60Coγ辐照对甘蓝型油菜农艺性状和品质的影响

以800,1000和1200 Gy 3种剂量60Coγ射线处理甘蓝型油菜品系761和532的风干种子。分析了60Coγ射线辐射对油菜种子发芽率、主要农艺性状和品质性状的影响。结果表明:辐照处理的种子发芽率随照射剂量增加而下降,但不同基因型受到影响不同;辐射处理对M1的株高及生长量有明显抑制,辐射处理不同数量性状的效应不一致,对分枝部位的效应最显著,但千粒重和每角果粒数无显著变化;800~1000 Gy辐照处理使油菜种子含油量有不同程度提高,脂肪酸中芥酸和油酸含量变异较大。     

重离子辐照诱变育种应用及其生物学效应研究进展

重离子辐射育种以其程序简单、突变效率高、突变谱广等特点,受到育种工作者的广泛关注。其作用的机制是通过注入的高能带电粒子与生物体内的分子或原子发生弹性、非弹性的碰撞,导致生物体内的电离损伤,进而使染色体发生序列或结构改变。其生物学效应在个体水平主要表现为叶形、花色、花形、株型等变化,在生理水平主要表现为过氧化物酶类含量的改变,在分子水平主要表现为生物体内基因表达变化、转座子、甲基化的激活等。本文简要介绍了重离子辐射作用的基本原理,重离子辐射对生物体的生物学效应以及在育种应用中的最新研究进展。     

玉米几个光合作用性状与生物学产量及籽粒产量的关系

运用简单相关、多元回归和偏相关分析,以及通径系数分析,研究了一个玉米双列杂交组中21个基因型的五个光合作用性状与生物学产量和籽粒产量之间的关系。结果表明灌浆期的 CO_2交换率、单株总叶面积、实际籽粒灌浆期长度以及经济系数等性状对籽粒产量有正的直接效应;其中前三个性状也对生物学产量有正的直接效应。这表明在玉米理想型育种中,通过这些性状的改良来提高上述两种产量是完全可能的。但抽丝期对这两种产量的直接效应都呈小的负值,这表明要靠延长抽丝期来提高产量是没有必要的。     

陆地棉种子品质性状与棉花产量性状的遗传相关性分析

采用包括基因型与环境互作的双子叶作物种子遗传模型和农艺性状遗传模型，分析了陆地棉五个亲本及其Ｆ１、Ｆ２棉子仁的油分含量、油分指数、蛋白质含量和蛋白质指数、棉子的子指、容重、仁壳比和仁指以及棉花植株单株产量、革株铃数、单铃重的两年实验资料，估算了棉仁营养品质性状及棉子物理性状与棉花在艺性状间的各项近传协方差分量。结果表明，棉子仁营养品质和种子物理性状与单株产量遗传相关均不显著，油分含量、油分指数、蛋白质指数、子指、容重和仁指的细胞质效应、母体遗传效应与单株铃数的相应遗传效应存在显著的负向协方差，其互作协方差也为显著的负值。这６个种子性状与单铃重的遗传关系列相反，这些效应均为负相关。衣分与大多数种子性状不存在明显的遗传相关性，仅与蛋白质指数、子指和仁指有明显的细胞质和母体效应的正相关。     

水稻不同籼粳分化品系主要农艺性状配合力的比较分析

分析比较了4个籼粳遗传分化程度不同的品系与8个常规籼稻品种配组杂交9个农艺性状的配合力效应。结果表明,一般配合力效应及特殊配合力效应与亲本的籼粳遗传分化程度没有明显的关系,4个不同遗传分化品系在9个性状上的一般配合力表现各异,总体上以偏籼品系G2417－1及偏粳品系G3005－4－1表现较好。122／G2417－1、4480／G2615、IR70／G3005－4－1、双桂35／G2615和明恢63／G2123等组合具有较高的单株产量特殊配合力。从2种配合力对杂种性状的影响程度看,在每穗实粒数、结实率、千粒重和单株产量等性状上,杂种主要受特殊配合力的作用,在抽穗期、株高、单株有效穗数、穗长、每穗总粒数等性状上,杂种主要受一般配合力的作用,但特殊配合力的作用亦不容忽视。抽穗期、单株有效穗数、每穗实粒数、结实率、单株产量等性状的超亲优势与两种配合力显著正相关,而多数性状的一般配合力与亲本表型效应值无显著的相关关系。     

高蛋白春小麦品系90－824的配合力分析

本研究利用９０－８２４（籽粒蛋白质含量达２１％）与５个农艺亲本组成６（６－１）双列杂交设计，分析了一般配合力（ＧＣＡ）和特殊配合力（ＳＣＡ）。结果表明，参试品种籽粒蛋白质含量和农艺性状的ＧＣＡ均极显著，ＳＣＡ方差除株粒数外，其它性状达显著水平，从ＧＣＡ方差与ＳＣＡ方差比例看，籽粒蛋白质含量的遗传以加性遗传效应为主，但存在非加性效应。９０－８２４的蛋白质含量的ＧＣＡ效应值最大，而株粒重、株粒数、百粒重和穗粒数的ＧＣＡ效应亦相对较高，是较理想的高蛋白亲本。９０－８２４／７８－０３和９０－８２４／陇春８号在农艺性状上的ＳＣＡ最大，而蛋白质含量的ＳＣＡ居中，是较好的组合     

Co—r射线在小麦育种上性状改良的应用研究

利用^60Co-r射线辐照小麦干种子诱导性状变异，异变个体中出现性状不遗传的有双穗和超矮秆变异性状，可遗传的变异有熟期、粒色、多性状变异体。通过对多性状变异系进行过氧化物酶同工酶分析，变异系较原照射材料带型差异明显，有丢失有增加，说明辐射效应的真实存在。根据性状诱变的规律，阐述了辐射育种在选择方法上的特点。     

高羊茅种子产量与主要农艺性状的通径分析

对高羊茅的7个农艺性状与单株种子产量进行了相关和通径分析.结果表明,7个农艺性状与单株种子产量均呈极显著正相关,其相关系数大小依次为单株穗数＞每穗粒数＞穗长＞千粒重＞茎重＞株高》叶片重.7个性状与单椿种子产量直接通径系数大小依次为叶片重＞株高＞单株有效穗数＞每穗粒数＞千粒重＞茎重＞穗长.叶片重、单株有效穗数和每穗粒对种子产量的贡献较大,茎重和穗长的效应较小,提高单株种子产量,要增加单株有效穗数和每穗粒数,并兼顾千粒重的提高.     

陆地棉种子性状直接效应和母体效应的遗传分析

采用二倍体种子遗传模型及其分析方法，分析了陆地棉５个品种及其配制的Ｆ１、Ｆ２和正反回交一代（ＢＣ１、ＢＣ２、ＲＢＣ１和ＲＢＣ２）世代籽指、种仁率、容重和油分４个种子性状的直接效应、母体效应和细胞质效应。分析结果表明，４个棉子性状的遗传均以母体效应为主，种子直接遗传效应作用较小。各性状的直接效应与母体效应的协方差不显著。通过母体植株的遗传表现对这些性状选择更为有效。可以根据籽指小和容量大等性状母体植     

钴离子抑制种子引发对绿豆抗旱性的诱导过程

以陕西农家品种绿豆为材料，研究了钴对种子萌发，种子引发及幼苗生长的影响，结果表：在０．２－１．０ｍｍｏｌｅＬ＾－１浓度范围内，钴离子能够延迟缓豆种子萌发，抑制幼苗生长，这种效应随钴浓度的增加而加大，种子引发能够加快种子萌发，促进幼苗生长，提高细胞膜稳定性，植物对渗透胁迫的适应，在引发过程中，加入２ｍｍｏｌｅＬ＾－１ＣｏＣｌ２能够抑制种子引发对植物抗旱性的诱导作用，但不影响种了萌发，进一步实验表明，     

Evaluation of breeding semidwarf rice by induced mutation and hybridization

Summary Semidwarf indica varieties of rice (Oryza sativa L.) were developed by induced mutation. They generally have a yield capacity equal to that of the semidwarf varieties (T(N)1, IR 8 and others) selected from hybridization. Genetic studies showed that semidwarf genes induced in the mutants and spontaneous ones in existing varieties are at the same locus. These semidwarf mutants, selected in Taiwan and from an American long-grain variety, Centura Patna 231, were compared with their parents, the semidwarf variety Dee-goe-woo-gen, T(N)1 and IR 8. The semidwarf mutants average about 35% shorter than their tall parents. The plant height is reduced by shortening five internodes from the top, while panicle length is not affected. The mutants, Dee-geo-woo-gen, and improved short-statured varieties had similar patterns of internode elongation. The mutants derived from varieties sensitive to photoperiod have lost the sensitivity. One more crop can be grown within a year. All induced and hybrid-derived semidwarf varieties were highly susceptible to bacterial leaf blight when Xanthomonas oryzae was inoculated although some of their parents were moderately resistant. The mutation rate from irradiation of this semidwarf gene was estimated to be 0.1% in I-kung-bau, a native variety of Taiwan. This particular type of mutation has not yet been reported in japonica varieties. However, several promising strains with reduced plant height, earlier maturity and more grain yielding were recently obtained from the California japonica variety, Calrose, by X-irradiation. The merits of mutation breeding in rice are discussed.     

Genetic analysis of semidwarf mutants induced in indica rice (Oryza sativa L.)

The mode of inheritance of five semidwarf (SD) mutants and allelic relationship with DGWG (sd1) locus was studied. The five SD mutants viz., Basmati 370 (SD1), Basmati 370 (SD2), Basmati 370 (SD3), TCA 2 (SD) and TCA P2-5 (SD) when crossed with their tall parents exhibited monogenic inheritance of 3 tall: 1 semidwarf in the F2 progenies. The SD mutants were also crossed with semidwarf varieties (DGWG and Bala) possessing sd1 gene. Crosses between Basmati 370 (SD1) × Bala, Basmati 370 (SD3) × Bala and TCA 2 (SD) × DGWG produced tall F1 hybrids and in F2 generation, modified dihybrid ratios (9 : 6 : 1 and 9 : 7) were observed indicating that the mutants Basmati 370 (SD1), Basmati 370 (SD3) and TCA 2 (SD) are non-allelic to sd1 gene. Whereas, the mutants Basmati 370 (SD2) and TCA P2-5 (SD) when crossed with Bala produced semidwarf F1 hybrids and in F2 generation, segregation for plant height was not observed indicating that these mutants are allelic to sd1 gene. The three non-allelic SD mutants identified in the present study can be used in rice breeding as alternative gene sources for semidwarfism. This revised version was published online in July 2006 with corrections to the Cover Date.     

单季晚粳稻高产株型的探讨

依株高、剑叶长和穗形3个形态指标,把产量达到500公斤左右的育成品系分为6种株型。各型的特点:1型是大穗,优势穗平均实粒数超过或将近200粒;2型是短叶密穗;3型是中间型;4型是稀长穗;5型是大粒;6型是矮秆多穗。认为大穗是高产株型的突破口,1型的高产潜力最大。但株型上还需改良。     

Mutation induction with ion beam irradiation of lateral buds of chrysanthemum and analysis of chimeric structure of induced mutants

We compared the effects of ion beam and gamma ray irradiation on mutation induction in axillary buds of chrysanthemum, and analyzed the chimeric structure of the resulting mutants. Axillary buds were irradiated with carbon ions at 2 Gy (mean linear energy transfer 122 keV/μm), helium ions at 10 Gy (mean 9 keV/μm), and gamma rays at 80 Gy, all of which have the similar effects on survival. The lower five nodes of the shoots elongating from the irradiated buds were cut one by one, and new shoots were allowed to grow from the axillary buds. This procedure was repeated twice, and flower color mutation was investigated. Chimeric structure was analyzed by comparing the flower color of mutants to that of plants regenerated from the roots. Flower color mutants emerged at a high frequency (17.4–28.8%), and there were no significant differences in the mutation frequency between the treatments. All the flower color mutants induced with gamma rays were periclinal chimeras. In contrast, some mutants obtained with ion beams had the same flower color as that of the plants derived from the roots. This suggests that they were solid mutants, where both LI and LIII tissues were derived from the same mutated cell. Solid mutants were also obtained when irradiated with 5 Gy of helium ions, which had less effect on survival and mutation than other treatments. Factors for obtaining solid mutants only with ion beams are also discussed.     

Inheritance of morphological traits of periwinkle mutants with modified contents and yields of leaf and root alkaloids

Periwinkle Catharanthus roseus is a medicinally important plant producing anticancer and antihypertension alkaloids. Two mutants, one dwarf and one semidwarf and both, with a high alkaloid content in the roots and one mutant with a wavy leaf margin and a high alkaloid content in its leaves were obtained after induced chemical mutagenesis with ethyl methane sulphonate and N-nitroso-N-ethylurea in the variety ‘Nirmal’, which is resistant to dieback disease. These mutants were evaluated in the M₃ and M₄ generations. The dwarf and semidwarf mutants differed from the parental variety for many morphological characters, while the mutant with the wavy leaf margin differed mainly in leaf size and leaf thickness. Although both dwarf and semidwarf mutants showed a significantly higher alkaloid content in their roots in both generations, only the semidwarf mutant gave a significantly higher (23%) root alkaloid yield than the parental variety. The mutant with the wavy leaf margin showed a significantly higher alkaloid content in the leaves in both the M₃ and M₄ generations and also had a significantly higher (21%) leaf alkaloid yield than the parental variety. All three mutants were found to be controlled by monogenic recessive genes; the genes for ‘dwarfness’ and ‘semidwarfness’ were allelic to each other, with the allele for semidwarfness being dominant over the allele for dwarfness. The gene for the wavy leaf margin was inherited independently of the genes for dwarfness and semidwarfness.     

Mutagenic response of rhodes grass (Chloris gayana Kunth.) to gamma rays. II. Studies on second (M2) generation parameters

Summary The effect of gamma rays on parameters such as chlorophyll mutation frequency and spectrum, mutagenic effectiveness and efficiency and viable mutation frequency and spectrum were studied in M₂ generation of Rhodes grass employing nine doses of gamma rays. The chlorophyll mutation frequency increased in a linear fashion at low and medium doses and was erratic at higher doses. The chlorophyll mutant spectrum ineluded albina, xantha, chlorina, viridis, tigrina, striata, albo-xantha and albo-viridis. The frequency of these mutants varied with treatments. A dose rate of 60 krad was found to be effective as well as efficient both on M₁ and M₂ plant basis in inducing chlorophyll mutations. The highest frequency of viable mutations was found in 50 krad treatment. Viable mutants found were: nodal variant, peduncle variant, lax ears, coxcomb ears, earhead proliferation, level of fingers, incurved fingers, gappy ears, apical sterility, partial sterility and high sterility.     

Selection of Semidwarf, Early Maturing and Blast Resistant Mutants after Mutagenic Seed Treatment in Two Locally Adapted Indian Rice Cultivars

The objective of this study was to induce semidwarf, early maturing and blast resistant mutants in two adapted Indian rice cultivars. Seeds of the rice cultivars ‘Madhu Malti’ and ‘Phul Patas 72’ were treated with gamma rays and ethyl methane sulfonate (EMS) as well as a combination of gamma rays and EMS. A total of 96 dwarf (< 75 cm) and semidwarf (< 100 cm) and 104 early flowering/maturing M₂ plants were identified among the 18,060 M₂ plants observed. Sixty-eight blast resistant M₂ plants were also identified. The true mutant status of these plants has yet to be determined in progeny tests. The induction of desired mutant types in locally adapted cultivars could prove to be superior over their introduction from non-adapted foreign materials via backcrossing in that the important agronomic characteristics of adaptation to the local environment are retained in the mutants.     

EMS诱变甜高粱突变体筛选与鉴定

为了创制优良甜高粱种质资源,改良高配合力父本性状,为甜高粱遗传育种奠定基础,本试验利用24 h+0.25%甲基磺酸乙酯(EMS)水溶液诱变甜高粱甜C-1,从M2代中筛选鉴定优良突变体用于下一步遗传育种。研究表明叶色突变主要发生在M1代,且大部分不能遗传,M1代发现的突变,M2代中依然能够大量发现同类突变。在M2代田间鉴定中发现的突变体类型主要有叶色白化和黄化突变、穗型突变为纺锤型、颖壳包被度变异为1/2和3/4包被、颖壳颜色突变为黑褐色、籽粒增大、籽粒突变为白色、芒性消失、全生育期缩短。利用EMS诱变可以改良现有优良父本性状,加速杂交种的选育,且发现大量的突变体对甜高粱基因功能的挖掘和遗传育种有积极的意义。     

小麦矮秆突变体的遗传分析

对辐射诱发的小麦矮秆突变系进行了遗传分析,鉴定出这些矮秆突变系主要受1～2个主要的隐性矮秆基因所控制,而且这些隐性矮秆基因并未带有不良的基因多效性,即胚芽鞘相应地缩短而影响出苗率,说明辐射诱变方法可以创造自然界所缺少的矮源。     

籼稻多蘖矮半矮秆基因的遗传分析和基因定位

对籼稻标记基因系材料多蘖矮的遗传分析表明, 其矮生性状是由2对隐性半矮秆基因控制的,分别为sd1和一个新的半矮秆基因,该基因初步定名为sdt3。以多蘖矮与南京6号杂交F₂的分离群体为基础,应用SSR标记进行连锁分析,将半矮秆基因sdt3定位于第11染色体的SSR标记SSR98和SSR35之间,分别相距0.06 cM、0.13 cM,二者之间的物理距离约为93kb。以南京6号为轮回亲本与多蘖矮进行回交和自交获得由半矮秆基因sdt3控制的近等基因系（新多蘖矮）,以赤霉素处理表明由sdt3控制的半矮秆系新多蘖矮对赤霉素不敏感。