The Occurrence of Delayed Stem Senescence in Relation to trans-Zeatin Riboside Level in the Xylem Exudate in Soybeans Grown under Excess-Wet and Drought Soil Conditions

Abstract

Delayed stem senescence (DSS) after pod maturation in soybean (Glycine max) lowers the quality of products in the mechanized harvest. The effects of drought and excess wet soil conditions on the occurrence of DSS were studied with special reference to remobilization of vegetative nitrogen and supply of cytokinin via xylem. Excess wet soil treatment was applied throughout the reproductive period to field-grown soybean in 2003 (Exp.1) and short-term drought stress treatment was applied during the reproductive period to pot-grown soybean plants in 2004 (Exp.2). The degree of DSS at pod maturing was evaluated by the DSS score from “1” for severe DSS to “5” for completely synchronous senescence of pods and vegetative parts. The DSS score in Exp.1 varied from 2.2 to 2.5 and that in Exp.2 from 2.8 to 3.7. Excess wet soil treatment in Exp.1 promoted the occurrence of DSS, while drought stress treatments during the periods of flowering to pod elongation, later seed-filling and seed maturing decreased it. The soybean plants that showed distinct DSS had lower ratios of seed number to vegetative dry weight at seed maturity and a lower rate of nitrogen remobilization from vegetative organs to seeds during the latter half of the reproductive period. The trans-zeatin riboside (t-ZR) level in xylem exudate tended to be higher in soybeans with severer DSS than in those normally matured in both experiments showing increased t-ZR concentration and/or higher exudation rate. These results suggest that DSS can be caused by a wet soil water condition, which lowers pod/seed number and increases vegetative organs mediated by the increased supply of cytokinin through xylem during seed-filling.     

2008年辽宁省国家菜用(鲜食)春播大豆区域试验评价

以2008年国家菜用（鲜食）春播大豆区域试验参试品种（系）为材料,试验分析了在辽宁种植的参试品种（系）的农艺性状、鲜荚性状、鲜荚产量及籽粒产量。结果表明,11个品种（系）从播种到鲜荚采摘生育日数为104～149d,株高为41．3～141．9cm,主茎节数为10．3～20．8个,单株荚重32．4～55．5g,标准荚数（两粒荚）178～247个／kg,标准荚长4．3～5．7cm,荚宽1．2～1．4cm,百粒鲜重49．4—72．5g,鲜荚产量10035～14769kg,拼,百粒干重21．9—34．5g,籽粒产量2386—3333kg／hm^2,有6个品种（系）为菜用大豆类型,适合在沈阳地区种植。     

不同播期对春大豆生态性状的影响

将来自北纬22.7°至北纬50.2°的19个春播大豆品种在2 a内分4期进行播种,研究了播期对不同生育期类型春大豆的形态和产量等生态性状的影响.结果表明:株高和主茎节数随着播期的延迟逐渐降低,并且降低幅度随着播期的延迟而增加.在各种熟期类型品种中,中早熟类型品种的株高和主茎节数降低的幅度最大.不同播期下大豆植株的地上生...     

大豆底荚高度QTL定位及候选基因挖掘

底荚高度是衡量大豆品种是否适宜机械收获的关键指标。底荚高度较低的品种在机械收割过程中可能造成植株部分被切断或漏割,引起总产量损失。因此,大豆底荚高度候选基因对大豆机械化育种至关重要。本研究利用完备区间作图法(Inclusive Composite Interval Mapping, ICIM)对208染色体片段代换系群体(chromosome segment substitution lines, CSSL)进行大豆底荚高度QTL定位,获得9个与大豆底荚高度相关的QTL,分布在8条连锁群上。结合BSA重测序结果,将与大豆底荚高度相关的QTL定位到C1连锁群上1.1Mb和L连锁群上0.05Mb的区间内,并对其进行基因注释。通过基因注释数据库和信息学分析,在两个共识QTL区间内获得5个可能与大豆底荚高度相关的候选基因。这些结果可以为大豆底荚高度QTL精细定位以及机械化优质高产大豆品种的选育提供理论依据。     

Pod Dehiscence in Relation to Pod Position and Moisture Content in Soybean

Abstract

The relationship between pod dehiscence and the position and moisture content of pods was examined in two soybean cultivars, Fukuyutaka and Keito-daizu. The frequency of pod dehiscence at different parts of the stem was assessed by the strain-gauge method. Pods of the two cultivars were classifi ed into indehiscent, dehiscent (dehisced by the strain-gauge method) and naturally dehiscent pods. The moisture content of pods was measured after drying in a hot-air oven at 105±1°C for 24 hrs. In both Fukuyutaka and Keito-daizu, the pods at maturity were not dehisced at any part of the stem due to the high moisture content of pods. After maturity, the frequency of pod dehiscence at the upper part of the stem increased as the moisture content of pods decreased in both Fukuyutaka and Keito-daizu. A similar tendency was observed in both the fi eld and the pot experiments. The frequency of pod dehiscence was higher at the upper part of the stem and increased as the moisture content of pods decreased.     

不同熟期类型大豆品种在玉豆间作模式下农艺性状和产量的比较研究

为筛选适宜间作的大豆品种,以早、中、晚熟三种类型共16个大豆品种（系）为试验材料,在玉米大豆间作和大豆净作（为对照）模式下比较研究其农艺性状和产量构成因素。结果表明,各熟期类型品种在间作条件下的株高、平均节间长、倒伏率均显著高于净作对照,且早熟品种的株高、底荚高、主茎节数、平均节间长以及倒伏率显著低于中、晚熟品种。早、中熟品种在间作下的有效分枝数与对照差异不显著,而晚熟品种显著高于对照。各熟期类型品种在间作模式下的产量都显著低于相应的对照,早熟类型品种的单株有效荚、单株粒数、百粒重、单株产量以及公顷单产均极显著低于中、晚熟类型品种,而这些性状在中、晚熟品种间差异不显著。早、中熟品种在间作下的单株有效荚率均显著高于对照,晚熟品种的单株有效荚率显著高于中熟品种,中熟品种显著高于早熟品种。然而各品种类型间作下的完整粒率与净作对照无显著差异,中、晚熟品种的完整粒率显著高于早熟品种。通过相关性分析,间作下倒伏率与株高、主茎节数、平均节间长呈极显著正相关;单株有效荚率、单株粒重、完整粒率、产量均与生育期呈极显著正相关;玉豆共生期占全生育期比重与有效荚率、完整粒率、产量呈极显著负相关。上述结果表明,在玉米大豆间作模式下,中、晚熟大豆品种相比早熟品种有较长的光补偿时期,能获得较高的产量,是适宜与玉米间作种植的大豆品种类型。     

玉米自交系生理成熟后子粒自然脱水速率分析

玉米生理成熟后子粒自然脱水速率是影响收获时子粒含水量的重要因素之一。以179份玉米自交系为试验材料,分别在生理成熟期和收获期测定子粒含水量,分析生理成熟后子粒脱水速率。通过聚类分析,179份玉米自交系按子粒脱水速率快慢可分为4类,属于子粒脱水速率快的自交系有13份,平均脱水速率为1.29%/d。利用2 824个SNP标记,将13份快速脱水的玉米自交系划分为5个杂种优势群,可为选育收获期子粒含水量低、适宜机收子粒的玉米品种提供参考。     

Yield components,dry matter,LAI and LAD of soybeans in Northeast China

Pod and seed number are the most important yield components of soybean [Glycine max (L.) Merr.]. Leaf area index (LAI), leaf area duration (LAD) and dry matter accumulation during the reproductive period strongly influence yield components. Our objectives were: to investigate if differences in yield components exist among genotypes differing in both yield and maturity; and to examine the dynamics of dry matter accumulation, LAI, and LAD during the reproductive period for the high-yielding genotypes. Sixteen soybean genotypes within three maturity groups were grown in Hailun, China in a randomized complete block design with three replications, across 2 years. Maturity groups were selected to differ by approximately 7 days in mean days to R₇ (5% of pods are mature pod color). Dry matter accumulation, LAI, and LAD were measured at R₂, R₄, R₅, and R₆ stages, respectively in each year. Yield, yield components and harvest index were determined at maturity. Late maturity genotypes had higher yield than early ones. Majority of the seed yield and components were positioned in the middle and upper part of the plant. Both pod number and seed number were higher in high-yield genotypes in each group. Seed number per pod contributed to increased yield in the high rainfall year but was not related to the variation in yield of the genotypes evaluated. Significant variations were found for LAI, LAD and dry matter within each maturity group. Higher accumulation of dry matter, higher LAI and LAD during reproductive stages were found to be closely related to high-yield genotypes in each group. No relationship was found between harvest index (HI) and seed yield.     

不同熟期大豆品种遗传改良过程中光合特性和冠层农艺性状的变化

对1923～2008年间育成的吉林省主推的57个大豆品种按中早熟、中熟和中晚熟品种进行分类,研究了不同熟期组品种各冠层农艺性状和叶片部分光合特性指标的演化趋势及其与产量的关系。结果表明,各熟期品种的产量、百粒重、株高、单株叶面积、叶柄长、始粒期的光合速率和SPAD与育成年代均成正相关,单株分枝数与育成年代成负相关;单株荚数、单株荚重、单株粒数、单株粒重、单株茎重、始粒期SPAD与产量成正相关,其中单株荚重与产量显著相关。总体上看,中早熟和中晚熟品种各性状的演化趋势及其与产量的关系较相似,它们的百粒重、株高、单株粒数、单株叶面积、叶柄长、始粒期光合速率及始粒期SPAD与育成年代及产量都成正相关;始粒期SPAD在所有性状中表现最稳定,在各熟期组中与育成年代及产量均成正相关。     

合丰号大豆主要推广品种农艺性状的改进与变化

本文通过对1959--195年合丰号大豆15个主要推广品种农艺性状遗传改进的研究，结果表明：单株粒重、单株荚数、单株粒数、主茎荚数、每节荚数、主茎粒重、粒茎比随着年代的推进呈先减后增的趋势；每荚粒数随着年代的推进减增交替进行；生育期前期早、中前期晚，后期比较适中；百粒重、株高、分枝数、生育前期随着年代的推进呈先增后减的趋势；茎粗、生育后期呈前期和后期增加，中期减少的趋势；干茎重、秆的强度随着年代推进呈增加的趋势；分枝粒数中期以前和后期减少，中后期增加；分枝荚数、分枝粒重随着年代的推进增减交替进行；底荚高度随着年代推进呈降低趋势；节间长度前、后期短，中期长；主茎节数变化不大，后期较多。     

辽宁省杂交育成大豆品种主要农艺性状的遗传改进

辽宁省从１９６７年到１９９３年杂交育成大豆品种主要农艺性状遗传改进的趋势是：单株粒重、单株荚数、每荚粒数、单株粒数、百粒重、分枝荚数、分枝粒数、分枝粒重、茎粗增加，生育期、株高、倒伏度减少，其中单株粒重、单株荚数、单株粒数、生育期、株高、茎粗先期变化大而后期变化小，每荚粒数、百粒重、分枝荚数、分枝粒数、分枝粒重先期变化小而后期变化大；主茎节数、主茎荚数、每节荚数、主茎粒数、主茎粒重、生育后期、粒茎比呈先增后减趋势；节间长度、分枝数、生育前期、干茎重呈先减后增趋势     

Yield and dry matter dynamics of vegetative and reproductive organs in Japanese and US soybean cultivars

ABSTRACT

Recently, US soybean cultivars have exhibited higher yields than Japanese soybean cultivars. To identify the determinants for this yield difference in reference to dry matter dynamics, recently developed US cultivars and Japanese commercial cultivars were cultivated in drained paddy fields in 2012 and 2013. The total dry matter (TDM) of each cultivar was measured at the initial seed-filling stage (R5), at 30 d after R5, and at maturity (R8). From R5 to R8, the DM of abscised leaves and petioles were measured. The actual HI (with abscised leaves and petioles) and apparent HI (without abscised leaves and petioles) were determined at R8. US soybean cultivars showed higher yields and apparent TDM (without abscised leaves and petioles) than did Japanese cultivars at R8. However, the difference in actual TDM (with abscised leaves and petioles) production was not significant between US and Japanese cultivars at R8. On the other hand, the actual HI was higher in US cultivars than in Japanese cultivars. US cultivars exhibited a higher TDM distribution to the pod before R5 and a higher pod growth rate from R5 to 30 d after R5. US cultivars tended to show greater crop growth rates (CGRs) from R5 to 30 d after R5. The higher yield in US cultivars was associated with the higher actual HI, which was considered attributable to a greater TDM productivity during the seed-filling period and higher DM distribution in the pod before R5.     

Forage soybean performance in mediterranean environments

Livestock producers are interested in growing forage soybean [Glycine max (L.) Merr.] in summer and ensiling alone or in mixtures with corn or sorghum. Four row spacings (20, 40, 60, and 80 cm), four seeding rates (50, 100, 150, and 200 kg seeds per hectare) and four harvesting stages for forage production (V₅, R₂, R₄, and R₆) were evaluated under irrigated conditions in a randomized split–split plot design with three replications in three different locations in Turkey with Mediterranean-type climate in 2004 and 2005. Dry matter (DM) yield was significantly reduced with increased row spacings in all locations. There was no significant difference between 20, 40, or 60 cm row spacings while 80 cm provided the lowest yield. Increased seeding rates (50, 100, 150, and 200 kg seeds per hectare) generally increased DM yield, although the most suitable row spacing varied by location. DM yield was significantly affected by harvest maturity increasing with advancing maturity in all locations. DM constituent plant components were generally unaffected by row spacing and seeding rate but harvest maturity did significantly affect DM partitioning. As expected, leaf blade fractions decreased continually as plant maturity increased, while stem and flower plus pod fraction increased from V₅ to R₆. In general, row spacing and seeding rate did not significantly affect crude protein, degradable protein, and in vitro dry matter digestibility of soybean forage, but all decreased significantly with advancing maturity. These studies demonstrated soybeans managed for forage in a Mediterranean-type environment can average of 9.3 and 11.3 t ha⁻¹ dry matter yield at R₄ and R₆ stages, respectively, while averaging 13.3% crude protein, 8.2% degradable protein, and 60.6% in vitro dry matter digestibility.     

国家区试鲜食春大豆重要农艺性状的演变

为指导鲜食春大豆高产优质新品种的选育与推广,分析了2004-2017年国家区试鲜食春大豆品种的14个重要农艺性状及其演变规律。研究结果显示:国家区试鲜食春大豆品种性状的遗传变异十分丰富,变异系数为5.9%～33.49%,遗传变异系数最大的性状是单株有效鲜荚数,而采青天数、标准二粒荚荚长和荚宽的遗传变异系数较小。随着年度的递进,鲜食春大豆的株型、鲜荚产量、口感、荚型性状获得了逐渐的改良。主成分分析表明,荚数与生育生长、鲜荚产量、株型、荚率、品尝品质和荚型因子是鲜食春大豆性状变异的最主要影响因子。相关性分析显示,鲜荚产量与单株有效分枝数、百粒鲜重、单株鲜荚重、标准二粒荚荚长极显著正相关,与500 g标准荚数极显著负相关,与其余性状相关性不显著。A级口感率与采青天数、株高、主茎节数、单株有效荚数等性状极显著负相关。因此,鲜食春大豆品种选育时,应注重分枝多、粒大荚长而饱满的亲本组配及后代选择,协调荚型、株型和生育期的改良,从而选育出高产优质鲜食春大豆新品种。     

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     

Post-flowering leaflet removals increase pod initiation in soybean canopies

Much of the yield variation in soybean (Glycine max L. Merrill) crops is related to changes in pod and seed number. Pod number is the result of pod initiation and pod abscission while seed number is the result of potential seed per pod and seed abortion. However, the physiological regulation of these processes is not well understood. A field experiment was conducted to investigate the role of post-flowering changes in source size and canopy structure on pod initiation, pod abscission and seed abortion in soybean. Two soybean genotypes: DM48 and A7409 (maturity groups IV and VII, respectively) were used. Leaflet removal treatments (L) consisted of removing none (L0), one (L1) or two (L2) lateral leaflets of every developed trifoliate leaf present. Leaflet removals were applied twice: the first at full bloom and the second shortly after the beginning seed stage. Crop growth rate (CGR), leaf area index (LAI), light interception (LI), and relative leaf growth rate, were determined during the periods in which numerical components are established. For the period between the first and the second leaflet removal, CGR remained unchanged among L treatments in both genotypes because LAI reductions were compensated through an increase in the net assimilation rate of the remaining leaves. The first leaflet removal increased the relative leaf growth rate and the number of pods initiated (PI) and these increases were inversely related to the remaining LAI in both genotypes. Moreover, the inverse relationship between LAI and PI was sustained at LAI below and above critical (i.e., LAI for 95% LI) and was not related to CGR or LI. The number of pod abscised also increased with the level of leaflet removal during the first and main abscission period in both genotypes and the percentage of pod abscission was directly related to the seed growth rate per unit leaf area during the abscission period. Seed abortion was inversely related to LAI after the second leaflet removal. Only the highest level of leaflet removals (i.e., L2) was able to reduce seed size in both genotypes. Whereas pod abscission, seed abortion and seed size could be related to indicators of canopy assimilatory capability pod initiation was not, suggesting that other physiological mechanism/s operate in the regulation of pod initiation. In addition, our results suggest that early (i.e., at flowering) canopy closure may negatively impact pod initiation in soybean. To the best of our knowledge, this study is the first to document that the number of initiated pods is inversely related to LAI in soybean canopies.     

内蒙古地区不同生育期组大豆品种的应用分析与评价

为明确内蒙古2 500℃以上有效积温区不同播期适宜种植的大豆品种及种植密度,本文以MG000、MG00、MG0、MGⅠ生育期组大豆品种为试验材料,开展不同播期、密度试验,通过产量特征分析,确定各生育期组品种的适宜播种期及种植密度。结果表明:MG000组品种适宜作救灾播种品种,适宜生育日数为85~90 d,最佳种植密度在24万~30万株·hm~(-2),叶面积指数范围为2.0~2.2;MG00和MG0组品种适宜晚播,适宜生育日数为90~100 d,最佳种植密度24万~30万株·hm~(-2),叶面积指数范围分别为2.3~2.7、2.8~3.1;MGⅠ组品种种植应适时晚播,适宜生育日数为100~110 d,最佳种植密度21万~24万株·hm~(-2),叶面积指数范围为3.0~3.3。     

Yield stability of induced-early-maturing mutants of mungbean (Vigna radiata) and their use in a multiple-cropping system

The performance of seven mutants of mungbean along with parental types was studied at 41 different sites in three summer crop seasons from 1980 to 1982. The performance of mutants was also studied in spring in the fallow period preceding cotton, and in early summer in the fallow period between wheat harvest and rice/maize planting, to assess their suitability of growing as a catch-crop in these fallows.

The mutants yielded significantly higher and matured 2–4 weeks earlier than parental types, leaving sufficient time to sow the succeeding crops. The mutants were characteristically short-statured, and superior to their parents with respect to number of pods per plant, seed weight, harvest index and productivity per day, but similar in numbers of seeds per pod and seed protein content.

The stability of yield was estimated through regression analysis. Significant genotypic differences were observed among mutants and varieties. Some mutants were widely adapted whereas others performed better in favourable environments. The parental types tended to respond well under poor environments.

Owing to their higher yield potential, early and uniform maturity, and wide adaptability, four mutants were approved as commercial varieties in 1986. These mutants yield 30–50% higher than the parents, mature in 55–70 days, and are suited to both summer and spring crop seasons. Of these four mutants, two can be grown in the fallow period between wheat harvest and rice/maize planting. Because of their determinate plant type, non-shattering pod and top fruit-bearing habit, these mutants are also amenable to intercropping practices and mechanised harvesting operations.

The role of induced mutations for the improvement of mungbean is discussed.     

High Carbon Requirements for Seed Production in Soybeans [Glycine max (L.) Merr.]

Abstract

In soybeans, increase in the dry weight of seed (IWS) during the seed-filling period (SFP) is nearly half that of the whole plant (IWP). Hence, the contributions of assimilate during SFP to seed growth in soybeans is apparently lower than that in other cereal crops. However, analysis of the assimilate budget for seed production based on dry matter could be misleading in soybeans because the carbon (C) contents of seed and that of other organs are different due to the differences in lipid and protein content and respiration loss in each organ results in underestimation of the C contribution to seed production. In field soybeans, irrespective of shading and thinning, IWS/IWP and harvest index (HIW) for dry weight were slightly lower than ICS/ICP and HIC for C, respectively. Of the ¹³C fed at the vegetative stage and early SFP, 3.4% and 16.4%, respectively were accumulated in the seed, 0.9% and 28.2%, respectively, in the pod shell and 26.8% and 37.8%, respectively were respired before maturity. Ninety-six percent of seed C was assimilated during the SFP. Respiratory loss of ¹³C fed at the early SFP was larger than that from ¹³C at the vegetative stage, showing that seed production requires much more C than leaf or stem growth. These results suggest that the difference in C contents between plant organs has little effect on the estimation of assimilate partition into soybean seeds based on dry matter, and high respiration loss for seed growth reduces the partition of dry matter into seeds.     

果蔗间种菜用大豆的主要性状表现及其相关性分析

在果蔗间种条件下,考察13个菜用大豆的全生育期、株高、主茎节数、主茎分枝数、单株荚数、鲜百粒重、标准荚率、单粒荚率、瘪荚率和单株产量等性状表现,并进行相关性分析。结果表明:不同菜用大豆农艺性状存在差异,其中95C-10、桂鲜豆1号等5个品种单株产量较好;单株产量与主茎节数、单株荚数、标准荚、多粒荚呈显著正相关。因此,在果蔗间种菜用大豆时,要增加产量,应选主茎节数、单株荚数、标准荚和粒数较多的品种。