Homoeological relationships between the f chromosome of Brassica rapa and the e chromosome of Brassica oleracea

Eight plants of the putative double monosomic addition line (DMAL, 2n= 20) were developed by crossing a monosomic chromosome addition line of radish [f(A)‐type monosomic addition line (MAL) (2n= 19)] carrying the f chromosome of Brassica rapa (2n= 20, AA) with another [e(C)‐type MAL (2n= 19)] having the echromosome of Brassica oleracea (2n= 18, CC). The homoeological relationships between the two alien chromosomes were investigated by morphological, cytogenetic and random amplified polymorphic DNA (RAPD) analysis. Seventeen morphological traits that were not present in the radish cv. ‘Shogoin’ were observed in both MALs and these traits were substantially exhibited in DMAL plants. At the first metaphase of pollen mother cells (PMCs), the two parental MALs showed a chromosome configuration of 9II +1I, demonstrating impossibility of recombination between the R and the added chromosomes. The DMALs formed 10II in approximately 73% of PMCs, with one bivalent showing loose pairing between two chromosomes differing in size. In an attempt to identify the two MALs by RAPD‐specific markers using 26 selected random primers, 13 and 20 bands were specific for the f(A)‐type and the e(C)‐type MALs, respectively; 12 bands were common to both MALs (26.7%). In conclusion, the f chromosome of B. rapa is homoeologous to the e chromosome of B. oleracea. The genetic domain (genes) for 17 morphological traits are linked to each homoeologous chromosome bearing 27% of the corresponding RAPD markers.     

The study of introgressive lines of Triticum aestivum × Aegilops speltoides by in situ and SSR analyses

Fluorescence in situ hybridization (FISH) with a genome‐specific repeat, Spelt1, and wheat simple sequence repeat (SSR) markers were used to analyse the chromosome constitution of two Triticum aestivum×Aegilops speltoides introgressive lines. The lines 170/98i and 178/98i carried one and two subtelomeric regions of Ae. speltoides (per haploid genome), respectively, marked by Spelt1 repeats according to FISH data. SSR analysis detected homoeologous substitution of wheat chromosome 7D with Ae. speltoides chromosome 7S in the lines 178/98i and 170/98i as well as the assumed terminal translocation in the short arm of chromosome 3A in the line 178/98i. Anthocyanin pigmentation of the coleoptiles was found in the lines 170/98i and 178/98i and resulted from the 7S (7D) substitution. It was demonstrated that Spelt1 could be effectively used for the rapid identification (without DNA isolation) of terminal translocations of T. aestivum×Ae. speltoides introgressive lines as well as for further analysis of the stability of the hybrid plants.     

Chromosomal effects in the endogenous contents of non-structural carbohydrates and proteins measured in wheat substitution lines

In hexaploid bread wheat, Triticum aestivum (2n = 6x = 42), little work has been carried out to study the genetic control of the synthesis of reduced, non‐reduced and total non‐structural carbohydrates and soluble proteins in aerial and rooting structures. The aim of this paper was to determine the chromosomal location of genes determining carbohydrate and protein synthesis that could be used for diagnostic selection in segregating breeding populations. A set of wheat intervarietal chromosome substitution lines [‘Chinese Spring’ (CS) × synthetic wheat (Triticum diccocoides×Aegilops squarrosa) (Syn)], was used. Plants were cultivated in hydroponic solutions to the fully expanded third leaf stage. Carbohydrate and protein contents and dry matter were determined for aerial and root parts. The root dry weight did not show significant differences between the parental varieties and the substitution lines, except for 5A, 2B and 6B, which had significantly lower dry weights. The aerial dry weight was significantly higher for Syn and the 2A substitution line. The ratio aerial dry weight/root dry weight was significantly higher in Syn, 1A, 2A and 4B. The protein content of the plant showed highly significant differences between both parental lines but 6A and 1D of the substitution lines showed highly significant differences, with contents as high as that for Syn. Syn produced significantly lower total aerial carbohydrates. The substitution lines 2A, 5A, 6A, 7A, 2B, 3D, 5D and 6D showed highly significant total carbohydrate content increases in the aerial parts compared with both parental lines. The non‐reduced carbohydrate contents showed a pattern similar to that of the total carbohydrates. Syn had a lower reduced carbohydrate content than CS. Only the 5A, 2B, and 1D substitution lines had a highly significantly different content of reduced carbohydrates than CS. In roots, Syn produced the lowest values for every type of sugar. The highest significant values for total carbohydrates were found in substitution lines 2B, 4B, 5B, 6B, 1D and 6D. The non‐reduced carbohydrate levels were significantly higher than CS in 2B, 5B, 6B and 6D substitution lines. Only the substitution lines 3B and 1D showed a significantly higher reduced carbohydrate content in roots compared with CS. The photoassimilate partitioning in Syn, 1 A, 2A and 4B favoured the aerial parts but, in contrast, higher partitioning to the roots was found in the 7B, 1D and 3D substitution lines. Both groups appear to carry interesting patterns worth incorporating in wheat cultivars.     

Analysis of spaced-plant and micro-plot performance for yield-related traits in octoploid and hexaploid primary triticales

Summary Twenty-nine primary triticales (x Triticosecale Wittmack), derived from homozygous, uniform wheat and rye inbreds, were evaluated (i) to assess wheat, rye and interaction effects for yield-related characters, (ii) to estimate correlations between these characters, and (iii) to investigate the possibility of predicting micro-plot performance from early spaced-plant tests. The triticales (12 octoploid, 17 hexaploid) were tested under space-planting and in micro-plots in three-replicate, randomized block designs in 1983 and 1984, respectively. In general, hexaploid triticales performed significantly better than octoploids. Strong wheat and wheat x rye interaction effects were found, making it difficult to predict the performance of primary triticales from their constituent parental genotypes. At both ploidy levels under space-planting kernel weight per spike showed significant positive correlations with spikelets per spike, kernels per spikelet, and 1000-kernel weight. No significant associations were detected between spaced-plant and micro-plot performance for octoploids, indicating severe disorders at this ploidy level. In hexaploid triticales spikes per plant, kernel weight per spike, and kernels per spikelet observed in spaced-plants appeared to be useful indicators of grain yield in micro-plots.     

小麦重组自交系群体HMW-GS的检测与分析

利用重组自交系群体--RILL-8群体的131个系为材料,检测和分析了其高分子量麦谷蛋白亚基及亚基组合.结果表明,RIL-8群体Glu-A1、Glu-B1、Glu-D1位点编码的亚基分别为1、N,7 9、7 8和5 10、2 12,主要存在7种亚基组合类型.不同亚基及亚基组合类型在相同位点上仅存在1对等位基因差异,可以用其进行相同位点不同亚基及亚基组合对品质性状效应值的估算.     

杂交水稻制种父母本花期相遇诊断技术研究

以四川全省试验资料为基础，研究了杂交水稻制种父母本生长发育、抽穗开花的规律及影响父母本播差期安排的主要因子，建立了相应的预测模型和四川杂交水稻制种父母本花期相遇微机诊断系统（ＤＳＦＰＭＰＨＲＳＰ），在四川杂交水稻制种生产中推广应用，提高调差精度２～３ｄ，增产杂交稻一代种子１５０～３００ｋｇ／ｈｍ２。     

大白菜-结球甘蓝易位系AT4系列抽薹相关基因表达差异的cDNA-AFLP分析

抽薹开花时间是大白菜(Brassica rapa ssp.pekinensis)的重要性状,未熟抽薹直接影响大白菜的产量和品质.本研究以添加结球甘蓝(Brassica oleracea var.capitata)4号染色体片段的大白菜-结球甘蓝易位系AT4系列为材料,结合抽薹性鉴定,获得了45株耐抽薹和15株易抽薹植株;利用cDNA-扩增片段长度多态性(cDNA-amplified fragment length polymorphism,cDNA-AFLP)技术,对不同春化处理的耐抽薹和易抽薹植株叶片差异表达片段进行分离,获得了126条与抽薹性相关的差异表达条带,这些差异包括条带的有无和表达量的差异;通过差异条带回收、克隆和测序,获得了74条差异表达序列.同源性比对结果表明,61条差异表达序列具有同源序列,其中41条差异表达序列功能预测涉及代谢、能量、细胞物质运输、信号转导、表达调控、DNA修饰、细胞周期等,20条差异表达序列功能未知;13条在NCBI中找不到同源序列,可能是一些新基因.本研究获得了耐抽薹大白菜-结球甘蓝易位系,为耐抽薹大白菜新品种的培育提供新材料;同时获得了耐抽薹和易抽薹材料间的差异表达序列,为获得影响大白菜抽薹性的关键基因,揭示大白菜抽薹开花机制提供支撑.     

籼型杂交稻不育系农A的选育

用珍汕９７Ｂ×钢枝占的后代与珍汕９７Ａ连续回交１８代育成的籼型杂交水稻不育系农Ａ,株高８３．７ｃｍ左右,播种至抽穗天数早季７５ｄ,晚季７６ｄ,株型紧凑,叶片数１４片,每穗粒数２４５．４粒,千粒重２３ｇ,长粒型,颖壳淡金色。自交结实率为０％,花粉总不育度９９．９９％,柱头外露率７５％左右,颖花张开角度较大、异交率高、繁殖制种产量高。经与多个恢复系配组,其产量及构成产量因素的性状的配合力均较强。     

节水防污型农田水利系统构建及其效果分析

不合理的农田水肥管理是造成农业面源污染的主要原因之一。为了探寻灌区水稻节水、增产和减污相统一的措施,提出运用由田间、草沟、塘堰湿地和骨干沟"四道防线"组成的系统净化农田排水,并在广西桂林市青狮潭灌区及广西灌溉试验中心站开展了系统的试验研究。通过站内不同水肥处理下对田间节水、水稻增产、氮磷流失减少指标的分析,优选水稻田间最优水肥管理模式,即采用间歇灌溉模式、施氮肥总量不变、适当减少氮肥基肥增加追肥用量;在站外根据现有的水系分布构建"四道防线"系统,分析了各道防线对农田排水的净化效果以及提高净化效果的主要措施。由"四道防线"构成的节水防污型农田水利系统对农田氮磷排放具有良好的净化效果,实现了减少农田面源污染和修复农田水环境的目的。     

抗白叶枯病籼稻DV_(85)在籼粳交中的遗传表现

抗白叶枯病籼稻品种DV_(85)与粳型广亲和系的亲和性较差。抗性基因在F_2代的分离,经卡平方测验,其抗感分离比显著偏离正常值,为异常分离。相关性分析显示这种异常分离与结实率、穗长、每穗粒数和千粒重无关。本文就籼粳杂交的配组形式和不同生育阶段对抗性基因分离的影响也进行了分析讨论。