Pod set related to photosynthetic rate and endogenous ABA in soybeans subjected to different water regimes and exogenous ABA and BA at early reproductive stages

BACKGROUND AND AIMS: The physiological reasons for reduced pod set in soybean (Glycine max) caused by drought during anthesis are not established. The objective of this study was to investigate the involvement of photosynthetic rate (A), pod endogenous abscisic acid (ABA) and exogenously applied ABA and 6-benzylaminopurine (BA) in regulating pod set in soybean during drought. METHODS: Two pot experiments were done in a controlled-environment glasshouse. In expt I, soybeans were either well-watered (WW) or droughted by withholding water from 4 d before to 4 d after anthesis (DAA). In expt II, soybeans were drought-stressed (DS) from -4 to 4 DAA. From -2 to 4 DAA, some of the WW and DS plants were treated with 0.1 mm ABA or 1 mm BA. KEY RESULTS: Drought stress decreased A, but increased pod ABA concentration ([ABA]). Pod set decreased only when A had decreased by 40 %, and pod [ABA] had increased 1.5-fold. Beyond the thresholds, pod set correlated positively with A and negatively with pod [ABA]. Exogenously applied ABA decreased A and pod set in WW plants, whilst it increased A and pod set in DS plants; exogenous BA had opposite effects. In these plants, pod set correlated linearly with A. CONCLUSIONS: Drought-induced decrease in A is significant in inducing pod abortion, probably as a consequence of carbohydrate deprivation. The effects of ABA and BA on pod set may be partially due to their effects on photosynthate supply.     

Identification of QTLs for seed and pod traits in soybean and analysis for additive effects and epistatic effects of QTLs among multiple environments

Soybean seed and pod traits are important yield components. Selection for high yield style in seed and pod along with agronomic traits is a goal of many soybean breeders. The intention of this study was to identify quantitative trait loci (QTL) underlying seed and pod traits in soybean among eleven environments in China. 147 recombinant inbred lines were advanced through single-seed-descent method. The population was derived from a cross between Charleston (an American high yield soybean cultivar) and DongNong594 (a Chinese high yield soybean cultivar). A total of 157 polymorphic simple sequence repeat markers were used to construct a genetic linkage map. The phenotypic data of seed and pod traits [number of one-seed pod, number of two-seed pod, number of three-seed pod, number of four-seed pod, number of (two plus three)-seed pod, number of (three plus four)-seed pod, seed weight per plant, number of pod per plant] were recorded in eleven environments. In the analysis of single environment, fourteen main effect QTLs were identified. In the conjoint analysis of multiple environments, twenty-four additive QTLs were identified, and additive QTLs by environments interactions (AE) were evaluated and analyzed at the same time among eleven environments; twenty-three pairs of epistatic QTLs were identified, and epistasis (additive by additive) by environments interactions (AAE) were also analyzed and evaluated among eleven environments. Comparing the results of identification between single environment mapping and multiple environments conjoint mapping, three main effect QTLs with positive additive values and another three main effect QTLs with negative additive values, had no interactions with all environments, supported that these QTLs could be used in molecular assistant breeding in the future. These different effect QTLs could supply a good foundation to the gene clone and molecular asisstant breeding of soybean seed and pod traits.     

矮生菜豆豆荚产量构成因素的通径分析

以8个矮生菜豆品种为材料,研究了单株豆荚产量与其主要构成因素的关系,结果表明,单株豆荚产量及作为豆荚产量构成因素的主茎高、分枝数、花序数、豆荚数、豆荚长和豆荚重在品种间均存在极显著的差异;但这些产量构成因素与单株豆荚产量之间,无论是表型相关系数还是遗传相关系数或是环境相关系数均未达到显著水平。通径分析结果显示,一个与单株豆荚产量关系密切的性状。其对单株豆荚产量的效应总是由于存在一个或多个负向的间接通径系数而被削弱。从而掩盖了该性状对单株豆荚产量的遗传效应,从表型和遗传通径系数看,对单株产量最为重要的是单株结荚数及单株花序数。单株分枝数、主茎高和豆荚重其次。豆荚长则较为次要。根据通径分析结果,就矮生菜豆丰产性育种中各有关性状的选择进行了讨论。     

Pod Formation and Its Geotropic Orientation in the Peanut, Arachis hypogaea L., in Relation to Light and Mechanical Stimulus

Gynophore elongation, pod formation and pod orientation in thepeanut plant (Arachis hypogaea L.) were studied in relationto the effects of light and dark conditions, mechanical stimulus,and growth substances. It was found that the proembryos controlgynophore elongation, probably by secretion of growth regulatorswhich stimulate cell division in the intercalary meristem locatedproximal to the ovules. The stimulus of pod production causesthe development of the proembryo into a mature embryo simultaneouslywith the growth of pod tissues and the cessation of gynophoreelongation. Darkness was found to be an essential factor forthe induction of pod formation. Pod formation did not occurin any of the treatments performed in the light, including theapplication of different growth substances on the ovary. A mechanicalstimulus is needed, in addition to darkness, for the normalthickening and diageotropic orientation of the pod, caused bya higher growth rate of the basal proximal side of the pod.The two ovules are always located on the upper wall of the diageotropicallyoriented pod (ventral suture). A possible mechanism which causessuch an orientation is discussed.     

甘草野生种群果实与种子形态特征的地理变异研究

目的：研究甘草荚果和种子形态特征地理变异规律并分析其形成的生态学机制。方法：采用样方调查的方法测定全国4省区8个旗县甘草野生种群的地上植株形态特征,采用双重筛选逐步回归分析方法探讨甘草荚果和种子形态特征的地理变异规律及其形成的生态学机制。结果：（1）不同甘草种群的荚果数、荚果腺毛长度、种室数目、每荚种子粒数和结实率5项指标的差异达到了极显著水平（P〈0．01）;荚果长度、荚果厚度、荚果腺毛密度和种子长度4项指标的差异达到了显著水平（P〈0．05）。（2）荚果厚度、种室数目等5项形态特征与经度呈显著相关,只有荚果腺毛长度1项指标与纬度显著相关。结论：甘草野生种群荚果与种子形态特征存在显著的地理变异,其变异趋势以经向变异为主,光照因子差异是导致地理变异的主要原因,其次为温度因子和水分因子,其相关关系可用多元回归模型解释。     

A model to predict seed number per pod from early pod growth rate in pea (Pisum sativum L.)

Seed number per pod in pea is variable. After fertilization,any number of ovules may abort in the pod. This paper describesan analysis of the relationship between pod growth and seedabortion rate. Pod dry weight was highly correlated to pod lengthbefore the final stage in seed abortion. By measuring pod lengthduring the period of seed formation and counting the seeds inthe same pods at the end of this period, we show that seed numberper pod was correlated with early pod elongation. From thesedata we propose and test a model for predicting seed numberper pod from early pod elongation rates. Key words: Pea, pod length, pod growth, seed number, modelling     

Effect of cocoa pod age on egg distribution and egg parasitism of the cocoa pod borer in Malaysia

The effects of pod age on oviposition, and on egg and larval survival of the cocoa pod borer (CPB), Conopomorpha cramerella (Snellen), were investigated. CPB were allowed to oviposit on a batch of 50 pods for a period of 7 days over several exposure dates. Numbers of CPB eggs/pod and survival to larval emergence from the pods were recorded. Pods were harvested when ripe and analyzed for larval survival within the pod. The oviposition pattern varied with pod age. Older pods less than 7 weeks before ripening (WBR) were preferred, suggesting greater nutritional value or chemical attraction of the older pods. The proportion of eggs parasitized by Trichogrammtoidea bactrae fumata Nagaraja (TBF), the number of eggs lost and the proportion surviving to larval emergence from the pod were independent of pod age. Egg parasitism was low, implying that TBF was not an effective natural enemy. Mass-releases of TBF should be intensified during cropping periods with higher proportions of susceptible pods (<10 WBR). Survival of larvae in the presclerotic layer (preSCL) was high and independent of pod age. Larval mortality at the SCL (sclerotic layer) was dependent on pod age and was high in older pods. Larval density influenced the survival of larvae inside the pod and was dependent on pod age. Larval mortality associated with SCL hardness and thickness is one of the criteria for the selection of CPB resistant cocoa clones.     

The effect of pod growth stages in cowpea on aphid reproduction and damage by the cowpea aphid, Aphis craccivora (Homoptera: Aphididae)

Cowpea, Vigna unguiculata was infested at the young, mid-fill and mature pod growth stages with, respectively, one, two and three pre-reproductive adult apterae of Aphis craccivora per pod in a screen house. A. craccivora caused pod shrivelling at the young and mid-fill pod stages, on which the aphid was more fecund. All levels of infestation caused significant reduction in seed yield irrespective of age of pod.     

菜用大豆感官品质性状遗传变异及品质育种目标性状分析

以全国菜用大豆主产区154个品种为试验材料,考察感官品质性状综合位、6个一级、5个二级感官性状及7个有关理化性状的遗传变异,分析它们间的相关,从而概括出品质育种目标的主要性状。结果表明：感官性状综合品质位、6个一级、5个三级感官性状均存在牟它的遗传变异,其中二级感官性状的遗传变异度均大于一级感官性状。有关理化性状中,百英鲜直、百粗鲜直、可容性糖的遗传变异系数较大,遗传力较高,选择潜力较大;英长、英厚、英宽的遗传变异系数、遗传力中等,单英粒数的遗传变异系数、遗传力偏低。相关、偏相关和通径分材结果,粒英外观、熟食口味、生食口感对感官品质综合评定值直接效应显并较大;其中英厚、英长、百英鲜直对粒英外观的直接效应显,甜味及可溶性糖为影响蒸食品味的主要图素,硬度对生食口感直接负效应显。菜用大豆品质育种中,感官品质鉴定应在蒸食口味、生食口感、粒英外观、粒色、生样可剥性、熟食香味六个一级性状基础上综合评价,注重前三项性状的选择,它们可以结合用百英鲜重、英长、英厚、可溶性糖含量、鲜味、豆醒味、粘性、硬度等性状进行辅助选择。     

Changes in free polyamines and related enzymes during stipule and pod wall development in Pisum sativum

Level of free polyamines, their key metabolic enzymes, and other features related to ageing were examined during stipule and pod wall development in pea (Pisum sativum). Free polyamine titre (per unit fresh mass) in both the organs, the specific activities of arginine decarboxylase and ornithine decarboxylase in the pod wall, gradually decreased with maturation. In stipule, these enzymes attained peak activity at 15 days after pod emergence and declined thereafter. Ornithine decarboxylase activity was greater in pod wall than in stipule; while, arginine decarboxylase activity was higher in stipule. Activity of degradative enzyme diamine oxidase increased with the onset of senescence in both the organs. Chlorophyll and electrical conductance had a inverse relationship throughout the experimental period, whereas, the chlorophyll content was directly related with polyamine levels in both stipule and pod wall during aging. On the other hand, protein and RNA contents were positively correlated with free polyamines throughout the test period in stipule, but in the pod wall this was true only for the later stages of development.     

Effectiveness of late copper and streptomycin sprays for the control of halo-blight of beans (Pseudomonas phaseolicola)

Two sprays of copper oxychloride or streptomycin sulphate (0–1 % a.i., 675 1/ha) applied to dwarf beans at first flowering and at pod set reduced pod infection by c. 70%. When applied as single sprays at pod set, copper was more effective than streptomycin and reduced pod infection by 50%. Although a copper spray at pod set increased the proportion of pods suitable for processing, more effective control was obtained with a regular spray programme, commencing at the seedling stage.     

A Flower and Pod Staging System for Soybean

Flower and pod abscission limit soybean yield. A system forquantifying flower and pod development based on the morphologicalappearance of the flower prior to and following anthesis hasbeen developed to aid in studies of pod abscission. Changesin the appearance of the corolla, primarily the banner petal,are used to distinguish the different stages of the system.External pistil dimensions have been correlated with internalfeatures for each stage of development. From anthesis to podset, pistil length and weight increase almost two- and fivefold,respectively, and ovule development progresses from unfertilizedegg cells to embryos surrounded by cellular endosperm. Pod determinedare correlated with ovule length and width and embryo cell number.Flower and pod stages can be determined in situ, thus permittingnon-destructive observation and experimental manipulation offlowers or pods without necessarily impeding their development.Stages have been identified that indicate precisely when podset occurs and when young pods cease growing and ultimatelyabscise. This system of flower and pod staging is useful instudies designed to assess effects of abiotic or biotic stressand genetic factors on pod set and abortion. Abscission, anthesis, Glycine max (L.) Merr, embryo development, pod set     

Internal recycling of respiratory CO2 in pods of chickpea (Cicer arietinum L.): the role of pod wall, seed coat, and embryo

It has previously been proposed that respiratory CO2 released from the embryo in grain legume pods is refixed by a layer of cells on the inner pod wall. In chickpea this refixation process is thought to be of significance to the seed carbon budget, particularly under drought. In this study it is reported that the excised embryo, seed coat, and pod wall in chickpea are all photosynthetically competent, but the pod wall alone is capable of net O2 evolution over and above respiration. The predominant role of the pod wall in refixation is supported by measurements of fixation of isotopically labelled CO2, which show that more than 80% of CO2 is fixed by this tissue when provided to the pod interior. Chlorophyll concentrations are of the same order for embryo, seed coat, and pod wall tissues in younger pods on both an area and a fresh weight basis, but decline differentially with development from 12-30 d after podding. Imaging of chlorophyll distribution in the pod wall suggests that less than 15% of chloroplasts are located in the inner layer of cells thought to refix CO2 in legumes; this would be sufficient to refix less than 40% of respired CO2. It is concluded that while all tissues of the pod are capable of refixing respiratory carbon, the entire pod wall is responsible for the majority of this process, rather than a specialized layer of cells on the inner epidermis. The role of this fixed carbon in the pod for reallocation to the seed is discussed     

呲效隆对花生光合作用及产量的影响

花生结荚期施用0.1～10 mg/L吡效隆(4PU-30)溶液,能增加叶片的厚度,提高叶片叶绿素含量和光合速率,促使叶片中的同化物向荚果运输和积累增多,从而促进了荚果生长和发育,使结荚率、饱果率以及百果重和百仁重增加,最终使单株荚果产量增产12.6％左右,吡效隆的最适浓度为 1 mg/L。     

Effects of morphactin and other auxin transport inhibitors on soybean senescence and pod development

Because triiodobenzoic acid increases pod number, albeit variably, in soybean (Glycine max), we tested other auxin-transport inhibitors. Morphactins, especially methylchlorflurenol (MCF), were found to be very active (optimal concentration 10 micromolar) when sprayed onto the foliage. Applications at 1 week after the start of flowering were most effective, producing a 40% increase in pod number with little inhibition (12%) of stem elongation. MCF increased the number of pods initiated (reaching 1 cm length) at least partially by prolonging the initiation period, while pod abortion (failure of pods > 1 cm long) remained low. Generally, MCF did not increase seed yield (dry weight/plant); more, but smaller seeds, were formed by the treated plants. The promotive effect of MCF on pod initiation seems to be independent of its inhibition of stem elongation, which is insignificant at 10 micromolar. MCF delayed pod maturation by 3 to 4 days, while foliar yellowing, blade abscission, and petiole abscission were retarded by 2, 4, and 2 days, respectively. MCF has only a small effect on senescence and that could be indirect, due to a delay in pod development. Other auxin-transport inhibitors tested, including N-1-naphthylphthalamic acid, produced little or no increase in pod number; however, 0.1 millimolar 5-[2′-carboxyphenyl]-3-phenylpyrazole caused a 27% increase. These results implicate auxin as a potential regulator of pod development, and they show that soybean seed yield is not simply sink limited.     

人工合成甘蓝型油菜特长角性状的遗传分析

以人工合成甘蓝型油菜特长角品系H218普通甘蓝型油菜中油821和MSP334为材料, 配制成两个杂交组合的各6个世代群体, 即P1、P2、F1、F2、B1、B2, 研究了全果长、果身长、果喙长3个角果性状的遗传特点。结果表明, 两个组合的全果长、果身长、果喙长在F2群体中近乎呈现连续正态分布, 显示为多基因控制的数量性状。两个组合的全果长广义遗传力为65.89%~70.77%、狭义遗传力为44.01%~46.78%, 基因数目均为5对; 果身长广义遗传力为60.14% ~ 63.38%、狭义遗传力为46.89%~47.38%, 基因数目均为6对; 果喙长广义遗传力为26.36% ~ 46.44%, 狭义遗传力为18.08%~37.87%, 基因数目均为2对。基因效应初步分析表明, 两个组合的3个性状基因效应均符合加性-显性二基因互作模型, 存在显著的上位性效应。两个组合的全果长、果身长、果喙长加性效应、显性效应都很重要, 全果长、果身长的加性效应大于显性效应, 果喙长显性效应大于加性效应。     

油菜抗裂果性研究简述

本文简述了油菜易裂果性的危害、抗裂果性研究的意义及国内外研究现状和进展;也介绍了我国现有的主要抗裂果性油菜资源,并提出国内应开展油菜抗裂果性遗传机理研究和转基因研究的建议。     

Variation and inheritance of peroxidase activity and phenol and saccharide content in cacao in relation to susceptibility to black pod disease

The relationship between susceptibility to black pod disease and activity of peroxidases in crude extracts and soluble phenols and saccharides contents was studied in the pod cortex and in the seeds of three cacao clones: SNK413 (lowly susceptible), SNK10 (highly susceptible) and ICS95 (mildly susceptible) and in the F1 (SNK413×SNK10) and the F′1 (SNK10×SNK413) progeny. Phenol content and peroxidase activity in seeds increased as the pods matured; they were not the same in the proximal, middle and distal parts within the same pod at maturity. This variation could be correlated to the stage of development of the seeds. Total soluble saccharides and ketohexoses in the pod cortex did not vary significantly from one clone to another and could not be related to the susceptibility of the pods. Nevertheless, their contents were 2 to 4 times less in the F1 and F′1 progeny. Total soluble phenols, flavanol and hydroxycinnamic derivatives in the pod cortex were higher in the SNK413 clone. Hydroxycinnamic derivatives were not detected in the SNK10 clone and this character was transmitted to the progeny when SNK10 was male (F1 progeny). Phenolic cornpounds decreased in the F1 and F′1 progeny. These results suggest that phenolic compounds and peroxidase activity could be correlated to the susceptibility of cacao clones to black pod disease and that crossing two clones of different susceptibility produces hybrids with lower phenols and saccharides contents which may be responsible for their poor tolerance to black pod disease.     

The translocation of 14C photosynthate from leaves and pods in Phaseolus vulgaris

Field experiments were undertaken to study the pattern of distribution of photosynthate produced by the leaves and the pods of Phaseolus vulgaris (cv. Purley King) by means of the ¹⁴C technique. It was found that the ^UC photosynthate produced by a trifoliate leaf (38 days after anthesis) was shared almost equally between the leaf and the pod at its axil with 33–50% of the fixed ¹⁴C finding its way to the seeds in that pod. However, during the early stages of pod development (10 days after anthesis) some 13–14% of the fixed ¹⁴C was detected in the stem, indicating the inadequacy of the pod as a sink at that stage. When the pod was treated, virtually no ¹⁴C was detected in other parts of the plant. Of the ¹⁴C fixed by pod photosynthesis in the later stages (38 days after anthesis), 55–60% was translocated to the seeds within the same pod. These results indicate the importance of current photosynthesis during the pod fill stage in P. vulgaris as has been suggested in other grain legume crops.