Effect of Planting Date on Yield and Yield Components of Grain Sorghum Hybrids

In Kansas, productivity of grain sorghum [Sorghum bicolor (L.) Moench] is affected by weather conditions at planting and during pollination. Planting date management and selection of hybrid maturity group can help to avoid severe environmental stresses during these sensitive stages. The hypothesis of the study was that late May planting improves grain sorghum yield and yield components compared with late June planting. The objectives of this research were to investigate the influence of planting dates yield and yield components of different grain sorghum hybrids, and to determine the optimal planting date and hybrid combination for maximum biomass and grains production. Three sorghum hybrids (early, medium, and late maturing) were planted in late May and late June without irrigation in Kansas at Manhattan/Ashland Bottom Research Station, and Hutchinson in 2010;and at Manhattan/North Farm and Hutchinson in 2011. Data on dry matter production, yield and yield components were collected. Grain yield and yield components were influenced by planting date depending on environmental conditions. At Manhattan (2010), greater grain yield, number of heads per plant, were obtained with late-June planting compared with late May planting, while at Hutchinson (2010) greater yield was obtained with late May planting for all hybrids. The yield component most affected at Hutchinson was the number of kernels∙panicle−1 and plant density. Late-May planting was favorable for late maturing hybrid (P84G62) in all locations. However, the yield of early maturing hybrid (DKS 28-05) and medium maturing hybrid (DKS 37-07) was less affected by delayed planting. The effects of planting dates on yield and yield components of grain sorghum hybrids were found to be variable among hybrid maturity groups and locations.

A telomere-to-telomere genome assembly of Hongyingzi,a sorghum cultivar used for Chinese Baijiu production

Sorghum(Sorghum bicolor(L.)Moench)is a world cereal crop used in China for producing Baijiu,a distilled spirit.We report a telomere-to-telomere genome assembly of the Baijiu cultivar Hongyingzi,HYZ-T2T,using ultralong reads.The 10 chromosome pairs contained 33,462 genes,of which 93%were functionally annotated.The 20 telomeres and 10 centromeric regions on the HYZ-T2T chromosomes were predicted and two consecutive large inversions on chromosome 2 were characterized.A 65-gene reconstruction of the metabolic pathway of tannins,the flavor substances in Baijiu,was performed and may advance the breeding of sorghum cultivars for Baijiu production.

Molecular mechanisms of stress resistance in sorghum: Implications for crop improvement strategies

Abiotic stresses, such as drought, salt, extreme temperatures, and heavy metal pollution, are the main environmental factors that limit crop growth and yield. Sorghum, a C4 grass plant with high photosynthetic efficiency, can grow in adverse environmental conditions due to its excellent stress resistance characteristics. Therefore, unraveling the stress-resistance mechanism of sorghum could provide a theoretical basis for developing and cultivating various stress-resistant crops. This understanding could also help to create a conducive environment for using marginal soil in agriculture and ensuring food security. In this review, we discuss the adaptation mechanisms of sorghum under drought, salinity, temperature, and soil heavy metal stresses, the specific response to stress, the screening of sorghum-resistant germplasm, and the identification and functional analysis of the relevant genes and quantitative trait loci(QTL). In addition, we discuss the application potential of different stress-tolerant sorghum germplasms reported to date and emphasize the feasibility and potential use in developing and promoting highly stress-tolerant sorghum in marginal soil.

Characterization of subunits encoded by Sn RK1 and dissection of combinations among these subunits in sorghum(Sorghum bicolor L.)

Sucrose nonfermenting-related protein kinase 1(SnRK1)is one of the critical serine/threonine protein kinases.It commonly mediates plant growth and development,cross-talks with metabolism processes and physiological responses to biotic or abiotic stresses.It plays a key role in distributing carbohydrates and sugar signal transporting.In the present study,eight SnRK1 coding genes were identified in sorghum(Sorghum bicolor L.)via sequences alignment,with three forαsubunits(SnRK1α1 to SnRK1α3),three forβ(SnRK1β1 to SnRK1β3),and one for bothγ(SnRK1γ)andβγ(SnRK1βγ).These eight corresponding genes located on five chromosomes(Chr)of Chr1–3,Chr7,and Chr9 and presented collinearities to SnRK1s from maize and rice,exhibiting highly conserved domains within the same subunits from the three kinds of cereals.Expression results via qRT-PCR showed that different coding genes of SnRK1s in sorghum possessed similar expression patterns except for SnRK1α3 with a low expression level in grains and SnRK1β2 with a relatively high expression level in inflorescences.Results of subcellular localization in sorghum leaf protoplast showed that SnRK1α1/α2/α3/γmainly located on organelles,while the rest four of SnRK1β1/β2/β3/βγlocated on both membranes and some organelles.Besides,three combinations were discovered among eight SnRK1 subunits in sorghum through yeast two hybrid,includingα1-β2-βγ,α2-β3-γ,andα3-β3-γ.These results provide informative references for the following functional dissection of SnRK1 subunits in sorghum.

A Survey of the Major Sorghum Production Regions for Foliar and Panicle Diseases during the 2022 Growing Season in Senegal, West Africa

Sorghum is a vital commodity and greatly contributes to the daily calorie needs for millions of the inhabitants in Senegal, West Africa. Yet, sorghum productivity and profitability are impacted by diseases. In the 2022 growing season, 122 farmers’ fields across 7 regions, notably Diourbel, Fatick, Kaffrine, Kaolack, Kolda, Tambacounda, and Thies were surveyed for foliar and panicle diseases. During the survey, stops were made at 30 km intervals and at each stop, 2 - 5 fields were evaluated. In each field, 40 plants mostly at soft to early hard dough stages of development were assessed using a W-shaped pattern to cover the whole field. A total of 13 diseases, including leaf blight, anthracnose, Zonate leaf spot, Sooty stripe, rough leaf spot, oval leaf spot, long smut, grain mold, and covered kernel smut were documented. The most predominant diseases were leaf blight, anthracnose, and zonate leaf spot. The prevalence of leaf blight was 100%, while anthracnose and zonate leaf spot were found in 93 out of the 122 fields surveyed, indicating a 76% prevalence, respectively. Across the regions, the prevalence of rough leaf spot was 47%, covered kernel smut (32%), oval leaf spot (19%) and target leaf spot (19%). Mean incidence of leaf blight was high in all regions, ranging from 94% (Kaolack) to 100% (Fatick and Tambacounda). The highest mean incidence of anthracnose (62%) and covered kernel smut (16%) was noted in Tambacounda region. In the region of Thies, the highest mean incidence of zonate leaf spot (49%) was recorded. The mean severity of leaf blight (37%) was highest on plants assessed in the region of Kaffrine, followed by those in the regions of Kaolack, Tambacounda, and Kolda. Anthracnose infection was most intense on plants evaluated in Kolda, while zonate leaf spot was most severe in the region of Tambacounda. Fields with incidences of 85% and above were considered as “hotspots” to evaluate sorghum germplasm for disease resistance. This survey is significant because the information obtained will be beneficial to plant pathologists, sorghum producers, government officials, and funding agencies to prioritize research projects that ensure productivity and food security.

Reaction of Sorghum Differentials to Grain Mold Infection in Puerto Rico

Grain mold, associated with many fungi, is the most important disease of sorghum, causing both yield and quality losses. In this study, 23 sorghum differentials used in pathotype characterization of anthracnose and head smut pathogens were evaluated for grain mold resistance under favorable conditions in Isabela, Puerto Rico. Lines BTx643 and IS18760 exhibited the lowest grain mold severity, indicating that these two may possess genes for grain mold resistance. These two lines also recorded the highest germination rates 94.7% and 97.6%, respectively, and their seed weight was among the heaviest. In conclusion, these two lines can be utilized in breeding programs to develop grain mold-resistant hybrid lines.

Phenotypical and gene co-expression network analyses of seed shattering in divergent sorghum(Sorghum spp.)

Sorghum[Sorghum bicolor(L.)Moench],a multipurpose C4 crop,is also a model species of the Poaceae family for plant research.During the process of domestication,the modification of seed dispersal mode is considered a key event,as the loss of seed shattering caused a significant increase in yield.In order to understand the seed shattering process in sorghum,we further studied eight previously identified divergent sorghum germplasm with different shattering degrees.We described their phenotypes in great detail,analyzed the histology of abscission zone,and conducted a gene co-expression analysis.We observed that the abscission layer of the most strong-shattering varieties began to differentiate before the 5-10 cm panicles development stage and was completely formed at flag leaf unfolding.The protective cells on the pedicels were also fully lignified by flowering.Through the weighted gene correlation network analysis(WGCNA),we mined for candidate genes involved in the abscission process at the heading stage.We found that these genes were mainly associated with such biological processes as hormone signal transmission(SORBI_3003G361300,SORBI_3006G216500,SORBI_3009G027800,SORBI_3007G077200),cell wall modification and degradation(SORBI_3002G205500,SORBI_3004G013800,SORBI_3010G022400,SORBI_3003G251800,SORBI_3003G254700,SORBI_3003G410800,SORBI_3009G162700,SORBI_3001G406700,SORBI_3004G042700,SORBI_3004G244600,SORBI_3001G099100),and lignin synthesis(SORBI_3004G220700,SORBI_3004G062500,SORBI_3010G214900,SORBI_3009G181800).Our study has provided candidate genes required for shedding for further study.We believe that function characterization of these genes may provide insight into our understanding of seed shattering process.

Farmers’ Perception of Phenotypic Variation of Different Types of Sorghum Cultivated in Burkina Faso

Sorghum bicolor is a multi-purpose species adapted to many agroecological zones of Burkina Faso. In the local farming system, different types of sorghum are cultivated together. Such farming conditions could increase gene flow between the different types of sorghum and contribute to the evolution of their main morphological characteristics. Understanding the effect of the farming system on the characteristics of different types of sorghum could contribute to building a strategy for the management of its genetic diversity. A survey and accessions collection was carried out in ten villages selected in two agroclimatic zones of Burkina Faso. A total of 133 accessions were collected and thirty local names were recorded. The results revealed a significant variability within sorghum characteristics based on farmers’ descriptions. Four types of sorghum were identified by farmers based on their uses. These are sweet grain sorghum, grain sorghum, sweet sorghum and dyer sorghum. Most of farmers (54.6%) practised intercropping, and 28.86% of them intercropped several types of sorghum in the same or nearby fields. A high coincidence of the flowering period of the types of sorghum was observed by farmers in both agroclimatic zones. The results also showed that most of the farmers (55.7%) noted changes in the morphological characteristics of different types of sorghum. These variations included the reduction in potential yields and changes in grain taste and colour within the same type. Understanding these variations could help conserve and sustain sorghum genetic resources in Burkina Faso.

Textural and functional analysis of sorghum flour cookies as ice cream inclusions

Flour serves as one of the primary ingredients of cookies,which affects dough properties,physical changes during baking,and post-baking cookie properties.Two gluten-free cookie formulations were developed with the goal of use as inclusions in frozen desserts.Blonde and chocolate cookies were made with sorghum flour or all-purpose wheat flour and then evaluated for physical and chemical properties.To determine functionality in a frozen state,texture analysis was conducted on cookies at−30℃,−17°C,and 20℃,replicating various ice cream storage temperatures.To simulate the process effect of incorporating the product into a frozen dessert,cookies were crumbled mechanically,and the crumbles were separated based on size.When evaluating cookies,no significant differences(P<0.05)were observed in width(W),thickness(T),spread,and W/T ratio for flour source within formula.Blonde cookies had lower moisture contents than chocolate cookies;further,blonde cookies made from sorghum flour had less moisture than those made with wheat flour.As the cookie temperature decreased from 20℃to−17℃,cookie hardness increased,with flour type having no effect.Within formula,cookies had similar instrumental color parameters.However,blonde cookies made from sorghum flour produced more smaller-sized pieces than those made from wheat flour.The results of this study demonstrate that sorghum flour cookies have desirable properties for use as inclusions in ice cream and other frozen desserts.

Genotypic Divergence, Photosynthetic Efficiency, Sodium Extrusion, and Osmoprotectant Regulation Conferred Salt Tolerance in Sorghum

Salt stress is one of the major limitations to modern agriculture that negatively influences plant growth and productivity.Salt tolerant cultivar can provide excellent solution to enhance stress tolerance with plantfitness to unfavorable environments.Therefore,this study was aimed to screen salt tolerant sorghum genotypes through evaluating of different morphological,biochemical,and physiological attributes in response to salinity stress.In this study,we have been evaluated total six sorghum genotypes including Hybrid sorgo,Debgiri,BD-703,BD-706,BD-707,and BD-725 under salt stress(12 dS m^(-1) NaCl).The response variables included length and weight of root and shoot,root:shoot ratio(RSR),photosynthesis(A),transpiration rate(E),elemental concen-trations(K^(+),Na^(+) and K^(+)/Na^(+)),photochemical efficiency of photosystem II(F_(v)/F_(m)),water use efficiency(WUE)and pigment content(chlorophyll a,and b).The results revealed that saline environment significantly reduced all response variables under study of sorghum genotypes,however,Hybrid sorgo remained unmatched by recording the maximum root and shoot traits.The same genotype recorded higher photosynthetic efficiency which was attributed to Na^(+) extrusion,K^(+) uptake and higher K^(+)/Na^(+) ratio(1.8 at stress),while these mechanisms were not fully active in rest of genotypes.Moreover,this study also implies the involvement of proline in imparting tolerance against saline environment in Hybrid sorgo genotype.Overall,BD-703 remained the most salt sensitive genotype as evident from the minimum morphological growth traits and the least biosynthesis of osmoprotectants.Thesefindings open new research avenues for salt stress alleviation by identifying elite salt-to-lerant genotypes of sorghum for breeding programs.

Farmer Participatory Evaluation of Sorghum Hybrid in Niger

Participatory varietal selection (PVS) with farmers and Seed Companies was conducted at Maradi research station (07°05'E/13°48'N) and in farmer field to evaluate and select sorghum hybrid varieties for high yield and other important agronomic traits. The experimental design was a randomized complete block with three replications where flowering (days), plant height (cm) and yield (kg) were collected. The analysis of variance showed highly significance among treatments of all traits measured Environment and Genotype by Environment interactions also contributed significantly to the performance of yield components. The highest average grain yield was recorded from hybrids P9511A x ST9007-5-2-1 (4289 kg/ha), NE223A x 90SN1 (3666 kg/ha), NE223A x Sepon 82 (3533 kg/ha) and NE223A x P9405 (3519 kg/ha) across locations. Farmers’ preferences were the panicle size, good seed set, earliness, and seed color. Hence, in a variety selection farmer’s preferences focus more on prioritized yield-related trait. The best varieties ranked by traits of interest were P9511A x ST9007-5-2-1, NE223A x 90SN1, NE223A x P9405 and P9511A x SEPON 82 that performed well under their circumstances. The results showed that farmers’ preferred varieties match with researchers. Therefore, based on objectively measured traits, farmers’ preferences and the agro ecologies of the site, varieties NE223A x 90SN1 and P9511A x ST9007-5-2-1 were found promising for production.

Effect of ultrasound and microwave pretreatment on sprouting,GABA,bioactive compounds,and other physicochemical properties of sorghum

Aim of this study is to see how ultrasound(US)and microwave(MW)pretreatments affectγ-aminobutyric acid(GABA)and physicochemical parameters of sorghum sprouts.Before sprouting,the sorghum was treated with the US at different time intervals(10,15,20 min)and MW at various power levels(10%,30%,50%).Sample treated by the US for 15 min showed the highest sprouting percentage of 97.33%.Both treatments induced stress in grain resulting in GABA accumulation substantially from the control where US for 15 min and MW at 10%power level had the highest of 87.14 and 66.97μg/g,respectively.US treatment for 20 min showed the highest total phenolic content(TPC)of 21.26 mg GAE/100 g,while on 10 min of treatment,it showed the highest antioxidant activity of 84.53%DPPH inhibition.The water absorption capacity and oil absorption capacity were the highest of 0.86 g/g and 0.98 g/g in the MW-treated sample at 10%output power respectively.In conclusion,the ultrasound treatment successfully accelerated the sprouting rate and GABA content while retaining total phenolic content,making it beneficial for developing functional foods.

Development of sorghum mutants with improved in vitro protein digestibility by CRISPR/Cas9 editing of kafirin genes

Sorghum(Sorghum bicolor(L.) Moench) is a major world crop that is a reliable source of fodder and food grain in arid regions. However, unlike other cereals, sorghum grain has low nutritional value, owing mainly to the resistance of its storage proteins(kafirins) to protease digestion. Changing the composition of kafirins or their primary structure may address this problem. To induce mutations in kafirin-encoding genes that were expected to disturb their accumulation in endosperm cells, we used a genome-editing approach. By Agrobacterium-mediated genetic transformation of immature embryos of cv. Avans, we obtained 14 transgenic plants with genetic constructs for site-directed mutagenesis of the k1C5 and g KAF1 genes encoding 22 k Da a-and 28 kDa γ-kafirins, respectively. Sequencing of 5 regenerants obtained by using k1C5-addressing vector revealed two plants with mutations. T_1 progeny of these mutants had higher in vitro digestibility of endosperm proteins(86%–92%), in comparison with the donor Avans(63%–67%). The kernels of these plants had a thick vitreous endosperm. A mutant with increased in vitro protein digestibility and vitreous endosperm, carrying a mutation in the target sequence, was also obtained by use of the gKAF1-addressing vector. Thus, using genome editing technology, we have obtained mutants with improved kafirin digestibility that can be used in sorghum breeding.

Study on Distribution Characteristics and Occurrence Form of Soil Fluorine in Sorghum Base of Renhuai City

In order to find out the effects of soil fluorine on ecological environment and crop safety in the sorghum cultivation base of Renhuai City, Guizhou Province, the content and the occurrence forms of soil fluorine and its influencing factors of Maoba Town were investigated and studied. The results showed that the total fluorine content in the soil of the sorghum base ranged from 668.60 to 2 596.80 mg/kg, with an average of 1 483.25 mg/kg, which was 3.10 and 1.85 times of the national soil background value and the average value of the soil in endemic areas, respectively. The spatial distribution of fluorine in the soil of the study area was uneven, and the fluorine content was in the order of Anliang Village>Yangliu Village>Houba Village>Xiongfeng Village. The soil fluorine contents of various forms varied greatly, and the distribution law was as follows: residual state>water soluble state>organically bound state>exchangeable state>Fe/Mn-F state. The residual fluorine content was the highest, accounting for more than 99% of total fluorine content, while the sum of other four forms was less than 1%, with their respective proportions ranging from 0.10% to 0.30%. The content and proportion of available fluorine in water-soluble and exchangeable states were relatively low, which had limited influence on the surrounding water environment and crop safety. The physicochemical properties of soil, such as pH, organic matter, cation exchange capacity and clay particles had a certain influence on the occurrence forms of soil fluorine, thus changing the availability and migration of soil fluorine, which might endanger the ecological environment safety, food safety and human health.

Using Sorghum Stalk as a Partial Replacement of Lime in the Stabilization of Red Clay Soil for Road Sub-Grade Construction

This research aimed at testing the viability of using Sorghum Stalk Ash (SSA) as a partial replacement of lime in the stabilization of red clay soils for road subgrade construction. Red clay soils have been identified as highly expansive soils, which are affected by both climatic conditions and loading patterns. The consideration of both traffic loading patterns and climatic effects on these soils has been taken into account. A penetration test of 2.5 mm has been used on both pure red soils and stabilized soils at 10% and 15% partial replacement of lime with SSA and showed an improvement in the CBR of stabilized red clay soils up to 11.6%. Again, the PI of stabilized soils at 15% partial replacement of lime reduced up to 11.2%. The results obtained on both CBR and PI of these red clay soils are within the recommended values for the effective subgrade required for laying both permanent and flexible pavements. As a result, a recommendation of making use of SSA to lower the quantities of lime and its costs used in the stabilization of highly expansive soils have been tested through this research. However, further research on a more percentage partial replacement of lime to improve the PI of these soils to below 10% while keeping the CBR levels within the road construction regulations is welcomed.

3个高丹草品种在新疆北疆地区的生产性能综合评价

为筛选出适宜在新疆北疆地区推广种植的高丹草品种,采用随机区组设计,测定了3个冀草系列高丹草品种(冀草5号、冀草2号、冀草8号)的株高、干鲜比、草产量等指标,并利用灰色关联法进行了生产性能综合评价。结果表明,根据3个品种在北疆地区的生育期可将冀草5号、冀草2号、冀草8号分别划分为早、中、晚熟品种。冀草5号的株高最高,为325.30 cm,冀草2号的草产量最高,其鲜草产量为127 556.19 kg/hm^(2),干草产草量可达30 613.49 kg/hm^(2)。灰色关联度综合评价结果由高到低的顺序为冀草2号>冀草5号>冀草8号。说明冀草2号高丹草更适宜在新疆北疆地区推广种植。

179份高粱种质资源表型鉴定与遗传多样性分析

为充分挖掘利用优异高粱种质资源,选育高粱新品种,提高黑龙江省高粱种质资源利用效率,以179份高粱资源为试验材料,运用相关分析、聚类分析等方法综合分析12个农艺性状。结果表明,179份高粱种质资源在12个农艺性状上,均表现出丰富的遗传多样性,变异系数变化在13.70%~128.32%,大小表现为着壳率>粒形>角质率>株高>单穗粒重>壳色>粒色>穗柄长>千粒重>穗柄径>茎粗>抽穗日数。相关分析得出,单穗粒重与千粒重、株高、抽穗日数、茎粗、穗柄径和穗柄长呈显著(P<0.05)或极显著(P<0.01)正相关,千粒重与穗柄径、茎粗呈极显著(P<0.01)正相关,着壳率与千粒重呈极显著(P<0.01)负相关。聚类分析可将179份高粱资源分成4个类群,宜在不同类群间选配亲本开展杂交以培育新种质。筛选出DY042、DY048、DY155三份资源可用作食用高粱改良的基础材料。DY062可作为提高粒重、穗重,降低着壳率的亲本加以利用。

新疆高粱种质资源萌发期抗旱性综合评价

为研究新疆本土高粱(Sorghum)种质资源的抗旱性并筛选萌发期有效抗旱指标,以来源于不同地区的207份高粱种质资源为研究对象,采用PEG-6000溶液模拟干旱胁迫条件,对高粱萌发相关的10个指标进行分析,在主成分分析基础上采用隶属函数法对各高粱品种的抗旱性进行综合评价。结果表明:在干旱胁迫下,高粱的各萌发指标均受到影响。其中,相对发芽势与萌发抗旱指数相关性最强,前3个主成分累计贡献率为78.328%,分别反映高粱在干旱胁迫下的生长、萌发及发育情况。根据综合得分将207份种质划分为5类,即高度抗旱种质12份、抗旱种质28份、中等抗旱种质87份、干旱敏感种质64份和高度敏感种质16份。筛选出高粱萌发期抗旱性鉴定的重要指标为相对芽鲜重、萌发抗旱指数、相对干物质转运率,建立了可准确评估高粱萌发期抗旱性的回归方程,为高粱萌发期抗旱性种质筛选提供理论依据。

HPLC同时测定甜高粱中10种黄酮类化合物含量及抗氧化活性对比研究

试验旨在建立同时测定甜高粱不同部位中10种黄酮类化合物含量的高效液相色谱(HPLC)检测方法,并对总黄酮提取物抗氧化能力进行评价。试验以甜高粱陇甜粱2号成熟期籽粒、茎秆及全株为研究对象制备总黄酮提取物,利用HPLC同时测定不同部位总黄酮提取物中的儿茶素、氯化芹菜定、花旗松素、芦丁、槲皮素、木犀草素、柚皮素、高北美圣草素、芹菜素及麦黄酮含量。结果显示,10种黄酮类化合物分别在各自线性范围内与色谱峰峰面积线性关系良好,R^(2)为0.9984~0.9999,平均加样回收率为95.0%~105.8%,RSD为1.03%~2.86%。抗氧化性测定结果表明,甜高粱不同部位总黄酮提取物对羟基自由基、超氧阴离子自由基、1,1-二苯基-2-三硝基苯肼(DPPH)自由基和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS^(+))自由基均具有一定的清除能力,不同浓度下清除率均表现为籽粒>全株>茎秆;籽粒总黄酮提取物浓度为1.00 g/L时,籽粒总黄酮提取物对DPPH自由基的清除率高于VC和2,6-二叔丁基-4-甲基苯酚(BHT)。相关性分析结果表明,不同部位总黄酮提取物含量与不同自由基清除率及总还原能力(FRAP)均呈正相关。研究表明,该试验方法简便,结果准确性较高,可用于甜高粱中黄酮类化合物含量的测定;甜高粱不同部位总黄酮提取物具有抗氧化活性。

氮肥不同追施方式对甜高粱叶片光合特性及产量的影响

【目的】研究氮肥不同追施处理下甜高粱不同生育期光合特性的变化规律及最佳氮肥追施方式。【方法】设置大田试验,分析空白不施肥(CK)、B_(1)(2次沟施追氮肥)、B_(2)(2次滴施追氮肥)、B_(3)(4次滴施追氮肥)等4种氮肥不同追施处理对6种甜高粱品种不同生育阶段叶片的光合特性、水分利用效率(WUE)动态规律及生物产量的影响。【结果】甜高粱叶片的Pn、Tr、Ci、WUE在不同生育期不同氮肥追施处理下的变化趋势不一致,品种和处理间存在变化规律差异的现象。同一品种在同一生育阶段氮肥不同追施处理的光合特性有差异,叶片光合特性受氮肥追施处理的影响。Pn的变化范围在5.50~28.52μmol CO_(2)/(m^(2)·s),大力士在B_(3)处理处于最高值,比CK显著提高39.91%。全部品种在B_(2)处理的Tr值与CK处理的Tr值差异均不显著。拔节和乳熟期B_(3)处理所有品种的Gs值与CK处理的Gs值差异均不显著。WUE的变化范围在3.05~16.86μmol/mmol,拔节期只有B_(2)处理晋甜杂3号WUE值比CK显著提高71.28%,其他所有处理所有品种均与CK差异不显著。开花期B_(1)处理所有品种的WUE值均与CK不显著。生物产量变化范围在47.51~85.85 t/hm^(2),氮肥追施处理比CK增产幅度为7.66%~53.67%。大力士在所有处理的产量均高于其他品种,且B_(1)、B_(2)、B_(3)处理产量最高的品种顺序均一致,大力士>晋甜杂3号>辽甜3号。【结论】大力士、晋甜杂3号、辽甜3号在当地的适应性较好,B_(2)处理能够改善光合条件,使产量和水分利用效率达到最大,该处理是促进干旱区高粱生长发育的最佳氮肥滴管追施模式。