棉花体细胞培养再生不育株的性状及细胞学研究

研究了以陆地棉（Ｃｈｉｒｓｕｔｕｍ）晋棉７号、冀合３２１、冀棉７１３、珂字棉３２１、珂字棉２０１等品种为外植体的体细胞培养获得再生突变不育株的形态性状及减数分裂过程中染色体的行为。与再生可育株相比，不育株的株型、分枝、叶、花各器官均较小。花柱、柱头、花丝、花药小而呈萎缩干瘪状，花药不开裂。减数分裂不正常，染色体普遍丢失减少，不能正常配对，出现很多单价体和染色体桥。产生二分体、三分体和多分体，也有正常的四分体。雌配子体和雌配子发育也不正常，胚囊结构不完整，反足细胞迟迟解体，表现雌雄不育。     

石刁柏性别表现与同工酶的关系

采用聚丙烯酰胺凝胶电泳对石刁柏（ＡｓｐａｒａｇｕｓｏｆｆｉｃｉｎａｌｉｓＬ．）雌雄植株不同器官及不同组织的过氧化物酶同工酶谱进行了研究，结果表明，除根部外，尽管鳞片、茎尖、拟叶等器官酶谱有明显差异，但雌雄株间差异有相同的趋势。雄株均比相应的雌株少一条酶带，雌雄植株组织培养获得的愈伤组织和茎尖过氧化物酶同工酶酶谱差异也有类似的规律。说明石刁柏性别差异与过氧化物酶同工酶的数目有关，过氧化物酶同工酶谱的差异可以作为性别鉴定的指标。     

Development and application of functional markers in maize

Summary Functional markers (FMs) are derived from polymorphic sites within genes causally involved in phenotypic trait variation (Andersen, J.R. & T. Lübberstedt, 2003. Trends Plant Sci 8: 554–560). FM development requires allele sequences of functionally characterized genes from which polymorphic, functional motifs affecting plant phenotype can be identified. In maize and other species with low levels of linkage disequilibrium, association studies have the potential to identify sequence motifs, such as a few nucleotides or insertions/deletions, affecting trait expression. In one of the pioneering studies, nine sequence motifs in the dwarf8 gene of maize were shown to be associated with variation for flowering time (Thornsberry, J.M., M.M. Goodman, J. Doebley, S. Kresovich, D. Nielsen & E.S. Buckler, 2001. Nat Genet 28: 286–289). Proof of sequence motif function can be obtained by comparing isogenic genotypes differing in single sequence motifs. At current, the most appropriate approach for this purpose in crops is targeting induced local lesions in genomes (TILLING) (McCallum, C.M., L. Comai, E.A. Greene & S. Henikoff, 2000. Nat Biotechnol 18: 455–457). In central Europe, maize is mainly grown as forage crop, with forage quality as major trait, which can be determined as proportion of digestible neutral detergent fiber (DNDF). Brown midrib gene knock out mutations have been shown to be beneficial for forage quality but disadvantageous for overall agronomic performance. Two brown midrib genes (bm1 and bm3) have been shown to be involved in monolignol biosynthesis. These two and additional lignin biosynthesis genes have been isolated based on sequence homology. Additional candidate genes putatively affecting forage quality have been identified by expression profiling using, e.g., isogenic bm lines. Furthermore, we identified an association between a polymorphism at the COMT locus and DNDF in a collection of European elite inbred lines.     

植物抗病毒基因工程研究进展

简要讨论了近年来植物抗病毒基因工程的方法策略,主要有:植物自身的抗病毒基因策略、来源于病毒的抗性基因策略、干扰素、核酶等抗性策略;并分析了其存在问题及发展趋势。     

Environmental factors influence the expression of resistance to sorghum midge, Stenodiplosis sorghicola

Host plant resistance is an effective means of controlling sorghum midge (Stenodiplosis sorghicola). We studied the influence of environmental factors on expression of resistance to sorghum midge in three midge-resistant and two midge-susceptible genotypes. Midge-resistant lines AF 28, ICSV 197, and TAM 2566 suffered 8.8 to 17.3% damage across seven so wings compared to 25.6%damage in ICSV 112, and 69.4% damage in CSH 5. Susceptibility of the midge-resistant lines (AF 28, ICSV 197, and TAM 2566) decreased with an increase in open pan evaporation, maximum and minimum temperatures, and solar radiation; while the midge-susceptible lines (ICSV 112 and CSH 5) showed a poor interaction with these factors. Midge damage in ICSV 197 showed a negative correlation with minimum temperature and relative humidity and positive correlation with sunshine hours,while the reverse was true for CSH 5. Grain growth rate between 0 and 3 days after anthesis was lower in crops sown on 1st October, when AF 28 and ICSV 197 suffered maximum midge damage. Maximum and minimum temperatures and maximum relative humidity influenced the moisture content of the grain, grain growth rate, and sorghum midge damage. There was considerable variation in genotype × environment interaction for expression of resistance to sorghum midge,and the implications of these results have been discussed in relation to development of sorghum cultivars with resistance to this insect. This revised version was published online in August 2006 with corrections to the Cover Date.     

Recurrent selection for maysin, a compound in maize silks, antibiotic to earworm

A thorough knowledge of the inheritance of maysin, a flavone glycoside with antibiosis to corn earworm, Helicoverpa zea Boddie, in the silks of maize will assist breeders in choosing the most efficient method of incorporating this trait into elite inbreds. Two breeding populations, one having exotic origin (EPM), the other from southern inbred lines (SIM) were subjected to six cycles of recurrent selection for increased silk maysin. Ten per cent of the individuals evaluated in populations were selected for recombination as S₁ progenies in each cycle. Progress was evaluated as C0 to C6 population cycles in a randomized complete‐block experiment with five replications in 1997 and 1998. Maysin fresh weights in silks of the C0 populations were 0.54% for EPM and 0.36% for SIM. Responses of 0.19% per cycle in EPM and 0.22% per cycle in SIM resulted in an EPM (C6) population with 1.76% maysin and an SIM (C6) population with 1.69% maysin. Silk maysin concentrations above 0.2% begin to substantially reduce larval growth and prevent completion of the life cycle when husk coverage is sufficient to force the insect to feed on silks while entering the ear. Chlorogenic acid and two analogues of maysin, apimaysin and 3′‐methoxymaysin, were found in such minor quantities in silks that they could not be credited with any impact on antibiotic activity against the insect. Selection has effectively increased silk maysin concentration in both EPM and SIM. Trait responses for maysin are highly heritable and will allow the plant breeder to introgress resistance to the corn earworm into elite material easily.     

Chromosome association and pollen fertility in some interspecific hybrids of Lilium

Summary Meiotic observations in PMCs were made in eight kinds of interspecific hybrids in Lilium. Three hybrids, 6134-S × L. cernuum. L. regale × L. leichtlinii maximowiczii and L. auratum platyphyllum × L. henryi showed respectively the mean chromosome association frequencies of 1.4_II, 0.8_II and 1.5_II per cell at MI which were the lowest values hitherto reported in Lilium hybrids. In L. longiflorum × L. henryi, 33.3° of the cells had 1 or 2 multivalents of three to five chromosomes in addition to uni- and bivalents. 12° bivalents and 12 univalents were invariably observed in the triploid hybrid L. longiflorum × L. cernuum. The hybrids between the species belonging to the different sections of the genus generally showed high pollen sterility, with some exceptions. A more or less remote genomic homology was found between the different sections in Lilium.     

种植密度对棉花分离世代产量性状表现及育种选择的影响

通过裂区设计对Ｆ２代４个群体在三种密度下表现进行了研究，子棉产量、皮棉产量在不同密度、不同群体间存在显著差异；Ｆ２代群体与密度间存在互作，不同群体要求的适宜密度不同。Ｆ２代群体间单株结铃数差异显著，单株结铃数在不同密度差异显著，随密度增加单株结铃数减少，但小区总结铃数呈增加趋势；密度与群体间存在互作，密度的大小对４个Ｆ２群体的单株结铃数影响程度不同。Ｆ２代４个群体间衣分差异显著，但单铃重、衣分在不同密度下差异不显著，且互作不显著。种植密度对不同群体的育种选择具有较大影响。     

参与式植物育种与可持续利用生物多样性--以广西玉米为例

遗传多样性是植物育种的基础,但“遗传侵蚀”现象十分严重。以长期技术供给为主要任务而形成的自上而下的农业研究和推广与需求相脱节,它在新的农村经济社会条件下已不适应。通过对广西玉米育种机构研究人员、科研管理人员及县、乡(镇)、村有关指导农业生产的管理干部和技术员进行访谈,对玉米种植的社区农户进行了深入的调查。运用系统科学的方法对广西玉米遗传多样性降低的影响因素进行分析得出结论和对策,同时通过《玉米种质遗传多样性与农民参与式育种研究》项目在广西实施为案例,进行调查和分析,以促进新的研究理念的形成。     

精量播种条件下冬小麦的高产优质初探

为了研究冬小麦在小播量条件下的产量和品质表现，2001～2003年在北京安排了两个年度的秋播试验。参试品种有DS1号、临抗1号、冀麦30、鲁麦21和京411，京411是对照品种，播种量是22．5kg／hm^2。2001-2002年度，参试品种中临抗1号的最高产量达到6652．5kg／hm^2；2002-2003年度中，京411、鲁麦21、临抗1号、DS1号、冀麦30的平均产量分别达到8537．6，7403．7，7353．75，6836．25，6169．8kg／hm^2，品种的品质也较好。试验中，这些品种有正常的生育表现，较强的分蘖能力，旺盛的生理活动。在产量结构中，这些品种的单株穗数较多。