芥菜型油菜多室基因Bjmc2的精细定位

芥菜型多室油菜的产量比普通两室油菜更高,定位乃至克隆多室基因可为油菜遗传改良及解释多室角果形成机制创造条件。本研究通过验证JD11-2家系衍生群体仅在BjMc2位点上存在差异,可用于BjMc2的定位。采用AFLP结合BSA法分析BC₅和BC₆群体,筛选到1个与BjMc2连锁的AFLP标记并转化为SCAR标记SC1。基于该AFLP标记序列信息,利用白菜同源序列设计SSR引物和SCAR引物,获得11对SSR标记和1对SCAR标记。通过在芥菜型油菜BAC文库中的挑选,获得2个覆盖目标区域的单克隆,由此开发1个SSR标记。将获得的SCAR和SSR标记扫描BC₇群体,构建了两室性状基因BjMc2的遗传连锁图,两侧最近标记ZX17和BACsr96与目标基因之间的遗传距离分别为0.048 cM和0.340 cM,并定位到白菜A7 scaffold000019的946~1014 kb之间,约68 kb物理距离。     

芥菜型油菜与甘蓝型油菜嫁接嵌合体的性状表现

以芥菜型油菜(B. juncea)作砧木,以甘蓝型油菜(B. napus)作接穗,形成嫁接嵌合体（以下简称“甘+芥”嫁接嵌合体）,对其植物学性状、农艺性状和32P标记的难溶性磷矿粉的吸收能力进行了研究。结果表明,“甘+芥”嫁接嵌合体除叶片出现紫色性状外,其他性状与甘蓝型油菜没有差异,但其农艺性状明显优于甘蓝型油菜和芥菜型油菜。其根系对肥料中难溶性磷吸收能力强,而且多数转移到地上部分,在体内分布较合理。     

Characterization of tribenuron-methyl-induced male sterility in Brassica juncea L.

Significant heterosis has been documented in Brassica juncea L. that are grown as agriculturally important oilseeds, vegetables and condiments crops. Male sterility induced by chemical hybridizing agents is an important pollination control system in hybrid crop breeding. Herein, we show that tribenuron-methyl (TBM), a sulfonylurea herbicide, is an effective male gametocide in B. juncea when used at a very low dosage. In the present study, foliar application of various rates of TBM induced a significant increase in pollen sterility in B. juncea (90.57–100%). TBM-treated plants exhibited reductions in size of floral organ and yield components; however, lower dose of TBM (0.075 g a.i. ha^–1) did not cause a significant reduction in seed yield per plant. Tapetum cells of TBM-treated plants were hypertrophied and degenerated earlier, and abnormal meiosis was observed at the meiotic stage. A significant decrease of acetohydroxyacid synthase (AHAS) activities was detected in buds of plants treated with 0.10 g a.i. ha^–1 TBM, and RT-qPCR analysis showed that TBM exposure perturbed AHAS expression in small buds, which support that TBM induces male sterility in B. juncea by targeting AHAS expression. Our results suggest that TBM could be used as an efficient chemical hybridization agent in B. juncea, which has practical implications for the application of hybrid breeding in B. juncea.     

An improved cytoplasmic male sterile (Diplotaxis berthautii) Brassica juncea: identification of restorer and molecular characterization

We report the development of an improved cytoplasmic male sterile (CMS) system of Brassica juncea carrying cytoplasm of the wild species Diplotaxis berthautii. Flowers of the CMS line are smaller than the euplasmic line but have improved nectaries. Anthers are slender and fail to extend to the level of stigma. Female fertility of the CMS line is comparable to the euplasmic line. Fertility restorers of Moricandia arvensis and D. catholica-based alloplasmic CMS systems of B. juncea were found capable of restoring male fertility to this new CMS line. The fertility restoration is monogenic and gametophytic. Southern analysis showed that the cytoplasm of the CMS line is different from euplasmic B. juncea and other CMS systems restored by the same restorer lines. Northern analysis of the CMS, fertility restored and euplasmic lines using eight mitochondrial gene probes revealed altered atpA expression associated with male sterility. Cleaved amplified polymorphic sequence (CAPS) markers were identified for the plastid gene psbB, which could be useful for a quick identification of this CMS line. S.R. Bhat and P. Kumar contributed equally to this work.     

Path Analysis of Important Growth Functions of Indian Mustard (Brassica juncea L. Czern and Coss)

Field experiment conducted at the Viswavidyalaya Farm during the winter seasons of 1980—81 to 1983—84 to study the effects of major six productive functions viz. number of inflorescence bearing primary branches, number of inflorescence bearing secondary branches, leaf area indices at flowering, number of seeds/siliqua, number of siliqua/m² and test weight of grains on the grain yields of eight elite varieties of Indian mustard ( Brassica juncea L. Czern and Coss) when sown on three different times revealed that correlations between them were close and positive in all the varieties. Path analysis of the data, further, showed that except the inflorescence bearing primary branches and the seeds/siliqua all other attributes showed high direct influences on grain yield; the maximum direct influence was obtained from number of siliqua/m².     

Combination of resistance to Verticillium longisporum from zero erucic acid Brassica oleracea and oilseed Brassica rapa genotypes in resynthesized rapeseed (Brassica napus) lines

Resynthesized (RS) forms of rapeseed (Brassica napus L.; genome AACC, 2n = 38) generated from interspecific hybridization between suitable genotypes of its diploid progenitors Brassica rapa L. (syn. campestris; genome AA, 2n = 20) and Brassica oleracea L. (CC, 2n = 18) represent a potentially useful resource to introduce resistance against the fungal pathogen Verticillium longisporum into the gene pool of oilseed rape. Numerous cabbage (B. oleracea) accessions are known with resistance to V. longisporum; however, B. oleracea generally has high levels of erucic acid and glucosinolates in the seed, which reduces the suitability of resulting RS rapeseed lines for oilseed rape breeding. In this study resistance against V. longisporum was identified in the cabbage accession Kashirka 202 (B. oleracea convar. capitata), a zero erucic acid mutant, and RS rapeseed lines were generated by crossing the resistant genotype with two spring turnip rape accessions (B. rapa ssp. olerifera) with zero erucic acid. One of the resulting zero erucic acid RS rapeseed lines was found to have a high level of resistance to V. longisporum compared with both parental accessions and with B. napus controls. A number of other zero erucic acid RS lines showed resistance levels comparable to the parental accessions. In the most resistant RS lines the resistance and zero erucic acid traits were combined with variable seed glucosinolate contents. Erucic acid‐free RS rapeseed with moderate seed glucosinolate content represents an ideal basic material for introgression of quantitative V. longisporum resistance derived from B. oleracea and B. rapa into elite oilseed rape breeding lines.     

Drought effects on yield and its components in Indian mustard (Brassica juncea L.)

Effects of drought on yield and yield components were investigated during the spring season 2000–2001 by growing 14 Indian mustard genotypes under irrigated and rain-fed conditions at Bharatpur and Jobner. A disease and pest management schedule was followed when required. The drought susceptibility index (DSI) for seed yield and component characteristics was calculated to characterize the relative tolerance of genotypes. Plant height, primary branches, secondary branches per plant, 1000-seed weight and seed yield were reduced under rain-fed conditions. The top five genotypes at Bharatpur that showed tolerance to moisture stress for seed yield, as indicated by their lowest DSI, were, in descending order PSR-20, PRO-97024, JMMWR-941, IS-1787 and PCR-7, whereas at Jobner these were JMMWR-941, RC-1446, PSR-20, RH-819 and 'Varuna'. Of these, PSR-20 and JMMWR-941 were among the top six at both locations. These genotypes also showed relatively low DSI for one or more characteristics, such as primary branches per plant, secondary branches per plant, harvest index and seed : husk ratio. Genotypes with the lowest DSI, particularly for seed yield at both locations, would serve as useful donors in the breeding programme for improving the drought tolerance of existing Indian mustard cultivars.     

Development of IP and SCAR markers linked to the yellow seed color gene in Brassica juncea L.

Previous studies showed that the yellow seed color gene of a yellow mustard was located on the A09 chromosome. In this study, the sequences of the molecular markers linked to the yellow seed color gene were analyzed, the gene was primarily mapped to an interval of 23.304 to 29.402M. Twenty genes and eight markers’ sequences in this region were selected to design the IP and SCAR primers. These primers were used to screen a BC₈S₁ population consisting of 1256 individuals. As a result, five IP and five SCAR markers were successfully developed. IP4 and Y1 were located on either side of the yellow seed color gene at a distance of 0.1 and 0.3 cM, respectively. IP1, IP2 and IP3 derived from Bra036827, Bra036828, Bra036829 separately, co-segregated with the target gene. BLAST analysis indicated that the sequences of newly developed markers showed good collinearity with those of the A09 chromosome, and that the target gene might exist between 27.079 and 27.616M. In light of annotations of the genes in this region, only Bra036828 is associated with flavonoid biosynthesis. This gene has high similarity with the TRANSPARENT TESTA6 gene, Bra036828 was hence identified as being the gene possibly responsible for yellow seed color, in our research.     

Introgression of a gene restoring fertility to CMS (Trachystoma) Brassica juncea and the genetics of restoration

A dominant gene restoring fertility to a cytoplasmic male sterile (CMS) line of Brassica juncea was derived from the somatic hybrid Trachystoma ballii+B. juncea. Its introgression resulted from forced pairing between chromosomes of the cultivar ‘Pusa Bold’ and chromosomes of the fusion hybrid. Segregation ratios of this fertility restorer gene followed a monogenic pattern. The introgression of the fertility restorer gene did not cause any abnormalities, such as reduced fertility; pollen and seed fertilities of the restored plants were over 90%. Restored fertile and CMS plants exhibited similar Southern hybridization patterns when probed with the mitochondrial probe atp6.     

Peroxidase Activity in Relation to Plant Height and Seed Yield in Indian Mustard (Brassica juncea L. Coss)

Peroxidase levels were assayed in 12 genotypes and in 36 F₁cross progenies of Indian mustard ( Brassica juncea L. Coss) at twelve stages of development, starting from seed germination till seed formation. The levels of peroxidase activity and the coefficient of variation emphasized the role of differential enzyme activity at different stages of development. Genotypes were also evaluated for plant height and seed yield. The correlations of peroxidase activity in 24 h soaked seeds with plant height and seed yield were significantly positive while those of enzyme activity in 45 days old plants with these traits were significantly negative. The study suggests the changing role of enzyme at two critical stages of plant development.     

Gene flow from transgenic oilseed Brassica juncea (L.) Czern. into weedy Sinapis arvensis L. (wild mustard)

Gene flow from acetolactate synthase‐resistant (HR) Brassica juncea oilseed canola to related weed, Sinapis arvensis (density 1 plant/m²) was assessed in a 100 m² field plot of HR B. juncea. Two HR F₁ hybrids (H1 and H2) were detected among 109 951 seedlings screened with imazethapyr (hybridization frequency – 1.8 × 10^?5). Hybridity was confirmed using flow cytometry, B. juncea‐specific amplified fragment length polymorphisms (AFLPs) markers, genomic in situ hybridization (GISH) and PCR‐based detection of B. juncea's HR gene. H1 and H2 had 2n = 27 and 2n = 45 chromosomes, corresponding 3x (SrAB) and 5x (SrAABB) genomic structures and reduced male fertility, 3.2 and 16.6% pollen viability, respectively. H1 was self‐incompatible, whereas H2 set seed when selfed (B. juncea trait). Selfed F₂, F₃ and F₄ plants showed HR trait persistence and vigorous growth and high (80–100%) pollen fertility in 22% and 39% of the F₂ and F₃ plants, respectively. No progeny were obtained from F_1, F₂ or F₃ hybrids × S. arvensis backcrosses, suggesting the likelihood of introgression of traits is low to negligible.     

Phenotypic variation and the relationships among mustard (Brassica juncea L.) germplasm from Pakistan

An investigation was conducted to determine the extent of diversity and relationships among the Brassica juncea germplasm from Pakistan using morphological characters. A total of 52 accessions, including the collected germplasm as well as commercial cultivars/improved lines, were studied under field conditions at Tsukuba, Japan during 1995 and 1996. All the accessions were characterized for 35 agro-morphological characters from seedling emergence to crop maturity. Morphological data were analyzed by numerical taxonomic techniques using two complementary procedures: cluster and principal component analyses. Phenograms based on Euclidean distance placed the accessions into six groups during both years. Landrace groups were primarily associated with morphological differences among the accessions and secondarily with the breeding objectives and horticultural uses. The mustard germplasm collected from Pakistan showed a comparatively low level of phenotypic variation amongst themselves and were genetically similar to the oilseed cultivars. However, the oilseed forms and vegetable cultivars were genetically distinct. This study revealed that the evaluated germplasm appears to have a narrow genetic base which undergoes a high level of genetic erosion. This is perhaps due to the use of the same ancestors in the selection of new lines for similar horticultural traits, replacement by major crops and changes in agricultural land uses. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characterization of different cytoplasmic male sterility systems in Indian mustard (Brassica juncea L. Czern & Coss)

Six cytoplasmic male sterility (CMS) systems, viz. moricandia, ogura, oxyrrhina, siifolia, tournefortii and trachystoma of Indian mustard (Brassica juncea L.) were characterized for agronomic and floral characteristics. Introgression of alien cytoplasm caused alterations in different floral traits in ogura, siifolia, tournefortii and trachystoma CMS systems. Varied response to different genetic backgrounds of CMS lines indicated the presence of cytoplasmic–nuclear interaction in alteration of floral traits. On the basis of floral characteristics, CMS systems could be grouped into distinct classes. Siifolia, tournefortii and trachystoma CMS lines had narrow petals, while moricandia, ogura and oxyrrhina had wider petals, which were distinguishable on the basis of visual observations. The ratio between length and width of petals were >2.0 in wide petal group but <2.0 in narrow petal group. Further, the relative position of anther and stigma, which was estimated as the ratio between stamen and style length could differentiate the CMS systems. Stamens were longer than styles in oxyrrhina, equal in moricandia and shorter in ogura, siifolia, tournefortii and trachystoma male sterile lines. Non‐viable pollen grains were present in moricandia and oxyrrhina systems, but absent in other systems. In tournefortii and trachystoma, few flowers showed petaloid corolla. All male sterile lines, except trachystoma, which showed crooked siliqua formation were at par with their respective maintainers for flower initiation, plant height, primary branches, seeds per siliqua, seed yield, harvest index, oil and protein content. In general, flower senescence and maturity occurred earlier in male sterile lines than in their respective maintainer lines.     

以NIRS定量分析甘蓝型油菜、芥菜型油菜饼粕赖氨酸含量

作物品质育种工作需要快速和准确,并且不破坏种子的情况下来测定有关参数,但传统的品质鉴定方法在分析速度和效率以及种子的留存上存在局限性,难以满足上述要求.近红外反射光谱分析技术(near infrared reflectance spectroscopy,NIRS)是一种不需要对种子进行前处理,即可得到几乎全部农产品品质参数的分析技术[1].NIRS技术现已广泛应用于农产品[2]、食品[3]、果汁[4]、饲料[5]等的分析检测.我国该技术的应用虽起步较晚,但在农作物品质分析上已取得了一些可喜的进展[6,7].用近红外仪测试油菜种子的含油量、饼粕的蛋白质含量与硫甙含量,已基本接近和达到化学分析所需求的精度[8].     

Genetic diversity in mustard (Brassica juncea L.) germplasm from Pakistan as determined by RAPDs

The genetic diversity and the relationships among a collection of mustard (B. juncea) germplasm, including 41 accessions collected from Pakistan, 6 oilseed cultivars/ lines and 5 Japanese vegetable cultivars, were evaluated using random amplified polymorphic DNA (RAPD) markers. A total of 198 polymorphic amplified products were obtained from 30 decamer primers. Of these, 14 were unique to the accession PAK-85835 and 37 were specific to PAK-85839. Based on pair-wise comparisons of RAPD amplification products, genetic similarity was estimated using similarity coefficients of Nei & Li (1979) and a dendrogram was constructed using the unweighted pair-group method with arithmetic averages (UPGMA). Cluster analysis based on these genetic similarities placed most of the collected germplasm and oilseed cultivars/lines close to each other, showing a low level of polymorphism between the oilseed accessions collected in Pakistan. However, the clusters formed by the oilseed collections and cultivars were distinct from those formed by the vegetable cultivars. A low level of genetic variability of oilseed mustard in Pakistan was attributed to the selection for similar traits and horticultural uses. The farmers' preference for more remunerative crops and perhaps the close parentage of these accessions further contributed towards their little diversity. The study demonstrated that the RAPD is a simple and fast technique to compare the genetic relationships and the patterns of variation among accessions of this crop. This revised version was published online in August 2006 with corrections to the Cover Date.     

Interactive Effect of Nitrogen and Sulphur on Growth and Yield of Rape-seed-Mustard (Brassica juncea L. Czern. and Coss. and Brassica campestris L.) Genotypes

A simple randomized field experiment was conducted to assess the growth and yield of rape-seed-mustard in relation to sulphur and nitrogen interaction. Three levels of sulphur (0, 40 and 60 kg ha⁻¹) in combination with three levels of nitrogen (60, 100 and 150 kg ha⁻¹) were tested as treatments, T₁, T₂, T₃, T₄, and T₅. Results indicated significant favourable effects of sulphur and nitrogen, when applied together, on yield components, seed and oil yield. Maximum response was observed with treatment T₃ (having S and N of 40 and 100 kg ha¹, respectively). Percentage oil content of seed was maximal at T₄ (having S and N of 60 and 100 kg ha¹) in both cultivars. The increase in N dose from 100 to 150 kg ha⁻¹ without any change in applied S, i.e. 60 kg ha¹ (T₅), decreased the percentage oil content. The seed and oil yield, however, were similar to T₃. Favourable responses of S and N interaction on leaf area index, rate of photosynthesis and biomass production were also observed.     

Testing for Tolerance to Aphids in Indian Mustard, Brassica juncea (L.) Czern and Coss.

Brassica juncea plants were screened for aphid tolerance using three methods. Seven and 14 days old seedlings grown in wooden trays in a glasshouse were kept between infector trays with heavy aphid infestation. There were no surviving plants in the susceptible genotypes 50 days after sowing but survival rates ranging between 80 and 90 % were observed for selection 44. The progenies of the surviving plants were tested under natural infestation in the field. Plants were scored for leaves without aphids 40 days after sowing, healthy plants at harvest and seed yield in g/m² For most of these lines, the aphids’ survival, life span and fecundity (nymphs produced per adult) were recorded after introducing five newly-born nymphs on excised fifth leaves cultured in petri dishes. Selections showing greater tolerance to aphids than the check cultivars were identified in the progenies of a cross RLM-514 × T-6342. It was concluded that the excised leaf method can provide a reliable measure of the lines’ reaction to aphids.     

芥菜型油菜BjuB.KAN4基因调控类黄酮的途径

MYB类转录因子KAN4有调控植物原花青素合成的功能。为了探究芥菜型油菜中MYB转录因子KAN4对原花青素合成的调控机理,本研究以芥菜型油菜紫叶芥为实验材料,克隆了一个BjuB.KAN4基因,编码266个氨基酸,BjuB.KAN4蛋白包含一段高度保守的MYB-like DNA结合结构域,属于1R-MYB转录因子家族成员。基因表达分析表明, BjuB.KAN4在根中表达量显著高于叶和茎中, GUS组织化学染色分析试验推测,该基因可能在根茎叶的维管组织中表达。利用毛状根体系过表达BjuB.KAN4发现,类黄酮合成途径的部分关键酶基因Bju.CHS和Bju.DFR等的表达量在紫叶芥和四川黄籽的转基因根系中均显著增加,紫叶芥转基因根系中总黄酮含量为2.798 mg g^-1,是对照组的1.3倍,四川黄籽中总黄酮含量为2.567 mg g^-1,是对照组的1.2倍。在拟南芥中异源表达BjuB.KAN4发现,转基因植株总黄酮含量为0.237mgg^-1,是野生型的1.5倍,原花青素含量为0.363mgg^-1,较野生型...