Dry matter production and panicle characteristics of high yield and good taste indica hybrid rice varieties

Indica hybrid rice (Oryza sativa) production aims to achieve two crucial targets: high yield and good taste. This study selected three types of indica hybrid rice according to grain yield and taste value, including high yield and good taste (HYGT), low yield and good taste (LYGT), and high yield and poor taste (HYPT), to analyze yield components, corresponding growth characteristics, and rice taste quality. When values were averaged across varieties and years, there were almost no differences in taste value between HYGT and LYGT; HYGT showed a significant increase in yield, owing to a higher number of panicles and spikelets per panicle, with a respective increment of 16.2 and 20.6%. The higher grain yield of HYGT compared with LYGT was attributed to three key factors: a higher leaf area index (LAI) during heading, a higher ratio of grain to leaf, and a higher biomass accumulation at maturity. HYGT and HYPT achieved similar high yields; however, HYGT had more panicle numbers and lower grain weight. In addition, HYGT showed a significantly higher taste value than HYPT, attributed to its significantly lower protein and amylose contents, with reductions of 8.8 and 15.7%, respectively. Lower protein and amylose contents might be caused by a proper matter translocation from vegetative organs to panicle. This study suggested that reasonable panicle characteristics and translocation efficiency from vegetative organs to panicle during heading to maturity are the key factors in balancing yield and rice taste quality. These results will provide valuable insights for rice breeders to improve the grain yield and quality of indica hybrid rice.     

Decreased panicle N application alleviates the negative effects of shading on rice grain yield and grain quality

Light deficiency is a growing abiotic stress in rice production. However, few studies focus on shading effects on grain yield and quality of rice in East China. It is also essential to investigate proper nitrogen (N) application strategies that can effectively alleviate the negative impacts of light deficiency on grain yield and quality in rice. A two-year field experiment was conducted to explore the effects of shading (non-shading and shading from heading to maturity) and panicle N application (N_DP, decreased panicle N rate; N_MP, medium panicle N rate; N_IP, increased panicle N rate) treatments on rice yield- and quality-related characteristics. Compared with non-shading, shading resulted in a 9.5–14.8% yield loss (P<0.05), mainly due to lower filled-grain percentage and grain weight. N_MP and N_IP had higher (P<0.05) grain yield than N_DP under non-shading, and no significant difference was observed in rice grain yield among N_DP, N_MP, and N_IP under shading. Compared with N_MP and N_IP, N_DP achieved less yield loss under shading because of the increased filled-grain percentage and grain weight. Shading reduced leaf photosynthetic rate after heading, as well as shoot biomass weight at maturity, shoot biomass accumulation from heading to maturity, and nonstructural carbohydrate (NSC) content in the stem at maturity (P<0.05). The harvest index and NSC remobilization reserve of N_DP were increased under shading. Shading decreased (P<0.05) percentages of brown rice, milled rice, head rice, and amylose content while increasing (P<0.05) chalky rice percentage, chalky area, chalky degree, and grain protein. N_MP demonstrated a better milling quality under non-shading, while N_DP demonstrated under shading. N_DP exhibited both lower chalky rice percentage, chalky area, and chalky degree under non-shading and shading, compared with N_MP and N_IP. N_DP under shading decreased amylose content and breakdown but increased grain protein content and setback, contributing to similar overall palatability to non-shading. Our results suggested severe grain yield and quality penalty of rice when subjected to shading after heading. N_DP improved NSC remobilization, harvest index, and sink-filling efficiency and alleviated yield loss under shading. Besides, N_DP would maintain rice’s milling, appearance, and cooking and eating qualities under shading. Proper N management with a decreased panicle N rate could be adopted to mitigate the negative effects of shading on rice grain yield and quality.     

Comparative analysis on grain quality and yield of different panicle weight indica-japonica hybrid rice(Oryza sativa L.) cultivars

Indica-japonica hybrid rice(Oryza sativa L.) cultivars showed high yield potential and poor tasting quality when compared with common japonica rice cultivars. Large panicle is a prominent factor of high yield for indica-japonica hybrid rice cultivars, and the panicle weight varies greatly among different indica-japonica hybrid rice cultivars. It is important to research on yield and grain quality of different panicle weight indica-japonica hybrid rice cultivars. In this study, two different panicle types indica-japonica hybrid cultivars were used to research on the relation of yield and grain quality. The yields of two heavy panicle weights indica-japonica hybrid cultivars were significantly higher than that of two medium panicle weight rice cultivars. The cooking and eating quality and starch properties of different panicle type cultivars were evaluated. Yongyou 6715(medium panicle) and Yongyou 1852(heavy panicle) got the relatively higher cooking and eating quality. Rice cultivars with medium panicle weight had more large starch granules and higher relative crystallinity than cultivars with heavy panicle weight. Transition temperature and retrogradation enthalpy(ΔHret) of medium panicle type cultivars were significantly higher than that of heavy panicle type cultivars. There was no significant difference in amylose content among different panicle type cultivars. Protein content of heavy panicle type cultivar was higher than that of medium panicle type cultivar, and protein content is the main factor affect cooking and eating quality in this study. The cultivar Yongyou 6715 got the highest taste value with the lowest protein content. Thus, it is suggested that the emphasis on improving rice cooking and eating quality of indica-japonica hybrid rice cultivars is how to reduce the protein content in rice grain. According to the results of this study, medium panicle type with high grain weight is the desired panicle type for high quality indica-japonica hybrid rice breeding.     

Effect of wide-narrow row arrangement in mechanical pot-seedling transplanting and plant density on yield formation and grain quality of japonica rice

Mechanical pot-seedling transplanting is an innovatively developed transplanting method that has the potential to replace mechanical carpet-seedling transplanting. However, the initial pot-seedling transplanting machine lacked optimized density spacing and limited yield potential for japonica rice. Therefore, ascertaining the optimized density by wide-narrow rows and the appropriate transplanting method for yield formation and grain quality of japonica rice is of great importance for high-quality rice production. Field experiments were conducted using two japonica rice cultivars Nanjing 9108 and Nanjing 5055 under three transplanting methods in 2016 and 2017: mechanical pot-seedling transplanting with wide-narrow row(K, average row spacing of 30 cm); equidistant row(D, 33 cm×12 cm); and mechanical carpet-seedling transplanting(T, 30 cm×12.4 cm). In addition, five different density treatments were set in K(K1–K5, from 18.62×10~4 to 28.49×10~4 hills ha~(–1)). The results showed that the highest yield was produced by a planting density of 26.88×104 hills ha~(–1) in mechanical pot-seedling transplanting with wide-narrow row with a greater number of total spikelets that resulted from significantly more panicles per area and slightly more grain number per panicle, as compared with equidistant row, and yield among density in wide-narrow row showed a parabolic trend. Compared with mechanical carpet-seedling transplanting, the treatment of the highest yield increased yield significantly, which was mainly attributed to the larger sink size with improved filled-grain percentage and grain weight, higher harvest index, and increased total dry matter accumulation, especially the larger amount accumulated from heading stage to maturity stage. With the density in wide-narrow row decreasing, processing quality, appearance quality, and nutrition quality were all improved, whereas amylose content and the taste value were decreased. Compared with mechanical carpet-seedling transplanting, mechanical pot-seedling transplanting improved processing quality and nutrition quality, but decreased amylose content and deteriorated appearance quality. These results suggested that mechanical pot-seedling transplanting with wide-narrow row coupling produced a suitable planting density of 26.88×10~4 hills ha~(–1) and may be an alternative approach to improving grain yield and quality for japonica rice.     

Combined effect of shading time and nitrogen level on grain filling and grain quality in japonica super rice

There is limited information about the combined effect of shading time and nitrogen(N) on grain filling and quality of rice. Therefore, two japonica super rice cultivars, Nanjing 44 and Ningjing 3, were used to study the effect of shading time and N level on the characteristics of rice panicle and grain filling as well as the corresponding yield and quality. At a low N level(150 kg N ha~(–1), 150 N), grain yield decreased(by 21.07–26.07%) under the treatment of 20 days of shading before heading(BH) compared with the no shading(NS) treatment. These decreases occurred because of shortened panicle length, decreased number of primary and secondary branches, as well as the grain number and weight per panicle. At 150 N, in the treatment of 20 days of shading after heading(AH), grain yield also decreased(by 9.46–10.60%) due to the lower grain weight per panicle. The interaction of shading and N level had a significant effect on the number of primary and secondary branches. A high level of N(300 kg N ha~(–1), 300 N) could offset the negative effect of shading on the number of secondary branches and grain weight per panicle, and consequently increased the grain yield in both shading treatments. In superior grains, compared with 150 N NS, the time to reach 99% of the grain weight(T_(99)) was shortened by 1.6 to 1.7 days, and the grain weight was decreased by 4.18–5.91% in 150 N BH. In 150 N AH, the grain weight was 13.39–13.92% lower than that in 150 N NS due to the slow mean and the maximum grain-filling rate(GR_(mean )and GR_(max)). In inferior grains, grain weight and GR_(mean) had a tendency of 150 N NS150 N BH150 N AH. Under shaded conditions, 300 N decreased the grain weight due to lower GR_(mean) both in superior and inferior grains. Compared with 150 N NS, the milling and appearance qualities as well as eating and cooking quality were all decreased in 150 N BH and 150 N AH. Shading with the high level of 300 N improved the milling quality and decreased the number of chalky rice kernels, but the eating and cooking quality was reduced with increased chalky area and overall chalkiness. Therefore, in the case of short term shading, appropriate N fertilizer could be used to improve the yield and milling quality of rice, but limited application of N fertilizer is recommended to achieve good eating and cooking quality of rice.     

Uniformity of wheat yield and quality using sensor assisted application of nitrogen

Proximal sensing, or obtaining information from close range, is a potentially useful tool for measuring the crop nitrogen status in real-time The objective of this study was to use proximal sensing of crop canopy spectral reflectance to evaluate variable-rate application of nitrogen in terms of its effect on yield and grain quality of winter wheat (Triticum aestivum L.). The sensor used was the Hydro-Precise N-Sensor System. Yield and grain quality maps were used as a basis for full-scale field trials with winter wheat growing under four nitrogen application treatments: a large (274 kg ha^?1), recommended (167 kg ha^?1) and two sensor-assisted (167 kg ha^?1) rates. The recommended rate of 167 kg N ha^?1 was given in a three-split application that meets the present Danish regulations to reduce nitrogen leaching. These require arable farmers to decrease nitrogen fertilizer application to 90% of the economically optimal level. Each farm’s baseline is calculated to take into account land quality, land allocated to each crop, and crop rotation. In the two sensor-assisted applications the Hydro-Precise N-Sensor System directs the last two of the three-split N application. Grain samples were collected directly from the grain flow of a combine harvester and analysed for protein, water and starch content. Grain data were related to and compared with combine yield meter registrations. Within the field, the variances of protein yield (698–1208 kg ha^?1) and grain protein (9.5–13.4%) were large. The nitrogen application treatments affected the average protein content (10.5–12.3%) and grain yield (9.87–10.42 t ha^?1) strongly. The grain starch content was largest in the uniform and sensor applied systems and smallest in the high nitrogen application treatment. Applying nitrogen according to the Hydro-Precise N-Sensor System did not increase grain yield or the protein and starch contents. Minor differences only were observed in both protein content and yield between uniform-rate N application and sensor-based variable-rate N application.     

模拟酸雨对小麦产量及籽粒蛋白质和淀粉含量及组分的影响

以宁麦13和徐麦31两种小麦(Triticum aestivum)品种为材料,通过盆栽试验研究了不同pH值酸雨对小麦产量和籽粒品质的影响。结果表明:模拟酸雨抑制了小麦的生长,减少了生物量的积累。pH值2.0酸雨处理后宁麦13的单穗粒数和单茎产量分别较对照下降了48.6%和56.7%,徐麦31则分别下降了31.2%和39.7%,差异显著。小麦籽粒主要营养成分对酸雨胁迫响应不同,酸雨处理提高了籽粒氨基酸、蛋白质含量,pH值2.0酸雨处理后,宁麦13和徐麦31小麦籽粒中氨基酸含量分别比对照高36.6%和30.9%,总蛋白含量分别比对照高20.6%和15.1%,均与对照差异显著。而小麦可溶性糖、淀粉和脂肪含量较对照降低,且总体表现为酸度增强变化幅度增大。不同蛋白组分也对酸雨胁迫反应不同,酸雨处理提高了籽粒中清蛋白和球蛋白含量,而降低了谷蛋白含量和谷/醇。pH值2.0的酸雨处理后,宁麦13和徐麦31的清蛋白含量较对照分别增加了13.1%和23.9%,但与对照差异不显著。酸雨胁迫降低了总淀粉和支链淀粉含量,宁麦13和徐麦31的pH值2.0酸雨处理总淀粉含量分别较对照下降了11.8%和20.2%,与对照差异显著,但对直链淀粉含量影响不明显。可见酸雨不仅影响小麦的产量,而且对品质也有明显影响。酸雨处理尽管提高了籽粒总蛋白含量,但降低了谷蛋白和谷/醇,降低了其加工品质。     

异地栽培对优质早稻太子玉晶米质的影响

优质早稻太子玉晶异地栽培试验证明，异地栽培对水稻子粒灌浆饱满程度和结实率有极显著的影响；精米率，整精米率，垩白粒率和胶稠度的影响也达到极显著水平。直链淀粉含量，湖化温度受栽培环境变化影响较小，株高和粒型等性状比较稳定，异地栽培条件下，处理982B的米质优于处理982A和对照。垩白度大小显著影响稻米精米率和整精米率。     

早籼产量与品质的相关性研究

本研究选用20个早籼品种(系)分期播期研究了产量与品质的相关。结果如下:早籼正季栽培时产量与糙米厚度和容重显著相关,与精米垩白指数和直链淀粉含量呈一定程度的相关,与其他品质性状相关不密切。大多数早籼品种(系)作连作晚稻栽培时产量下降,品质提高,而早籼品种8004作连作晚稻栽培时品质提高,产量并不下降,表现高产。     

施氮量对强筋小麦籽粒产量和品质的影响

在水浇地高产麦田研究了施氮量对强筋小麦籽粒产量和品质的影响。结果表明,适当增加氮肥施用量可以提高各产量构成因素的水平,因而产量增加,过量施用氮肥虽可以增加公顷穗数,但穗粒数和千粒重下降,而导致产量降低。增加氮肥的施用量能够改善强筋小麦的营养品质和加工品质,但随着施氮量的增加改善的幅度降低。综合施氮量对小麦产量及构成因素和品质性状的影响效应,认为在较高土壤肥力的麦田适宜施氮量为240kg/hm2左右。     

Long-term impact of a precision agriculture system on grain crop production

Research is lacking on the long-term impacts of field-scale precision agriculture practices on grain production. Following more than a decade (1993–2003) of yield and soil mapping and water quality assessment, a multi-faceted, ‘precision agriculture system’ (PAS) was implemented from 2004 to 2014 on a 36-ha field in central Missouri. The PAS targeted management practices that address crop production and environmental issues. It included no-till, cover crops, growing winter wheat (Triticum aestivum L.) instead of corn (Zea mays L.) for field areas where corn was not profitable, site-specific N for wheat and corn using canopy reflectance sensing, variable-rate P, K and lime using intensively grid-sampled data, and targeting of herbicides based on weed pressure. The PAS assessment was accomplished by comparing it to the previous decade of conventional, whole-field corn-soybean (Glycine max L.) mulch-tillage management. In the northern part of the field and compared to pre-PAS corn, relative grain yield of wheat in PAS was greatly improved and temporal yield variation was reduced on shallow topsoil, but relative grain yield was reduced on deep soil in the drainage channel. In the southern part of the field where corn remained in production, PAS did not lead to increased yield, but temporal yield variation was reduced. Across the whole field, soybean yield and temporal yield variation were only marginally influenced by PAS. Spatial yield variation of all three crops was not altered by PAS. Therefore, the greatest production advantage of a decade of precision agriculture was reduced temporal yield variation, which leads to greater yield stability and resilience to changing climate.     

Comparison of grain yield and quality of different types of japonica rice cultivars in the northern Jiangsu plain,China

In recent years, an increasing number of different types of japonica rice cultivars have been released in the southern rice region of China. The grain yield and quality of these new cultivars showed significant differences in large scale planting. However, the causes of the differences remain little known. Therefore, three typical types of japonica rice cultivars were used in this study to investigate their grain yield and quality. A scanning calorimeter(DSC), X-ray powder diffractometer(XRD), rapid viscosity analyzer(RVA) and taste analyzer were used to evaluate the cooking and eating properties. The results showed that the yield of non-soft hybrid japonica rice cultivars was significantly higher than that of non-soft inbred japonica rice cultivars and soft inbred japonica rice cultivars. Soft inbred japonica rice cultivars had a low amylose content and moderate protein content, which are the main reasons for the superior cooking and eating quality. In addition, the relative crystallinity of soft inbred japonica rice cultivars was significantly higher than that of non-soft inbred and non-soft hybrid japonica rice cultivars, which is considered the major factor resulting in higher transition temperature and gelatinization enthalpy(ΔHgel). Non-soft hybrid japonica rice cultivars had a higher number of large starch granules than soft inbred and non-soft inbred japonica rice cultivars. The setback value(SB) and breakdown value(BD), indirectly reflecting the cooking and eating quality of the three types of japonica rice cultivars, also confirmed that soft inbred japonica rice cultivars with a low SB value and a high BD value had better palatability than the other two types. This study provides guidance for future plantation of different types of japonica rice cultivars in large rice-producing areas.     

Development of elite restoring lines by integrating blast resistance and low amylose content using MAS

Blast resistance and grain quality are major problems in hybrid rice production in China. In this study, two resistance (R) genes, Pi46 and Pita, along with the gene Wx^b, which mainly affects rice endosperm amylose content (AC), were introgressed into an elite indica restoring line, R8166, which has little blast resistance and poor grain quality through marker-assisted selection (MAS). Eight improved lines were found to have recurrent genome recovery ratios ranging from 88.68 to 96.23%. Two improved lines, R163 and R167, were selected for subsequent studies. R167, which has the highest recovery ratio (96.23%), showed no significant differences in multiple agronomic traits. In contrast, R163 with the lowest recovery ratio (88.68%) exhibited significant differences in heading date and yield per plant compared with the recurrent parent. At two developmental stages, R163 and R167 had greatly enhanced resistance to blast over the recurrent parent. Similar trends were also observed for agronomic traits and blast resistance in R163- and R167-derived hybrids when compared with the counterparts from R8166. In addition, R163, R167, and their derived hybrids significantly improved the grain quality traits, including amylose content (AC), gel consistency (GC), chalky grain rate (CGR), and degree of endosperm chalkiness (DEC). It confirmed the success of efficiently developing elite restoring lines using MAS in this study.     

Foliar application of nutrients for spring barley cultivation in arid conditions of Middle Volga

The aim of this work is to study the effect of complex fertilizers containing macronutrients and micronutrients in a chelate form, Nutrivant Plus Cereal and Helatonik, applied as foliar nutrients, on the grain yield and the quality of Volgar’ spring barley. Grain yield increases to 26% in the years of insufficient moisture (HCS = 0.4–0.6). Moisture availability during the period from mid-May until the end of June (r = 0.86) has a significant effect on the volume of spring barley harvest. As a result of the use of the foliar additives, the quality of grains remains high while the yield grows.     

稻田套播和氮素对中筋小麦产量和品质的调节效应

采用稻田套播与传统条播两种栽培方式系统比较的方法,研究不同氮肥运筹下稻田套播方式对中筋小麦扬麦10号籽粒产量和品质的调节效应。结果表明:稻田套播方式对中筋小麦籽粒产量和品质影响显著。与传统条播方式相比,在同一氮肥运筹下套播方式中筋小麦除籽粒总淀粉及其组分含量显著高于条播方式外,籽粒产量、蛋白质含量、蛋白质产量、磨粉品质和面粉品质以及淀粉糊化特性的主要指标低于传统条播,且差异显著。稻田套播方式不利于中筋小麦扬麦10号优质的形成,在江苏淮南地区中筋专用小麦采用稻田套播方式宜适当增加施氮量且追氮适度后移。     

寒地水稻高产群体产量构成因素分析

通过对不同肥密因素构成的60个质量群体进行调查。结果表明:寒地水稻高产群体有效穗数集中在450万~495万穗.hm-2,穗粒数应控制在90~130粒,在此限度内,穗粒数对产量影响不明显;产量构成因子在不同产量群体中表现不同,在高产群体中表现为结实率穗粒数穗数粒重;在中产群体中表现为穗数穗粒数结实率粒重;在低产群体中表现为穗数结实率穗粒数粒重。     

水稻粒长遗传及其功能基因研究进展

随着人民生活水平的提高,稻米需求呈现多样化趋势,在产量仍作为重要指标的同时,稻米品质也越来越受到重视.提高产量、改良稻米品质是现代水稻育种的两个主要目标,而水稻粒长不仅是影响水稻产量的重要农艺性状,还与外观品质性状密切相关,细长粒稻米通常表现较好的外观品质,且世界上的大多数地区的消费者更偏爱于长粒型的稻米.因此,改良水...     

沙壤土不同强筋小麦品种对氮素利用的效应

在沙壤土高肥水平条件下,设置了不施氮肥和施氮肥270 kg/hm2 2个处理,研究了生产上常用的5个强筋小麦品种的产量、品质和氮素利用率的差异.结果表明,在施氮条件下,郑麦9023和豫麦68两个品种均表现为高产和较高的氮素利用率,有利于进一步改善郑麦9023和豫麦68的品质,提高小麦子粒的蛋白质含量.两种处理条件下,西农979均表现为产量较高,但该品种氮素利用率低,施氮后氮素利用率进一步下降;皖38的氮素利用率较低,但施氮后氮素收获指数和氮素利用率略有降低,子粒品质得到明显改善;施氮后豫麦34的产量显著提高,但品质未得到明显改善.     

玉米-大豆轮作及氮肥水平对玉米农艺性状及产量的影响

以郑单958为试验材料,采用裂区试验设计,研究吉林东部半山区玉米-大豆轮作、连作及4个氮肥水平(0 kg/hm²(F1)、90 kg/hm²(F2)、180 kg/hm²(F3)和270 kg/hm²(F4))对玉米农艺性状及产量的影响。结果表明,轮作处理在干物质积累、叶面积、叶面积指数及籽粒产量方面均优于连作处理,而对其他产量构成因素并未形成优势;F3、F4处理在株高、相对叶绿素含量(SPAD)、叶面积指数、产量构成及产量等指标均显著高于不施氮肥的F1处理(P<0.05),高水平氮素(F3、F4)投入对穗粗、百粒重和籽粒产量有一定促进作用,降低了秃尖长度,对行粒数及穗行数影响不明显(P>0.05);F3、F4处理较F1处理籽粒增产幅度达18.45%和16.52%。为此,在吉林东部半山区玉米轮作系统的氮肥施用量以180 kg/ hm²左右为最佳。