitioning. CP 01‐2390 had the highest leaf Pn and shoot biomass, and CP 80‐1743 had the lowest GLA, shoot biomass and NUE among genotypes. Nitrogen rate affected leaf SPAD, GLA, shoot biomass and NUE, but had much less effect on leaf Pn. Green leaf area and biomass increased with increasing N rates. Our results suggest that a two‐pronged approach, selection of genotypes with high NUE while working to optimize N rates and delivery can improve sugarcane yields on sand soils.     

2013—2014年广西甘蔗品种区域试验总结

为改善广西蔗区甘蔗品种结构单一化局面,加速品种的更新换代。对广西甘蔗新品种在2013—2014年区域试验中的产量、蔗糖分的稳定性和适应性以及农艺性状等表现进行分析和评价,筛选出综合性状表现优良的甘蔗新品种推荐审定和充实蔗区。2年新植1年宿根的试验结果表明,12个参试材料中,‘GT06-244’、‘GT06-1721’、‘GT07-994’、‘LC05-136’和‘GT06-3283’综合表现较好,平均蔗茎产量比对照增产20.20%、10.59%、8.94%、3.15%和1.60%,平均蔗糖分比对照分别高0.16、0.17、0.46、0.93和0.36个百分点。‘GT06-244’表现高产、中糖,稳定性好,极易脱叶;‘GT06-1721’表现高产、中糖,抗病性好,抗倒性强;‘GT07-994’和‘LC05-136’表现早熟、高产、高糖,宿根性好;‘GT06-3283’表现中产、高糖。上述品种均达到广西糖料蔗推荐审定标准,可根据生产的需要,在适宜地区进一步示范种植和推广应用。     

气象因素对甘蔗生产的影响及环境互作基因研究进展

甘蔗产量与蔗区的自然条件、生产条件、耕作制度、栽培管理技术措施和品种特性有密切关系,而与气象因素也息息相关。降雨量对甘蔗伸长期,成熟期有关键影响,与产量有正相关关系,挖掘利用不同作物的抗旱基因,可以提高甘蔗抗旱能力。大气相对湿度、温度、光照是影响甘蔗伸长、糖分累积和单产的重要因素。甘蔗的产量和含糖量受干旱、台风、洪涝灾害、低温高湿等气候因子的影响。本研究通过分析蔗区降水量、湿度、日照等气象因素对甘蔗产量的影响,结合甘蔗抗逆基因的研究进展,提出发展分子标记用于辅助选择甘蔗育种,研究不同灾害性天气对甘蔗产量性状之间的影响,对于甘蔗的生产有着指导性意义和巨大的经济意义。     

气候变化对我国小麦产量的影响

本研究采用英国Hadley中心的区域气候情景PRECIS (Providing Regional Climate for Impacts Study),结合校正的CERES-Wheat 模型,对21世纪70年代（2070s）气候变化情景下我国小麦的产量变化进行了研究。结果表明,在PRECIS预测的2070s气候变化条件下,我国雨养小麦和灌溉小麦的平均单产较基准年（1961－1990平均值）约减少20%,其中雨养小麦的减产幅度略高于灌溉小麦,春小麦或春性较强的冬小麦减产明显,减产的区域主要集中在东北春麦区和西南冬麦区。