不同倍性蝴蝶兰杂交后代的染色体倍性研究

 对不同倍性蝴蝶兰小孢子母细胞减数分裂及其杂交后代的根尖染色体数进行了检测。结果表 明,除三倍体和三倍体杂交未能产生杂交后代外,不同倍性蝴蝶兰杂交后代的倍性均出现分离。二倍体和 二倍体、二倍体和四倍体杂交均产生二倍体、三倍体和四倍体;二倍体和三倍体杂交产生二倍体、三倍体、 五倍体和非整倍体;三倍体和四倍体随正反交不同而异,三倍体@四倍体的后代倍性有三倍体、四倍体、 八倍体和非整倍体,而四倍体@三倍体的后代倍性有三倍体、四倍体、五倍体和非整倍体;四倍体和四倍 体杂交产生二倍体、三倍体、四倍体、五倍体、六倍体和非整倍体。不同倍性蝴蝶兰的小孢子母细胞减数 分裂普遍存在微核、落后染色体和三分体等异常现象,导致小孢子和杂种后代的倍性出现多样性。     

Acquisition of triploid germplasms by controlled hybridisation between diploid and tetraploid in Chinese jujube

‘Chenguang’ is the first released tetraploid cultivar (2n = 4x = 48) of Chinese jujube (Ziziphus jujuba Mill.) induced by colchicine. The purpose of this study was to create triploid germplasms by using ‘Chenguang’ as a parent. The controlled crosses between autotetraploid ‘Chenguang’ and diploid ‘Dongzao’ were carried out from 2013 to 2015 by maintaining the 2 parents in a nylon net and employing bees as pollinator. A total of 606 fruits were produced, yet only 17 seeds were obtained from ‘Dongzao’ and none from ‘Chenguang’. Direct sowing of the seeds in greenhouse showed a higher seedling rate than embryo culture. Four progeny plants were eventually obtained in the greenhouse and all of them were confirmed as authentic hybrids by SSR marker technique. At last, 3 triploids and 1 diploid were identified by flow cytometric analysis. Consequently, tetraploid ‘Chenguang’ with high pollen vitality and pollen number per anther could be used as a reliable 2n pollen provider, and the 2x × 4x cross combination type is more suitable for triploid creation in Chinese jujube. This is the first successful production of triploid hybrids by controlled cross between diploids and tetraploids in jujube.     

以柑橘多胚性二倍体母本倍性杂交培育三倍体

2009-2012年,以柑橘8个多胚性二倍体品种为母本与近年始花的5个异源四倍体体细胞杂种和1个同源四倍体分别杂交,培育三倍体新种质。连续4年共配置15个杂交组合,授粉4 442朵花,坐果1 484个,平均坐果率33.4%;用于幼胚挽救的果实1 075个,共培养幼嫩种子12 578颗,经生芽、生根诱导获得再生植株2 832个;以流式细胞仪对所有再生植株倍性检测,15个组合共获得三倍体401个,四倍体121个;移栽成活三倍体349个,四倍体98个。对W. 默科特 × NH组合89个株系的三倍体的SSR分子鉴定表明,所有三倍体后代均为双亲的有性杂种。     

柑橘10个品种实生后代多倍体的发掘及SSR鉴定

秋季采摘柑橘成熟果实并剥取种子,将小粒种籽和瘪籽播于MT培养基,待萌发长出2～3片真叶时,取其叶片检测倍性;将饱满种籽播种于露地,对其幼苗首先通过形态筛选获得似多倍体的植株,然后取其叶片用流式细胞仪进行倍性检测;最后对获得的多倍体植株进行SSR分子鉴定。试验结果表明,获得早金甜橙、卡特夏橙、塔罗科血橙、日辉橘、Ortanique橘橙、默科特橘橙、华农本地早橘、朱红橘和Flame葡萄柚等9个品种的四倍体分别为6、1、3、12、3、6、2、1和10株;获得早金甜橙、塔罗科血橙、Itabori甜橙和Ortanique橘橙等4个品种的三倍体分别为1、1、2、4株。用13对多态性SSR引物对胚抢救获得的三倍体和四倍体的来源进行鉴定,发现早金甜橙、Itabori甜橙的三倍体再生植株为异源三倍体;塔罗科血橙、Ortanique橘橙的三倍体可能为同源三倍体;早金甜橙和Ortanique橘橙的四倍体可能为同源四倍体;塔罗科血橙四倍体为异源四倍体。采用37对多态性引物对从饱满种籽中获得的8个品种四倍体的来源进行鉴定,发现均为同源四倍体。这些自然发掘的多倍体资源对柑橘无核育种和相关基础研究具有重要价值。     

以异源四倍体体细胞杂种为父本与二倍体杂交创造柑橘三倍体的研究

 2001～2002连续两年, 以沙田柚、本地早橘、中秋橘、HB柚、国庆4号温州蜜柑等二倍体品种为母本, 以NS (橘柚+无酸甜橙) 、NH (橘柚+ HB柚) 、SH (无酸甜橙+ HB柚) 、VM (伏令夏橙+橘橙) 、HD (甜橙+丹西橘) 等优良四倍体体细胞杂种的花粉授粉, 通过胚挽救技术获得再生植株。经细胞流式仪和染色体计数观察表明, 两年从10个授粉组合中共获得244株三倍体和10株四倍体。在这些三倍体中有147株来自沙田柚为母本的组合。目前已有172株三倍体和4株四倍体植株移栽成活。这些材料为进一步选育无核三倍体品种奠定了基础。     

Colchicine- and trifluralin-mediated polyploidization of Rosa multiflora Thunb. var. inermis and Rosa roxburghii f. normalis

Rosa multiflora Thunb. var. inermis and Rosa roxburghii f. normalis are two important diploid species for rose breeding. Interspecific crosses between diploid species and tetraploid rose cultivars result in triploids with generally decreased fertility. A most promising gene transfer strategy is the production of fertile tetraploid plants before mating with tetraploids. In our study, germinating seeds of R. multiflora and R. roxburghii were treated with colchicine, and cotyledon-stage seedlings of R. multiflora were treated with colchicine or trifluralin in order to obtain tetraploid plants. Also, various concentrations of antimitotic agents and different treatment durations were tested. The results showed the antimitotic agents affected the plant morphological characteristics (i.e. plant height, stem diameter) of R. multiflora and R. roxburghii. Twenty-three tetraploid plants were obtained from the germinating seed treatments (21 from R. multiflora and two from R. roxburghii), but no tetraploid plants were obtained from the seedling treatments. The highest rate of chromosome doubling (25.0%) was achieved when germinating seeds of R. multiflora were treated with 0.2% colchicine for 12 h. At the same time, marked morphological variation was observed and analyzed among tetraploid plants and their corresponding diploids of R. multiflora.     

Production and characterization of new triploid seedless progenies for mandarin improvement

Eighty-six triploid Citrus plants were recovered from interploid crosses between a natural tetraploid selection of the tangerine ‘Dancy’ (Citrus reticulata Blanco, cultigroup ‘Tangerine’), used as the pollen parent, and two seedy selections of diploid mandarins (C. reticulata Blanco) as well as one clementine (Citrus clementina Hort. ex Tan.): ‘Fortune’ mandarin, ‘Wilking’ mandarin and ‘Monreal’ clementine. Flow cytometric analysis was used for screening the triploid plantlets and the ISSR-PCR technique was used to characterize the obtained triploids through a double approach, confirming the hybrid nature of the offspring and allowing the analysis of the genetic pool obtained. Selection among triploid genotypes generated from elite seedy parents will give us a better chance to obtain superior mandarin cultivars characterized by true seedlessness.     

Somaclonal variation in Tricyrtis hirta plants regenerated from 1-year-old embryogenic callus cultures

The Liliaceous perennial Tricyrtis hirta, sometimes called ‘Japanese toad lily’, has recently become popular as an ornamental for pot and garden uses. Highly embryogenic callus cultures of this plant predominately consisted of diploid cells but also contained tetraploid cells after 1 year of establishment. In the present study, plans regenerated from the 1-year-old embryogenic callus cultures were subjected to ploidy level analysis and morphological characterization following 3 years of cultivation. Among 37 plants examined, 28 kept the diploid level (2n = 2x = 26) but nine were tetraploid (2n = 4x = 52) as indicated by FCM analysis and chromosome observation. Although no morphological alterations were detected in 26 out of 28 diploid regenerants, the remaining two showed noticeable variations: both were severely dwarf and had crimped leaves and many malformed flowers. The tetraploid regenerants had several horticulturally attractive characteristics compared with the diploid controls, such as longer shoots, thicker stems, and larger flowers. Thus regeneration of tetraploid plants from 1-year-old embryogenic callus cultures offers a possibility to improve the horticultural value of T. hirta, although regeneration of trueness-to-type plants is essential for utilizing the cultures for micropropagation and genetic transformation.     

Growth and development of ovules of banana,plantain and enset (Musaceae)

Sterility has profound effects on the development of reproductive tissues in members of the Musaceae and limits genetic improvement required to deal with new diseases. Ovules of seeded diploid Musa acuminata (AA) and edible triploids (AAA) from the same cytogenetic group, plus edible triploids containing genomes of the M. balbisiana cytogenetic group (AAB, ABB) and the related genus Ensete sp. were studied to determine the effects of sterility on the growth and development of the ovule and its tissues. Specimens were collected from subtropical and Mediterranean environments in Australia.At anthesis, the ovules of triploid plants were 36% larger than the ovules of diploid plants. The diploid ovules ceased growth shortly after the inflorescence emerged from the pseudostem. In contrast, the triploid ovules continued to grow 7–10 days past anthesis, increasing in size by 70%.All ovules of diploid M. acuminata ssp. had an embryo sac at anthesis, against 97% for triploids. At anthesis the embryo sacs in diploid ovules occupied 2.7% of the nucellus compared with 1.5% in triploid ovules. The embryo sacs did not grow between bunch emergence and anthesis, once formed they maintained the same size. Many embryo sacs were not positioned correctly, flush with the nucellar cap. The diploid M. acuminata ssp. had 75% of embryo sacs correctly positioned against 10% in the edible triploids. The proportion of balbisiana genome (B) did not affect ovule or nucellus size or shape, or cell number across the nucellus. It increased the embryo sac presence 96–100% of ovules.The sterile edible triploid bananas have embryo sacs at anthesis but many are incorrectly positioned, which may contribute to their sterility. The balbisiana genome in the edible triploids was associated with a 2.4-fold increase in the number of correctly positioned embryo sacs and this may contribute to the increased fertility associated with the B genome.     

Tetraploid muskmelon alters morphological characteristics and improves fruit quality

Tetraploid muskmelon plants were induced successfully from diploid Cucumis melo inbred M01-3 (2n = 24) by colchicine. The morphological characteristics and fruit qualities of diploid and tetraploid muskmelons were investigated. The results showed that the leaves and flowers of the tetraploid plants were markedly larger, the plants were obviously higher, and the stems were thicker than those of the diploid plants. Transmission electron microscope observation revealed that the numbers of chloroplast, granule and grana, and the length of chloroplast and granule of the tetraploid plant leaves were significantly more or longer than those of the diploid plants. The soluble solid, soluble sugar and vitamin C contents in the tetraploid fruit were distinctly higher than those in the diploid fruit. The weight of the tetraploid fruit was 30% heavier than that of the diploid fruit. And the seeds from the tetraploid plants were broader and thicker than those from the diploid plants. Together, our results suggest that the tetraploid muskmelon exhibited better agronomical characteristics than the diploid muskmelon and the tetraploid muskmelon could be used as the improved variety and a potential germplasm for the development of triploid fruit.     

Analysis of effects of auxin on fruit size of tetraploid and diploid tomato fruits

Selfed and auxin-treated fruits of tomato (Lycopersicon esculentum Mill.) were obtained from tetraploid and diploid plants and compared to determine why selfed tetraploid fruits are smaller. Application of auxin to ovaries produced tetraploid fruits as large as normally set (selfed) diploid fruits but led to reduced fruit size in diploid fruits, reflecting a further potential for tetraploid fruit development. The selfed tetraploid fruits were found to be smaller because they had fewer cells per fruit. Cell size (diameter) at the end of fruit development was similar for all fruit types. DNA per cell did not closely match cell size during development, especially during the cell division stage. Protein per cell also failed to follow cell size. Protein per DNA showed one peak at around day 10 of fruit development and possibly a second one at day 30.     

不同倍性西瓜果实不同糖含量比较

试验采用8组高代自交二倍体品种西瓜,相应人工诱导的同源四倍体及二倍体和四倍体杂交的同源三倍体为材料,分析不同倍性西瓜总糖、果糖、葡萄糖和蔗糖含量的差异。结果表明,不同倍性西瓜果实成熟时期总糖、果糖、葡萄糖和蔗糖含量存在差异,总糖和果糖含量有同样趋势,为四倍体〉三倍体〉二倍体;葡萄糖含量为四倍体〉二倍体〉三倍体;蔗糖含量为三倍体〉四倍体〉二倍体。     

Characterization of tetraploid plants regenerated via protoplast culture of Iris fulva and their crossability with Japanese irises

Characteristics such as flower form, size and color of outer and inner perianths, anthocyanins in outer perianths, size, color and fertility of pollen and self-fertility of diploid and tetraploid lines regenerated via protoplast culture of Iris fulva were examined and compared with those of the diploid wild line. Among these characteristics, flower form, inner and outer perianth sizes of the tetraploid lines were noticeable, because these lines had upward flower forms and bigger flowers than diploid lines. Furthermore, reciprocal crosses between diploid or tetraploid lines of I. fulva and I. ensata and those of I. fulva and I. laevigata were performed. Three seedlings were obtained from the cross of tetraploid I. fulva × diploid I. laevigata through embryo rescue. One of them was identified as the interspecific hybrid between tetraploid I. fulva and I. laevigata by flow cytometoric (FCM), cytological and molecular (RAPD) analyses. This is the first report on production of hybrids from these lines. I. fulva has unique brown flowers, and this trait could be very useful for flower color breeding of I. laevigata which lacks this color. Therefore, the hybrid of I. fulva (4×) × I. laevigata may be the best available gene source for brown color breeding of this species.     

不同倍性西瓜果实维生素C含量比较研究

以10个西瓜品种的二倍体及其人工诱导的同源四倍体、三倍体为材料,研究不同倍性西瓜成熟果实Vc含量的差异及果实发育过程中Vc含量的变化。结果表明,不同倍性西瓜中Vc含量差异较大,9个品种三倍体或四倍体的Vc含量高于二倍体(P<0.05);不同倍性西瓜果实中Vc含量变化规律基本相同,幼果期较高、果实膨大期较低、成熟期较高,且呈近似"V"型变化曲线。其峰值的出现顺序为2X、3X、4X,倍性越高,其峰值出现越晚。不同染色体倍性西瓜果实Vc含量较高的时期均为成熟期。     

抗菌肽MB39基因导入‘皇家嘎啦’苹果及其四倍体植株的培育

 采用农杆菌介导法, 将抗菌肽MB₃₉基因转入‘皇家嘎啦’苹果, 获得了7 个转基因株系。通过秋水仙素诱变染色体组工程育种技术, 由转化体叶片获得了20 个四倍体植株。经PCR 检测和Southern Blotting 杂交证明, 抗菌肽MB₃₉基因已经整合到皇家嘎啦苹果的染色体组中。转基因株系TR21、TR23 提高了对火疫病的抗性。采用流式细胞技术( Flow Cytometry) 确定植株为四倍体。     

三倍体枇杷与其四倍体和二倍体亲本光系统活性差异

为探寻三倍体枇杷光合作用效率及光系统活性的特点,于2018-2019年的3、7、12月,连续两年对两个杂交三倍体Fj代B431 xGZl和B431 xGZ23,及其四倍体母本B431、二倍体父本GZ1、GZ23的叶片净光合速率(Pn)和快速叶绿素荧光诱导动力学曲线(OJIP曲线)进行了测定及JIP-test分析.结果表...     

黄皮西瓜化学诱变及四倍体利用研究初报

用 0 .2 %秋水仙碱对二倍体黄皮西瓜 2 6 0 8进行处理 ,观察器官变异特征和生理变化 ,比较不同方法对鉴定变异四倍体的可靠性 ,并对不同倍数体和不同基因型黄皮西瓜果实外观着色状况进行分析 ,结果表明 :四倍体的变异株率为 12 .4 % ,采用二倍体普通西瓜♀×待鉴定变异株♂进行杂交鉴定四倍体方法简便可靠 ;利用四倍体黄皮西瓜配制三倍体黄皮无籽西瓜组合 ,外观着色明显改善 ,商品率提高 ,栽培难度降低。     

Fruit set,seed development and embryo germination in interploid crosses of citrus

Interploid crosses of diploid Kinnow mandarin, Succari sweet orange and Sweet lime with tetraploid Kinnow were made reciprocally for the production of triploid plants. Low fruit set and occurrence of underdeveloped or empty seeds was common in all interploid crosses. The hybrid fruits harvested after 12–14 weeks or 7 months after pollination produced many underdeveloped and few developed seeds; however, tetraploid Kinnow as seed parent yielded more developed seeds per fruit. The under developed seeds were devoid of endosperm. Nucellar embryony was higher in the diploid than in the tetraploid strain of Kinnow. Immature embryos of seeds harvested 12–14 weeks after pollination were cultured in vitro on MS media supplemented with adenine sulphate (20 mg l⁻¹) and malt extract (500 mg l⁻¹). Maximum germination (75%) of hybrid embryos from underdeveloped seeds was obtained in 4× × 2× cross of Kinnow strains. The germinated plantlets were transferred into pots and noted 59–89.3% survival rate in various crosses.     

In situ induction of chromosome doubling in vine cacti (Cactaceae)

Vine cacti have economic potential as exotic fruits in semi-arid and arid lands due to their high water use efficiency. The goal of this study was to attain autopolyploid plants by applying the antimitotic agents colchicine and oryzalin on axillary vegetative buds and germinating seeds. The diploid Hylocereus monacanthus and the tetraploid H. megalanthus; the interspecific triploid hybrid S-75, were studied. The effects of different concentrations and exposure times on bud survival and germination rate were recorded. A negative effect on vegetative bud survival was observed in the triploid hybrid. An inhibitory effect on germinating seeds was species specific, being greater on H. monacanthus with oryzalin and on H. megalanthus with colchicine. Putative polyploids were identified by comparing stomatal density between donor plants and plants arising from treated buds or seeds. Flow cytometric analysis and chromosome counts confirmed polyploidization in 14 autotetraploid H. monacanthus, 1 autohexaploid S-75 hybrid, and 14 autooctaploid H. megalanthus. This is the first report of artificial autopolyploidization in species of vine cactus, providing valuable novel plant material for further breeding programs.     

中国树莓属8个种染色体数目与核型

采用“去壁低渗法”对我国树莓属８个种１８个类型的染色体数目和１２个类型的核型进行了研究。发现我国牛迭肚、绿叶悬勾子、库叶悬勾子有二倍体２ｎ＝２ｘ＝１４和四倍体２ｎ＝４ｘ＝２８类型；茅莓为四倍体２ｎ＝４ｘ＝２８；覆盆子有二倍体２ｎ＝２ｘ＝１４和三倍体２ｎ＝３ｘ＝２１类型；黄树莓、黑树莓、美洲黑莓均为二倍体２ｎ＝２ｘ＝１４。核型结果表明，树莓属染色体均小形，由中部着丝点染色体和亚中部着丝点染色体组成。