Differences in Flowering Habit between Determinate and Indeterminate Types of Soybean

Summary

The differences of flowering habit, yield and yield components between determinate (cultivar Tatisuzunari) and indeterminate (cultivar Touzan 69) soybean were examined in relation to raceme order. Although flowering habit, i.e., successive flowering from basal to apical nodes was the same in both types, the succession of flowering on low order racemes on the main stem increased more rapidly (1.4 nodes per day) in Tatisuzunari than in Touzan 69 (0.8 nodes per day). In Tatisuzunari flowering on a higher order raceme began after flowering of the first order raceme had finished, but in Touzan 69 flowering on the first order raceme continued upto higher nodes accompanied with flowering on higher order racemes thus producing a higher number of flowers. In Tatisuzunari, the flower shedding rate was higher, the higher was the raceme order, but in Touzan 69 the shedding rate was highest in the first and second order racemes. The pod setting ratio on all racemes was higher in Tatisuzunari than in Touzan 69. In Tatisuzunari, the 100 seed weight was similar on every raceme, although that on the second order racemes with compound leaves was slightly higher. In Touzan 69, it decreased with the increase of raceme order. The second order raceme with compound leaves played a pivotal role for the determination of total number of nodes, number of flowers, pod setting ratio, number of pods per plant and 100 seed weight in Tatisuzunari. However, in Touzan 69, racemes contributing to yield were limited to the first and second racemes. In Touzan 69, leaf length decreased drastically from basal to apical nodes, favoring the even distribution of light in the canopy, whereas, in Tatisuzunari, the leaf length increased from lower to higher nodes.     

Roles of Auxin and Cytokinin in Soybean Pod Setting

Abstract

Soybean plants differentiate abundant floral buds, but most of them fail to grow pods and abort during development. Many studies indicated promotive effects of exogenously applied cytokinin on pod setting, but the effects of auxin application on pod set are ambiguous. In this study, we examined the changes in the concentrations of endogenous auxin and cytokinin in racemes and the effects of application of the two hormones on pod setting to clarify the role of auxin and cytokinin in soybean pod setting. The long-raceme soybean genotype IX93-100 was grown in pots and in the field. The auxin (IAA, indoleacetic acid) concentration in racemes was high for a long period from pre-anthesis to 9 days after anthesis (DAA) of the first flower on a raceme, but the cytokinin concentration was high for a short period, with a peak at 9 DAA. The IAA concentration was higher in distal portions of racemes, but the cytokinin concentration was higher in basal portions of racemes. In pot-grown plants, IAA applied to racemes tended to reduce the number of flowers and pods. In contrast, 6-benzylaminopurine (BA) applied to racemes before anthesis tended to reduce the number of flowers and pods, and that applied around 7 DAA significantly increased the pod-set percentage. However, these effects of IAA and BA application were slight in field-grown plants. These results indicate that the concentration of endogenous auxin and cytokinin in racemes changes in a different manner, and that cytokinins have a positive, and auxin a negative effect on pod setting when respective hormones are applied to racemes after the anthesis stage.     

Intra-Raceme Variation in Pod-Set Probability Is Associated with Cytokinin Content in Soybeans

Summary

A large proportion of flowers abscise during development in soybean (Glycine max L. Merr.). A reduction in this abscission might increase pod and seed number, and thereby can lead to an increased yield. Previous studies showed that pod-set probability was greater at proximal positions of individual racemes, and that the probability was enhanced by the exogenously applied cytokinins. However, whether intra-raceme variation in the pod-set probability relates to endogenous cytokinin levels remains unknown. To address this question, intra-raceme variation in cytokinin content and pod-set probability was investigated. A soybean genotype 1X93-100, which has long racemes, was grown in an environmentally controlled chamber (30/20°C day/night temperature, 15 h day length, 600 μmol m^–2s^–1 photosynthetic photon flux density). Flowers, which were divided into three floral positions (proximal, middle, distal) on individual racemes, were sampled at intervals after anthesis. The cytokinins in the samples were identified by gas chromatography-mass spectrometry (GC-MS) and further quantified by enzyme immunoassay (EIA). The GG-MS analysis revealed that cis-zeatin riboside (c-ZR) and isopentenyl-adenosine (iPA) were predominant forms of cytokinin in soybean racemes. The total amount of these cytokinins in racemes, which was monitored by EIA, peaked one to two weeks after the first flowering on a raceme, when pod development was initiated. Within individual racemes, the total cytokinin concentrations were greater at more proximal floral positions, as was the probability of pod set. Removal of proximal flowers at anthesis enhanced both cytokinin concentrations and pod set at middle positions on the raceme. Thus, pod-set probability was significantly associated with the cytokinin concentration at different floral positions within individual soybean racemes.     

Flowering and fruit set dynamics at phloem-isolated nodes in soybean

The dynamics of flowering and pod set of soybean (Glycine max (L.) Merrill) was evaluated in two greenhouse experiments with a girdled node system. Plants (cv. Elgin 87) were grown in 3.0 l pots filled with a soil–vermiculite mixture (2:1, v/v) and the main stem below node seven (node one was node with unifolioliate leaves) (one-node treatment) or node five (three-node treatment) was girdled when the first flower opened at node seven. The main stem above node seven was removed as were the leaves at nodes five and six on the three-node treatment. Flower production, from daily counts of open flowers, followed a bi-modal distribution with the first cohort representing flowers on the main raceme while the second cohort contained flowers from sub-branches. Pods ≥10 mm long were marked with acrylic paint and the color was changed every 2 or 3 days to define at maturity when the surviving pods were initiated. The initiation of surviving pods followed the same pattern as flowers, and pods in the first cohort had nearly 100% survival while second cohort generally had survival rates <60%. Initial development of pods in the second cohort coincided with lower concentrations of stem sugars and a rapid increase in pods with ≥3 mm seeds. The three-node treatment had more flowers and pods in the first cohort and more pods at maturity. Utilization of large amounts of assimilate by rapidly growing early pods may contribute to the high levels of abortion of late developing flowers and pods. Thus, synchronous flowering may increase pod set by decreasing this competition between early and late developing pods.     

蓖麻花序特征及花芽分化的初步研究

本文对蓖麻花序特征、顶芽分化及内源IAA和ABA含量变化进行初步研究,结果表明：不同品种（系）间雌花率及雌花密度均存在极显著差异。蓖麻雌花并非完全单性花,各品种（系）雌花均存在退化雄蕊痕迹,但其发生率不同,单雌后代品系明显高于品种材料。单雌花序与两性花序的雌花中均存在退化雄蕊,且无显著差异,但花序中下部与上部之间差异显著。顶芽石蜡切片观察表明：蓖麻在5叶期以前,其顶芽基本处于叶芽生长阶段;在6-9叶期,顶芽逐渐进入花芽分化、生长阶段,而此阶段,顶芽内源IAA、ABA含量变化也十分明显。不同性别花序和花的内源激素含量测定结果显示：IAA含量,单雌花序＞雌花＞两性花序＞雄花;ABA含量,雄花显著高于雌花,但两性花序却明显低于单雌花序;IAA/ABA值,雌花＞单雌花序＞两性花序＞雄花;说明IAA含量和IAA/ABA相对含量可能在花性分化中具有较为重要的作用。     

Photoperiod sensitivity after flowering and seed number determination in indeterminate soybean cultivars

Seed and pod numbers are the main yield components in soybean (Glycine max (L.) Merrill). They are related to canopy photosynthesis during a critical period, occurring between the R1 (beginning of flowering) and R6 (full seed) stages. We investigated the relationship between the duration of the critical period and the number of seeds produced. Response to photoperiod during post-flowering stages was evaluated in indeterminate soybean cultivars from maturity groups (MG) IV and V. The study was conducted under field conditions with two sowing dates (normal and late). Plants were grown under natural photoperiod throughout the experiment or exposed, from the R3 stage (beginning pod) onwards, to artificially extended regimes of 2 h longer than natural daylength. Duration of the R3–R6 period increased in response to the extension of photoperiod, and cultivars of MG V exhibited a stronger sensitivity to photoperiod than those of MG IV. Exposure to long photoperiods promoted node production, mainly in branches, and increased node fertility. Within each sowing date, the increased duration of R3–R6 under longer photoperiods was corresponded with increments in pod and seed number. Seed number was related to the duration of R3–R6, particularly when the length of the period was corrected for temperature differences between treatments. Seed number was also related to the integral of solar radiation during R3–R6. The possibility of using sensitivity to photoperiod after flowering as a criterion for increasing yields through increasing seed number are discussed.     

不同结荚习性大豆开花结荚鼓粒进程的比较研究

通过３年田间观测，比较研究了３种结荚习性不同的大豆品种，开花，结荚，鼓粒进程铁丰２４号出苗后第６９．５天始花，花期１８．５天，植株中部先开花，渐次向上向下开放；辽豆１０号出苗后第５２．５天始花，花期４０．５天，开花次序与辽豆１０号相同。豆Ｈ－５０６４出苗后第５４．０天始花，花期４０．天，花花次序与辽豆１０号相同。铁丰２４号全株结荚率为３３．５３％，主花序，副花序，分枝的结荚率分别为３６．８４％，４     

The effect of photoperiod on flowering and TPS production in the warm tropics

Summary Three similar field experiments with five cultivars were carried out to evaluate the effect of a 5-hour extension of the natural daylength and a 3-hour night break on flowering and TPS production in the warm tropics. Shoot length, number of inflorescence positions per plant and number of flowers per inflorescence varied considerably between the experiments. In each experiment, the supplementary photoperiods delayed cessation of shoot growth and thereby increased the orders of branching and the number of inflorescence positions per plant. The photoperiod treatments significantly increased the number of flowers at the last produced inflorescence positions, but not at other ones. Pollen production and quality, berry set, seed set and 100-seed weight were not affected by the photoperiod treatments. TPS production was characterized by variability in flowering and low and variable seed production per flower.     

Characteristics of Flowering and Pod Set in Wild and Cultivated Types of Soybean

Abstract

Characteristics of flowering and pod set were compared between wild and cultivated types of soybean grown in pots (1/5000 a) in a vinyl house. The wild type had 10-fold more nodes than the cultivated type. The flowering habit of the wild type was similar to that of the indeterminate type. The wild type developed 10-fold more flowers than the cultivated type, but set relatively few pods. During the process of domestication from wild to cultivated type, i) the pole climbing characteristic disappeared and development of branches and racemes with compound leaves was repressed, resulting in a decreased number of nodes, ii) flower production decreased and the rate of pod set increased markedly, and iii) the number of pods decreased, but seed size became bigger.     

Influence of Day Length on Stem Growth,Flowering, Morphology of Flower Clusters,and Seed-Set in Buckwheat (Fagopyrum esculentum Moench)

Abstract

The effects of day length on main stem growth, flowering, morphology of flower clusters and seed-set were examined in three buckwheat cultivars Shinanonatsusoba (summer eco-type), Miyazakizairai (autumn eco-type) and BLO 1999 (a long cluster line which usually develops DM clusters at Kade Research Ltd., Canada). Long-day treatment prolonged the stem elongation period, elevated the first flowering node, delayed the first flowering day, increased the numbers of nodes, flower clusters and flowers on the main stem, and decreased the increase rate of flowering-cluster number, the number of seeds and the seed-set ratio on the main stem. It also increased the frequency of DM clusters, the length of the flower clusters and the number of sub-flower-clusters per cluster in Shinanonatsusoba and Miyazakizairai as well as in BLO 1999. The effects of day length varied among the growth parameters and there were three types of responses to day length. The difference between the summer and autumn eco-type cultivars in the responses to day length was elucidated in four groups of parameters; (1) main stem elongation; (2) first flowering node and first flowering day; (3) increase rate of flowering-cluster number on the main stem; and (4) the number of seeds and seed-set ratio.     

兜兰属植物花期调控研究进展

兜兰由于独特的花朵造型、绚丽的花朵色彩、持久的观赏花期而具有极高的观赏价值,是国际上的高档花卉.但由于生态环境的破坏以及人们对其过度采挖,兜兰现已成为世界上最濒危的植物物种之一,许多种类已濒临灭绝,所有兜兰野生种均被列入《濒危野生动植物种国际贸易公约》(CITES)附录I而被禁止交易.目前,市场上流行的兜兰品种大多是由...     

竹叶兰花器官发育过程及生理特性研究

本研究通过解剖形态学观察,并检测主要代谢物质、抗氧化酶活性以及内源激素含量的变化,阐述竹叶兰花器官发育特征及生理特性,为新花卉作物的开发利用提供理论依据.结果表明:(1)广州地区户外栽培条件下,竹叶兰全年可开花,为总状花序,单朵次第开花,整枝花期188d;(2)根据花器官发育特征分为5个时期:花芽分化期、萼片伸长期、合...     

Effects of Day Length and Air Temperature on Stem Growth and Flowering in Sesame

Abstract

The effects of day length and air temperature on the growth and flowering of sesame (Sesamum indicum L.) were examined to analyze the effect of seeding date on the seed yield. Short day (10-h light/14-h darkness) treatment decreased the final stem-length relative to natural day length (14.1～13.4-h), although it hardly affected the length of the stem-elongation period. The short-day treatment shortened the duration to the first flower and lowered the first flowering-node. It prolonged the flowering period, but decreased the flowering-node number on the main stem resulting from the slower rate of increase in nodes with flowers. Under a low day/night temperature condition (23/18ºC), the stem growth was very slow and flowering did not occur. As compared with a high temperature (30/23ºC), a low temperature (22/15ºC) during 15 days after emergence suppressed the seedling growth temporarily, but the seedlings resumed growth after the temperature treatment. The growth and flowering behavior after the treatment were unaffected by a low temperature during the seedling stage. On the other hand, a low temperature during the flowering period decreased the flowering-node number resulting from the slower rate of increase in nodes with flowers, although it prolonged the flowering period. In this study, the decrease in the flowering-node number by short days and low temperature was smaller than that by delay of seeding date as observed in our previous study. Thus, the effects of day length and air temperature were not the sole factors responsible for the effect of seeding date on the flowering-node number.     

辽宁省引进的花生高产品种开花特性（简报）

从全国各地引进的109个花生品种(系)中筛选出的5个适合辽宁地区生长的高产品种，分别为徐花5号、R03-3、唐油4号、丰花5号和汕油101，比较研究这5个品种在辽宁地区的开花特性。结果表明，5个花生品种在辽宁地区出苗后27～36d进入始花期；唐油4号始花期较早(6月18日)，花期较长(50d)，单株总开花量(258朵)和有效花量(87朵)较多；丰花5号和汕油101各指标居中；而徐花5号和R03-3始花期较晚(6月28日)，花期较短(37d和41d)，单株总开花量较少(160朵和185朵)。徐花5号第1、2对侧枝开花总量占全株总花量的比例最高，为86.8%；汕油101所占比例最低，为74.9%。5个品种侧枝上第1、2节位开花量较多，其余各节位开花数量较少，仅开2~4朵花。徐花5号、R03-3和丰花5号整个花期的每5d开花量呈单峰曲线变化，而唐油4号和汕油101呈双峰曲线变化，高峰期过后，各品种每5d开花量均迅速减少。 [     

早晚熟夏大豆品种花荚形成的比较

通过对１７个有限、亚有限型夏大豆品种的研究结果,鼓粒前的花荚期长短是选择夏大豆品种生育期长短的重要因素。不同熟期类型品种间生殖器官发育规律存在差异,早熟品种较晚熟品种花、荚形成发育快、时间短、脱落也快。当早熟品种生育重心进入鼓粒前的中、大荚形成发育过程中（相当于Ｒ４阶段）时,晚熟品种的相对时期还处在花和幼小英     

Effect of plant density on the inflorescence production of stems and the distribution of flower production in potato

Summary A knowledge of the pattern of flowering and seed production is required for the development of large-scale field production of True Potato Seed (TPS). At the highland experimental station of the International Potato Center in Peru, data on flowering and seed production were collected from three cultivars planted at three densities. Main stems in which flowering was delayed ceased shoot growth at an earlier stage and produced fewer inflorescences. Inflorescences produced later had fewer flowers, a lower berry set and yielded less seed. Inflorescences flowering at the same time performed similarly, irrespective of their position on the plant. Increasing plant density resulted in cessation of shoot growth at an earlier stage and concentrated inflorescence and flower production at primary positions of early-flowering shoots. With cvs Renacimiento and Yungay a higher plant density increased the percentage of flowers produced in the first three weeks of the flowering period, but with cv. Atzimba the effect of plant density on the distribution of flower production was off-set by a slower stem development.     

白菜型春油菜果喙生长与其生产特性研究

通过不同品种（系）的田间小区试验及剪喙处理,研究白菜型春油菜果喙生长状况、叶绿素含量及生产力。结果表明：果喙长度在开花后14d基本定型,平均果喙长度占果身长度的38．9％。叶绿素含量为叶片大于果喙,果喙大于果壳,果喙叶绿素含量平均为果壳叶绿素含量的2．7倍以上。剪喙后,角果长度、宽度、果壳干重、角粒数、千粒重和角粒重均呈下降趋势。剪喙时间愈早,对角果生长及其生产力的影响程度愈大。开花后14d剪喙处理的角粒重下降率为20％左右。     

Predicting growth and development of pigeonpea: flowering response to photoperiod

Data from sowing-date and other experiments conducted for nine cultivars at three locations ranging from 1°30′S to 27°15′N were analysed for photoperiod response. All cultivars were found to have a qualitative response to photoperiod. The results of the analysis show that cultivars previously reported to be “relatively insensitive” to photoperiod were, in fact, highly sensitive. Flowering in short-duration cultivars was delayed by up to a 100 days when daylength in the photoperiod-inductive phase exceeded a critical value. Medium- and long-duration cultivars delayed flowering by over 150 days in response to photoperiod. A model was able to predict this wide range in flowering dates.     

Effect of Synthetic Cytokinin Application on Pod Setting of Individual Florets within Raceme in Soybean

Abstract

The application of synthetic cytokinin (6-benzylaminopurine, BA) to racemes of soybean genotype IX93-100 at 7 days after anthesis (DAA) enhanced pod-set percentage of the florets at the 5th position and above (numbered from the base on rachis). The endogenous cytokinin (trans-zeatin riboside) content of individual florets was measured at the 1, 3, 5, 7th position every 3 days after anthesis. Cytokinin was detected only from the florets at 9 DAA, and the content was higher in the more proximal florets while it became negligible in the 7th floret. These results suggest that an increase in the amount of cytokinin in individual florets might enhance the pod setting of the florets positioned at the middle or distal part within the raceme.     

Detection of epistasis,and estimation of additive and dominance components of genetic variation for synchrony in pod maturity in mungbean (Vigna radiata (L.) Wilczek)

Genetics of days to first flowering, first pod maturity, 90% pod maturity, and duration of the period from first flower to 90% pod maturity (DDd₁) and from first pod maturity to 90% pod maturity (DDd₂) [degree of non-synchrony of pod maturity] were investigated in mungbean using the triple test cross (TTC) technique. Ten diverse genotypes were crossed with two true breeding testers (L₁ and L₂) and the F₁ hybrid of the tester lines (L₃). The resultant single and three-way crosses were evaluated in two seasons (kharif and spring/summer).Epistatic variation was found to be an integral part of inheritance of days to first flower in both seasons and days to first pod maturity only in kharif season. Further partitioning of total epistasis revealed that additive×additive (i type) interactions had a major role in the inheritance of these traits.In the absence of epistasis both additive and dominance genetic components were significant for days to 90% pod maturity, DDd₁, and DDd₂ in both seasons, and for days to first flower in spring/summer season. The additive genetic component was predominant for days to 90% pod maturity and DDd₂ in both seasons and for DDd₁ in spring/summer season, whereas the dominance component was important for days to first flower and DDd₁ in the spring/summer season. The direction of dominance was towards early maturity of 90% pods and late maturity of the first pod. The significant additive genetic component in DDd₁ and DDd₂ could be exploited in later generations for developing mungbean genotypes with improved synchrony in pod maturity.