Response of wheat genotypes to sowing date and boron fertilization aimed at controlling sterility in a rice-wheat rotation in Nepal

Spikelet sterility in wheat (Triticum aestivum L.) is emerging as a production threat in different parts of Nepal. This study was aimed at determining the effects of sowing date and boron application in controlling spikelet sterility in four different genotypes of spring wheat in a rice-wheat system in the western hills of Nepal. Four genotypes of known different responses to boron were planted on 21 November, 6 December and 21 December, 1994 with or without boron application at 1 kg B ha-1 (i.e. 9 kg borax ha-1) on a soil that was known to be deficient in boron.The effect of sowing date was significant for the phenology, yield components, percentage sterility and grain yield. Sterility was significantly increased in the crop planted on 21 December, which had also the lowest 1000 seed weight and grain yield; there was an almost 50% grain yield reduction compared to the crop planted on 21 November. Terminal moisture stress (i.e. lack of moisture during the later part of the development) was observed in the late sown crop which also amplified the extent of sterility associated with boron deficiency. Genotypes differed in response to sowing dates and boron treatment for all of the phenological events measured, yield components, grain yield and percentage sterility. SW-41 and BL-1022 had significantly higher sterility at all sowing dates. BL-1249 showed a consistently lower% sterility over all sowing dates and boron treatments. The addition of boron significantly increased the number of grains set per spike thereby decreasing the total sterility in boron responsive genotypes SW-41 and BL-1022 while those not susceptible did not respond. The boron concentration in the flag leaf at anthesis was increased in treatments with added B in the soil but genotypes did not differ in boron concentration for any soil treatment.     

晚播小麦叶片衰老代谢和粒重变化的比较研究

对７个小麦品种在晚播条件下的叶片衰老生理特性和粒重变化进行了比较研究。根据小麦叶片的衰老特征相差差异,将７个小麦品种区分为３个类型;后健型、早衰型和中间型。在小麦旗叶的衰老过程中,后健型小麦品种旗叶叶绿素和类胡萝卜素含量显著高于早衰型,脂质过氧化产物ＭＤＡ含量显著低于早衰型,小麦粒重降幅依次为早衰型〉中间型〉后健型,并讨论了活性氧代谢在小麦叶片衰老过程中可能作用。     

冬麦春播条件下旗叶光合特性、叶绿素荧光参数变化及其与产量的关系

以长江中下游、西南麦区的5个优良冬播小麦品种为材料,在忻定盆地春播(早播、适播)条件下,于2013-2014年对开花期、灌浆期的旗叶光合指标、叶绿素含量及叶绿素荧光参数进行测定,并分析这些参数与产量的相关性.结果表明： 品种间大多荧光参数(除叶绿素外)差异显著,且相关性显著;叶绿素变异系数较小(0.12～0.17),吸收光能为基础的性能指数(PI_abs)变异系数较大(0.32～0.39),两参数与产量偏相关系数为0.70～0.81;早播条件下,籽粒产量与PI_abs(灌浆期、开花期)、灌浆期叶绿素呈显著正效应,与灌浆期旗叶在I点的相对可变荧光强度(V_i)呈显著负效应,且产量的81.1%～82.8% (2013、2014年)可由这3因素的变异决定;不同品种表现出不同的播期效应,且两年变化趋势基本一致：扬麦13(春性、中早熟)旗叶光合速率、叶绿素及绝大多数荧光参数和产量均显著高于其他品种,且适宜早播.早播条件下灌浆期旗叶叶绿素含量、PI_abs、光合速率可作为选择高光效小麦资源的重要评价指标.     

不同环境条件下小麦氮代谢关键酶活性及籽粒品质

研究了两种环境条件下3个不同蛋白含量小麦品种的氮代谢关键酶活性及籽粒品质的差异.结果表明,龙口试验点的小麦旗叶硝酸还原酶(NR)、谷胺酰氨合成酶(GS)和籽粒谷胺酰氨合成酶活性均显著高于泰安试验点,3个品种间的酶活性顺序均为：济麦20＞优麦3号＞PH971942.优质强筋小麦品种的籽粒综合品质性状在龙口试验点的表现优于泰安试验点. 灌浆期环境因素与小麦籽粒品质和酶活性存在显著的相关性,灌浆期间的较高气温、适当干旱和寡照环境有利于提高小麦籽粒品质.龙口试验点的中、强筋小麦品种和泰安试验点的中筋小麦品种蛋白质含量与旗叶NR和GS活性均达显著正相关.小麦品种用途不同,对环境条件的要求不同,适宜的环境条件提高了氮代谢关键酶的活性,利于改善小麦品质.     

Distribution of photosynthate produced before and after anthesis in tall and semi-dwarf winter wheat, as affected by nitrogen fertiliser

In 2 years the distribution of radioactivity recovered in entire shoots of field-grown winter wheat was determined at various times after exposing the top two leaves (flag leaf or second leaf) to ¹⁴CO₂ for 30 s. In 1976 when ¹⁴C was supplied to either leaf 14 days before anthesis, 30% was in the ear at anthesis. Less than 5% was in the leaf exposed to ^I4CO₂. The remainder was equally divided between the stem above and below the flag-leaf node when the flag leaf had been exposed, and was mainly in the lower part of the stem when the second leaf had been exposed. By maturity the proportion in the stem had decreased; 20% of the total activity was in the grain and 30% was still in the ear structures. When ¹⁴C was supplied 10 days after anthesis, the proportion in the ear 24 h later ranged from 42 to 69% of that in the whole shoot when the flag leaf was exposed, and from 6 to 28% when the second leaf was exposed. At maturity these proportions increased to 92 and 85% when the ¹⁴C had been supplied to flag leaves and second leaves respectively. When ¹⁴C was supplied 25 days after anthesis to either flag leaves or second leaves, more than 90% of the activity was in the mature ears. Less than 5% of the ¹⁴C remaining at maturity from any treatment was still in the leaf exposed to ¹⁴CO₂. Between 2 and 6% of ¹⁴C supplied after anthesis was in the non-grain parts of the ear. The proportion of the ¹⁴C in the ear was greatest for the semi-dwarf varieties Maris Fundin and Hobbit, less for Maris Huntsman, and least for Cappelle-Desprez. These varietal differences were large 24 h after exposure to ¹⁴CO₂, especially in 1976. They were small and rarely significant at maturity. Nitrogen fertiliser up to 210 kg N ha^-1 had negligible effects on the distribution of ¹⁴C, although it greatly increased growth and yield, especially in 1975.     

Photosynthetic characteristics and enzymatic antioxidant capacity of flag leaf and the grain yield in two cultivars of Triticum aestivum (L.) exposed to warmer growth conditions

Using late sowing practice, the reproductive growth (anthesis and kernel filling) phase of two wheat cultivars, HD 1553 and HD 2307 was exposed to warmer growth conditions, and the effect on grain yield was examined. The grain weight declined in late-sown plants of both cultivars, but the number of grains per spike decreased drastically in HD 1553 plants. In this cultivar exposure to warmer temperature during reproductive phase led to 67% fewer grains per spike. Examination of photosynthetic and enzymatic antioxidant capacity in flag leaves of late-sown plants revealed a marked reduction in chlorophyll and carotenoid pigmentation in addition to a decline in the activity of H2O2 metabolising enzymes in HD 1553 cultivar. The photo-oxidative pigment loss due to warmer growth conditions in late-shown HD 1553 plants could lead to a reduction in flag leaf photosynthesis and contribute to poor grain yield.     

The Effect of Changing Sowing Date on Leaf Structure and Gas Exchange Characteristics of Wheat Flag Leaves Grown under Mediterranean Climate Conditions

Comparisons of leaf structure and gas exchange characteristicshave been made between flag leaves of four old genotypes ofcultivated tetraploid wheats and three current varieties ofhexaploid Triticum aestivum grown under Mediterranean climateconditions. For some genotypes the effect of varying the sowingdate was investigated. In the hexaploid wheat Kolibri the effectof sowing date on leaf structure and gas exchange of the penultimateleaf was also studied. Flag leaves differed significantly in photosynthetic capacityand leaf structure characteristics between genotypes, withineach ploidy level. When the mean values for each ploidy levelwere considered, there were no significant differences in valuesfor photosynthesis per unit leaf area, stomatal conductance,intercellular CO₂ concentration, residual CO₂ conductance andwater-use efficiency between the tetraploid and hexaploid wheatssown on the same date. When comparisons were made of leaf structurethe only significant differences observed were in adaxial andabaxial stomatal frequencies and leaf area: mean values of theseparameters were higher in tetraploid than in hexaploid wheats. The changes in leaf structure in response to varying sowingdate were significant and followed the same pattern in all thegenotypes studied: a xeromorphic adaptation was observed inlater sowings in response to warmer climate. Such structuralchanges affected some gas exchange characteristics. For example,the area of flag leaves decreased by 60% in the hexaploid wheatKolibri from first to last sowing, which led to a transpirativeloss of 49% per single leaf, in spite of the fact that transpirationrate per unit leaf area increased by 26%. Penultimate leavesof cv. Kolibri followed a fairly similar adaptive pattern inlater sowings as compared with flag leaves. The adaptive significanceof changes in leaf structure and gas exchange characteristicswith varying sowing date under Mediterranean climate conditionsis discussed. Key words: Photosynthesis, leaf structure, wheat     

Contribution of Pre-Anthesis Assimilates and Current Photosynthesis to Grain Yield,and their Relationships to Drought Resistance in Wheat Cultivars Grown Under Different Soil Moisture

We investigated the relative importance of pre-anthesis assimilates stored in plant parts, mainly in the stem, and post-anthesis photosynthesis to drought resistance in wheat (Triticum aestivum L.) cultivars Hongwangmai (drought resistant) and Haruhikari (drought sensitive) subjected to two soil moisture regimes: irrigated and non-irrigated. In the irrigated treatment, soil moisture was maintained near field capacity throughout the growing season, while in the non-irrigated treatment water was withheld from 81 d after sowing until maturity. Drought stress reduced grain yield of Hongwangmai and Haruhikari by 41 and 60 %, respectively. Remobilization of pre-anthesis assimilates to the grain (remobilization) was reduced by drought in Hongwangmai but increased in Haruhikari. The contribution of pre-anthesis assimilates to the grain decreased under non-irrigated treatment in Hongwangmai. However, under water stress, Hongwangmai maintained a higher net photosynthetic rate in the flag leaf than Haruhikari. These results indicated that maintenance of post-anthesis photosynthetic rate was related to drought resistance in Hongwangmai rather than to remobilization under drought stress.     

The effect of thidiazuron on the yield of wheat grown with varying nutrient supply

The effect of the synthetic cytokinin thidiazuron on the yield of wheat growing under conditions of varying nutrient supply was investigated. Applications of thidiazuron during the early growth stages of wheat promoted tillering but reduced yield. Applications of thidiazuron during flag leaf senescence had little effect on yield. However, the yield of plants was increased at all levels of nutrient supply by treating plants with paclobutrazol during the early growth stages followed by thidiazuron during flag leaf senescence. Yield increases were greatest in moderately nutrient stressed plants, but were accompanied by a reduction in the N concentration of the grain. Possible reasons for the interaction between thidiazuron and paclobutrazol in increasing the yield of wheat are discussed.     

不同播期冬小麦株型构建及其生育特征

针对黄淮平原中部冬小麦区秋季旱涝频发导致小麦播种推迟的现状,设计冬小麦10月15日(适期播种)、10月30日(中晚期播种)、11月15日(晚期播种)、11月30日(超晚期播种)、2月15日(早春播种)和3月1日(春播)6个播期,研究不同播期冬小麦株型构建及生长发育特征.结果表明： 随着冬小麦播期的推迟,其生长发育进程加快,早春播种和春播与适期播种相比生育期缩短115~130 d;10月30日(中晚期播种)之后的5个播期与适期播种相比株高降低,成穗数和有效小穗数减少;迟播小麦的叶位下移,冠层空间降低,叶面积减少;收获指数随播种期推迟由0.46(适期播种)提高到0.53(春播);冬小麦产量随播种期推迟显著下降,减产幅度最高达43.6%;冬小麦春季播种未经过冬季和早春阶段的自然低温处理,无春化过程依然可形成产量.     

A wheat canopy model for use in disease management decision support systems

A model is described which predicts those aspects of wheat canopy development and growth which are influential in determining the development of epidemics of foliar pathogens, the efficacy of foliar applied fungicides and the impact of disease on yield; specifically the emergence, expansion and senescence of upper culm leaves in relation to anthesis date. This focus on upper leaves allowed prediction of leaf emergence dates by reference to anthesis, rather than sowing. This avoided the step changes in flag leaf emergence date with temperature, reported with earlier models, without the additional complexity of a stochastic approach. The model is designed to be coupled to models of foliar disease, where the primary effect on yield is via reduction in green canopy area and hence interception of photosynthetically active radiation. Mechanisms were incorporated to allow observations of crop development during the growing season to update state variables and adjust parameters affecting future predictions. The model was calibrated using experimental data, and validated against independent observations of crop development on four wheat cultivars across seven contrasting sites in the UK. Anthesis date and upper culm leaf emergence were always predicted within one week of their observed dates.     

Boron supply into wheat (Triticum aestivum L. cv. Wilgoyne) ears whilst still enclosed within leaf sheaths

The present study investigates whether there is significant remobilization of (10)B previously loaded in the flag and penultimate leaves into the young, actively growing ear enclosed within the sheaths of flag and penultimate leaves. It also explores whether B transport into the enclosed ear declines when air humidity in the shoot canopy increases. After 5 d (10)B labelling during the period from early to full emergence of the flag leaf, the plants were transferred into nutrient solutions containing either 10 microM (11)B or no added B for 3 d. Regardless of the subsequent B supply levels to the roots, (10)B contents in the ear continued to increase by up to 5-fold 3 d after the end of (10)B supply in the nutrient solution. During these 3 d, the ear experienced a rapid increase in biomass. However, the majority of B in the ear during the 3 d treatment period was from the newly acquired (11)B from root uptake, rather than retranslocation of (10)B previously deposited in the leaves. By comparing the relative distribution of (10)B, Rb (xylem-to-phloem transfer marker) and Sr (xylem-marker) in the ear and the flag leaf, the distribution of (10)B resembled that of Rb more than Sr. Canopy cover treatment greatly suppressed leaf transpiration and decreased the amount of newly acquired (10)B in the flag leaf and the ear, but not in the upper stem segments. The results suggest that whilst the young ear was still fully enclosed within the leaf sheaths without any significant transpiration activity, B transport into the ear is predominantly dependent on the long-distance B transport in the xylem driven by leaf transpiration and, therefore, on concurrent B uptake from the roots.     

Genotypic variation in response of barley to boron deficiency

Responses of a range of barley (Hordeum vulgare L.) genotypes to boron (B) deficiency were studied in two experiments carried out in sand culture and in the field at Chiang Mai, Thailand. In experiment 1, two barley genotypes, Stirling (two-row) and BRB 2 (six-row) and one wheat (Triticum aestivum L.) genotype, SW 41, were evaluated in sand culture with three levels of applied B (0, 0.1 and 1.0 μM B) to the nutrient solution. It was found that B deficiency depressed flag leaf B concentration at booting, grain number and grain yield of all genotypes. In barley Stirling, B deficiency also depressed number of spikes plant^-1, spikelets spike^-1 and straw yield. However, no significant difference between genotypes in flag leaf B concentration was found under low B treatments. Flag leaf B concentration below 4 mg kg^-1 was associated with grain set reduction and could, therefore, be used as a general indicator for B status in barley. In experiment 2, nine barley and two wheat genotypes were evaluated in the field on a low B soil with three levels of B. Boron levels were varied by applying either 2 t of lime ha^-1 (BL), no B (B0) or 10 kg Borax ha^-1 (B+) to the soil prior to sowing. Genotypes differed in their B response for grain spike^-1, grain spikelet^-1 and grain set index (GSI). The GSI of the B efficient wheat, Fang 60, exceeded 90% in all B treatments. The B inefficient wheat SW 41 and most of the barley genotypes set grain normally (GSI >80%) only at the B+. In B0 GSI of the barley genotypes ranged from 23% to 84%, and in BL from 19% to 65%. Three of the barley with severely depressed GSI in B0 and BL also had a decreased number of spikelets spike^-1. In experiment 3, 21 advanced barley lines from the Barley Thailand Yield Nursery 1997/98 (BTYN 1997/98) were screened for B response in sand culture with no added B. Grain Set Index of the Fang 60 and SW 41 checks were 98 and 65%, respectively, and GSI of barley lines ranged between 5 and 90%. One advanced line was identified as B efficient and two as moderately B efficient. The remaining lines ranked between moderately inefficient to inefficient. These experiments have established that there is a range of responses to B in barley genotypes. This variation in the B response was observed in vegetative as well as reproductive growth. Boron efficiency should be considered in breeding and selection of barley in low B soils. This revised version was published online in June 2006 with corrections to the Cover Date.     

不同年代冬小麦品种旗叶光合特性和产量的演变特征

选用20世纪50年代的望水白（WSB）和碧玛1号(BM1)、70年代的郑引1号(ZY1)和扬麦1号(Y1)及90年代的豫麦34(Y34)和宁麦9号(N9)冬小麦品种为材料,采用大田试验研究了小麦旗叶光合特性和籽粒产量的演变特征.结果表明：与其他年代品种相比,90年代品种灌浆期旗叶具有较高的叶绿素含量、净光合速率（P_n）、PSⅡ最大光化学效率(F_v/F_m) 和实际光量子效率（Φ_PSⅡ）,以及较高的光化学淬灭(q_P)和非光化学淬灭(q_N),并且其光合叶面积功能期长,衰老较慢.90年代品种收获指数高于50和70年代品种,平均群体产量分别比50和70年代品种提高了25.90%和11.29%.因此,在小麦品种改良过程中,花后光合能力的提高及光合持续期的延长是小麦产量增长的重要生理基础.     

Photosynthetic capacity and dry mass partitioning in dwarf and semi-dwarf wheat (Triticum aestivum L.).

Efficient use of space and high yields are critical for long-term food production aboard the International Space Station. The selection of a full dwarf wheat (less than 30 cm tall) with high photosynthetic and yield potential is a necessary prerequisite for growing wheat in the controlled, volume-limited environments available aboard long-term spaceflight missions. This study evaluated the photosynthetic capacity and carbon partitioning of a full-dwarf wheat cultivar, Super Dwarf, which is routinely used in spaceflight studies aboard U.S. space shuttle and NASA/Mir missions and made comparisons with other dwarf and semi-dwarf wheat cultivars utilized in other ground-based studies in plant space biology. Photosynthetic capacity of the flag leaf in two dwarf (Super Dwarf, BB-19), and three semi-dwarf (Veery-10, Yecora Rojo, IBWSN 199) wheat cultivars (Triticum aestivum L.) was assessed by measuring: net maximum photosynthetic rate, RuBP carboxylation efficiency, chlorophyll concentration and flag leaf area. Dry mass partitioning of carbohydrates to the leaves, sheaths, stems and ear was also assessed. Plants were grown under controlled environmental conditions in three replicate studies: slightly enriched CO2 (370 micromoles mol-1), high photosynthetic photon flux (1000 micromoles m-2 s-1; 58 mol m-2 d-1) for a 16 h photoperiod, 22/15 degrees C day/night temperatures, ample nutrients and water provided by one-half strength Hoagland's nutrient solution (Hoagland and Arnon, 1950). Photosynthetic capacity of the flag leaf was determined at anthesis using net CO2 exchange rate versus internal CO2 concentration curves measured under saturating light (2000 micromoles m-2 s-1) and CO2 (1000 micromoles mol-1). Dwarf wheat cultivars had greater photosynthetic capacities than the taller semi-dwarfs, they averaged 20% higher maximum net photosynthetic rates compared to the taller semi-dwarfs, but these higher rates occurred only at anthesis, had slightly greater carboxylation efficiencies and significantly increased chlorophyll concentrations per unit leaf area. The reduced-height wheat had significantly less dry mass fraction in the stem but greater dry mass partitioned to the ear than the taller semi-dwarfs (Yecora rojo, IBWSN-199). Studies with detached heads confirm that the head is a significant sink in the shorter wheat cultivars.     

QTL mapping of flag leaf-related traits in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Key message

QTL controlling flag leaf length, flag leaf width, flag leaf area and flag leaf angle were mapped in wheat.

Abstract

This study aimed to advance our understanding of the genetic mechanisms underlying morphological traits of the flag leaves of wheat (Triticum aestivum L.). A recombinant inbred line (RIL) population derived from ND3331 and the Tibetan semi-wild wheat Zang1817 was used to identify quantitative trait loci (QTLs) controlling flag leaf length (FLL), flag leaf width (FLW), flag leaf area (FLA), and flag leaf angle (FLANG). Using an available simple sequence repeat genetic linkage map, 23 putative QTLs for FLL, FLW, FLA, and FLANG were detected on chromosomes 1B, 2B, 3A, 3D, 4B, 5A, 6B, 7B, and 7D. Individual QTL explained 4.3–68.52% of the phenotypic variance in different environments. Four QTLs for FLL, two for FLW, four for FLA, and five for FLANG were detected in at least two environments. Positive alleles of 17 QTLs for flag leaf-related traits originated from ND3331 and 6 originated from Zang1817. QTLs with pleiotropic effects or multiple linked QTL were also identified on chromosomes 1B, 4B, and 5A; these are potential target regions for fine-mapping and marker-assisted selection in wheat breeding programs.

     

RuBP carboxylase activity in wheat following ear emergence and evaluation of the role of ear

Ribulose bisphosphate carboxylase activity and chlorophyll content were measured in the leaves and reproductive parts of two wheat cultivars after ear emergence. The chlorophyll content of the flag leaf was mostly higher than that of the awns and glumes. Awns had the highest chlorophyll content among reproductive parts. Light transmission to the lower leaves was higher in the dwarf cultivar Moti than in the medium tall cultivar Kalyansona. RuBP carboxylase activity in Kalyansona leaves was higher than in Moti leaves. In postanthesis stages there was no difference in RuBP carboxylase activity in the flag leaf and lower leaves between cultivars. Awns had the maximum activity of RuBP carboxylase followed by glumes and grains among ear parts. The relative capacity for photosynthesis in the ear parts was several times higher than in the flag leaf on a unit chlorophyll basis. It is suggested that in a crop canopy in the field, the spike(ear) may have a greater importance in grain development than has been previously estimated.     

Characterisation of grain yield and nitrogen level in relation to flag leaf senescence of wheat varieties

Three wheat cultivars ( Triticum aestivum L.), Splendeur, Hobbit and Maris Huntsman grown in pots were compared. Especially when compared to Splendeur, the flag leaf senesced most rapidly in Maris Huntsman, which presented the most rapid loss of moisture, chlorophyll and nitrogen. The uptake of exogenous nitrogen during the post-anthesis period was lower in the rapidly than in the slowly senescing variety. A higher concentration of free amino nitrogen in the flag leaf at a given sampling date was associated with a lower percentage decrease of soluble proteins at the following date. Acid proteinase activity in the flag leaf was inversely related to moisture percentage and free amino nitrogen level, but unrelated to the nitrogen loss of the flag leaf. Acid proteinase activity in the flag leaf was directly related to grain nitrogen percentage, but inversely related to grain yield. Grain yield was also directly related to the mean soluble protein content of the flag leaf through senescence.     

小麦品种的耐肥性与光合作用

本试验以耐肥性不同的三个冬小麦品种为试材,研究了品种的耐肥性与光合作用的关系。结果表明,旗叶的光合速率顺序为: 泰山一号(中度耐肥)>济南13(高度耐肥)>昌乐5号(不耐肥)。光合速率的绝对值虽因不同年度间环境条件的不伺而有所变动,但品种间的差别则保持相对稳定。增施氮肥,能使昌乐5号的光合速率明显降低,而泰山—和济南13的光合速率则因增施氮肥受到显著的促进。     

不同穗型小麦光能利用和旗叶13C同化物分配特性及对补灌水平的响应

为明确不同穗型小麦冠层光能利用和¹³C同化物分配特性的差异及对补灌水平的响应,以中穗型品种‘青农2号’和‘济麦22’、大穗型品种‘山农23’和‘山农30’为材料,设置3个水分处理:小麦全生育期不灌水(W₀)、节水灌溉(W₁,拔节期和开花期0～40 cm土层土壤相对含水量分别补灌至65%和70%)和充分灌溉(W₂,拔节期和开花期0～40 cm土层土壤相对含水量分别补灌至85%和90%),研究了不同处理对两种穗型小麦冠层光能利用和旗叶¹³C同化物分配特性的影响.结果表明:W₁处理两种穗型小麦品种开花后2、11、20和31 d的叶面积指数、冠层PAR截获率和利用率均显著高于W₀处理,再增加灌水至W₂处理,上述各指标无显著变化.¹³C示踪表明,济麦22和山农23的W₁旗叶¹³C同化物在籽粒中的分配量比W₀分别高159.34和171.1 g·hm^-2,分配比例分别高6.5%和6.5%,与W₂无显著差异;两种穗型品种W₁的籽粒产量亦显著高于W₀,与W₂无显著差异.不同穗型品种比较,节水灌溉条件下中穗型品种在开花后2和11 d、大穗型品种在开花后20和31 d具有较高的冠层光合有效辐射(PAR)截获和利用能力;中穗型品种济麦22旗叶¹³C同化物在籽粒的分配量和分配比例比大穗型品种山农23分别低6.8%和2.7%.