杂交兰×蕙兰种间杂交后代的核型特征分析

以杂交兰品种"韩国桃花"(大花蕙兰×墨兰)为母本、蕙兰为父本杂交获得种间杂交F1代,对亲本及F1代株系的染色体数目和形态特征进行了分析。结果表明,亲本及F1代染色体数均为40,母本"韩国桃花"的核型为2n=2×=40=26m+14sm,属2B型;父本蕙兰的核型为2n=2×=40=26m+14sm,属2B型;杂种F1代核型出现了多种类型,分别为:14m+26sm、4m+36sm、22m+18sm、8m+32sm、10m+28sm+2st、24m+16sm、10m+24sm+6st、32sm+8st、12m+28sm、4m+34sm+2st、16m+24sm、40sm等类型,其中2B型占85%;3B型占15%。这可能为多亲本基因重组的结果。     

杂交兰×蕙兰种间杂交后代的核型特征分析

以杂交兰品种“韩国桃花”（大花蕙兰×墨兰）为母本、蕙兰为父本杂交获得种间杂交F1代,对亲本及F1代株系的染色体数目和形态特征进行了分析。结果表明,亲本及F1代染色体数均为40,母本‘韩国桃花”的核型为2n=2x=40=26m＋14sm,属2B型;父本蕙兰的核型为2n=2x=40=26m＋14sm,属2B型;杂种F1代核型出现了多种类型,分别为：14m＋26sm、4m＋36sm、22m＋18sm、8m＋32sm、10m＋28sm＋2st、24m＋16sm、10m＋24sm＋6st、32sm＋8st、12m＋28sm、4m＋34sm＋2st、16m＋24sm、40sm等类型,其中2B型占85％;3B型占15％。这可能为多亲本基因重组的结果。     

甘蔗斑茅的杂交利用及其杂种后代鉴定系列研究Ⅲ.甘蔗斑茅远缘杂交后代细胞遗传分析

以甘蔗与斑茅杂交和回交后代为供试材料，进行染色体计数与核型分析，结果表明，在5个供试材料中，海南斑茅92-105的体细胞染色体数2n＝60=60m，属原始的1A型染色体，其他材料的核型均属2B型。以拔地拉（2n=80=70m+10sm）为母本、海南斑茅92-105为父本的杂交后代崖城96-66的体细胞染色体数目为2n=70=68m+2sm；以崖城96-66为母     

平邑甜茶与扎矮山定子杂交后代的倍性鉴定及核型分析

为了确定平邑甜茶[Malus hupehensis（Pamp.）Rehd]与扎矮山定子[Malus Baccata（L.）Borkh]杂交后代的倍性特征和核型特点,以风油精为预处理液采用常规压片法对杂交后代进行染色体数目观察和核型分析,以亲本和普通山定子为对照。结果表明：供试材料中6株皱叶型株系均为四倍体,2n=4x=68。染色体均为小型,染色体长度比差异不大,核型组成由中部着丝点染色体（m）和亚中部着丝点染色体（sm）组成。株系10#、14#、15#、19#、28#、33#核型公式分别为,2n=4x=44m＋24sm,2n=4x=60m＋8sm,2n=4x=20m＋48sm,2n=4x=52m＋16sm,2n=4x=56m＋12sm,2n=4x=48m＋20sm,核型分别为1B、2B、2A、2B、1A和1B类型;1株光叶株系为非整倍体,2n=43,核型公式为2n=22m＋18sm＋3st,核型为2B类型。表现为株系之间的核型不完全相同。试验为丰富无融合生殖型砧木的育种理论,获得新的苹果无融合生殖型砧木提供有益的借鉴。     

Presto×晋农190杂种F_2-3及双亲的核型分析

为创制六倍体小黑麦(TriticosecaleWittmack)-普通小麦(Triticum aestivumL.)异染色体体系,将六倍体小黑麦的优良基因导入到普通小麦中,以六倍体小黑麦品种Presto为母本、普通小麦品种晋农190为父本,配置杂交组合,对双亲及其杂种F2种子根尖细胞进行有丝分裂观察,确定其染色体数目并进行核型分析。结果发现,双亲的染色体数目均为42,父本晋农190的核型公式为2n=42=36m(2SAT)+6sm,核型类型为1A;母本Presto的核型公式为2n=42=26m(4SAT)+4M+12sm,核型类型为2A。杂种F2中F2-3为双单体附加系,其核型公式为2n=44=36m(3SAT)+4sm+1m+1m,核型类型为1A。通过对染色体的形态、短臂和长臂的长度、臂比及相对长度系数进行分析,可初步推断杂种F-3附加的可能是母本的7号和21号染色体。     

小麦属2个种间杂种及3个亲本的核型分析

【研究目的】本研究旨在通过细胞学鉴定判断小麦属2个种间杂种的真实性,了解其亲本的染色体组及倍数性;【方法】本试验采用了常规染色体组型分析方法;【结果】分析和报道了小麦属2个种间杂种及其3个亲本的核型,根据核型分析的有关参数,阐明了两个杂种1894×Ps5、新7×Ps5及其亲本新7、1894和Ps5的核型特征,其核型分别为：新7(2n=6x=42)：2M+12sm+28m(2SAT)(2B),1894(2n=6x=42)：2M+20sm+18m(2SAT)+2st(2B),Ps5(2n=4x=28)：2M+12sm(2SAT)+12m+2st(2B),1894×Ps5(2n=5x=35)：2M+19m+12sm+2st(2B),新7×Ps5(2n=5x=35)：1M+21m+13sm(2B);【结论】由此鉴定了2个杂种的真实性--均为真杂种,并确认了亲本新7和1894的第一套和第二套染色体均分别为A组和B组,倍数性均为6x,它们的第三套染色体属什么染色体组有待进一步研究。     

竹叶兰和香港毛兰的核型分析

采用压片法研究了竹叶兰〔Arundina graminifolia（D.Don) Hochr〕和香港毛兰〔Eria gagnepainii Hawkes et. Heller.〕的染色体数目和核型。结果表明：竹叶兰的染色体数目2n=40,有2条随体,其核型公式为：2n=2x=40=16m+22sm+2st,染色体相对长度组成为2L+18M2+18M1+2S;香港毛兰染色体数目2n=36,核型公式为2n=2x=36=28m+8sm,染色体相对长度组成为4L+18M2+12M1+2S。两者均为二倍体,染色体主要由中部和近中部着丝点染色体组成。核型分类前者为1A型,后者为2B型,都较为对称。     

4种大花蕙兰与国兰杂交F1代核型分析

首次报道4种大花蕙兰与国兰杂交后代染色体形态与核型。结果如下：绿宝石×春剑（Cym. Lovely Valley‘Evergreen’×Cym. Longibracteatum）后代2n=3x=45m+15sm,核不对称系数为59.75℅,2B型;天使×蕙兰（Cym. KLR565×Cym. sinense）后代2n=3x=42m+18sm,核不对称系数为59.33℅,2B型;夏绿×春剑（Cym. Summer Queen×Cym. Longibracteatum）后代2n=2x=30m+10sm,核不对称系数为58.58℅,2B型;圣蕾芬×春剑（Cym. Saint Raphin×Cym. Longibracteatum）后代2n=2x=34m+6sm,核不对称系数为57.15℅,2B型;结合兰属植物若干稳定特化的形态学特征,讨论了兰属植物的核型进化。     

5种新颖亚洲百合染色体核型分析

为了给百合杂交育种提供细胞遗传学依据,采用常规压片法,进行了5个新颖亚洲百合品种的核型分析。结果表明:5个亚洲百合品种均为二倍体,染色体24条。‘Original love’的核型公式为2n=2x=24=4sm+18st+2t,‘Ceb dozzle’的核型公式为2n=2x=24=16sm(3SAT)+8st,‘Indian summerset’的核型公式为2n=2x=24=2sm+22st,‘Red alert’的核型公式为2n=2x=24=6sm+18st,‘Party diamond’的核型公式为2n=2x=24=22st(3SAT)+2t(2SAT)。5个品种均为3B型核型。‘Party diamond’的核型不对称系数为91.67%,其余4个品种的核型不对称系数范围在73.13%~79.37%之间。‘Ceb dozzle’、‘Party diamond’2品种染色体有随体,其他3个品种无随体。本研究将为百合杂交育种的亲本选配和杂种早期鉴定提供细胞遗传学依据。     

10个甘蔗品种染色体核型分析与比较

通过10个甘蔗品种的核型分析,研究其染色体组成系统演化和血缘构成的基本特征,为甘蔗育种选配亲本提供细胞学依据。以10个甘蔗品种的根尖为材料,采用改良的酶解去壁低渗法制备染色体标本,再利用Ikaros软件进行核型分析。‘粤糖86-368’的核型公式为2n=111=2M+103m+4sm+2T,‘桂糖11’的核型公式为2n=106=96m+10sm,这2个品种的核型分类均属于1B型;‘新台糖10’的核型公式为2n=108=98m+10sm,‘新台糖16’的核型公式为2n=111=4M+101m+6sm,‘新台糖20’的核型公式为2n=110=98m+10sm+2st,‘新台糖22’的核型公式为2n=110=2M+96m+12sm,‘粤糖93-159’的核型公式为2n=108=2M+88m+18sm,‘闽糖69-421’的核型公式为2n=109=95m+14sm,‘云蔗89-151’的核型公式为2n=111=91m+20sm这7个品种的核型分类均属于2B型;‘云蔗99-91’的核型公式为2n=108=84m+22sm+2st,核型分类属于2C型。研究结果说明,‘粤糖86-368’、‘桂糖11’这2个品种的进化程度都还比较原始;‘云蔗99-91’、‘云蔗89-151’进化程度最高;其余6个品种进化程度中等。     

U.S. Economic Growth vs. Environmental Conditions

A widely-held belief is that stricter environmental regulations stifle economic growth. To determine empirically the effect of environmental conditions and policies on state-level per capita income growth, a Barro-type economic growth model was estimated for the years 1982 to 1991, which correspond to two consecutive troughs in the business cycle. States with better environmental conditions had significantly higher income growth rates during this period. At the same time, stricter environmental policies did not significantly depress income growth. Data used include recently developed, consistent measures of environmental policy and quality for individual states, as well as data from the 1980 U.S. Census and Bureau of Economic Analysis.     

Cytology of Phleum sp. affin. P. montanum C. Koch

Diploid, tetraploid, and hexaploid plants occurred in foreign plant introductions of P. sp. affin. P. montanum from Turkey and Iran. Within-progeny variations in polyploid levels indicate that divergent races occurred as interspersed but natural populations. One to six B-chromosomes of varying sizes in addition to the normal chromosome complement were present in some plants. Their behaviours appeared essentially similar to those recorded for other species. Certain of the plants examined exhibited cytological features similar to those observed in known hybrids. These included prophase pycnosis, stickiness, split metaphase I plates, unoriented chromosomes at M-1, and low levels of pollen stainability. These features were absent in microsporocytes of other plants. Low open-pollination seed set characterized all plants examined. This may be due to hybridity or possibly to response to ecological conditions of the new environment.Results of co-operative work of the Crops Research Division, A.R.S., U.S. Department of Agriculture, and the Wisconsin Agricultural Experiment Station, Madison, Wisconsin.Former Graduate Student, Department of Agronomy, Wisconsin Agricultural Experiment Station, and Geneticist, Crops Research Division, Agricultural Research Service, U.S. Department of Agriculture.     

秈粳稻杂交育种研究

作者研究了秈粳杂种的生育特性及结实性等经济性状的遗传变异,认为以出穗期为主要指标进行选择,结合其他性状的变异动态,逐步确立优良系统,有助于提高选择的效率,和建立较为合理的杂交育种程序与方法。