棉花质核不育材料晋A的发现与观察

发现并系统观察了棉花雄性不育材料晋Ａ。通过镜检、自交、测交、回交、开放授粉和网罩试验表明，此材料不育性完全而稳定，陆地棉品种可作其完全保持系，海岛棉品种可使其育性恢复，是我国新发现的又一质核不育材料。其不育胞质来自陆地棉，但与其它胞质系不同，这一发现为棉花三系配套、实现产量上的突破提供了新的胞质基因源。     

Low light intensity and flower bud abortion in Asiatic hybrid lilies. I. Genetic variation among cultivars and progenies of a diallel cross

Summary When Asiatic lilies are forced during the winter period, additional light is needed to prevent flower bud abscission and flower bud blasting. Growth room experiments showed considerable differences among eight lily cultivars in their response to low light. Among these cultivars, Connecticut King and Enchantment appeared to be the most sensitive to low light conditions while Uncle Sam and Scout were the least sensitive.Analysis of an incomplete diallel cross between nine cultivars showed significant differences in general combining ability (GCA) for flower bud abortion, number of buds, forcing time, plant height and leaf scorch under winter greenhouse conditions. Enchantment had the highest positive GCA for bud abortion, indicating a high sensitivity to low light conditions. Uncle Sam had the lowest GCA. Pirate and Scout appeared to have a high GCA for sensitivity to leaf scorch. Connecticut King was found to be a probable source of cytoplasmic male sterility. The data suggest that male sterility is associated with better response to low light conditions.     

芝麻基因雄性不育系的研究

通过群体改良对芝麻雄性不育原始材料进行基因重组，产生了大量优秀变异。用系内连续姊妹交，回效等手段育在敢综合农艺性状良好，不育度为９９％以上，不育株率稳定在５０％左右可供可杂交种生产应用的ｍｓ８６－１不育系。形态学研究证明，所选不育系雄蕊败育彻 底，雌蕊发育正常，具有正常的结籽能力；小孢子败育发生在四分体后的无液泡小孢子期；雄性不育性具有良好的环境稳定性。根据初步的遗传分析推测，不育性可能不是受单隐     

离子注入水稻种子萌发过程中的自由基和SOD酶研究

用能量30Kw_1剂量6×10~(16)N~ /cm~2的氮离子束辐照水稻早籼品种广陆矮4号,用ESR波谱术和氮蓝四唑(NBT)还原法测定水稻种子萌发过程中的自由基和SOD酶的变化.在室温和低温下测定离子注入水稻干种子的ESR谱,结果表明:辐照后的水稻干种子有较高的自由基产额;低温测定ESR波谱显现出二条谱峰,这为糖和蛋白质在电离辐射作用下产生的特征峰.种子萌发过程中的自由基变化是在种子吸水8小时时自由基浓度锐减,16小时降至最低点;自由基清除酶之一SOD酶,随着吸水时间的增加,酶活性逐渐增加,SOD酶的清除作用主要表现在生物体内源自由基的清除.最后生物体内自由基和SOD酶形成动态平衡.     

Chromosomal location of fertility restoring genes for ‘wild abortive’ cytoplasmic male sterility using primary trisomics in rice

Summary Identification and location of fertility restoring genes facilitates their deployment in a hybrid breeding program involving cytoplasmic male sterility (CMS) system. The study aimed to locate fertility restorer genes of CMSWA system on specific chromosomes of rice using primary trisomics of IR36 (restorer), CMS (IR58025A) and maintainer (IR58025B) lines. Primary trisomic series (Triplo 1 to 12) was crossed as maternal parent with the maintainer line IR58025B. The selected trisomic and disomic F₁ plants were testcrossed as male parents with the CMS line IR58025A. Plants in testcross families derived from disomic F₁ plants (Group I crosses) were all diploid; however, in the testcross families derived from trisomic F₁ plants (Group II crosses), some trisomic plants were observed. Diploid plants in all testcross families were analyzed for pollen fertility using 1% IKI stain. All testeross families from Group I crosses segregated in the ratio of 2 fertile: 1 partially fertile+partially sterile: 1 sterile plants indicating that fertility restoration was controlled by two independent dominant genes: one of the genes was stronger than the other. Testcross families from Group II crosses segregated in 2 fertile: 1 partially fertile+ partially sterile: 1 sterile plants in crosses involving Triplo 1, 4, 5, 6, 8, 9, 11 and 12, but families involving triplo 7 and triplo 10 showed significantly higher X² values, indicating that the two fertility restorer genes were located on chromosome 7 and 10. Stronger restorer gene (Rf-WA-1) was located on chromosome 7 and weaker restorer gene (Rf-WA-2) was located on chromosome 10. These findings should facilitate tagging of these genes with molecular markers with the ultimate aim to practice marker-aided selection for fertility restoration ability.     

Restriction analysis of the mitochondrial DNA of male-sterile and maintainer lines of pearl millet, Pennisetum americanum L.

Mitochondrial DNA from two pairs of cytoplasmic male-sterile (cms) and maintainer lines of pearl millet was investigated by restriction-enzyme analysis and Southern-blot hybridization using three mitochondrial gene probes. Each pair of male-sterile and maintainer lines was of a different nuclear origin. The objective was to distinguish differences in the DNA base-sequence organization of the mitochondrial genomes of cms and maintainer lines from the two sources. Restriction-enzyme analysis revealed differences between the different cms and maintainer lines. Southern-blot hybridization experiments using cloned mitochondrial gene probes further distinguished differences between different lines. It is expected that the restriction-fragment-length polymorphisms revealed in the Southern-blot-hybridization experiments will be useful in distinguishing and classifying cms and maintainer lines obtained from different nuclear backgrounds.     

Genetic and cytogenetic studies with a male sterile mutant of common wheat (Triticum aestivum)

Summary Genetic and cytogenetic studies were done on a male sterile mutant of the wheat variety Probus. Association of the 4A chromosome carrying the ms gene was studied in the F₁ of the male sterile Probus with Chinese Spring ditelo 4AS, with Transec and with line T4AS-DRS respectively. The presumption that the genetic male sterility of the mutant was due to a terminal deletion of the short arm of chromosome 4A could be confirmed.Linkage studies showed that the ms gene was at 17 map units from the dwarfing gene (Rht3) of Minister dwarf. This allows selection of short male sterile plants at the seedling stage.     

甘蓝型油菜Pol CMS育性恢复基因的RAPD标记

采用恢、 保回交群体和集团分离分析(BSA), 筛选了860个10 mer随机引物, 找到了与甘蓝型油菜波里马细胞质雄性不育系(Pol cms)育性恢复基因(Rf)连锁的两个RAPD标记AH19690和AI16830。 它们位于Rf的一侧,与该基因的遗传图距分别为5.9 cM和13.6 cM,两标记间的遗传图距为7.8 cM。这两个RAPD标记的发掘,为进一步利用分子标记     

Genetics of thermosensitive genic male sterility in rice

Summary Inheritance of thermosensitive genic male sterility (TGMS) in Norin PL12 and IR32364TGMS and their allelic relationship were studied from F₁, F₂ testcross (TC) and F₃ generations of the crosses made with the two mutants and several fertile tester parents. F₂, TC and F₃ segregation behavior for pollen and spikelet fertility indicated that the TGMS trait in the two mutants was controlled by a single recessive gene. Allelic relationship studies indicated that TGMS genes of the two mutants were different. Since TGMS gene in Norin PL12 has been designated as tms ₂ , the TGMS gene present in IR32364TGMS is tentatively designated as tms ₃ (t) until allelic test is done with another TGMS gene (tms ₁ ) reported from China in a line 5460S seeds of which were not available.     

Performance of pearl millet isonuclear hybrids involving different cytoplasmic male-sterility systems

The performance of pearl millet hybrids involving four sources of cytoplasmic male sterility (CMS), including the most-exploited A₁ source, was compared to evaluate the effects of cytoplasm on grain yield. The mean grain yield of hybrids possessing A₂, A₃ and A₄ cytoplasms was either similar to or significantly higher than that of their counterpart hybrids with A₁ cytoplasm. Hybrids based on A₃ and A₄ cytoplasms produced, on average, 8% more grain compared with those based on A₁ cytoplasm. This suggested that these CMS sources could be used as alternatives to A₁ cytoplasm to widen the cytoplasmic base of hybrids. The results indicated that most of the variation in hybrids was accounted for by pollinator and cytoplasm × pollinator interactions, suggesting the use of genetically diverse pollinators in pearl millet hybrid breeding.