木薯成熟种茎多倍体诱导及鉴定

以木薯品种SC205和新选048的成熟种茎为材料,利用秋水仙素对侧芽进行滴液法处理诱导多倍体,使用流式细胞仪鉴定木薯植株倍性,并通过形态学、解剖学、生理学方法鉴定和分析多倍体、嵌合体和二倍体特征特性。结果表明:通过诱变处理获得了木薯四倍体和嵌合体植株,四倍体和嵌合体植株与二倍体相比表现出最上部全展叶第1和第2叶叶形指数降低、叶片厚度增加,气孔密度变小,叶绿体数目增加,气孔长度、保卫细胞长度和宽度增大,叶绿素a含量、叶绿素b含量、类胡萝卜素含量、叶绿素总量、SPAD值增高,净光合速率、气孔导度、胞间CO2浓度、蒸腾速率增大。     

药用万寿菊多倍体的诱导与特征分析

为获得四倍体药用万寿菊材料,采用秋水仙素对药用万寿菊‘内蒙1号’的种子进行多倍体诱导研究。以0.15%浓度的秋水仙素处理露白的万寿菊种子24 h,幼苗变异率较佳,可达到56%。幼苗定植于田间,初步筛选并标记形态变异植株,自花授粉后采收种子播种并观测子代形态指标,对形态变异明显的植株进行流式细胞仪检测,确定获得15株纯合四倍体。通过将四倍体与二倍体进行比较,四倍体植株茎粗、栅栏组织厚度、栅栏组织与海绵组织的比例和单朵花重量显著高于二倍体植株,四倍体植株总叶量、叶宽、叶长、叶长宽比、叶片气孔密度和单株花朵数量显著低于二倍体植株。获得的四倍体万寿菊植株单株花总重量比二倍体显著增加。     

秋水仙素对猪屎豆的诱变及同源四倍体种质创制的研究

猪屎豆是重要的农业植物资源,在绿肥、饲用和药用等方面都有重要的开发潜力,然而目前关于猪屎豆的品种培育还处于空白,生产上缺乏优良品种导致生产性能参差不齐的问题突出,开展多倍体育种研究可为今后猪屎豆种质资源创新利用和培育新品种奠定材料基础。本研究以二倍体猪屎豆为实验材料,通过不同质量浓度秋水仙素和不同处理时间对猪屎豆露白种子进行多倍体诱导,探讨秋水仙素对二倍体猪屎豆的诱变效果,并利用流式细胞倍性检测和根尖染色体核型分析对诱变后代的倍性进行检测,进一步比较分析二倍体和同源四倍体的气孔和保卫细胞大小以及叶片和种子形态等特征变化。结果表明：与对照相比,秋水仙素处理抑制了猪屎豆种子胚根的生长和下胚轴的伸长,使种子胚轴发生诱变而缩短变粗。研究发现以100 mg/L的秋水仙素浓度浸泡12 h时猪屎豆种子四倍体诱导率最高,为13.33%,总体效果最佳。与二倍体相比,同源四倍体植株叶片下表皮的气孔长度和宽度、保卫细胞长度和宽度显著增加而气孔密度显著降低;同源四倍体植株的叶片宽度和叶柄宽度显著增加,而叶片长度和叶柄长度显著缩短;同源四倍体植株的叶形指数显著减小。此外,同源四倍体植株所获种子较二倍体显著增大,种子百粒重较二倍体显著增加。综上所述,本研究掌握了秋水仙素诱导加倍猪屎豆的方法,并成功获得了同源四倍体猪屎豆新种质,为猪屎豆遗传育种及相关基础研究奠定了种质基础。     

木薯品种华南12号（SC12）同源四倍体诱导及鉴定

多倍化可伴随产生一些优良的农艺性状，如抗逆性增强、器官体积变大、生物量增加等，多倍体育种为木薯新品种培育提供了一个重要途径。本研究以木薯品种SC12离体单芽茎段为诱导材料，比较不同浓度秋水仙素对外植体诱导率的影响，并对木薯二倍体与同源四倍体不同株系进行形态学、解剖学和农艺特性比较。结果表明，以0.03 g/L浓度的秋水仙素诱导SC12同源四倍体效率最高，为7.78%；通过流式细胞仪和根尖染色体数目观察对筛选的20个植株进行倍性鉴定，获得了11个同源四倍体和5个嵌合体植株，同源四倍体为检测株系的55%，变异植株为检测株系的80%；二倍体和同源四倍体植株表现出显著的形态和生理差异，在形态上表现为四倍体植株变矮、茎杆变粗、叶尖盾化，叶片由披针形向拱形过渡，同源四倍体裂叶长/裂叶宽显著降低、叶绿素含量显著增加；通过解剖学发现四倍体叶片保卫细胞的长、宽、叶绿体数目均显著增加，分别比二倍体增加2.33%、28.99%、117.79%；气孔数显著降低，比二倍体减少40.06%；四倍体变异株保卫细胞呈椭圆形，二倍体保卫细胞趋近于圆柱形；四倍体叶片厚度和栅栏组织厚度均显著高于二倍体，比对照分别增加24....     

橡胶树不同倍性的气孔性状差异研究

以通过流式细胞倍性检测鉴定出的橡胶树二倍体、三倍体、四倍体植株为研究对象,对不同倍性植株的气孔性状进行观察和统计。结果表明:不同倍性间的橡胶树叶片的气孔长度、气孔宽度、气孔密度均存在极显著差异。随着橡胶树倍性的提高,气孔的长度和宽度均增大,而气孔密度减小。二倍体、三倍体和四倍体的气孔长度范围分别为10.65~15.29、14.04~18.89、15.15~19.37μm,气孔宽度范围分别为7.13~10.65、8.58~11.83、10.38~13.83μm,气孔密度范围分别为520.62~867.69、402.53~764.80、381.79~555.32个/mm~2。以气孔长度15.15μm、气孔宽度10.38μm和气孔密度555.32个/mm~2为临界值,可以鉴定二、四倍体混合群体中的四倍体。三倍体和二倍体、四倍体在气孔长度值、宽度值和密度值在分布区间上均存在较大的重复,但以气孔长度14.04μm,气孔宽度8.58μm和气孔密度764.80个/mm~2为临界值,可以筛除二、三、四倍体混合群体中的部分二倍体,提高多倍体鉴定的效率。     

N+离子注入对同源四倍体水稻诱导效果的影响

以IR36、紫血稻、多胚苗品系APⅣ为材料,研究了N 注入对秋水仙素诱导水稻同源四倍体效果的影响。结果表明,当秋水仙素处理24 h时,经剂量为0.52×1016N /cm2的N 注入处理,种芽成活率提高,但在其后代中没有筛选到四倍体水稻植株,而用剂量为6.34×1016N /cm2的N 注入处理的后代中发现了四倍体水稻植株;当秋水仙素处理48 h或48 h以上时,经剂量为0.52×1016N /cm2的N 处理不但使种芽的成活率提高,而且还提高了诱导四倍体的效率,而剂量为6.34×1016N /cm2的N 注入处理会使四倍体诱导效率明显下降。     

Oryzalin离体诱导小果型西瓜四倍体及倍性鉴定研究

以3个二倍体小果型西瓜优良自交系048、032、047-1为试验材料,研究培养方式、Oryzalin浓度、处理时间对离体诱导西瓜四倍体的诱变效果,并对变异植株进行形态学比较、气孔测定及染色体鉴定。研究结果表明,采用液体培养的四倍体诱导率比固体培养高。在含50 mg/L Oryzalin的液体培养基中振荡处理2 d,四倍体诱导率最高达33.3%。变异植株通过染色体计数法鉴定得出染色体数为44,确定为四倍体植株。再生植株表现为叶片肥厚,叶色深绿,茎节缩短,株型紧凑矮小,茎蔓挺直,叶形指数变小;叶片气孔密度明显减小,保卫细胞体积增大,叶绿体数目增多;花瓣颜色深黄,且增宽、增厚。此结果说明Oryzalin对不同基因型的四倍体诱变效果存在一定差异。     

野生二倍体鸭茅染色体加倍及杂交利用研究

对滇中朗目山野生二倍体鸭茅用秋水仙素处理萌动种子，获得了混倍体鸭茅(同一植株根尖中二倍体细胞和四倍体细胞混存)，混倍体鸭茅的形态学特征及生长发育均与二倍体无明显差异；从混倍体鸭茅自然传粉后代中，获得了纯合同源四倍体鸭茅。同源四倍体鸭茅的气孔和种子均较二倍体大，但形态、发育与二倍体差异较小。以诱导所得混倍体为母本，与四倍体栽培种杂交，杂交F1代为四倍体，其形态学特征及物候发育均介于野生二倍体和四倍体栽培种之间，早期生长与四倍体栽培种相当，优于野生二倍体，繁殖性能与野生二倍体相当，强于四倍体栽培种，分蘖、再生性及干物质产量均强于二倍体，但明显不如四倍体栽培种。以鸭茅野生二倍体为母本，与四倍体栽培种进行杂交，获得的杂交三倍体高度不孕，但早期生长、分蘖、再生等明显优于母本二倍体，杂交三倍体开放传粉后代倍性复杂，混倍体、四倍体和五倍体都有。     

橡胶树种质资源的倍性鉴定

倍性鉴定是橡胶树种质资源鉴定评价的基础工作之一。本研究利用流式细胞仪对国家橡胶树种质资源圃内的橡胶树种质资源进行全面的倍性鉴定,对嵌合体的四倍体细胞比例进行分析,并比较不同倍性的气孔性状差异。从5177份野生种质中发现三倍体11份,四倍体1份。从552份魏克汉种质中发现,三倍体9份,四倍体2份,嵌合体14份。14份嵌合体的四倍体细胞比例在49.06%~78.26%之间。不同倍性间的气孔长度、宽度和密度差异均极显著,气孔长度和宽度的排序为四倍体>三倍体>嵌合体,气孔密度的排序相反。研究结果对利用四倍体种质资源开展橡胶树倍性间杂交育种具有重要应用价值。     

秋水仙素应用于大麦育种的初步研究

用0．04%的秋水仙素溶液处理分蘖盛期的二棱皮大麦（浙皮1号）的植株，在M1代即获得四倍体类型，同时还获得许多早熟、大穗、高植等性状变异的二倍体大麦植株，并从这些变异株中选得一优良株，经加速培育即在生产上示范推广．且很快通过了省级审定，定名为闻诱3号。     

Oryzalin Treatment of Potato Diploids Yields Tetraploid and Chimeric Plants from which Euploids could be Derived by Callus Induction

Shoot apices from six diploid potato genotypes for polyploidisation were treated with oryzalin and colchicine solutions at different concentrations and incubation times. In addition to chimeric plants, diploids, one octoploid and completely ploidy doubled plants (4x) were regenerated in these experiments. Tetraploid plants were obtained for three of the six genotypes treated with oryzalin, and no tetraploid plants were obtained after colchicine treatments of any of the genotypes. The best result of 43% tetraploid plants was achieved using 28.8 μM oryzalin and 24 h of incubation with the L37 genotype. Moreover, we determined that doubled plants should not be selected on the basis of a single measurement and require additional ploidy checks in successive clonal generations. Some L37 plants that were initially identified as tetraploids by flow cytometry produced diploid or mixoploid plants in the next clonal generation. Morphological characters of doubled L37 plants were compared with the original genotype. The PVY resistance present in a parental clone was maintained in all regenerants and significant differences among ploidy variants were found for some quantitative characters. Molecular AFLP analyses did not show any differences among genotypes. Since polyploidizing substances may produce a large proportion of chimeric plants, we applied a method to increase the number of tetraploid plants. Callus culture of chimeric leaf explants was performed on regeneration medium and tetraploid shoots were obtained in four of the six genotypes tested. The best result of 40% tetraploid plants was achieved with explants from the L37 genotype. This method was successful in producing additional tetraploid genotypes from mixoploid plants obtained after oryzalin treatments.     

大麦(Hordeum vulgare L.)花药培养再生植株染色体的遗传分析和酯酶同工酶的研究

通过观察82株大麦花药培养再生植株根尖细胞有丝分裂和56株花粉母细胞（PMC）减数分裂过程中染色体的结构和分离情况。结果表明，单倍体和二倍体植株各为17．1％和35．4％，混倍体植株47．5％，在混倍体植株中，有二倍体、三倍体、四倍体甚至六倍体细胞和一些非整倍体细胞，但仍以单倍体、二倍体和四倍体细胞为主。根尖细胞有丝分裂过程中有染色体结构的变异，如染色体断片，环状染色体等。二倍体PMC减数分裂过程中染色体分离有异常现象，如染色体“桥”，但绝大多数能正常完成。而单倍体和四倍体不能正常完成，单倍体染色体分离以2：5或3：4为主，并在中后期Ⅰ看到染色单体分离现象，四倍体细胞染色体有多种联会形式。酯酶同工酶（EST）聚丙烯酰胺凝胶电泳（PAGE）结果表明，利用Estl座位不同等位基因的分离规律可检出再生植株中的纯合体与非纯合体。不同的二倍体花粉植株在性状上出现明显的分离现象，观察到二类性状有显著差异的植株，Ⅰ类和Ⅱ类，Ⅰ类占6．6％，Ⅱ类占93．4。     

Contribution of synthetic tetraploids (AAAA) and diploids (AA) to black Sigatoka resistance and bunch weight to their triploid progenies

The generation of banana triploids from tetraploid-diploid crosses requires knowledge on the influence of the parents on black Sigatoka resistance and agronomic traits to the triploid progenies. The objective of this investigation was to determine the influence of tetraploid and diploid parents on black Sigatoka resistance and agronomic traits in the triploid progenies generated from tetraploid-diploid crosses. The mating scheme was designed as a 4 × 5 North Carolina II mating design. Due to problems in seed set and germination, progenies from 2 male parents with 4 female parents were evaluated at two sites in Uganda. The results showed that the male-parent triploid progeny heritability estimate for the number of leaves at harvest was greater than the female parent estimate. The diploid parents had higher correlation coefficients for the total leaves at harvest with the triploid progenies than tetraploid parents with triploid progenies. Disease development over time took more days in diploid parents than in the tetraploid parents with the triploid progenies as intermediates. These results suggested that diploids transferred black Sigatoka resistance to the triploid progenies as measured by the number of standing leaves and disease development overtime. There was a positive correlation (P < 0.05) between tetraploid female parents and triploid progenies for plant height and bunch weight. The triploid progeny-tetraploid female parent heritability estimates for plant height (0.92) and bunch weight (0.72) were highly significant. These results indicated that the female synthetic tetraploids influenced plant height and bunch weight in the triploid progenies. Therefore, it is important to select the tetraploids with heavy bunches to effectively improve yield in triploid progenies generated by tetraploid-diploid crosses. The tetraploid-diploid progenies had a significant (P < 0.05) family-by-site interaction for bunch weight indicating that new banana genotypes need to be tested across different environments to select stable genotypes to promote to end-users.     

Comparisons of tetraploid progenies of potato dihaploids,their chromosome-doubled derivatives and second generation dihaploids

Summary Comparisons were made between tetraploid progenies obtained by crossing dihaploid and chromosome doubled dihaploid potatoes with tetraploids. Dihaploids obtained from a doubled dihaploid produced some progenies from 2xx4x crosses which were as high yielding and had as good tuber characteristics as control progenies produced by intercrossing heterozygous tetraploids. It was found that there was a slight reduction in tuber yield associated with inbreeding but selection could be made among highly inbred material for useful parents. Other characters were little affected by inbreeding. It was concluded that haploidisation and chromosome doubling could be used to produce homozygous clones for use by breeders without greatly depressing the agronomic value of their offspring.     

The effect of variety and fertilizer nitrogen level on red clover production

Established swards of two diploid and two tetraploid red clover varieties sown pure received 0, 75, 150, 225 or 300 kg ha^?1 N fertilizer and were cut three times in June, August and October 1971. The total yields of herbage DM for red clover varieties ranged from 8.01 to 11.32 t ha^?1; swards sown with tetraploids Hungaropoly and Hera Pajbjerg were superior by 25% in DM yield and 23% in CP yield. The red clover contribution to these total yields of DM ranged from 6.05 to 10.69 t ha^?1; tetraploid clovers outyielded diploids by 42% in DM yield and 39% in CP yield. The mean effect of N level on yield and on compositional attributes was slight. Total yields of herbage DM, averaged over all varieties, ranged from 9.50 to 10.22 t ha^?1 and of total herbage CP from 1.76 to 1.91 t ha^?1. The influence of N level on the red clover contribution was negligible. DM yields ranged from 8.54 to 8.72 t ha^?1 and CP yields from 1.60 to 1.64 t ha^?1. Superiority of tetraploid clovers over diploids was again confirmed. Red clover swards sown pure can give high yields without the application of fertilizer N.     

Minimizing inbreeding in tetraploids derived through sexual polyploidization

Diploid (2n = 2× = 24) potato (Solarium) species that produce 2n gametes are being utilized in potato breeding programs. Three breeding schemes involving these diploids are presently used by potato breeders to transfer this genetic material from diploid parents to their tetraploid offspring. Derived tetraploids may arise through tetraploid × diploid, tetraploid × haploid-species, or diploid × diploid hybridizations. The inbreeding coefficient of derived tetraploids is a complex function of the coancestry of the parents, the inbreeding of the parents, the coefficient of double reduction in the tetraploid parent, and the frequency of single exchange tetrads in the diploid parent(s), and it depends on the mechanism of 2n gamete formation. For the two breeding strategies involving tetraploid female parents, there is less inbreeding in the derived tetraploid from a diploid parent producing 2n pollen by first division restitution than 2n pollen by second division restitution when the frequency of single exchange tetrads in the diploid is less than 2/3. In bilateral sexual polyploidization, the inbreeding coefficient of a derived tetraploid for a given set of parents from a first division × first division restitution cross is less than the inbreeding coefficient of a second division × first division restitution cross which is less than the inbreeding coefficient of a second division × second division cross when the frequency of single exchange tetrads is less than 2/3.     

利用流式细胞术对29份火龙果种质染色体的倍性鉴定

火龙果为仙人掌科量天尺属和蛇鞭柱属植物,不同类型火龙果种质的染色体倍性尚不明确。为明确所收集的种质资源以及创制的新材料的染色体倍性,利用流式细胞技术对29份火龙果材料进行了倍性鉴定。结果显示,供试的18份种质资源中共鉴定出二倍体火龙果14份,四倍体4份,无三倍体材料。通过不同倍性亲本杂交和秋水仙素诱变所创制的8份后代材料经鉴定发现有二倍体材料1份,三倍体材料3份,四倍体材料4份,这表明火龙果属间杂交和化学诱变可获得多倍体材料。研究结果对火龙果资源的遗传学评价以及开展倍性杂交育种提供重要的参考依据。