Physio-morphological Studies of F1 Hybrids in Rice (Oryza sativa L.): Photosynthetic ability and yield

Summary

Photosynthetic ability in terms of CO₂ exchange rate and leaf area, dry matter accumulation (dry weight) and other important growth components along with yield and yield contributing characters in two F₁ hybrids of Akebono × Chiyonishiki (A × C) and Zenith × Akebono (Z × A) were studied. The photosynthetic rate at the flowering stage was lower than that at the panicle initiation stage in all the inbred parent cultivars and F₁ hybrids. Heterosis in photosynthetic rate was higher at the panicle initiation stage than that at the flowering stage. Pre-anthesis leaf area in the F₁ hybrid was significantly larger than that in the parent cultivars. However, the post- anthesis decline in leaf area was more rapid in the F₁ hybrids than in the parent cultivars and its magnitude was the highest in the F₁ hybrid of Z × A which was tall having long and curved panicles. Pre-anthesis dry matter accumulation in both hybrids was significantly higher in the F₁ plants than the parental cultivars, but post-anthesis dry matter accumulation in the F₁ hybrid was lower than the mid-parental value in Z × A. The degree of heterosis in grain yield varied with the hybrid combination, an average heterosis being 1.03. Heterosis in grain yield was closely associated with heterosis in harvest index.     

不同土壤肥力麦田小麦干物质生产和产量的差异

为明确不同土壤肥力下小麦干物质生产和产量的差异,于2019-2020年小麦生长季,选择了产量潜力分别为10 500 kg·hm-2和9 000 kg·hm-2的超高产土壤肥力和高产土壤肥力两种麦田,以济麦22为材料,比较分析了不同土壤肥力麦田小麦的群体动态、干物质生产、籽粒灌浆特性、穗部特征和产量构成的差异.结果表明,...     

Genotypic Differences in Dry Matter Accumulation,Nitrogen Use Efficiency and Harvest Index in Recombinant Inbred Lines of Rice under Hydroponic Culture

Abstract

To examine the possibility of breeding high-yielding cultivars with high nitrogen use efficiency for dry matter accumulation (NUEd) and to provide simple criteria for the selecting and breeding high-yielding cultivars with high NUEd as well as useful information for the mapping of quantitative trait loci (QTL) controlling NUEd, we cultured recombinant inbred lines (RILs) of rice hydroponically in 2000 and 2001. RILs with a higher grain yield tended to show greater total dry matter accumulation (TDMA) and higher harvest index (HI), while increasing TDMA resulted in a decrease in HI. The contribution ratio of the TDMA to grain yield (2000 : 67.3%, 2001 : 68.2%) was higher than that of HI in both 2000 and 2001. Even at the same high-yielding level, there was a significant difference in the TDMA and HI values. In both years, the contribution ratios of NUEd and total nitrogen absorption (NTA) to TDMA were about 62.0 and 38.0%, respectively. The contribution ratio of the NUEd to grain yield was higher than those of the NTA and HI in both 2000 (41.6%) and 2001 (42.9%). These results suggested that the high-yielding rice plants generally displayed high TDMA and HI values. Further increase in rice grain yield should be based on the further increase in TDMA than in HI, and to increase TDMA leading to a high grain yield, the emphasis also should be put on improving NUEd in RILs.     

玉米杂交当代优势研究进展

杂种优势利用是玉米种质遗传改良与技术创新的理论基础。利用杂交当代(F₀)优势来提高玉米子粒产量和改善品质是研究的重点。综述了近年来玉米杂交当代优势的研究进展,并探讨了杂种当代优势有效利用的主要途径。     

不同水分管理模式和播后镇压对小麦干物质积累及产量的影响

为明确不同水分管理模式和播种后镇压对小麦干物质积累及产量形成的影响,以烟农19为材料,在大田条件下设置雨养(RI)、雨养+播后镇压(RC)、传统漫灌(TI)、传统漫灌+播后镇压(TC)、微喷灌(MI)和微喷灌+播后镇压(MC)处理,研究不同处理对小麦干物质积累及产量的影响。结果表明,与RI和TI处理比较,MI处理产量分别提高了44.2%和11.0%;RI处理产量最低,是由于穗数、穗粒数和粒重的显著下降所致,而TI处理产量较MI处理下降是由穗粒数和粒重显著降低导致。雨养和传统漫灌下播后镇压较其未镇压处理显著提升了产量,分别提高14.1%和6.2%。与TI和RI处理比较,MI处理开花期和灌浆期具有较高的群体叶面积指数(LAI)、旗叶叶绿素含量(SPAD值),籽粒平均灌浆速率和成熟期干物质积累量;相比未镇压处理,镇压后,雨养和传统漫灌下LAI提升,雨养和微喷灌处理下灌浆期旗叶SPAD值显著增加,籽粒灌浆速率提高,从而促进了粒重增加和群体干物质积累。总之,微喷灌+播后镇压能促进小麦群体的形成,延缓叶片衰老,提高小麦的穗粒数及千粒重,从而增加小麦产量,为试验区推荐小麦栽培模式。     

Characterization of sorghum genotypes for traits related to drought tolerance

Grain sorghum (Sorghum bicolor L. Moench) is a genetically diverse cereal crop grown in many semiarid regions of the world. Improving drought tolerance in sorghum is of prime importance. An association panel of about 300 sorghum genotypes from different races, representative of sorghum globally, was assembled for genetic studies. The objectives of this research were to (i) quantify the performance of the association panel under field conditions in Kansas, (ii) characterize the association panel for phenological, physiological and yield traits that might be associated with tolerance to limited moisture (drought), and (iii) identify genotypes with higher yield potential and stability under different environments that may be used in the sorghum breeding program. Results show large diversity for physiological and yield traits such as chlorophyll content, leaf temperature, grain numbers and grain weight per panicle, harvest index and yield. Significant differences were found for plant height, grain weight and numbers per panicle, harvest index, and grain yield among and within races. The US elite lines had the highest number of grains and grain weight per panicle while the guinea and bicolor races recorded the lowest. Harvest index and yield was highest for the US elite lines and the caudatum genotypes. Overall, there was a negative correlation between plant height and grain weight, grain numbers and yield. Harvest index and grain numbers were negatively affected by moisture limitation for all the races. Among the races, the caudatum genotypes were more stable in grain yield across the different environments. Overall, there was a wide variability within the association panel for physiological and yield traits that may prove to be useful for improving drought tolerance in sorghum.     

氮硫互作对冬小麦干物质积累和籽粒产量的影响

为探明冀东地区氮硫肥对冬小麦干物质积累和籽粒产量的互作效应,选用冬小麦品种石农952为材料,通过裂区试验,以施氮量为主区［0 kg·hm^-2（N0）、180 kg·hm^-2（N1）、240 kg·hm^-2（N2）和300 kg·hm^-2（N3）］、施硫量为副区［82.5 kg·hm^-2（S1）、112.5 kg·hm^-2（S2）、142.5 kg·hm^-2（S3）和172.5 kg·hm^-2（S4）］,分析了不同处理下冬小麦旗叶叶绿素相对含量（SPAD）、叶面积指数（LAI）、干物质和氮素转运特性及籽粒产量的差异。结果表明,施氮量和施硫量显著影响冬小麦LAI和旗叶SPAD值。N1S2处理的开花期旗叶SPAD值最高,与N2S2和N3S2以外的其他处理差异显著;增施硫肥有利于冬小麦孕穗期LAI的提高,在各施氮水平下均以S2最高。施用氮硫肥对小麦花前干物质和氮素转运以及花后干物质和氮素积累均有显著影响,二者存在明显的互作效应。小麦籽粒产量为7 364.71~10 078.20 kg·hm^-2,且随施氮量增加而显著增加,其中N2S3处理显著高于N0和N1水平下的各施硫处理,但与N2和N3水平下的其他施硫处理无显著差异。施硫量对籽粒产量和千粒重均无显著影响。综合来看,适量施用氮硫肥有利于冬小麦获得较高的旗叶SPAD值和LAI,增强叶片光合能力,促进花后干物质积累和花前氮素转运,最终增加冬小麦产量,其中施氮240 kg·hm^-2和施硫82.5 kg·hm^-2是本试验条件下最适宜氮硫肥用量组合。     

Influence Of Temperature Shift After Flowering on Dry Matter Partitioning In Two Cultivars of Snap Bean (Phaseolus Vulgaris)That Differ In Heat Tolerance

Abstract

The Partitioning of Dry Matter (Ratio of Dry Weight of Individual Parts To That of Total Dry Matter) Was Analyzed In Snap Bean Cultivars, Haibushi, A Heat-Tolerant Cultivar, and Kentucky Wonder, A Heat-Sensitive Cultivar, At Four Temperatures After Flowering on The Subtropical Island of Ishigaki, Japan. The Temperature Regimes Included 27/23ºC (Day/Night) As Normal, 24/20ºC As Low, 30/26 As High, and 33/29ºC As Extremely High. Most Growth Traits Increased After Flowering Time (35 Das), Displaying A Plateau At 68-75 Das. The Total Dry Matter Was Similar Under All Temperature Conditions, But Differed With The Cultivar. Haibushi Had A Higher Value of Total Dry Matter Than Kentucky Wonder, Which Was Mainly Due To Higher Pod Dry Weight Although Stem and Root Dry Weights Were Lower In Haibushi. A Sharp Decline of Dry Matter Partitioning To Pods Was Observed At 33/29 ºC. In The Temperature Range of 24/20 To 30/26ºC, Haibushi Showed Higher Partitioning To Pods Than Kentucky Wonder, Independent of Temperature. on The Other Contrary, Kentucky Wonder Showed Higher Partitioning To Pods At 27/23ºC Than At 24/20ºC. These Results Showed That The Partitioning of Dry Matter, Which Varied With The Cultivar and Temperature, Played An Important Role In Achieving Higher Harvest Index In The Heat-Tolerant Than In The Heat-Sensitive Cultivars.     

小黑麦杂交F1代真假杂种的ISSR标记鉴定及遗传多样性分析

为了给ISSR标记技术应用于小黑麦杂种鉴定提供参考,利用ISSR标记对小黑麦品系P1和P_2有性杂交得到的F_1代群体进行分子鉴定,同时结合田间表型调查结果对F_1代群体进行遗传多样性分析。结果表明,66个杂交F_1代单株中,52个为真杂种,其中,5个单株无主茎、未结实,1个生长后期死亡。14条ISSR引物对46个正常结实真杂种扩增的多态性条带百分率为61.19%,其中,UBC822的多态性条带百分率为100%,UBC808和UBC815的多态性条带百分率均为75%。F_1代群体和父母本的遗传相似系数为0.62~0.94,说明杂交后代产生了丰富的遗传变异。聚类分析将杂交F_1代群体和父母本在阈值0.748处分为3大类群,第1类群包括1份材料(父本,P1),第2类群包括1份材料(母本,P_2),第3类包括46个杂交F_1代单株;杂交F_1代与父母本的遗传距离较远,先与母本聚为一类,之后与父本聚为一类。田间调查结果表明,7个性状中,除株高偏向于父本外,分蘖数、有效分蘖数、穗长、小穗数、穗粒数和穗粒重均偏向于母本,与父本的差距较大,这与ISSR分析结果基本相吻合。     

Effects of elevated atmospheric CO2 on grain quality of wheat

Wheat (Triticum aestivum L.) is one of the most important agricultural crops worldwide. Due to its high content of starch and unique gluten proteins, wheat grain is used for many food and non-food applications. Although grain quality is an important topic for food and feed as well as industrial processing, the consequences of future increases in atmospheric carbon dioxide (CO₂) concentrations on quality parameters such as nutritional and bread-making rheological properties are still unclear. Wheat productivity increases under CO₂ enrichment. Concomitantly, the chemical composition of vegetative plant parts is often changed and grain quality is altered. In particular, the decrease in grain protein concentration and changes in protein composition may have serious economic and health implications. Additionally, CO₂ enrichment affects amino acid composition and the concentrations of macro- and micro-elements. However, experimental results are often inconsistent. The present review summarises the results from numerous CO₂ enrichment experiments using different exposure techniques in order to quantify the potential impacts of projected atmospheric CO₂ levels on wheat grain yield and on aspects of grain composition relevant to processing and human nutrition.     

不同移栽基本苗对水稻新品种富友33生育及产量的影响

采用小区对比试验方法,探讨了不同移栽基本苗对水稻新品种富友33生育及产量的影响。结果表明,该品种单位面积收获穗数、齐穗期叶面积指数、齐穗期干物质积累量与移栽基本苗数呈正相关,茎蘖成穗率、齐穗期有效叶面积率及高效叶面积率、齐穗后干物质积累量占籽粒产量的百分比、收获指数与移栽基本苗数呈负相关,单位面积颖花量、成熟期干物质积累量与移栽基本苗数呈多元相关。移栽基本苗80.85万/hm2的K4处理单产9.61 t/hm2,比处理K3、K5、K2、K6分别增产了0.6%、0.9%、3.7%、6.7%。     

秋季耕作方式对旱地麦-玉二熟区小麦产量形成的影响

为明确秋季耕作方式对旱地麦-玉二熟体系小麦籽粒产量形成的影响,于2019年6月至2021年6月,在豫西典型旱作麦-玉二熟区的洛阳市孟津区小浪底镇明达村,选择前茬夏玉米免耕的田块,设置秋深松、秋免耕和秋旋耕3种耕作方式,分析了不同秋季耕作方式下两个试验年度的小麦籽粒产量及其构成因素和穗部性状以及2020-2021年度的小麦群体茎蘖数、孕穗后的旗叶净光合速率（P_n）和干物质积累转运特性。结果表明,秋季耕作方式对小麦产量、穗部性状、旗叶P_n和干物质积累转运特性均有显著的调节作用。与秋旋耕相比,秋深松的小麦茎蘖数除返青期外均显著增加,穗数增加5.74%~16.06%;秋深松虽然对小麦旗叶P_n无显著影响,但提高灌浆中后期的旗叶SPAD值,显著改善了干物质积累转运特性,从而使千粒重增加,其中2019-2020年度使穗长和小穗数分别提高7.50%和9.42%,最终使籽粒产量提高9.77%~19.09%。秋免耕后,小麦孕穗和抽穗期的叶片P_n、返青至开花期的干物质积累量、花前干物质转运量及其对籽粒产量的贡献率也较秋旋耕均显著降低,而花后干物质对籽粒产量贡献率提高7.35个百分点,从而保证了籽粒产量无显著下降。与秋免耕相比,秋深松下不同生育时期的茎蘖数均显著增加,孕穗至灌浆中后期的叶片P_n,灌浆中后期的旗叶SPAD值,返青-成熟期的干物质积累量,花前干物质转运量、转运效率及其对籽粒产量的贡献率分别提高7.16%~18.41%、10.27%、12.25%~19.97%、42.19%、4.02个百分点和11.95个百分点,其中2019-2020年度穗长和小穗数分别增加7.50%和8.41%,穗数和籽粒产量分别提高16.74%~17.63%和10.31%~23.63%。综上,秋深松不仅可增加小麦穗数,而且可改善旗叶光合及干物质积累转运特性,进而提高籽粒产量,是旱地麦-玉二熟区实现小麦高产的耕作方式。     

施氮量对超高产冬小麦花后光合特性及产量的影响

为给冬小麦超高产栽培中氮肥合理运筹提供参考依据,于2007-2008年在河南温县、兰考两试验点,以两个具有超高产潜力的冬小麦品种豫麦49和兰考矮早八为供试材料,在全生育期施氮0、90、180、270 和360 kg N ·hm-2（底施和拔节期追施各半）的条件下,研究了施氮量对冬小麦光合特性、干物质积累和籽粒产量的影响。结果表明,两试验点施氮量180和270 kg·hm-2处理的籽粒产量均达到了每公顷9 000 kg以上的水平,高于其他施氮处理,与不施氮和90 kg N ·hm-2处理间差异均达显著水平。进一步分析发现,与其他处理相比,180和270 kg·hm-2处理提高了两个小麦品种开花后旗叶光合速率和SPAD值,进而增加了花后干物质积累量。两试验点的施氮处理对大穗型品种兰考矮早八成穗数影响不显著,而施氮量180和270 kg·hm-2处理显著提高了多穗型品种豫麦49的成穗数;两品种穗粒数和粒重均表现为不施氮和90 kg N ·hm-2处理显著低于适宜施氮量（180和270 kg N ·hm-2）处理。两品种在两试验点获得最高产量的施氮量不同,豫麦49和兰考矮早八分别在270和180 kg·hm-2获得最高产量。由此可见,在本试验条件下,两个品种在施氮量180~270 kg·hm-2、基施和拔节期比例5∶5条件下,在稳定足够穗数的基础上,增加穗粒数,促进花后物质积累量,提高粒重,可实现超高产。     

Effects of free air carbon dioxide enrichment and nitrogen supply on growth and yield of winter barley cultivated in a crop rotation

The increase in atmospheric CO₂ concentration [CO₂] has been demonstrated to stimulate growth of C₃ crops. Although barley is one of the important cereals of the world, little information exists about the effect of elevated [CO₂] on grain yield of this crop, and realistic data from field experiments are lacking. Therefore, winter barley was grown within a crop rotation over two rotation cycles (2000 and 2003) at present and elevated [CO₂](375 ppm and 550 ppm) and at two levels of nitrogen supply (adequate (N2): 262 kg ha⁻¹ in 1st year and 179 kg ha⁻¹ in 2nd year) and 50% of adequate (N1)). The experiments were carried out in a free air CO₂ enrichment (FACE) system in Braunschweig, Germany. The reduction in nitrogen supply decreased seasonal radiation absorption of the green canopy under ambient [CO₂] by 23%, while CO₂ enrichment had a positive effect under low nitrogen (+8%). Radiation use efficiency was increased by CO₂ elevation under both N levels (+12%). The CO₂ effect on final above ground biomass was similar for both nitrogen treatments (N1: +16%; N2: +13%). CO₂ enrichment did not affect leaf biomass, but increased ear and stem biomass. In addition, final stem dry weight was higher under low (+27%) than under high nitrogen (+13%). Similar findings were obtained for the amount of stem reserves available during grain filling. Relative CO₂ response of grain yield was independent of nitrogen supply (N1: +13%; N2: +12%). The positive CO₂ effect on grain yield was primarily due to a higher grain number, while changes of individual grain weight were small. This corresponds to the findings that under low nitrogen grain growth was unaffected by CO₂ and that under adequate nitrogen the positive effect on grain filling rate was counterbalanced by shortening of grain filling duration.     

大麦单株产量性状的杂种优势及其稳定性分析

为研究不同环境下大麦单株产量性状的杂种优势及其稳定性,以113个(Nasonijo×泰兴9425)DH系配制226个杂交种构建的永久F_2群体及亲本为材料,分别调查参试材料在4个环境下的单株穗数、主穗粒数、千粒重、单株产量和单株生物量,利用方差分析、聚类分析及稳定性分析对大麦单株产量性状的杂种优势及其稳定性进行了分析。结果表明,大麦杂种F_1各被测性状大多表现中亲优势,超亲优势组合出现率相对较低。各被测性状的杂种优势不仅受自身遗传因素影响,而且受试点生态条件及年度气候条件的影响。杂种优势的稳定性因性状不同而异,千粒重和主穗粒数杂种优势的稳定性较好,单株生物量和单株产量杂种优势的稳定性较差,仅有2个组合在多环境下表现出稳定的强杂种优势。     

A comparison of inbred line and F1 testers for evaluating sorghum experimental lines in testcrosses

Selecting an effective tester for evaluating the hybrid performance and heterosis of new inbred lines is crucial to ensure their accurate evaluation. Most sorghum breeding programs use at least two elite inbred line testers when evaluating new inbred lines. These testcrosses provide valuable information, but the specificity of inbred line testers may incorrectly characterize experimental lines that would combine well with other genetic backgrounds. Reducing this risk by increasing the number of preliminary testcrosses is limited in breeding programs by resource availability. Efficiently diversifying testcrosses may be accomplished through the use of F₁ testers. Testcrosses made with F₁ testers simultaneously evaluate inbred lines against two genetic backgrounds. In preliminary testcrosses, this may reduce the probability of incorrectly discarding new lines or improve the efficiency of preliminary testcrossing. The objective of this research was to compare two sorghum inbred line testers to their respective F₁ as a tester for evaluating sorghum inbred lines (R-lines) in testcrosses for grain yield. The testers used were A.Tx623, A.Tx2752 and their F₁ hybrid, A.Tx623/B.Tx2752. Data from testcross hybrids from 33 different inbred lines grown in three environments indicated that the F₁ tester was comparable in accuracy and discriminatory efficiency to the inbred line testers. The results indicated that a single cross tester in sorghum can serve to effectively evaluate new germplasm.     

氮肥和密度对冬小麦光合生理和物质积累的影响

为给小麦高产栽培中氮肥和密度科学管理提供参考,以矮抗58和周麦22号为材料,研究了施氮量和播种密度对小麦植株光合生理、物质积累及产量性状的影响.结果表明,适量增施氮肥和增加密度能显著提高小麦叶面积指数、叶片叶绿素含量、净光合速率和群体干物质积累量,使植株在灌浆期仍能保持较高的光合能力,促进花后干物质的积累,有利于产量的提高.不同品种的籽粒产量对氮肥和密度的响应存在差异,周麦22号的平均籽粒产量高于矮抗58.在本研究条件下,矮抗58籽粒产量在375万基本苗·hm-2和360 kg·hm-2施氮量处理组合下最高;周麦22号籽粒产量在225万基本苗·hm-2扣240 kg·hm 2施氮量处理组合下最高.     

施氮量对强筋小麦物质积累与籽粒产量的影响

为探究冀东地区强筋小麦适宜施氮量,选用2个强筋小麦品种津农7号(氮高效型)和中麦998(氮低效型)为试验材料,设置0 kg·hm^-2(N₀)、180 kg·hm^-2(N₁)、210 kg·hm^-2(N₂)和240 kg·hm^-2(N₃)4个施氮量处理,研究施氮量对强筋小麦籽粒产量和干物质与氮素积累转运的影响。结果表明,在N₀～N₂处理范围内,2个强筋小麦品种的籽粒产量、花前干物质转运量和氮素转运量随施肥量增加均显著增加,N₃处理下2品种的籽粒产量和花前氮素转运量较N₂处理无显著变化,说明适量施氮可促进强筋小麦氮素转运与籽粒产量的提高。增加施氮量可促进花前干物质向籽粒的转运,津农7号的干物质转运率高于中麦998,2个品种的花后干物质对籽粒的贡献率为60.59%～77.16%,说明小麦籽粒产量主要来源于花后干物质积累。2个品种开花...