共查询到20条相似文献，搜索用时 375 毫秒
1.
Summary One main reason for the slow improvement of durum wheat in water-limited environments is the lack of clear understanding of the interrelationships among yield components and their compensatory changes under low and erratic moisture availability. Five cultivars, varying in many physiological attributes, were tested under different drought-stress conditions in field and greenhouse experiments. The cause-effect relationships of duration of vegetative period, duration of grain-filling period, number of spikes per m2, kernels per spike, kernel weight and grain yield per m2 were assessed. Furthermore, yield stability was evaluated. Yield reduction was largest under mid-season stress (58%), followed by terminal stress (30%) and early stress (22%). Cultivar Po was very sensitive to terminal stress.Path-coefficient analysis revealed a complex pattern of relationships among the six variables. An increase in vegetative period reduced the grain-filling period under all conditions. It increased number of kernels per spike under non-stress conditions. The direct effect of spikes per m2 on grain yield was significantly positive. However, more spikes per m2 resulted in fewer kernels per spike and a low kernel weight and, as a result, a negative relationship with grain yield under early stress. Grain-filling period had a strong influence on grain yield via kernel weight. Kernels per spike had the largest direct effect on grain yield. However, it was negatively correlated with kernel weight, especially under terminal stress. Grain yield heavily depended on kernels per spike under early stress and grain-filling period and kernels per spike under terminal stress.Variation in drought susceptibility index among cultivars was significant under early and terminal stress conditions, but not under mid-stress conditions. Yield potential and stability were not correlated for the different drought-stress conditions.Longer grain-filling period, increased number of kernels per spike and limited spike number per m2 can be used as selection criteria for sustainable yield in water-limited environments. 相似文献
2.
30余年来北部冬麦区小麦品种产量改良遗传进展 总被引：15，自引：0，他引：15
采用1965年以来北部冬麦区育成的10个主栽品种,在水、肥供应充足、病、虫、倒伏得到有效控制条件下,连续两年共进行4个点次试验;同时对1B/1R易位系和矮秆基因进行分子鉴定。结果表明,品种产量年遗传进展为64.63 kg hm-2 或1.20%,其较大幅度的提高出现在1980年丰抗号品种育成时期。丰抗2号和丰抗8号是该地区最早育成的含有1B/1R染色体和Rht-D1b矮秆基因的品种。主要农艺性状演变的总趋势是抽穗期提前、株高显著降低、生物学产量基本保持稳定、单位面积穗数减少、每穗粒数有所增加、千粒重和收获指数大幅度提高,其年遗传进展分别为－0.1%、－0.70%、0.35%、－0.50%、0.63%、1.12%和0.79%。通过减少不孕小穗和小花数来增加每穗粒数,通过提高灌浆速率来提高千粒重,再把高穗粒重与较多的单位面积穗数结合在一起,是北部冬麦区进一步提高产量的重要途径。 相似文献
3.
Selection for Yield and its Components in a Winter Wheat Population under Different Environmental Conditions in Albania 总被引：1，自引：0，他引：1
A. Collaku 《Plant Breeding》1994,112(1):40-46
Wheat breeding programmes in Albania depend upon the use of diverse genetic material of local origin and on special environmental conditions; the present study being conducted under drought stress conditions. Grain yield, yield components, plant height and test weight were estimated in an F5 generation of a winter wheat population at Kamez in 1989—90 and 1990—91 and at Lushnje in 1989—90. The highest values of heritability were observed for plant height, kernel weight and spike length. Due to drought stress the heritability of kernels per spike was low. None of the correlated responses was higher than the direct response for yield. Maximum genetic gain was expected when yield, plant height, spike length, kernels/spike and kernel weight were included in the index. 相似文献
4.
水分胁迫对甜玉米主要农艺性状及产量的影响 总被引：3，自引：1，他引：2
在大棚内采用人工供水的方法,研究不同水分胁迫下甜玉米品种主要农艺性状与产量的关系。结果表明,轻度干旱胁迫下可用株高、茎粗、散粉至吐丝间隔期(ASI)、穗粗、每穗粒数、千粒重等6个性状耐旱系数作为品种耐旱性鉴定的指标,而中度干旱胁迫下可用穗位叶面积、散粉至吐丝间隔期(ASI)、穗粗、每穗粒数、出籽率、千粒重这6个性状耐旱系数预测品种产量的耐旱系数。在不同程度水分胁迫下,散粉至吐丝间隔期(ASI)、穗粗、每穗粒数、千粒重等4个性状耐旱系数是不同品种耐旱性鉴定的重要指标,除此之外,株高、茎粗、穗位叶面积等决定植株形态的性状指标也对甜玉米耐旱性起一定作用。 相似文献
5.
大麦杂种优势利用研究,Ⅲ.大麦异棱型和同棱型F1杂种的杂种优势特征 总被引：1，自引：0，他引：1
研究了大麦4种杂交类型（含二棱×二棱、二棱×六棱、六棱×二棱和六棱×六棱）的F1杂种的性状表现和优势特征，比较了同棱型相配组（二棱×二棱和六棱×六棱）和异棱型相配组（二棱×六棱和六棱×二棱）的超高亲优势（Hh）组合数及其出现率。研究性状包括株高、穗长、穗下节间长、穗数、粒数、粒重、籽粒产量、籽粒蛋白质含量和赖氨酸含量等13个.结果表明,(1)二棱×二棱杂种的穗长较长、每株穗数较多、千粒重较高；六棱×六棱杂种的每穗粒数、每株粒数较多、籽粒产量较高；而异棱型相配杂种则比同棱型相配组有较高的株高、穗下节间长和千粒重。（2）4种杂交类型杂种的类型内杂种间变异，在大多数性状上均为同质，仅有株高、穗长和主穗粒数在六棱×六棱杂种中变异增大，有较大的选择潜力。（3）在13个数量性状中，有9个性状的Hh优势出现率与杂交类型显著关联；株高、穗下节间长和千粒重的Hh优势出现率在二棱×六棱和/或六棱×二棱杂种中最高，而主穗粒数、每穗粒数、每株粒数、每粒重和每株干重的Hh优势出现率则在六棱×六棱和/或六棱×二棱杂种中最高。（4）异棱型相配组杂种的株高、穗下节间长和千粒重的Hh优势率显著高于同棱型相配组杂种，依次为20/30对8/33、30/30对18/33和22/30对5/33；但同棱型相配组杂种籽粒产量的Hh优势率显著高于异棱型相配组杂种，为10/33对2/30。说明异棱型杂种易产生生物量和千粒重优势，而同棱型杂种易产生籽粒产量优势。 相似文献
6.
Genetic variation and interrelationships of agronomic characters in landraces of bread wheat from southeastern Iran 总被引：7，自引：0，他引：7
There is renewed interest in wheat landraces as important sources of genetic variation for agronomic characters. Fifty-three
pure lines of bread wheat (Triticum aestivum L.) derived from seven landraces collected from southeastern Iran were used to
estimate genetic variation and heritability for 13 developmental and quantitative characters. Path-analysis was used to partition
the genetic correlations between grain yield and six grain yield-related traits. Mean values of landraces were also compared
with three improved cultivars from California and Iran. Genotypic differences among the landraces and among the pure lines
collected from the landraces were highly significant for all characters considered. Compared with the modern cultivars, the
landrace genotypes were, on average, later in days to heading and taller than the cultivars but had lower values for number
of grains per spike, 1000-grain weight, grain yield and harvest index. Some landrace genotypes were similar to the modern
cultivars for grain yield. Moderate to high genetic variation was displayed by number of grains per spike, number of spikes
per plant, 1000-grain weight, and harvest index. The heritability estimates ranged from 59% for grain yield to 99% for days
to anthesis. Expected genetic advance (as % of the mean) was ≈34% for number of spikes per plant, number of grains per spike,
and 1000-grain weight. Days to heading and to anthesis correlated positively with number of spikes per plant, shoot biomass,
and straw biomass but negatively with number of grains per spike and harvest index. The strong direct effect of number of
spikes per plant on grain yield was completely counterbalanced by its indirect negative effects via number of grains per spike
and 1000-grain weight. Number of grains per spike and 1000-grain weight were positively correlated with grain yield, and they
had large direct effects. These two characters, however, were negatively correlated and exhibited a substantial counterbalance
effect via one another and via number of spikes per plant. The landraces could be improved by intercrossing the promising
genotypes identified in this study, with simultaneous selection for earliness, fewer number of spikes per plant, greater number
of grains per spike and heavier grains. For further improvement, crossing programs between the landraces and introduced germplasm
may be necessary.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Summary Near-isogenic tall (no dwarfing gene), semidwarf (Rht1 or Rht2) and dwarf (Rht1 + Rht2 or Rht3) spring wheat lines were evaluated for yield and yield components under irrigated and rainfed conditions. Under irrigated conditions, the dwarf and the semidwarf lines exhibited a significant yield advantage over the tall lines. Under rainfed conditions, the semidwarf lines outyielded the tall as well as the dwarf lines. Percent yield reduction in response to drought stress was highest with the dwarfs and lowest with the tall lines. Dry matter production of the tall lines and that of the semidwarf lines did not differ significantly and both produced significantly more dry matter than the dwarf lines under irrigated as well as rainfed conditions. Plant height and kernel weight decreased with increasing degree of dwarfness while number of kernels per spikelet, harvest index and days to heading increased under both moisture regimes. The dwarfing genes did not have any significant influence on number of tillers/m2 and spikelets per spike in either moisture regime. 相似文献
8.
Summary The evaluation aimed at identifying landrace genotypes adapted to the rather unfavourable growing conditions of durum wheat in Sicily, to be used as parental material in a breeding programme. The trial was carried out in three seasons experiencing varying climatic conditions, and included 75 landraces, 25 of which were selected under severe drought in Syria. Wide differences were observed for most traits among genotypes and seasons of evaluation. Yields of the best performing entries identified in each season never significantly differed from that of the best check variety. The top-yielding landraces were consistently better than the remaining entries for the three yield components, viz. number of spikes per plant, number of kernels per spike and mean kernel weight. In the driest season they were also significantly earlier in heading, confirming the importance of earliness under drought. An analytical breeding approach relying on an array of morpho-physiological traits as selection criteria did not seem appropriate for the given environment, as the variable stress level enhanced the importance of specific traits under specific situations. The genotypic response was largely season-specific. Nonetheless, five landraces were in the best group in all seasons. The selection made in Syria also appeared somewhat effective in Sicily, particularly in the less favourable seasons. 相似文献
9.
两个不同适应性冬小麦品种的竞争能力 总被引：9，自引：1，他引：8
采用生态学中的de Wit替代系列法研究了当前山东省高产广适性冬小麦品种鲁麦21和仅适应局部地区种植的冬小麦品种烟农15在混播条件下的竞争结局,并对其生长特性、资源分配模式及相关性状的差异进行了比较研究. 在混播条件下鲁麦21较烟农15具有明显的竞争优势, 具有更强的占有和利用共同资源的能力. 分蘖数、单位面积穗数、穗 相似文献
10.
Summary Some 238 landraces from Algeria and Tunisia representative of the mediterraneum typicum durum wheat type and 265 landraces from Syria and Jordan representing the syriacum type were grown in a semi-arid Mediterranean environment of Northern Syria characterized by moderate drought stress. The germplasm types were compared for mean value, level of variation and relationships with grain yield of various morpho-physiological traits possibly usable for indirect selection of best yielding materials. The syriacum germplasm showed higher yield mainly due to greater earliness of cycle, slightly longer grain filling period, shorter stature, lower early growth vigour and higher drought tolerance expressed by a visual score recorded in another, more stressful environment in the region. It also showed lower variation for all morpho-physiological characters except plant glaucousness, for which it was more variable. The wheat types differed not only for architecture but also for optima of individual morpho-physiological traits required to maximize the yield response in the given environment. Higher yield of syriacum materials was attained at same heading and three to four days delayed maturity with respect to average phenology of three well-adapted control cultivars, and it was favoured by increasing number of kernels per spike, early vigour and drought tolerance. Higher yield of mediterraneum typicum landraces was related to heading and maturity dates approaching those of the control cultivars and to increasing kernel weight, early vigour and drought tolerance. Plant stature hardly affected the yield. Both absent and strong glaucousness could confer a yield advantage in syriacum materials. 相似文献
11.
12.
Summary Twenty one diverse, standard and experimental cultivars of common spring wheat (Triticum aestivum L.) were tested for the effect of heat stress on phenology, yield and its components by growing the materials for 2 years under full irrigation during the hot summer (offseason), and the cool winter (normal) conditions. Heat tolerance was estimated for each variable by the heat susceptibility index (S) which scales the reduction in cultivar performance from cool to hot conditions relative to the respective mean reduction over all cultivars.Genotypes differed significantly in S for yield and its components. The ranking of cultivars in S over the 2 years was consistent for yield, kernels per spike and kernel weight, but not for spike number. Of the three yield components, the greatest genotypic variation in S was expressed for kernels per spike. However, S for yield could not be simply attributed to S in a unique component across all cultivars. On the other hand, a general linear model regression of summer yield on its components revealed that the most important yield component affecting yield variation among cultivars under heat stress was kernel number per spike. Kernel number per spike was positively associated across cultivars with longer duration and greater stabilty of thermal time requirement from emergence to double ridge. It is therefore concluded that kernel number per spike under heat stress is a reasonable estimate of heat tolerance in yield of wheat and that this tolerance is operative already during the first 2 to 3 weeks of growth. 相似文献
13.
Summary Three populations of winter wheat were formed by crossing Avrora to Sage, TAM W-101, and Danne. Approximately 10% of the F2 plants from these crosses were selected for high and low levels of number of tillers per plant, number of kernels per spike, 1000-kernel weight, and grain yield. Forty-eight solid seeded F3 lines obtained from the selected F2 plants were then selected for high and low expressions of yield components and grain yield. Realized heritabilities were estimated. Indirect responses of yield to yield component selection and direct response to selection for grain yield were measured. Heritabilities were low for tiller number, number of kernels per spike and kernel weights but were high or intermediate for grain yield when selection occurred in the F2 generation. When selection was practiced in the F3 generation, heritabilities for tiller number and yield were low, but were intermediate to high for number of kernels per spike and kernel weight and high heritabilities were found for kernel weight. Selection for kernel weight often increased grain yield; however, direct selection for grain yields was usually as effective.Journal article no. J-4488 of the Oklahoma Agri. Exp. Stn., Stillwater, Oklahoma 74074. 相似文献
14.
N. H. Samarah A. M. Alqudah J. A. Amayreh & G. M. McAndrews 《Journal of Agronomy and Crop Science》2009,195(6):427-441
Barley (Hordeum vulgare L.) is an important winter cereal crop grown in the semiarid Mediterranean, where late‐terminal drought stress during grain filling has recently become more common. The objectives of this study were to investigate the growth performance and grain yield of four barley cultivars under late‐terminal drought stress under both glasshouse and field conditions. At grain filling, four barley cultivars (Rum, ACSAD176, Athroh and Yarmouk) were exposed to three watering treatments: (1) well‐watered [soil maintained at 75 % field capacity (FC)], (2) mild drought stress at 50 % FC, (3) severe drought stress at 25 % FC in the glasshouse experiment and (1) well‐watered (irrigated once a week), (2) mild drought (irrigated once every 2 weeks), (3) severe drought (non‐irrigated; rainfed) in the field. As drought stress severity increased, gross photosynthetic rate, water potential, plant height, grain filling duration, spike number per plant, grain number per spike, 1000‐grain weight, straw yield, grain yield and harvest index decreased. In the glasshouse experiment, the six‐row barley cultivars (Rum, ACSAD176, and Athroh) had higher grain yield than the two‐row barley cultivar (Yarmouk), but the difference was not significant among the six‐row cultivars under all treatments. In the field experiment, Rum had the highest grain yield among all cultivars under the mild drought stress treatment. The two‐row cultivar (Yarmouk) had the lowest grain yield. In general, the traditional cultivar Rum had either similar or higher grain yield than the other three cultivars under all treatments. However, the yield response to drought differed between the cultivars. Those, Rum and ACSAD176, that were capable of maintaining a higher proportion of their spikes and grains per spike during drought also maintained a higher proportion of their yield compared with those in well‐watered treatment. In conclusion, cultivar differences in grain yield were related to spike number per plant and grain number per spike, but not days to heading or grain filling duration. 相似文献
15.
大麦种质资源成株期抗旱性鉴定及抗旱指标筛选 总被引：6，自引：0，他引：6
Yin-Ping XU Yong-Dong PAN Qiang-De LIU Yuan-Hu YAO Yan-Chun JIA Cheng REN Ke-Cang HUO Wen-Qing CHEN Feng ZHAO Qi-Jun BAO Hua-Yu ZHANG 《作物学报》2020,46(3):448-461
干旱是影响大麦生产的主要因素之一。在鉴定大麦种质资源成株期抗旱性的基础上,筛选抗旱指标,可为培育抗旱品种提供依据。本研究在2016和2017年在大麦生长主要需水期平均降雨量不足40 mm的甘肃省武威市进行田间试验,以30份大麦种质资源为研究对象,设置正常灌水和干旱胁迫处理,测定大麦株高、穗长、分蘖数、单株粒数、单株粒重、穗粒数、千粒重和产量,采用抗旱性度量值(D)、综合抗旱系数(CDC)、加权抗旱系数(WDC)、相关分析、频次分析、主成分分析、灰色关联度分析、隶属函数分析、聚类分析和逐步回归分析相结合的办法,对其进行抗旱性鉴定及抗旱指标的筛选。干旱胁迫对测定的各指标均有极显著影响。频次分析表明,各指标对干旱胁迫反应的敏感程度依次为产量、株高、单株粒重、穗长、单株粒数、分蘖数、穗粒数和千粒重。相关分析表明,产量与株高、穗长、分蘖数、单株粒数和单株粒重呈极显著正相关,与穗粒数呈显著正相关、与千粒重呈不显著正相关。主成分分析表明,5个主成分可以代表大麦抗旱性86.39%的原始数据信息量。基于D值、CDC值和WDC值的大麦种质资源抗旱性排序基本一致。灰色关联度分析表明,各指标单项抗旱系数值与D值间的关联度依次为产量、单株粒重、单株粒数、穗长、株高、分蘖、穗粒数和千粒重,各指标DC值与WDC值间的关联大小依次为单株粒重、产量、单株粒数、分蘖、穗长、穗粒数、株高和千粒重。根据D值进行聚类分析,将供试大麦种质资源依据抗旱性从强到弱分为5个抗旱等级,其中1级5份、2级1份、3级11份、4级10份、5级3份。除分蘖和千粒重外,其余指标的隶属函数值、CDC值、D值和WDC值均随着抗旱级别的升高而增大。回归分析表明, 5个测定指标均与D值密切相关。干旱胁迫对大麦种质资源成株期各指标均有极显著影响。确定了D值为适宜的抗旱鉴定指标。筛选出成株期抗旱性强的大麦种质资源甘啤7号、Z06-278-9、MERIT、NEVADA和西藏25,可为大麦抗旱育种、抗旱机制以及干旱调控缓解机制的研究提供技术支持。穗长、单株粒数、单株粒重、穗粒数、产量可作为大麦种质资源成株期简单、直观的抗旱评价指标。 相似文献
16.
O. P. Yadav 《Plant Breeding》2008,127(2):208-210
The crop cultivars targeted for drought prone areas need to combine drought tolerance and high yield. The present study was conducted to assess the performance of three selected pearl millet landraces, four exotic elite populations and their 12 crosses. They were evaluated for yield, yield components and a drought susceptibility index that was calculated using yield data from drought and non‐drought environments. In the non‐drought season, the exotic populations had significantly higher grain yield than landraces. However, in the severe drought season, the landraces produced significantly greater biomass, grain and stover yields than elite populations. There was a strong relation between panicle size and ability to produce panicles and delay in flowering under severe stress. The biomass and stover yield of crosses was significantly better than parental populations under both drought stress and near‐optimum conditions. The elite populations were most sensitive to drought while crosses were as drought tolerant as landraces because they combined larger panicle size of exotics and lesser delay in flowering of landraces. The results indicated that it is possible to combine drought adaptation with high yield potential through hybridization between adapted landraces and elite genetic materials. 相似文献
17.
Summary Twenty-nine primary triticales (x Triticosecale Wittmack), derived from homozygous, uniform wheat and rye inbreds, were evaluated (i) to assess wheat, rye and interaction effects for yield-related characters, (ii) to estimate correlations between these characters, and (iii) to investigate the possibility of predicting micro-plot performance from early spaced-plant tests. The triticales (12 octoploid, 17 hexaploid) were tested under space-planting and in micro-plots in three-replicate, randomized block designs in 1983 and 1984, respectively. In general, hexaploid triticales performed significantly better than octoploids. Strong wheat and wheat x rye interaction effects were found, making it difficult to predict the performance of primary triticales from their constituent parental genotypes. At both ploidy levels under space-planting kernel weight per spike showed significant positive correlations with spikelets per spike, kernels per spikelet, and 1000-kernel weight. No significant associations were detected between spaced-plant and micro-plot performance for octoploids, indicating severe disorders at this ploidy level. In hexaploid triticales spikes per plant, kernel weight per spike, and kernels per spikelet observed in spaced-plants appeared to be useful indicators of grain yield in micro-plots. 相似文献
18.
四川盆地及盆周山区玉米地方种质耐低磷胁迫研究 总被引：2，自引：0，他引：2
以来自四川盆地及盆周山区的22个玉米地方种质为材料,在低磷胁迫下对苗期缺磷症状,成株期株高、穗行数、百粒重、行粒数以及穗粒重等性状表现进行了研究。结果表明,低磷胁迫对玉米的主要农艺、经济性状均有不同程度的影响,其中对苗期缺磷症状及成株期穗粒重的影响最大,且不同玉米地方种质在苗期和成株期对低磷胁迫的反应不同,以苗期缺磷症状和成株期穗粒重的耐低磷胁迫系数的平均值作为耐低磷综合指数,能较好地反映玉米地方种质的耐低磷胁迫能力。将耐低磷综合指数按最短距离法进行聚类,可将22个玉米地方种质划分为三类。其中,第一类材料包括:汉源红包谷、汉源白包谷、汶川二白、江北大板牙,占鉴定总数的18.2%,它们的耐低磷综合指数在0.81以上,属于对低磷胁迫不敏感基因型;第二类材料包括南充秋子等4个玉米地方种质,占鉴定总数的18.2%,它们的耐低磷综合指数在0.73~0.77之间,属于对低磷胁迫反应中间型;第三类材料包括小金金皇后等14个地方种质,占鉴定总数的63.6%,它们的耐低磷综合指数在0.73以下,属于对低磷胁迫敏感基因型。 相似文献
19.
旨在为小麦育种和生产上预防倒伏、提高稳产能力提供参考。以来源于野生二粒小麦远缘杂交组合的82个高代系为试材,在西北农林科技大学试验站测定并分析抗倒性影响因子和产量性状的相关性。结果表明,（1）株高与抗倒性呈负相关关系,成熟期茎壁厚与抗倒性呈正相关关系,各个性状的抗倒性排序为株高>成熟期茎壁厚度>单穗重>单株重;（2）粒宽、穗粒数和单穗重呈极显著正相关关系(0.413**、0.767**);（3）倒伏引起千粒重、单穗重下降,导致减产;（4）小穗数、小穗粒数及穗粒数等产量因子及抗倒影响因子的杂种分离世代都出现小于低亲值的遗传特点,分离子代产量接近高亲值的单株占1.5988%,杂交育种中分离世代最低群体需在120株左右。选择茎壁厚、植株高度适中、增加粒宽（饱满大粒）和穗粒数（大穗、多花结实性好）,有望筛选出高产抗倒品种。 相似文献
20.
Summary Diverse landraces of wheat, collected from the semi-arid (150 to 250 mm of total annual rainfall) Northern Negev desert in Israel were considered as a potential genetic resource of drought resistance for wheat breeding. These materials were therefore evaluated for their reponses to drought stress in agronomical and physiological terms. Up to 68 landraces, comprising of Triticum durum, T. aestivum, and T. compactum were tested in two field drought environments, in one favourable field environment, under post-anthesis chemical plant desiccation which revealed the capacity for grain filling from mobilized stem reserves, under a controlled drought stress in a rainout shelter and in the growth chamber under polyethylene glycol (PEG)-induced water stress. Biomass, grain yield and its components, harvest index, plant phenology, canopy temperatures, kernel weight loss by chemical plant desiccation, growth reduction by PEG-induced drought stress and osmotic adjustment were evaluated in the various experiments.Landraces varied significantly for all parameters of drought response as measured in the different experiments, which was in accordance to their documented large morphological diversity. Variation in grain yield among landraces under an increasing drought stress after tillering was largely affected by spike number per unit area. Kernel weight contributed very little to yield variation among landraces under stress, probably because these tall (average of 131 cm) landraces generally excelled in their capacity to support kernel growth by stem reserve mobilization under stress. Yield under stress was reduced with a longer growth duration of landraces only under early planting but not under late planting. Landraces were generally late flowering but they were still considered well adapted phenologically to their native region where they were always planted late.Landraces differed significantly in canopy temperature under drought stress. Canopy temperature under stress in the rainout shelter was negatively correlated across landraces with grain yield (r=0.67**) and biomass (r=0.64**) under stress. Canopy temperature under stress in the rainout shelter was also positively correlated across landraces (r=0.50**) with canopy temperature in one stress field environment. Osmotic adjustment in PEG-stressed plants was negatively correlated (r=–0.60**) with percent growth reduction by PEG-induced water stress. It was not correlated with yield under stress in any of the experiments. In terms of yield under stress, canopy temperatures and stem reserve utilization for grain filling, the most drought resistant landrace was the Juljuli population of T.durum. 相似文献