Effects of Drought Stress and Re-watering on Growth and Yield of Different Maize Varieties at Tasseling Stage

[Objective] The aim was to explore the response of different maize vari- eties in Guangxi to drought stress and re-watering at tasseling stage, so as to pro- vide reference for study on drought resistance mechanism, breeding of drought-re- sistant varieties and selection of maize varieties for fall sowing. [Method] At the tasseling stage, total five degrees of drought stress （4, 8, 12, 16 and 20 d） and corresponding re-watering after drought stress were simulated by a tub planting ex- periment in greenhouse for five different maize varieties （Guidan 0810, Dika 008, Zhengda 619, Chenyu 969, Guidan 901）. Normal watering was set as the control. Sampling was carried out on Day 1 after drought stress and on Day 15 after re- watering, and the secondary root number, maximum root length, green leaf number, root dry weight and shoot dry weight were measured. At the harvest time, the ear yield per plant was measured. With yield as the basis, the drought resistance coef- ficient and drought resistance index were calculated. Cluster analysis was conducted for drought resistance coefficient. [Result] The shoot dry weight, root dry weight, secondary root number, maximum root length and green leaf number of maize in the treatment groups decreased compared with those in the control group. The ratio of each index between the treatment and control groups declined with the extension of drought stress. After re-watering, the re-growth amount of each index all de- creased as the stress time prolonged. Post-re-watering over compensation effect oc- curred in none of the indices except the maximum root length, after 4 days of drought stress. Under drought stress, the reductions of all the indices of Guidan 0810, Dika 008 and Zhengda 619 were smaller than those of Chenyu 969 and Guidan 901. After re-watering, the re-growth abilities of Guidan 0810, Dika 008 and Zhengda 619 were stronger than those of Chenyu 969 and Guidan 901. The drought resistance coefficients and drought resistance indexes of Guidan 0810, Dika 008 and Zhengda 619 were all greater than those of Chenyu 969 and Guidan 901. The results of drought resistance coefficient cluster analysis showed that the five maize varieties were classified into two groups： Guidan 0810, Dika 008 and Zheng- da 619 had strong drought resistance, while Guidan 901 and Chenyu 969 had weak drought resistance. [Conclusion] The root and shoot growth of Guidan 0810, Dika 008 and Zhengda 619 was slightly affected by drought stress during the tasseling period, and they restored the growth rapidly after re-watering, thus ensuring high biomass and yield. Therefore, Guidan 0810, Dika 008 and Zhengda 619 can be promoted as drought-resistant autumn maize varieties in Guangxi.

Dissection of the genetic architecture for tassel branch number by QTL analysis in two related populations in maize

Tassel branch number （TBN） is the principal component of maize tassel inflorescence architecture and is a typical quan- titative trait controlled by multiple genes. The main objective of this research was to detect quantitative trait loci （QTLs） for TBN. The maize inbred line SICAU1212 was used as the common parent to develop BC1S1 and recombinant inbred line （RIL） populations with inbred lines 3237 and B73, respectively. The two related populations consisted of 123 and 238 lines, respectively. Each population was grown and phenotyped for TBN in two environments. Eleven QTLs were detected in the BC1S1 population, located on chromosomes 2, 3, 5, and 7, accounted for 4.45-26.58% of the phenotypic variation. Two QTLs （qB11Jtbn2-1, qB12Ctbn2-1, qBJtbn2-1; q11JBtbn5-1, qB12Ctbn5-1, qBJtbn5-1） that accounted for more than 10% of the phenotypic variation were identified. Three QTLs located on chromosomes 2, 3 and 5, exhibited stable expres- sion in the two environments. Ten QTLs were detected in the RIL population, located on chromosomes 2, 3, 5, 8, and 10, accounted for 2.69-13.58% of the TBN variation. One QTL （qR14Dtbn2-2） explained 〉10% of the phenotypic variation. One common QTL （qB12Ctbn2-2, qR14Dtbn2-2, qRJtbn2-2） was detected between the two related populations. Three pairs of epistatic effects were identified between two loci with or without additive effects and accounted for 1.19-4.26% of the phenotypic variance. These results demonstrated that TBN variation was mainly caused by major effects, minor effects and slightly modified by epistatic effects. Thus, identification of QTL for TBN may help elucidate the genetic basis of TBN and also facilitate map-based cloning and marker-assisted selection （MAS） in maize breeding programs.

Detection of maize tassels for UAV remote sensing image with an improved YOLOX Model

Maize tassel detection is essential for future agronomic management in maize planting and breeding,with application in yield estimation,growth monitoring,intelligent picking,and disease detection.However,detecting maize tassels in the field poses prominent challenges as they are often obscured by widespread occlusions and differ in size and morphological color at different growth stages.This study proposes the SEYOLOX-tiny Model that more accurately and robustly detects maize tassels in the field.Firstly,the data acquisition method ensures the balance between the image quality and image acquisition efficiency and obtains maize tassel images from different periods to enrich the dataset by unmanned aerial vehicle(UAV).Moreover,the robust detection network extends YOLOX by embedding an attention mechanism to realize the extraction of critical features and suppressing the noise caused by adverse factors(e.g.,occlusions and overlaps),which could be more suitable and robust for operation in complex natural environments.Experimental results verify the research hypothesis and show a mean average precision(mAP_(@0.5)) of 95.0%.The mAP_(@0.5),mAP_(@0.5-0.95),mAP_(@0.5-0.95(area=small)),and mAP_(@0.5-0.95(area=medium)) average values increased by 1.5,1.8,5.3,and 1.7%,respectively,compared to the original model.The proposed method can effectively meet the precision and robustness requirements of the vision system in maize tassel detection.

Transcriptomes of early developing tassels under drought stress reveal differential expression of genes related to drought tolerance in maize

Tassel, the male reproductive organs in maize, its development is adversely affected by drought during tasseling. To determine drought tolerance mechanisms of tassel differentiation at transcriptome level, RNA-Seq was performed using RNA of early developing tassel from 10 maize inbred lines under well-watered （control） and drought-stressed conditions, respectively. Results showed that the most active pathway for drought stress in maize were related to metabolic regulation at RNA level. And some genes, encoding enzymes involved in carbohydrate and lipid metabolism, were significantly down-regulated in drought-stressed plants. While, the transcription factors and genes, encoding catabolic or degradative enzymes, were over-expressed in maize early developing tassels under drought-stressed conditions, and among them, the transcripts of genes encoding exon-junction complexes involved in ＇RNA transcript＇ and ＇mRNA surveillance＇ pathways were significantly affected by drought stress. In addition, many other genes related to drought stress showed transcriptional changes at the later period of stress.

Antioxidant and Antigenotoxic Activity of Bioactive Extracts from Corn Tassel

This study is designed to evaluate antioxidant and antigenotoxic activities of corn tassel extracts（CTTs）. The major bioactive components of CTTs include flavonoid, saponin and polysaccharide. The antioxidant properties of the three bioactive components of CTTs were investigated by Ferric Reducing Antioxidant Property（FRAP） and 1, 1-diphenyl-2-picrylhydrazyl（DPPH） assays. The activities of the extracts were determined by assessing the inhibition of mutagenicity of the direct-acting mutagen fenaminosulf, sodium azide, and indirect-acting mutagen 2-aminofluorene using the Ames test（strains TA98 and TA100）. The results showed that the extraction rates of flavonoid, saponin, and polysaccharide from the dried corn tassels were 1.67%, 2.41% and 4.76% respectively. DPPH and FRAP assay strongly demonstrated that CTTs had antioxidant properties. CTTs at doses of 625, 1250 and 2500 μg per plate reduced 2-aminofluorene mutagenicity by 12.52%, 28.76% and 36.49% in Salmonella typhimurium TA98 strain assay respectively and by 10.98%, 25.27% and 37.83%, at the same doses in Salmonella typhimurium TA100 assay system, respectively. 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide（MTT） assay showed that the different concentrations of CTTs inhibited the proliferation of MGC80-3 cells in a dose-dependent manner（P0.01）. It is concluded that these integrated approaches to antioxidant and antigenotoxicity assessment may be useful to study corn tassel as a natural herbal material.

Bioremediation of Lead(II) from Polluted Wastewaters Employing Sulphuric Acid Treated Maize Tassel Biomass

The ability to modify a waste by-product precursor, maize tassel biomass using sulfuric acid as the activating agent with specific focus on Lead(II) ion from water has been proposed. The treating of maize tassel using sulphuric acid is believed to enhance sorption capacity of Lead(II) ions. For this, batch adsorption mode was adopted for which the effects of initial pH, adsorbent dosage, contact time and initial concentration were investigated. Consequently, it was found that the adsorbent capacity depends on pH;since it increases up to 4.5 and then decreases. The highest percentage of Lead(II) ion removal was achieved in the adsorbent dosage of 1.2 g and at an initial concentration of 10 mg/L metal ion. In an attempt to determine the capacity and rate of Lead(II) removal, isotherm and kinetic data were modeled using appropriate equations. To this end, the adsorption data fitted best into the Langmuir model with an R2 (0.9997) while kinetically the Lead(II) adsorption followed the pseudo-second-order model. Furthermore, as a way to address issues related to sustainability, maize tassel is recommended since the process is considered to be a dual solution for environmental cleaning. From one side, it represents a better way to dispose the maize tassel which has no use after fertilization and on the other hand it is an economic source of carbonaceous materials.

Gorgeous Eight Years:SPINEXPO Moving into A New Journey Interview with Ms. Karine Van Tassel,the founder and organizer of SPINEXPO

Since the first International Textile Exhibition created by SPINEXPO in March 2003, Ms. Karine Van Tassel, the founder and organizer of SPINEXPO, dedicates herself to the display of the

Direct differentiation of ears and tassels from cultured shoot apices of maize

In vitro morphogenesis of inflorescences from the cultured corn seedling shoot tips was obtained on modified Murashige and Skoog (MS) medium in complete darkness. Some shoot tip meristems excised from seedlings of inbred line 515, inbred line 8112 and their filial generations would directly give rise to florets on modified MS medium supplemented with 2.0 mg/L N6-bezyladenine (6-BA) in five or six weeks. On the medium with 1.0 mg/L 6-BA and 0. 2 mg/L 2, 4-dichlorophenoxy acetic acid (2, 4-D), the explants swelled first, and produced multiple shoot clumps, then the culture of the shoot tips from all of the six inbred lines in experiment would ultimately initiate to develop ears and tassels accompanied by multiple shoot clumps developing on the medium with 1.0 mg/L 6-BA and 0. 2 mg/Lin-dole-3-butyric acid (IBA). The developmental patterns of the corn inflorescences were similar to the controls of normal plants in the field, but the number of the ears was much more than that of the tassels in vitro. It seemed that proper kinds and concentrations of exogenous hormones were necessary for the initiation and development of the inflorescences. The genotype of explants was responsible for the response to culture conditions. It could be inferred that there were different control mechanisms existing in the vegetative and reproductive developmental processes of maize, because the cultured shoot tips could directly produce the reproductive organs.

A tasseled cap transformation for CBERS-02B CCD data

The tasseled cap transformation of remote sensing data has been widely used in agriculture,forest,ecology,and landscape.In this paper,tasseled cap transformation coefficients appropriate for data from a new sensor(China & Brazil Earth Resource Satellite(CBERS-02B)) are presented.The first three components after transformation captured 98% of the four-band variance,and represent the physical characteristics of brightness(coefficients:0.509,0.431,0.330,and 0.668),greenness(coefficients:0.494,0.318,0.324,and 0.741),and blueness(coefficients:0.581,0.070,0.811,and 0.003),respectively.We hope these results will enhance the application of CBERS-02B charge-coupled device(CCD) data in the areas of agriculture,forest,ecology,and landscape.

In-field automatic detection of maize tassels using computer vision

The heading stage of maize is an important period during its growth and development and indicates the beginning of its pollination.In this regard,an automated method for maize tassel detection is highly important to monitor maize growth.However,the recognition of maize heading stage mainly relies on visual evaluation.This method presents some limitations,such as expensive and subjective.This work proposed a novel method for automatic tassel detection.In the proposed algorithm,a color attenuation prior model was used to model the scene depth of saturation graph to remove image saturation.An Itti visual attention detection algorithm was used to detect the area of interest.Texture features and vegetation indices were used to develop a classification model to eliminate false positives.Pictures were captured using a commercial camera for two years to verify the stability of the proposed algorithm.Three indices were calculated to quantitatively assess and rate the algorithms.Experimental results show that the proposed method outperforms other existing methods,and its recall,precision,and F1 measure values are 86.30%,91.44%,and 88.36%,respectively.Results indicate that the proposed method can effectively detect maize tassels in field images and remain stable with time.

AGO_18b negatively regulates determinacy of spikelet meristems on the tassel central spike in maize

The maize tassel represents an indeterminate male inflorescence. The number of primordia that a given inflorescence meristem produces is related to its determinacy, i.e., capacity for continued meristem activity.Transcription factors(TFs) controlling determinacy in tassel axillary meristems are well studied in maize, and small RNAs are known to influence tassel development by repressing targets, including tassel-related TFs. As core components of the RNA-inducible silence complex(RISC),Argonaute(AGO) proteins are required for small RNAmediated repression. Here, we characterized the biological function of AGO8b, a tassel-enriched AGO. The abundance of AGO8b transcripts gradually increased during tassel development from inception to gametogenesis and were enriched in the inflorescence meristem and axillary meristems of the tassel. Repressing AGO8b expression resulted in more spikelets, which contributed to a longer central spike of the tassel. Additionally, the transcripts of several HD-ZIP Ⅲ TFs that were canonical targets of micro RNA66(miR66) accumulated in the AGO8b repressed lines. We propose that AGO8b is a negative regulator of the determinacy of inflorescence and axillary meristems, and that it acts by interacting with the miR66-HD-ZIP Ⅲ TF regulatory pathway.

Batch equilibrium studies on the adsorptive capacity of powdered and pelleted maize tassel to remove PFOA and PFOS from aqueous medium

This study was aimed at evaluating the potential of raw maize tassel powder and pellets to remove PFOA and PFOS from water.Batch experiments were first conducted using ultrapure water to investigate the effects of pH,adsorbent dosage,initial PFASs concentration,contact time and temperature in adsorption efficiency of powdered and pelleted maize tassel.The optimum conditions for the removal of PFOA/PFOS observed for both maize tassel powder and pellets were as follows:pH 2.0,adsorbate initial concentrations of 20 mg g1,adsorbent dosage of 0.5 g(20 pellets),1 h contact time,all at 25℃.These optimum conditions were,thereafter,applied to surface water samples from Apies River in Pretoria,spiked with 20 mg L^(-1)PFOS/PFOA.Shimadzu LC-MS/MS was employed in analysis and the Langmuir and Freundlich isotherm models were used to determine the types of adsorption mechanism.High percentage removal 91.3%and 89.7%for PFOA and PFOS respectively using both MT powder and pellets were achieved.The maximum adsorption capacities identified for the monolayer of the Langmuir isotherm model was found to be between 41.6 mg g^(-1)and 58.82 mg g^(-1)for PFOA using powder and pellets respectively;and between 42.37 mg g^(-1)and 176.5 mg g^(-1)for PFOS for the same adsorbents respectively.These results showed very insignificant conformity to the Langmuir model;therefore it can be assumed that the Langmuir model was not obeyed.However,the experiments proved to be primarily consistent with the Freundlich model,with high correlation coefficient(R2)values ranging from 0.900 to 0.998 for both PFOA and PFOS.Maximum adsorption capacities of 142.8 mg g^(-1)and 78.57 mg g^(-1)for PFOA and 107.4 mg g^(-1)and 85.7 mg g^(-1)for PFOS at 25℃using both powder and pellets respectively were obtained suggesting that adsorption took place on heterogeneous layers for both targeted PFASs.

基于改进YOLO v7-tiny的玉米种质资源雄穗检测方法

针对玉米种质资源遗传多样性丰富导致雄穗大小、形态结构及颜色呈现较大差异,无人机搭载可见光传感器相比地面采集图像分辨率低,以及图像中部分雄穗过小、与背景相似度高、被遮挡、相互交错等情况带来的雄穗检测精度低的问题,提出了一种改进YOLO v7-tiny模型的玉米种质资源雄穗检测方法。该方法通过在YOLO v7-tiny中引入SPD-Conv模块和VanillaBlock模块,以及添加ECA-Net模块的方式,增强模型对雄穗特征的提取能力。利用自建的玉米种质资源雄穗数据集,训练并测试改进模型。结果表明,改进YOLO v7-tiny的平均精度均值为94.6%,相比YOLO v7-tiny提升1.5个百分点,相比同等规模的轻量级模型YOLO v5s、YOLO v8s分别提升1.0、3.1个百分点,显著降低了图像中雄穗漏检及背景误检为雄穗的发生,有效减少了单穗误检为多穗和交错状态下雄穗个数误判的情况。改进YOLO v7-tiny模型内存占用量为17.8 MB,推理速度为231 f/s。本文方法在保证模型轻量化的前提下提升了雄穗检测精度,为玉米种质资源雄穗实时、精准检测提供了技术支撑。

胡萝卜缨青贮替代全株玉米青贮对泌乳期文登奶山羊生产性能、乳品质、养分表观消化率、抗氧化能力及免疫功能的影响

本试验旨在探究胡萝卜缨青贮替代全株玉米青贮对文登奶山羊生产性能、乳品质、养分表观消化率、抗氧化能力及免疫功能的影响。选用体重(48.34±1.86)kg、产奶量(1.29±0.46)kg/d、产羔150 d左右的3胎文登奶山羊64只,随机分为4组,每组4个重复,每个重复4只羊。对照组饲喂基础饲粮,试验1、2、3组分别以胡萝卜缨青贮替代基础饲粮中20%、30%、40%的全株玉米青贮。试验周期为67 d,其中预试期7 d,正试期60 d。结果显示:1)与对照组相比,试验1、3组的平均日产奶量显著提高(P<0.05);试验1组的料奶比显著降低(P<0.05),4%标准乳产量显著提高(P<0.05);试验3组的平均日采食量显著提高(P<0.05)。2)与对照组相比,试验3组乳中β-胡萝卜素含量极显著提高(P<0.01),试验2组乳中β-胡萝卜素含量显著提高(P<0.05);试验2、3组乳中维生素A与叶绿素铜钠含量极显著提高(P<0.01)。各组乳中农药残留均未检出。3)与对照组相比,3个试验组的粗蛋白质表观消化率极显著提高(P<0.01),试验1、3组的干物质表观消化率、试验1组的粗脂肪表观消化率、试验3组的中性洗涤纤维表观消化率皆显著提高(P<0.05)。4)与对照组相比,3个试验组的血清免疫球蛋白G(IgG)含量显著提高(P<0.05),超氧化物歧化酶(SOD)与谷胱甘肽过氧化物酶(GSH-Px)活性极显著提高(P<0.01);试验1组的血清总蛋白(TP)和球蛋白(GLB)含量显著提高(P<0.05),尿素氮(UN)与丙二醛(MDA)含量显著降低(P<0.05),总抗氧化能力(T-AOC)极显著提高(P<0.01)。综上所述,在饲粮中以胡萝卜缨青贮替代20%全株玉米青贮可提高泌乳期文登奶山羊的产奶性能、乳品质、养分表观消化率、抗氧化能力和免疫功能。

干旱胁迫对不同生长期不同玉米品种生长性状的影响

为探究干旱对玉米不同生长期的生长性状及果穗性状的影响,以QXH0121(耐盐碱型)、B73(野生型)、PHM57(盐碱敏感型)3种不同耐盐碱能力的玉米品种为试验材料,通过盆栽控水,分别于拔节期、大喇叭口期、抽雄期进行干旱处理。结果表明:相较于非胁迫处理,干旱胁迫下3种玉米品种在拔节期、大喇叭口期及抽雄期均表现为株高及产量构成要素降低,而茎粗则无显著差异。无论拔节期、大喇叭口期或者抽雄期胁迫,3个品种耐旱程度均表现为QXH0121>B73>PHM57。拔节期的干旱胁迫对玉米株高影响最大,株高低于大喇叭口期和抽雄期;抽雄期的干旱胁迫对果穗性状影响最大。

基于混池测序及遗传图谱定位玉米雄穗分枝数基因

【目的】构建玉米雄穗分枝数极端混池和分子遗传图谱,对雄穗分枝数进行QTL定位,为探究玉米雄穗分枝数的发育机制及选育雄穗分枝数少的品种提供理论参考。【方法】将雄穗分枝少的自交系SNM131与雄穗分枝多的自交系HY813组配F_(2)代群体,统计群体各单株的雄穗分枝数,分析其遗传模式。从F_(2)代群体中分别挑选33个雄穗分株少的单株和38个雄穗分枝多的单株构建混池,对2个亲本和2个子代混池分别展开30×、17×和28×覆盖度的全基因组重测序,对测序数据进行关联分析,获得雄穗分枝数性状的定位区间。利用10K芯片对F_(2)代群体276个单株进行单核苷酸多态性(SNP)标记分型,所得数据用于构建遗传连锁图谱,并结合雄穗分枝数表型数据,利用全基因组复合区间作图法(GCIM)进行QTL定位。最后根据定位区间对应的B73参考基因组的物理区段上的基因注释信息,预测调控雄穗分枝数的候选基因。【结果】F_(2)代群体雄穗分枝数平均7.6个,F_(2)代群体在雄穗分枝数性状上偏向母本SNM131,以少雄穗分枝为主。全基因组重测序共获得1812886个SNP标记和24714个插入缺失标记(InDel),并基于混合分组分析法(BSA)进行雄穗分枝数性状分析,最终共获得6个显著关联区间,分布于玉米5、8和10号染色体。其中,10号染色体上一个峰值最高的关联区间(物理位置127.61~129.46 Mb),推测为控制雄穗分枝数性状的主效位点。构建的遗传连锁图谱包含2944个SNP标记,总图距3684.3 cM。基于遗传连锁图谱,利用GCIM法共定位到5个QTL,分别分布于1、4、6和10号染色体,单个QTL可解释1.9%~9.9%的表型变异。主效QTL被定位在10号染色体约0.56 Mb的物理区间(127.81~128.37 Mb),关联区间包含有15个有中、高功能变异位点的候选基因,其中TBN-S基因编码磷脂酰乙醇胺结合蛋白(PEBP),属于TFL1类基因,与花序分生和雄穗分枝数发育密切相关。【结论】通过田间表型鉴定、遗传连锁图谱构建和SNP标记定位,将控制玉米雄穗分枝数的主效QTL定位在10号染色体长臂约0.56 Mb物理区间内,包含15个中、高变异度的基因,预测TBN-S为候选基因。

4BL-1型白萝卜联合收获机缨叶聚拢装置优化与试验

为解决白萝卜机收过程中因缨叶聚拢不全导致损失率与损伤率高、切头合格率低等问题,该研究依据白萝卜缨叶物理力学特性,设计了一种白萝卜缨叶聚拢装置,以实现白萝卜缨叶从田间自然“半散开”状态聚拢成束,利于后续拔取作业。构建白萝卜缨叶聚拢装置运动学模型,确定“拢缨速比”的取值范围;构建装置结构参数和前进速度、拢缨速比及作业姿态等运动参数及拢叶机构倾角对缨叶聚拢性能影响的数学模型,并求解出各因素优选区间。以缨叶聚拢成功率、缨叶破损率为评价指标,开展三因素三水平正交组合试验,依据响应面法分析各因素对二者的影响效应,并对模型进行优化。试验结果表明:缨叶聚拢成功率影响显著性顺序为前进速度、拢缨速比、拢叶机构倾角;缨叶破损率影响显著性顺序为拢缨速比、拢叶机构倾角、前进速度;最优参数组合为:前进速度0.4 m/s、拢缨速比3.9、拢叶机构倾角86.3°。在最优参数组合下开展台架试验验证,结果表明:缨叶聚拢成功率、缨叶破损率分别为92.04%、8.81%,满足拔取式白萝卜联合收获机缨叶聚拢需求。研究结果可为白萝卜收获机械的设计提供参考。

GF-6 WFV传感器数据的缨帽变换系数推导

缨帽变换是影像增强中最常见的一种方法,已在遥感中得到了广泛的应用。但是,由于高分辨率卫星传感器(例如GF-6 WFV)通常缺乏短波红外波段,所以用常规的Gram-Schmidt(G-S)正交化方法得到的缨帽变换系数通常会存在湿度分量失真的问题。为此,文章选取了覆盖不同地区、不同时相、不同季节的12幅GF-6 WFV影像和6幅同步的Landsat8 OLI影像,首先利用GF-6和Landsat8的同步影像进行湿度分量回归,确定GF-6 WFV传感器的湿度分量系数,进而采用G-S逆推算法依次推导出亮度、绿度及其他分量,开发出了GF-6 WFV传感器的缨帽变换系数。研究发现:①通过调整缨帽变换湿度分量的推导顺序,即先推导湿度分量再推导亮度和绿度等分量,可以较好地推导出GF-6 WFV传感器的缨帽变换系数,并解决传统G-S正交化方法中存在的湿度分量失真问题;②GF-6 WFV缨帽变换各分量具有稳定的特征,地物在不同分量组成的特征平面内具有典型的“缨帽”分布特征;③尽管GF-6 WFV传感器与Landsat8 OLI传感器在波段设置和光谱响应方面存在一定差异,但它们缨帽变换对应分量之间具有较好的一致性,相关系数仍高达0.8。

播种期对光温敏无雄穗系玉米花粉育性的影响

为确定光温敏无雄穗系玉米育性转换的生态因子,筛选不育特性稳定的两系材料,选择合适的播期进行制种,以光温敏无雄穗系I17、I478、Ptvt3和Ptvt2为材料,以自交系478、B73为对照,在湖南省浏阳市进行田间分期播种试验,对9个播期玉米的雄花育性、雄穗性状、生育期和产量性状等进行分析。结果表明:玉米光温敏无雄穗系育性转换的主要影响因子是苗期的日均高温;I17对环境敏感的时期在V2—V6期间;I478对环境敏感的时期在V2—V4期间;Ptvt3对环境敏感的时期在V2—V4期间;Ptvt2对环境敏感的时期在V2—V5期间;I17适合在播期1、8、9播种,进行自交制种,在第1—6播期播种,作为两系不育系进行杂交种子生产;I478适合在播期1、2、8播种,进行自交制种,在第5—7播期播种,作为两系不育系进行杂交种子生产;Ptvt3适合在播期1、8、9播种,进行自交制种,在第2—7播期播种,作为两系不育系进行杂交种子生产;Ptvt2适合在播期1和播期2播种,进行自交制种,在第3—7播期播种,作为两系不育系进行杂交种子生产。Ptvt3相比I17、I478和Ptvt2具有繁殖产量高、生育期长等优点,且不育特性稳定,适合作为两系不育系进行生产应用。