Motes percentage and ginning outturn as affected with cotton cultivar and location

The present study was conducted to analyze cotton cultivar and location differences in motes, and to determine the relationships among these and ginning outturn. Therefore, the seed cotton of five promising hybrids namely;G.77 × Pima S6 and G.84 × (G.74 × G.68) growing in [Kafr El-Sheikh - Kafr El-Dawar - Etay El-Barood - Damietta], G.89 × Pima S6 growing in [El-Sharkia - El-Gharbiya - El-Dakahliya - El-Monofiya], G.83 × (G.75 × 5844) × G.80 and G.90 × Australian growing in [Sohag - El-Minia - Beni-Sueif - El-Faium] were used in this study. The results obtained indicate that the varieties exhibited different behavior responses to environmental conditions. On the whole, environmental factors associated with differences in place of growth, appeared to have much more influence on the number of motes than did varietal factors. Most of the locks for the promising hybrids at the different locations tend to cluster around the mean of 6 or 7 seeds per lock. There is a fairly marked tendency for the lock index, lint weight and lint percentage to decrease as the motes percentage increase. On the other hand, most of the promising hybrids under study tend to increase in the seed index as the motes percentage increase. However, the increasing in seed index as a result of the increasing in motes percentage for some cotton cultivars growing at different environments could be explain the difference in behavior for these cotton cultivars in lint percentage.

Effect of Different Hormone Combinations on Somatic Embryogenesis in Cotton Cultivar Xinluzao 33(Gossypium hirsutum L.)

[Objective] This study was conducted to evaluate the efficiency of somatic embryogenesis and plant regeneration for an upland cotton cultivar Xinluzao33 under the induction of different hormone combinations and thus to determine the optimal hormone combination. [Method] Calli of Xinluzao33(Gossypium hirsutum L.) were induced from seedling hypocotyl tissue by a range of DK and BK combinations. Embryogenic calli and embryos were induced on callus-inducing medium(CIM) without any hormones. Callus appearance and quality were compared to determine which medium was the optimal for callus induction. Embryogenesis ratio was calculated to determine which medium was the best for somatic embryogenesis and plant regeneration. [Result] Callus induction rate was 100% in all the 12 hormone combinations.The calli were yellow or kelly, and their texture was loose or soft under low concentrations of DK combinations, green or white, variably compact under high concentrations of DK combinations. The calli induced by BK combinations were kelly or green, covering creamy white substance. The best medium for callus induction was DK6(0.05 mg/L 2, 4-D and 0.10 mg/L KT). Embryogenic calli were successfully induced from all the combinations. The efficiency of embryogenic callus induction,embryogenesis, and plantlet regeneration were significantly different among the 12 combinations. The result showed that the embryogenesis ratio was the highest in BK3 combination(0.50 mg/L IBA and 0.50 mg/L KT), 72.86% of embryogenic calli differentiated into somatic embryos after being cultured on CIM for 80 d, and80.93% of the somatic embryos finally regenerated into plants on SEM(somatic embryo induction medium). [Conclusion] These results indicate that hormone combination BK3(0.50 mg/LIBA and 0.50 mg/L KT) was the best medium for somatic embryogenesis and plant regeneration from Xinluzao33.

Demographic parameters of cotton aphid, Aphis gossypii Glover （Homoptera： Aphididae） on five cotton cultivars

Life table parameters of the cotton aphid, Aphis gossypii Glover, were estimated on five cotton cultivars （‘ Sealand＇ ,‘Siokra＇ ,＇ Vararnin＇ ,‘ Bakhtegan＇ and ‘ Sahel＇ ）. Demographic parameters of the cotton aphid were assessed at 27.5 ± 1 ℃, 65% ＋ 10% RH and a photoperiod of 14：10 （L： D）h. The shortest developmental time for the nymphal stages was 5.5 days on ‘Siokra＇ and the longest was 6.1 days on‘ Sealand＇. The highest offspring per female was 29.6 on ‘Sahel＇ and the lowest was 15.3 on ‘Sealand＇. The rm values varied from 0.272 on ‘Sealand＇ to 0.382 （day^-1） on ‘Varamin＇. Jackknife estimates of the A. gossypii parameters on these cultivars indicated the greatest developmental rate and fecundity on ‘ Varamin＇ and the poorest on ‘ Sealand＇ cultivar.

Evaluation on the High Yielding, Stability and Comprehensive Performances of Check Cultivars in National Cotton Regional Trials in the Yangtze River Valley

[Objective] This study was to analyze the high yielding, stability, adaptabil-ity and main characteristics of check cultivars in national cotton regional trials in the Yangtze River Val ey in 2000-2013, with the aim to provide theoretical basis for the reasonable selection of check cultivars for cotton regional trials. [Method] GGE biplot analysis method was used to carry out the intensive analysis and comprehensive comparisons on the performances and differences of the 9 major characters of check cultivars, namely, lint cotton yield , stability, and other main traits including bol weight, bol number, lint percentage, fiber length, fiber strength, micronaire val-ue, plant height and seed index. [Result] Ezamian 10 was suitable in the majority of cotton planting regions in the Yangtze River Val ey, with the best high yielding abili-ty and perfect yield stability. The yielding ability of Xiangzamian 8 ranked the sec-ond, but its stability was the poorest. Xiangzamian 8 was of the specific adaptive cultivar with relatively good performance in high yielding but the poorest stability. The suitable planting areas of Xiangzamian 8 were limited to the cotton planting re-gion around Dongting Lake in Hunan province, Poyang Lake in Jiangxi Province, the Coastal region in Jiangsu Province and Wuhan district in Hubei Province. Xi-angzamian 2 performanced poorer in both yielding and stability, while Simian 3 ranked first in stability but the last in yielding ability. The dominant character of Xi-angzamian 8 and Xiangzamian 2 were high cotton plants and big bol s. Simian 3 performanced super in lint percentage and fiber length. Ezamian 10 was strong in cotton bol formation ability, lint cotton yielding, fiber strength and seed size, as wel as high micronaire value. [Conclusion] The outstanding performance of Ezamian 10 in high and stable yield in the Yangtze River Val ey in recent years has effectively promoted the high yielding ability of candidate varieties in cotton regional trials in the area.

Genotypic variation in spatiotemporal distribution of canopy light interception in relation to yield formation in cotton

Background: Within-canopy interception of photosynthetically active radiation(PAR) impacts yield and other agronomic traits in cotton(Gossypium hirsutum L.). Field experiments were conducted to investigate the influence of 6 cotton varieties(they belong to 3 different plant types) on yield, yield distribution, light interception(LI), LI distribution and the relationship between yield formation and LI in Anyang, Henan, in 2014 and 2015.Result: The results showed that cotton cultivars with long branches(loose-type) intercepted more LI than did cultivars with short branches(compact-type), due to increased LI in the middle and upper canopy. Although loose-type varieties had greater LI, they did not yield significantly higher than compact-type varieties, due to decreased harvest index. Therefore, improving the harvest index by adjusting the source-to-sink relationship may further increase cotton yield for loose-type cotton. In addition, there was a positive relationship between reproductive organ biomass accumulation and canopy-accumulated LI, indicating that enhancing LI is important for yield improvement for each cultivar. Furthermore, yield distribution within the canopy was significantly linearly related to vertical LI distribution.Conclusion: Therefore, optimizing canopy structure of different plant type and subsequently optimizing LI distribution within the cotton canopy can effectively enhance the yield.

Response of Yield and Related Attributes of Upland Cotton to Weather Variables

Cotton growth and development is effected by various ecological issues like temperature fluctuations, distribution and quantity of rainfall, relative humidity and winds which are the climate change attributes. A field experiment was carried out to find out the response of cotton to weather variables in terms of total variation in yield and quality. The effect of planting times and thermal temperatures (cumulative heat units) on yield of 4 cotton cultivars viz;CIM-600, CIM-616, CIM-622 & CRIS-641 was evaluated. Plants were sown on 6 planting times during the year 2015-2016 and 2016-2017 in an experiment conducted in randomized complete block design having three replications. Cotton cultivars depicted significant variances for number of bolls plant-1, boll weight and seed cotton yield. The cultivar CIM-616 depicted the highest seed cotton yield of 2083.60 kg·ha-1 on interpretation of highest bolls and boll weight. Maximum seed cotton yield was noted in planting time from 1st April to 15th April whereas early and late planting decreases the seed cotton yield on account of less accretion of cumulative heat units. Regression analysis depicted that rise of one unit (15 days) from early to optimal date (15th March to 15th April) enhanced the seed cotton yield by 93.76 kg·ha-1 (y = -93.764x2 + 521.04x + 1364). Delayed planting also reduces the seed cotton yield with the same ratio. It is therefore established that cotton must be cultivated from 1st April to 1st May to harvest good production in this type of climate.

不同熟性棉花品种棉铃时空分布及产量比较

【目的】研究新疆南疆地区不同熟性棉花品种棉铃时空分布及产量的差异规律,为新疆南疆地区选择适宜熟性品种种植提供理论依据。【方法】于2020年设置中早熟品种(中棉所96A)、中熟品种(塔河2号、新陆中73号),分析不同熟性棉花品种棉铃时空分布及其产量的变化规律。【结果】中熟品种(塔河2号、新陆中73号)的株高、茎粗显著高于中早熟品种(中棉所96A),塔河2号、新陆中73号的株高较中棉所96A分别增加了22.28%、9.84%,茎粗分别增加了25.01%、11.55%,中熟品种的果枝始节高度大于中早熟品种;“三桃”比例中伏前桃表现为塔河2号>新陆中73号>中棉所96A,伏桃为中棉所96A>新陆中73号>塔河2号,秋桃为新陆中73号>塔河2号>中棉所96A;棉铃空间分布上,中棉所96A的棉铃主要分布在中下部内围铃,而塔河2号和新陆中73号则分布在下部、上部内围铃;中熟品种中部外围铃的蕾铃脱落率高于中早熟品种相同部位;中早熟品种的单铃重显著高于中熟品种,中棉所96A的单铃重较塔河2号、新陆中73号分别增重了3.15%、7.73%,中棉所96A与塔河2号的籽棉产量比新陆中73分别提高了3.53%、2.70%。【结论】中早熟品种中棉所96A和中熟品种塔河2号均适宜在新疆南疆地区种植,可获得较高的产量。

Effect of Infestation of <i>Alabama argillacea</i>(Lepidoptera: Noctuidae) at Different Ages of Cotton Plants in Yield

The cotton leafworm is an important defoliating pest of cotton in Brazil, and occurs in all regions where the crop is cultivated. The purpose of this study was to evaluate the effect of larval densities of A. argillacea after different infestation periods on the yield components of four cotton cultivars. The experiment was carried out in Pindorama, SP, Brazil, in the 2008/2009 growing season. The cultivars IAC-25, DeltaOPAL, Fibermax 966 and Fibermax 993 were artificially infested with A. argillacea larvae at three times (30, 60 and 90 DAE) and four densities (0, 2, 4, and 6 larvae per plant). The average boll weight (g), fiber percentage (%), 100-seed weight (g) and yield (kg·ha-1) were evaluated. With increasing infestation density of A. argillacea, the cotton yield of the cultivars decreased. The presence of larvae significantly reduced the weight of 100 seeds of cultivar Fibermax 966. Initial infestations reduced the boll weight of IAC-25 and DeltaOPAL, while cultivars Fibermax 966 and Fibermax 993 were most affected by late infestations. Early infestation compromised fiber percentage of cultivar DeltaOPAL and late infestations were most harmful to cultivar Fibermax 966. Early A. argillacea infestation reduced the yield of DeltaOPAL, while infestations 60 DAE caused the most damage to IAC-25, and the other cultivars were not affected by the moment of infestation.

Screening of drought resistance indices and evaluation of drought resistance in cotton(Gossypium hirsutum L.)

Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drought resistance of different cotton cultivars.Eighteen physiological indices including root,stem,and leaf water contents(RWC,SWC,and LWC),net photosynthetic rate(Pn),the maximum photochemical quantum yield(Fv/Fm),the actual photochemical quantum yield(ΦPSII),non-photochemical quenching coefficient(NPQ),leaf water potential(LWP),osmotic potential(Ψs),leaf relative conductivity(REC),leaf proline content(Pro),leaf and root soluble protein contents(LSPC and RSPC),leaf and root malondialdehyde(MDA)contents(LMDA and RMDA),root superoxide dismutase,peroxidase,and catalase activities(RSOD,RPOD,and RCAT)were measured.Results indicated the 18 physiological indices can be converted into five or six independent comprehensive indices by principal component analysis,and nine typical indices(Fv/Fm,SWC,LWP,Pro,LMDA,RSPC,RMDA,RSOD,and RCAT)screened out by a stepwise regression method could be utilized to evaluate the drought resistance.Moreover,the 16 cotton cultivars were divided into four types:drought sensitive,drought weak sensitive,moderate drought resistant,and drought resistant types.The resistance ability of two selected cotton cultivars(drought resistant cultivar,Dexiamian 1;drought sensitive cultivar,Yuzaomian 9110)with contrasting drought sensitivities were further verified by pot experiment.Results showed that the responses of final cotton biomass,yield,and yield composition to drought were significantly different between the two cultivars.In conclusion,drought resistant cultivar Dexiamian 1 and drought sensitive cultivar Yuzaomian 9110 were screened through hydroponics experiment,which can be used as ideal experimental materials to study the mechanism of different cotton cultivars with contrasting drought sensitivities in response to drought stress.

我国短季棉品种的RAPD指纹图谱分析

本文选用了18个随机引物,对25个我国主要的短季棉品种作了RAPD多态性分析。并对各品种的指纹图谱进行了聚类和相似性分析。结果表明,大部分短季棉品种与其系谱吻合。主要从来自美国的金字棉中选育而成,它再次反映了我国现在推广的短季棉品种遗传基础比较狭窄,亟待发掘新的早熟棉基因资源。研究结果可对杂种优势利用的亲本选配提供理论依据。

根际微生物多样性与棉花品种对黄萎病抗性关系研究──Ⅰ.根际微生物数量与棉花品种对黄萎病抗性的关系

对抗、感黄萎病6个棉花品种的根际线虫、真菌、细菌和放线菌的数量在苗期和现蕾期采用选择性培养基和直接观察法进行了分析。分析结果表明：棉花对黄萎病的抗性与根际真菌和放线菌数量呈正相关；与根际线虫数量负相关；与根际细菌数量无显著相关性。

高产稳产型棉花品种鲁棉研28号选育及其栽培生理特性研究

本文在简要回顾鲁棉研28号选育过程的基础上,总结了鲁棉研28号的选育经验和体会,全面分析了鲁棉研28号的高产稳产特性及其生理学机制,旨在为后继优良棉花品种的选育和栽培提供参考。

利用分子标记和形态学性状检测的陆地棉栽培品种遗传多样性

利用RAPD、ISSR和SSR 3种分子标记方法和 2年田间实验对国内外 36个陆地棉栽培品种的遗传多样性进行了研究。以 3种分子标记在 36个品种之间扩增的 2 82条多态性位点所赋值的 0、1数据 ,采用Nei和Li的方法 ,计算的品种成对相似系数从 0 5 745到 0 92 91 ,其品种平均数从 0 65 4 7到 0 75 2 4 ;又以 2年品种表现的性状平均数经正态标准化后 ,采用欧氏距离计算了成对品种的遗传距离。分别以相似系数和遗传距离矩阵 ,采用类平均法进行聚类分析 ,其聚类结果把供试品种大致分为国外品种、新疆品种、早熟类型品种和我国的中熟棉品种等几个类群 ;类内进一步分组表明 ,分子标记确定的遗传关系基本上与品种系谱的种质系统一致 ,但并不能按系谱或种植生态区域简单地归属 ;尽管分子标记数据计算的相似系数矩阵和表现型计算的遗传距离矩阵存在极显著的相关关系 (r=- 0 .335 ) ,但以遗传距离进行聚类分析的类内分组的组间特征不明显。分子标记是检测类内品种间遗传差异的有效方法 ,研究结果为棉花育种亲本选配提供了理论依据。

中国棉花主栽品种DNA指纹图谱构建及SSR标记遗传多样性分析

【目的】采用SSR标记构建2008年中国3大棉区8个棉花主产省份32份棉花主栽品种的DNA指纹图谱并进行遗传多样性分析。【方法】从214对候选引物中筛选出36对多态性高、稳定性好且在染色体上分布均匀的引物作为核心引物,构建棉花主栽品种DNA指纹图谱。【结果】36对SSR引物在32份材料中共扩增出142种多态性基因型,每对引物的基因型从2—11种不等,平均每对引物扩增出3.94种基因型。9对引物在10个品种上具有特征带型。最少采用5对引物进行组合鉴定即可将32个棉花品种完全区分开。NTSYS-pc V 2.10软件分析表明,长江流域棉区品种间遗传差异最大,新疆棉区次之,黄河流域棉区最小。常规品种的遗传基础窄于杂交陆地棉。【结论】核心引物组合法相比特征谱带法更适用于构建中国棉花主栽品种DNA指纹图谱,品种间的亲缘关系与地理来源有一定的相关性。

根际微生物多样性与棉花品种对黄萎病抗性的关系研究 II.不同抗性品种根际真菌区系分析及其对棉花黄萎病菌的抑制作用

对棉花抗黄萎病品种（春矮早和８６－ ６）和感病品种（中棉１７和豫棉１２）的根际真菌区系进行了分析。结果表明每个品种都有自己独特的根际微生物区系，抗病品种根际微生物种数多于感病品种，区系组成更为复杂。抗病品种根际真菌优势种主要是漆斑菌 （Ｍｙｒｏｔｈｅｃｉｕｍ ）、粘帚霉（Ｇｌｉｏｃｌａｄｉｕｍ ）、曲霉（Ａｓｐｅｒｇｉｌｌｕｓ）和青霉（Ｐｅｎｉｃｉｌｌｉｕｍ ）等，感病品种则多为头孢霉（Ｃｅｐ ｈａｌｏｓｐｏｒｉｕｍ ）、镰刀菌（Ｆｕｓａｒｉｕｍ ）、矛束孢（Ｄｏｒａｔｏｍｙｃｅｓ）、粘帚霉（Ｇｌｉｏｃｌａｄｉｕｍ ）和漆斑菌（Ｍｙｒｏｔｈｅｃｉｕｍ ）等。采用平板对峙培养法测定了不同抗性棉花品种根际真菌区系各成员对棉花黄萎病菌的抑制作用，发现抗病品种根际真菌区系中对黄萎病菌具有抑制作用的真菌种数和比率都高于感病品种，而且抗病品种根际真菌的优势种对棉花黄萎病菌的抑制作用较强。这种差异在苗期和现蕾期更为明显，花铃期则显著减小。研究结果表明棉花品种对棉花黄萎病的抗性与根际真菌区系组成及其对黄萎病菌的抑制能力有一定关系。

我国陆地棉品种的遗传多样性研究初报

选用１８个随机引物，对２１个陆地棉品种作ＲＡＰＤ分析，并对各品种的指纹图谱进行了聚类和相似性分析。结果表明大部分品种与其系谱吻合。研究结果充分展示了ＲＡＰＤ技术可以作为棉花品种分类和遗传多样性研究的可行方法。

陆地棉品种间杂种的霜前皮棉产量及其杂种优势研究

利用 2 0世纪八、九十年代我国棉花生产上推广的主要品种 (系 )做亲本 ,组配 15个组合的正反交杂种 ,对其 F1 、F2 代杂种的霜前皮棉产量及其竞争、中亲和超高亲优势进行了研究。结果表明 ,陆地棉品种间杂交 ,F1 、F2 代正交与反交组合间的霜前皮棉产量及其竞争、中亲和超高亲优势均无明显差异。 3 0个正反交 F1 杂交种具竞争、中亲和超高亲优势 (以下简称三优势 )组合率分别为73 %、10 0 %和 83 %。其中竞争优势在 15 %以上的组合率为 46.7% ,最大竞争优势值为 40 .6%。 3 0个正反交 F2 杂交种三优势组合率分别为 60 .0 %、90 .0 %和 66.8% ,其中竞争优势在 10 %以上的组合率达 3 3 .3 % ,最大竞争优势值仍达 3 1.3 % ,F2仍具有较高的生产利用潜能。亲本鲁 11、石远 3 2 1等品种 (系 )表现遗传配合力高 ,是目前棉花杂交制种选用的优良高产亲本。

新疆早熟陆地棉品种更替过程中的株型特征及主要经济性状的演变

【目的】分析新疆早熟陆地棉品种更替产量提高过程中株型特征及主要经济性状的演变趋势,结合发展机采棉对品种特性的需求,阐述品种更替中适宜机采特性的变化,为新疆棉花新品种选育及栽培管理提供理论依据。【方法】于2015-2016年和2018年选择新疆近40年来自育早熟陆地棉(Gossypium hirsutum L.)不同年代(1980s、1990s、2000s和2010s)大面积主栽品种(新陆早1号、新陆早7号、新陆早13号和新陆早45号)为材料,在膜下滴灌栽培条件下,对不同年代品种的第一果节长度、果枝节间长度、节枝比、株高、果枝始节、始节高度、果枝夹角、果枝数、叶枝数、倒四叶宽和茎粗共11个株型指标及主要经济性状的演变进行分析。【结果】随品种更替,棉株第一果节长度、果枝节间长度和节枝比逐渐增加,株型由紧凑型向较松散型转变;株高、果枝始节和始节高度逐渐增加,上部果枝与主茎的夹角逐渐减小,果枝上举,具有高产株型特征;根据棉花机采对品种特性的要求,2010s品种果枝始节高度和果枝角度较符合机采棉对株型的要求;不同年代品种间果枝数、叶枝数、倒四叶宽和茎粗无明显差异。皮棉产量、总铃数和衣分均随品种更替逐渐增加,其中1980s、1990s、2000s和2010s品种皮棉产量较当年区域试验产量分别高23%-53%、16%-20%、13%-14%和-2%-6%,膜下滴灌现代高产栽培技术对产量的提高有重要作用,但2000s和2010s品种收获指数显著低于1990s品种。与1980s和1990s品种相比,2010s品种上部铃期短4-5 d,吐絮相对集中,对脱叶剂敏感,吐絮率均在95%以上,无显著差异,但生育期偏长;与审定时品种的生育期相比,1980s和1990s品种提前了3-7 d,2000s和2010s品种提前了0-3 d,这可能与膜下滴灌促早熟栽培技术应用有关。2000s和2010s品种棉纤维长度、比强度、伸长率和纺纱一致性明显改善,但马克隆值相对偏大,纤维强度的改善是以牺牲纤维细度为代价,纤维品质协调性不佳。【结论】品种更替产量提高过程中,棉花经济性状改善,但品种株型由紧凑型向较松散型转变,生育期偏长,收获指数偏低,棉纤维马克隆值偏大;随着机采棉种植模式的应用,选育和选用纤维品质优、适宜机采的品种是保障新疆棉花产业稳步发展的关键。

不同熟性棉花品种棉铃空间分布及产量品质形成的差异

通过研究不同熟性棉花品种棉铃空间分布及产量品质形成差异,为该地区选择适宜熟性品种提供理论依据。在南疆塔里木盆地进行不同熟性棉花品种棉铃空间分布及产量品质形成差异的研究。结果表明:不同熟性棉花品种的棉铃脱落率表现为早熟>中熟>中早熟;"三桃"比例中伏前桃表现为早熟>中熟>中早熟,伏桃表现为中早熟>中熟>早熟,秋桃表现为中熟>早熟>中早熟;单株铃数和单铃质量表现为中熟>中早熟>早熟;产量表现为中早熟>中熟>早熟;上半部平均长度和断裂比强度表现为中早熟>中熟>早熟;马克隆值表现为中熟>中早熟>早熟。中早熟品种不论在成铃率和"三桃"比例,还是在产量、品质等方面都表现出较强的适应性,中熟品种次之,早熟品种不太适应塔里木棉区种植。在目前种植条件下,中早熟品种更适合在南疆塔里木棉区种植。

适合棉花品种鉴定的SSR核心引物的筛选

本研究利用来自Cotton Marker Database(CMD)数据库中的2000个引物对32份审定棉花品种基因组DNA进行了PCR扩增,筛选出26个多态性核心引物,其中11个引物被推荐为棉花品种鉴定的首选核心引物,同时提出了核心引物理论上可区分的最大品种数的计算公式:N=G1×…×Gn,理论推测结果表明:利用11个首选核心引物进行棉花品种鉴定是可行的。建立在SSR指纹数据基础上的不同组合品种(系)间聚类分析以及对25份区试品系和A品种的真实性鉴定,结果表明:所有参试品种(系)遗传基础狭窄,32份审定品种间DNA水平上的差异与品种来源的系谱分析结果基本吻合,首选核心引物不仅可以对品种(系)的真实性做出鉴定,而且对遗传距离狭窄的品种(系)具有很好的鉴别力。