高粱与苏丹草杂种优势利用的研究

高粱与苏丹草杂种优势明显,F1单株生物产量性状高于双亲平均值,甚至超过或接近高亲。影响高粱-苏丹草杂交种单株茎叶鲜重的主要因素是主茎粗、叶长;决定单位面积鲜草产量的主要是密度、叶长和单株茎叶鲜重。多年随机区组试验结果表明,杂交种单位面积鲜草产量显著超过苏丹草,并以30万株/hm2为最适种植密度。杂交种营养品     

玉草1号产量构成因素和最适密度研究

研究了玉草1号的产量构成因素及其最适密度.结果表明,影响单位面积产量的主要因素是分蘖数、单椿产量和种植密度,其中种植密度对单位面积产量的影响最大.建立了多元回归方程Y=214.7138+23.0069X2+52.8086X5+1.323 3X6(X2、X5、X6分别代表分蘖数、单株产量和种植密度).分析出了最适种植密度,为45 000株/hm2.     

高粱杂交种株型性状与产量的遗传相关和通径分析

以相关分析法研究了 1 3个高粱杂交种 9个株型性状与单株子粒产量的关系 ,结果表明 :高粱杂交种高产的株型性状应是 :株高适中 ,株型紧凑 ,叶宽但叶长适宜 ,并着重对顶数三叶的长和宽进行合理选择 ,这样有利于合理安排群体密度 ,增加光合面积 ,提高产量     

不同种植密度对除虫菊产量及构成因子的影响

为探明除虫菊在育苗移栽条件下最佳种植密度，试验采用单因子随机区组设计，研究不同种植密度对产量、产值及构成因子的影响。结果表明，不同种植密度对单位面积除虫菊干花产量、干花产值、除虫菊素产量均达到了极显著水平，并呈抛物线关系，且影响除虫菊干花产量和除虫菊素产量最大的因子均是单位面积的有效花梗数。试验也表明，单株有效花梗数、花朵数和无效花梗率、花蕾率与种植密度呈负相关关系，而单位面积有效花梗数和花朵数与种植密度呈Logistic函数关系。另外随着种植密度的增加，除虫菊生育期有所缩短，特别是封行期缩短最明显，但根腐病的发病率与种植密度呈正相关。综合产量、产值及生育期、发病率、株高等因素，云南省除虫菊适种区域以漂浮育苗移栽，种植密度6.0万~9.0万株/hm2时最适宜。     

辣椒杂交制种高产栽培技术

辣椒杂交制种产量的高低主要取决于单位面积株数、单株杂交果数、单个杂交果种子粒数和杂交种子千粒重等因素,同时,栽培技术和杂交授粉技术也与之密切相关.本文就高产制种的几个关键技术措施概括如下.     

谷子杂交种产量与主要农艺性状的相关性及回归分析

为了明确影响谷子杂交种产量的主要因子,对短穗型、中偏短穗型、中偏长穗型和长穗型4类不同谷子杂交种产量与主要农艺性状进行相关性和回归分析。结果表明,4种类型谷子杂交种的穗长与其产量差异显著。相关性分析表明,产量与出谷率之间存在显著正相关;单株穗重与单株粒重、经济系数之间存在极显著正相关,有效分蘖数与单株穗重、单株粒重和经济系数之间存在显著正相关,穗码密度与单株草重之间存在显著正相关,千粒重与穗长之间存在显著正相关。回归分析表明,谷子杂交种产量与穗粗、出谷率和千粒重呈显著正相关。     

灯盏细辛栽培密度与产量关系研究

目的：通过试验,找出最佳栽培密度,进一步降低成本,提高单位面积产量和经济效益。方法：采用随机区组试验。结果：增加株行距有利于单株或单丛的生长发育;密度越大,单位面积产量越高;在构成产量的三因素中,株距贡献率最大,行距次之,双株略低于行距。栽培管理及育苗成本是株距>双株>行距。结论：最佳密度组合为（20cm×10cm）+双株。     

高粱──苏丹草杂交种的选育和利用

利用高粱、苏丹草强大的杂种优势，选育的高粱──苏丹草杂交种经试验、示范，不仅单株优势明显、单位面积产量高，而且品质也十分优良，用于养鱼和养牛，均获得成功。     

不同种植密度对高粱生长、产量及养分吸收的影响

为了明确密度与高粱[Sorghum bicolor (L.) Moench]农艺和经济性状以及养分吸收的关系,以‘晋杂23号’高粱为试验作物,采用大田试验方法,试验设4.5万株/hm2、7.5万株/hm2、10.5万株/hm2和13.5万株/hm2 4个种植密度,研究了不同种植密度对高粱生长、产量、产量构成因素以及养分吸收的影响。结果表明,随着密度增加,高粱株高显著增高,茎粗显著变细,单株叶面积和单株干重显著下降。在4.5万株/hm2~7.5万株/hm2范围内,籽粒产量随着密度增加呈显著性增加。密度在4.5万株/hm2~10.5万株/hm2时,单位面积穗数随密度增加呈显著性增加。随着密度增加,穗粒数显著性增加,而千粒重影响不显著。除磷以外,密度对高粱氮和钾吸收总量均无显著影响。密度对籽粒氮吸收量没有显著影响;在10.5万株/hm2~13.5万株/hm2范围内,磷和钾吸收量明显下降。与氮和磷不同,钾主要分配在秸秆中,只有少量钾转运到籽粒中。相关分析表明,种植密度与株高、生物产量、籽粒产量和单位面积穗数呈显著性正相关,而与茎粗、单株叶面积、单株干重、经济系数、穗粒数和千粒重呈显著性负相关。本研究表明,种植密度与高粱主要农艺和经济性状以及养分吸收息息相关,在高粱高产高效栽培中起着非常重要的作用。     

玉米杂交种产量性状与穗位叶光合性状关联度分析

玉米的产量是由多个因素共同作用的结果,果穗产量性状是其直接表现。玉米植株中部叶片尤其是穗位叶的光合性状对籽粒产量的形成具有重要作用。因此,分析玉米穗位叶光合性状与玉米杂交种产量性状间的相互关系对选育高产、优质、抗病、广适玉米新杂交种具有重要意义。此文应用灰色关联度分析方法,对玉米杂交种穗部产量性状与穗位光合性状间的相关性进行了分析。结果表明：与玉米杂交种单穗粒重最为相关的穗部光合性状是穗位茎节长,其次是叶面积、叶长、光合效率和比叶重等。对玉米杂交种穗部产量性状综合影响较大的穗位光合性状有穗位茎节长、叶长、比叶重等。     

不同类型高粱中胚轴伸长特性的研究

以84份不同类型高粱品种（系）为试验材料,研究高粱中胚轴伸长特性,并筛选不同中胚轴伸长特性种质,为进一步研究高粱出苗能力奠定基础。结果表明,所有参试材料中胚轴平均长度为6.5cm,不育系、保持系、杂交种、恢复系和地方品种中胚轴平均长度分别为4.7、5.1、5.8、7.0和8.4cm。不同类型高粱中胚轴伸长能力不同,其伸长能力表现为地方品种>恢复系>杂交种>不育系、保持系。以中胚轴长度为指标的UPGMA（类平均法）聚类分析结果显示,参试的84份种质可以分为5种类型,即极长中胚轴类型、长中胚轴类型、中胚轴长度中间类型、短中胚轴类型和极短中胚轴类型。杂交种中胚轴伸长的杂种优势属于负向中亲优势。     

Sorghum [Sorghum bicolor (L.) Moench] landrace variation and classification in North Shewa and South Welo, Ethiopia

Fourteen phenotypic characters were chosen for the purpose of obtaining taxonomic evidence on the resemblances of 177 accessions of sorghum from North Shewa and South Welo regions of Ethiopia. Canonical Discriminant Analysis (CDA) and Modeclus cluster analysis were conducted to see if the 177 accessions could form clusters based on their morphological characters, and to test the consistency of farmers’ naming of the five most common Sorghum landraces represented by 44 accessions. Multivariate analyses grouped the 177 accessions into three clusters linked by a few phenotypic intermediate landraces. A botanical key was established for easy classification of the Sorghum crop plants grown in the study area. The number of accessions of the five most common landraces named by the farmers formed dissimilar groups, suggesting that farmers’ naming of these Sorghum landraces are consistent. Midrib color, grain color, grain size, glume color, glume hairiness, and grain shape were the leading morphological characters used by the farmers in naming these Sorghum landraces. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic analysis of threshability in grain sorghum [Sorghum bicolor (L.) Moench]

The ease with which seeds are detached from panicles is one of the early domestication traits. Genotypes with sticky panicles are hard to thresh, and whenever threshed, the grain tends to remain attached to the glume which reduces market value and processability. This study was conducted to determine the genetic mechanisms underlying the threshability trait in sorghum. Four seed parents and eleven pollinators differing for threshability were intercrossed in Design II mating scheme and the resulting hybrids and the parents were grown in four environments. Threshability was estimated as the ratio of seed yield to panicle weight (TW) and proportion of seeds without sticky glumes (TG). Variation was significant among the entries, inbreds and hybrids with GCA for TG and TW varying markedly. Mean TG for inbred and hybrids of low threshable genotypes was not markedly different indicating that threshability trait is under the control of additive genes with dominant or partially dominant effects. Segregation analysis indicates that the TG trait may be under the control of few major genes with approximately one to three loci affecting the trait.     

Mapping of QTLs underlying flowering time in sorghum [Sorghum bicolor (L.) Moench]

Due to its critical importance in crop yield, the photoperiodic regulation of flowering time is considered an important trait in sorghum breeding programs. In this study, quantitative trait loci for flowering time were detected using an F₂ population derived from a cross between Kikuchi Zairai, a late-flowering cultivar originating from Japan and SC112, an early-flowering cultivar originating from Ethiopia. F₂ plants were grown with their parents under a natural day length and a 12 h day length. Two linkage maps were constructed using 213 simple sequence repeats markers. Nine quantitative trait loci controlling flowering time were identified in F₂ plants grown under a natural day length, whereas 7 QTLs were identified under a 12 h day length. Five QTLs controlling flowering time were shared under both of the day length conditions.     

Effect of humidity on intergeneric pollinations of iap (Inhibition of Alien Pollen) sorghum [Sorghum bicolor (L.) Moench]

The production of interspecific or intergeneric progeny involving Sorghum spp. is greatly enhanced by the presence of the iap (Inhibition of Alien Pollen) allele in sorghum [Sorghum bicolor (L.) Moench]. Variation in the expressivity of the iap phenotype has been observed in previous studies, leading to the hypothesis that the humidity during pollination is affecting the degree of alien pollen adhesion and pollen tube growth. The objective of this study was to determine the optimum humidity for maximum maize pollen tube growth on sorghum florets homozygous for iap. Growth chambers were used to create environments of 45, 65, and 85 % humidity with reciprocal crosses made between the 65 and 85 % humidity chambers. Maize pollen was dusted onto the stigmas of Tx3361 (iap iap) and ATx623 (Iap Iap). Pollen adhesion and germination were higher for pollinations with Tx3361 at all humidity levels but the greatest adhesion and germination was observed at 45 % humidity for Tx3361. Under this humidity, pollen tube growth to the style and ovary was observed. The results indicate that lower humidity maximizes maize pollen adhesion and germination on the stigmas of Tx3361. Analysis of the differences in adhesion between Tx3361 and ATx623 indicate that Iap affects pollen adhesion at the stigma surface and may be controlling pollen–pistil incompatibility in interspecific crosses in sorghum.     

Variability and Correlations in Grain Sorghum Genotypes (Sorghum bicolor [L.] Moench) Under Drought Conditions at Different Stages of Growth

Twenty-two genotypes of grain sorghum were grown under drought conditions by omitting one irrigation during stages of before flowering period, kernel filling period, and physiological maturity period at Assiut Univ. Farm in 1987 and 1988 seasons. The results obtained revealed that considerable variation existed among genotypes for all the studied traits. The most effective moisture stress treatment in reducing grain yield, panicle weight and plant height was during flowering stage. While 1000-kernel weight was much affected by moisture stress during grain filling period. The genotype x year interaction (σ²_gy) was large compared to genotype x irrigation treatment (σ²_gl) indicated that genotypes responded differently when they were grown from year to year. The genotypic variance (σ²_g) for all traits were large reflecting the importance of genetic variability. Both phenotypic and genotypic correlations among traits showed that plant height and 1000-kernel weight were highly correlated with grain yield, while leaf area index was low associated with plant height.     

Studies on Seed Residues Following Carbofuran Application in Sorghum (Sorghum bicolor [L.] Moench) with Reference to Viability

Soil application of different formulations of carbofuran at 3.0 and 1.5 g.a.i. metre row⁻¹ did not have any impact on vigour and viability of the resultant seeds of sorghum. Fresh seeds from encecap 'A', encecap 'B' and furadan treated plots contained higher residues than the permissible limits and in artificially aged seeds the quantities were below the permissible limits. The degradation was evident with the growth and development of seedlings grown from fresh and aged seeds. Residues from lower doses dissipated faster than higher doses. The general decline in percentage germination and vigour could not be attributed to the residual toxicity but only to the ageing phenomena.     

Developing new markers and QTL mapping for greenbug resistance in sorghum [Sorghum bicolor (L.) Moench]

Greenbug is a major damaging insect to sorghum production in the United States. Among various virulent greenbug biotypes, biotype I is the most predominant and severe for sorghum. To combat with the damaging pest, greenbug resistant sources were obtained from screening sorghum germplasm collection. This experiment was conducted to identify the genomic regions contributing resistance to greenbug biotype I in a sorghum accession, PI 607900. An F₂ mapping population consisting of 371 individuals developed from a cross of the resistant line with an elite cultivar, BTx623 (susceptible) were tested and scored for their response to greenbug feeding in the greenhouse. Significant differences in resistance were observed between the two parental lines and among their F₂ progeny in response to greenbug feeding at 7, 10, 14 and 21 days after infestation. A linkage map spanning a total length of 729.5 cM across the genome was constructed with 102 polymorphic SSR markers (69 genomic and 33 EST SSRs). Of those microsatellite markers, 48 were newly developed during this study, which are a useful addition for sorghum genotyping and genome mapping. Single marker analysis revealed 29 markers to be significantly associated with the plant response to greenbug feeding damage. The results from interval mapping, composite interval mapping and multiple interval mapping analyses identified four major QTLs for greenbug resistance on chromosome 9. These QTLs collectively accounted for 34–82 % of the phenotypic variance in greenbug resistance. Minor QTLs located on chromosome 3 explained 1 % of the phenotypic variance in greenbug resistance. The major allele for greenbug resistance was on chromosome 9 close to receptor-like kinase Xa21-binding protein 3. These markers are useful to screen more resistant genotypes. Furthermore, the markers tagged to QTL regions can be used to enhance the sorghum breeding program for greenbug resistance through marker-assisted selection and map-based cloning.