Effect of Bradyrhizobium Strain on Combining Ability for Nitrogen Fixation in Peanut (Arachis hypogaea L.)*

Improving the host genotype is one method of increasing biological nitrogen fixation by Bradyrhizobium in symbiosis with peanut (Arachis hypogaea L.), but host-strain interactions also must be considered. The objective of this study was to estimate the effect of Bradyrhizobium strains on the inheritance of traits related to nitrogen fixation. Eight parents and the F₁ generation of a diallel cross were evaluated in symbiosis with two bacterial strains for combining ability in a factorial arrangement in the greenhouse. The parents represented three taxa of cultivated peanuts. The two Bradyrhizobium strains NC 92 and NC 123 produced different general and specific combining ability, maternal (reciprocal general) effects, and reciprocal specific effects for the host genotypes. With strain NC 92, the peanut cultivars NC 7 and NC Ac 2821 had the best general combining ability for all traits evaluated; while, with strain NC 123, Robut 33-1 exhibited a high general combining ability (GCA) for nitrogenase activity and specific activity. Genotype NC Ac 2821, when inoculated with strain NC 123, had a negative GCA effect for nodule number, while with strain NC 92 this cultivar had the highest GCA effect. The importance of strain selection in evaluating lines in a breeding program is discussed.     

The Physiology of Seed Germination in Groundnut (Arachis hypogaea L) Cultivar GG-2. I. Effect of Seed Size

The seeds of groundnut cultivar GG-2 were categorized according to their test weight (100 seed weight) as bold (58.2 g), medium (37.9 g), small (24.9 g), small wrinkled (13.4 g) and control (30.3 g) seed lot. The variation in their size and dimension was also taken into account. The overall germination percentage was high for medium size seeds and was closely followed by bold seeds. The performance of the small and small wrinkled seeds was comparable to that of control. The seed vigour was found to be higher with heavier seeds. Small seeds exhibited equally good performance in response to seed germination and growth of the seedling components. There were no significant differences for the development of hypocotyl, epicotyl and plumule.     

Effect of waterlogging stress on grain nutritional quality and pod yield of peanut (Arachis hypogaea L.)

To investigate the effects of waterlogging stress on grain nutritional quality and pod yield, peanut plants were waterlogged for 3 and 6 days at 7, 14, 21, 28, 35, 42, 49, 56 and 63 days after gynophores touched the ground in 2019 and 2020. Results revealed that compared with the control treatment, the oil and starch content in grain increased, while crude protein and soluble sugar content decreased under waterlogging. Waterlogging stress increased the unsaturated fatty acids content but decreased the saturated fatty acids, essential amino acids, non-essential amino acids and total amino acids content. In addition, waterlogging stress decreased the total pod number per plant by 6.78%–49.33%, 100-pod weight by 1.11%–14.08% and 100-grain weight by 1.85%–16.41%, which caused a 34.33%–55.90% reduction in pod yield per plant. After the gynophore touched the ground for 7 days, waterlogging had a greater negative effect on grain nutritional quality, and longer waterlogging duration led to greater yield reduction. In summary, waterlogging stress caused peanut yield reduction and grain quality deterioration.     

Role of Testa, Cotyledons and Embryonic Axis in Seed Dormancy of Groundnut (Arachis hypogaea L.)

Experiments were carried out during winter–summer (January–June) season to understand the role of seed testa, cotyledons and embryonic axis in imparting dormancy of some groundnut cultivars belonging to different habit groups. Crop was harvested at four maturity stages; 90, 100, 110 and 121 days after emergence (DAE). After drying the pods in shade for 2 days, the germination of seeds with (GST) and without (GSW) testa in rolled germination towels and seeds, and embryonic axes (GEM) in culture media from individual plants of a cultivar was studied. Seed testa played an important role in imparting dormancy followed by the cotyledons, and embryonic axis. However, the nature of dormancy of embryonic axis appeared to be different from that of the testa and cotyledons. Results suggested that the dormancy in groundnut is regulated mainly by testa (a maternal tissue) in the Spanish type, but by cotyledons, and embryonic axis (both zygotic tissue) as well as testa in Virginia types. Thus the genetic control of seed dormancy in groundnut appears to be quantitative in nature.     

Rust Resistance and its Stability in Lines of Varying Productivity in Groundnut (Arachis hypogaea L.)

Twenty six lines of groundnut (Arachis hypogaea L.) of varying productivity were tested for yield under four treatments involving fungicidal control of rust and leafspots. Disease severity was measured at two stages of growth, namely 70 days (stage 1) and 90 days after sowing (stage 2). Instead of pod yield, a score (based on an Isd test and grouping over pod yield, shelling %, 100-kernel weight and % residual green leaf area at stage 2) was used to define performance status of the lines. A study of various character combinations revealed the importance of % residual green leaf area at both stages 1 and 2 in predicting the relative yield performance of lines. This result was obtained by comparing the % agreement of the status of lines given by a particular character set with performance status and was confirmed by a multiple regression analysis of pod yield on all other traits. Seven lines and three progenitor parents showed stability of performance with respect to rust resistance. They included lines derived from crosses between the national check, ‘Robut 33—1’, as one parent and either a rust resistant genotype, NC Ac 17090 or an early Russian accession of (Spanish type) ‘Chico’, as the other. It was suggested that breeding programmes should take into account performance status based on yield and disease severity instead of pod yield alone.     

温度和光周期对姜荷花生长的影响

为给姜荷花的标准化栽培生产提供一定的参考,以盆栽姜荷花为试验材料,采用不同温度、光周期对姜荷花进行研究。结果表明,25℃是姜荷花生长较适温度,高温对其萌发有一定的促进作用,过高或过低的温度都会导致其不开花;不同温度影响下,姜荷花萌发率、分蘖数及开花数具有一定的相关性,对姜荷花pH、EC的影响较小。光照时长延长至14~16 h时,可打破姜荷花休眠,实现周年生产;姜荷花分蘖数随光照时长的增加而显著提升,对开花时间、开花数未见显著影响;姜荷花各指标之间未呈现显著相关性,对姜荷花pH、EC有一定影响。     

花生巢式群体的脂肪含量遗传分析

巢式群体可以利用多个亲本解析复杂性状的遗传机制。本研究利用1个共同亲本与6个基础亲本所配置巢式组合F_2:3家系的种子脂肪含量数据,分析了花生脂肪含量的遗传模型,旨在探明不同的基础亲本组合中脂肪含量性状的遗传差异,为制定脂肪含量遗传改良的亲本选配和后代选择策略提供依据。6个组合的共同亲本为高脂肪含量的普通型大果品种豫花15号,其他6个基础亲本为不同脂肪含量和不同植物学类型的品种。结果表明,在不同杂交组合中脂肪含量的遗传模式有所不同,6个组合分别符合无主基因模型、1对主基因加性显性模型和2对主基因等显性模型3种遗传模式。各种遗传效应的估计值也各不相同,主基因遗传力从32%到80%,说明不同杂交组合中,控制脂肪含量的基因位点差异及其重组和分离方式不同。高脂肪含量双亲杂交后代的高脂肪含量个体较多,但主基因遗传力较低,不宜在早代实施表型选择;双亲脂肪含量差异较大的后代脂肪含量变异幅度更大,能够选择到不同脂肪含量的类型。本研究也表明,巢式组合具有较丰富的脂肪含量变异类型,揭示出脂肪含量性状遗传的复杂性和多基因调控的特点,为较全面地了解脂肪含量的遗传提供了基础。该巢式群体也将有助于进一步开展脂肪含量的QTL定位研究。     

花生野生近缘种生物素羧基载体蛋白基因的克隆与结构分析

根据栽培花生鲁花14生物素羧基载体蛋白基因accB1和accB2 cDNA序列设计基因特异引物,克隆了花生野生近缘种Arachis duranensis、A.rigonii、A.batizocoi和A.hoehnei的accB1和accB2 cDNA 序列.序列分析表明,accB1和accB2在栽培花生和野生近缘种中高度保守,氨基酸序列一致性分别高于98.6%和97.5%. A基因组A.duranensis、A.rigonii和B 基因组A.batizocoi、A.hoehnei 的accB1和accB2的氨基酸序列存在差异,但与基因组来源无关.花生野生近缘种A.duranensis、A.rigonii、A.batizocoi和A.hoehnei accB2基因组序列分析表明,栽培花生和野生近缘种的accB2的基因结构相同. A基因组的A.duranensis与B 基因组的A.batizocoi和A.hoehnei的accB2 基因组DNA核苷酸序列一致性分别为98.9%,98.8%,而A 基因组的A.rigonii与A.duranensis、A.batizocoi和A.hoehnei 的序列一致性分别为93.5%,93.6%,93.4%.研究表明,生物素羧基载体蛋白基因在栽培花生及野生近缘种中非常保守.     

Early generation testing for yield and physiological components in groundnut (Arachis hypogaea L.)

Selection of superior crosses of groundnut (Arachis hypogaea L.) in early generations would increase the probability of identifying superior lines. The objective of this study was to determine the potential of selecting for physiological traits identified in a yield model [crop growth rate (C), reproductive duration (DR) and partitioning (p)] in segregating populations. Forty populations and nine parental lines were evaluated in replicated trials in 1992 (F2, 1993 (F3) and 1994 (F4) at three locations in Niger. Physiological traits were estimated from final yield and biomass as well as data on flowering and maturity. Regressions from two different parent-offspring generations (F2: F3 and F3: F4) were calculated. The results were compared to determine if early generation performance accurately predicts the performance of cross bulks in later generations. Differences were observed among populations and parents for all traits. Effects of locations were significant for C, p and DR in F2 and F3 but nonsignificant for yield and C in F4. Regression coefficients from F3: F2 were 0.10 ± 0.08 for C, 0.45 ± 0.17 for p, 0.10 ± 0.03 for DR and 0.16 ± 0.03 for pod yield. Based on F3: F4 regression, the coefficients were 0.12 ± 0.23 for C, 0.46 ± 0.17 for p and 0.57 ± 0.17 for yield. Parent-offspring correlations were in most cases similar to the regression values. It was concluded that selection for yield and model components in early generation bulks may inneffective. This revised version was published online in July 2006 with corrections to the Cover Date.     

钙影响花生胚胎发育/败育特异蛋白质的筛选与鉴定

缺钙花生（Arachis hypogaea L.）严重空荚（胚胎败育）导致减产降质长期困扰南方花生生产。以大田足（施足钙）、缺（缺钙地大田本底）钙条件下花生的种植与观察为基础 ,利用改良的传统双向电泳、MALDI-TOF质谱和蛋白质数据库等手段,得到了7个与受钙影响花生早期胚胎败育/发育有关的差异表达蛋白。4^#差异蛋白是与菠菜（Spinacia oleracea）的70 kD的叶绿体被膜休克相关蛋白高度相似的缺钙组表达上调的特异蛋白; 6^#差异蛋白与三叶胶（Hevea brasiliensis）的线粒体前体中的ATP合酶的β链高度相似,该蛋白在缺钙幼胚缺失; 7^#差异蛋白在低钙组缺失,其与马铃薯（Solanum tuberosum）的肌动蛋白97或100类似,等等。研究结果提示,受钙胁迫花生幼胚败育可能与早期幼胚内能量转化、氧化还原系统、细胞内膜以及细胞骨架功能维持相关的功能基因的表达异常有关。初步揭示了受钙影响花生胚胎败育的分子机理。     

不同土壤类型对花生(Arachis hypogaea L.)籽实镉积累特性的影响

为了在不同土壤环境下选育出低镉(Cd)积累型花生品种以提高花生品质,以‘白沙1016号’品种花生(Arachis hypogaea L.)为供试作物,棕壤和潮土为供试土壤,采用盆栽试验的方法,研究了2种类型土壤对花生籽实Cd积累特性的影响。结果表明：2种类型土壤条件下的花生籽实生物量差异显著（P<0.05）;在供试土壤Cd处理范围内(≤10.0 mg/kg),籽实生物量均随2种土壤Cd处理浓度增加呈“低促高抑”现象。花生籽实对土壤Cd的生物富集系数均随2种土壤Cd处理增加呈显著降低趋势（P<0.05）,且土壤类型间差异不显著。花生籽实Cd含量和Cd生物富集量均随2种土壤Cd处理的增加而显著增加（P<0.05）,但两者在棕壤介质中均显著大于潮土（P<0.05）。土壤类型对花生籽实Cd积累差异的影响主要体现在籽实Cd含量和生物富集量方面。而土壤pH、氧化还原电位(Eh)等均是影响籽实对Cd积累差异的重要因素。     

Responses of Root Nodule Formation and Nitrogen Fixation Activity to Nitrate in a Split-Root System in Peanut (Arachis hypogaea L.)

Peanut is an important constituent of crop rotation systems with various vegetable crops, which need large amounts of inorganic nitrogen. Nitrate inhibits nodule formation and nitrogen fixation of the peanut plants in these cropping systems. To elucidate this nitrate-induced inhibition, an experimental method using a split-root system was designed and the inhibitory level of nitrate (14 m M ) was applied to half of the roots for 5 or 30 days in pot experiments. In the application of nitrate for 5 days, the dry weight, the nitrogen content, and both the number and the fresh weight of nodules for each half of the roots were unaffected by the nitrate applied to the other half. However, the nitrate induced significantly lower nitrogenase activity in the applied half. In the application for 30 days, nitrate induced a significantly higher nitrogen content in the applied half of the roots, and the inhibitory effect on nodulation and nodule development was observed not only in the applied half but also in the other half. Thus, the inhibitory effect of long-term nitrate application on the nodulation and nitrogenase activity of peanut may be systemic, but that of short-term nitrate application, in which external nitrate may regulate nitrogen fixation, may not be systemic.     

花生黄曲霉侵染抗性的AFLP标记

本研究利用抗、感黄曲霉菌侵染的花生品种为亲本配制杂交组合“J11×中花5号”,以其F₂分离群体为研究材料，采用AFLP技术和BSA分析方法，获得了与花生黄曲霉菌侵染抗性连锁的2个分子标记，标记与抗性间的遗传距离分别为8.8 cM和6.6 cM;利用获得的分子标记对抗、感黄曲霉的花生种质资源进行了分子鉴定，实验结果表明分子标记与抗性鉴定结果具有较高的一致性，证实了两标记应用于研究群体之外的育种潜力。该抗侵染分子标记的建立为开展花生抗黄曲霉辅助选择育种提供了有效的筛选技术。     

花生栽培种(Arachis hypogaea)类型间遗传差异的SSR分析

本文采用110对SSR引物分析28份花生栽培种资源(7份多粒型、5份龙生型、8份普通型和8份珍珠豆型)间的遗传差异,其中有46对引物在不同品种间检测出2～9个等位基因,多态性信息量(PIC)为0.080～0.869.对28份材料的聚类分析表明,SSR聚类结果与根据形态特征的分类结果基本一致,但在多粒型品种上存在一定差异.标记pPGSseq15C12在本研究中所有的珍珠豆型品种上均扩增出特异性条带,序列分析表明该标记在珍珠豆型与其它类型间扩增片段的差异是由于ATT重复次数不同所致.     

花生的荧光显带和rDNA荧光原位杂交核型分析

建立花生准确而详细的核型对于阐明其起源和开展其基因组研究十分重要。本研究采用DAPI显带和5S、45S rDNA探针双色荧光原位杂交对花生有丝分裂中期染色体进行了分析。结果表明,花生的单倍基因组总长度为(81.06±3.74) μm,最长染色体为(4.72±0.15) μm,最短染色体为(2.62±0.14)μm;有15对染色体显示了着丝粒区DAPI⁺带,其中10对为强带,5对为弱带;有2对5S rDNA位点和5对45S rDNA位点,其中1对5S与1对45S位点同线。综合染色体测量数据、DAPI⁺带和rDNA杂交信号,对花生染色体进行了准确配对和排列,建立了详细的分子细胞遗传学核型。花生的核型公式为2n=4x=40=38m+2sm(SAT),核型不对称类型属于2A型。     

低温积累与光周期对小麦发育特性调控的分子机理研究进展

温度和光照是影响小麦发育的主要因素,不但决定了小麦生态型的区域分布,也通过调控小麦的发育阶段、器官建成、穗分化起始及进程等因素而影响小麦的产量。本文介绍了低温春化和光周期对小麦发育特性影响的分子基础,对其调控机制及互作模式研究进展进行了综述。     

低温处理对蝴蝶兰生长发育及叶绿素荧光参数的影响

为研究温度对蝴蝶兰营养生长和生殖生长的影响,以3个蝴蝶兰品种为试验材料,采用叶绿素荧光测量方法和统计学方法,对不同温度处理下蝴蝶兰叶片生长情况和花梗抽梗情况进行研究。研究表明：（1）蝴蝶兰花芽分化需要经历春化作用,26/18℃（日/夜）处理处理可使3个品种在1个月内启动花芽分化,而29/21℃（日/夜）处理的对照组均无抽梗。（2）同时,生殖生长抑制营养生长,3个品种的成熟叶片平均长度均小于对照组。（3）低温处理导致Fv/Fm降低,Fo增高,叶绿素荧光参数能敏感地反映低温引起植株光合机构变化的情况,可间接地作为快速鉴定蝴蝶兰花芽分化的指标。