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1.
不同水分条件下小麦生理性状与产量的灰色关联度分析 总被引：8，自引：0，他引：8
为了解干旱胁迫条件下小麦冠层温度、旗叶光合性状的变化特点及其对产量的影响,以小麦回交导入系(IL)群体[(鲁麦14×晋麦47)×鲁麦14]BC3F5代的160个株系及其亲本为材料,分析了雨养和灌溉条件下,开花期和灌浆期冠层温度、冠气温差、旗叶叶绿素含量和叶绿素荧光动力学参数等性状的相关性以及不同性状与产量的灰色关联度。结果表明,在两种水分条件下IL群体多数性状表现超双亲,性状变异系数为1.19%～48.30%,性状均值偏向轮回亲本鲁麦14;雨养条件下抗旱亲本晋麦47的冠层温度及叶绿素荧光动力学参数比水地品种鲁麦14表现稳定,IL群体的性状稳定性(D值)超过轮回亲本。两种水分条件下,荧光动力学参数之间相关性表现复杂,Fv与Fm、Fo/Fm与Fv/Fm之间相关性最高,相关系数大于0.991。灰色关联度分析结果表明,两个发育时期的Fv/Fm和灌浆期的冠层温度对产量的影响较大,可以作为选择抗旱高光效小麦的重要评价指标。 相似文献
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Arvind Kumar Jrme Bernier Satish Verulkar H.R. Lafitte G.N. Atlin 《Field Crops Research》2008,107(3):221-231
Drought is the most important constraint reducing rice yield in rainfed areas. Earlier efforts to improve rice yield under drought mainly focused on improving secondary traits because the broad-sense heritability (H) of grain yield under drought stress was assumed to be low, however gains in yield by selecting for secondary traits have not been clearly demonstrated in rice. In present study, the effectiveness of direct selection for grain yield was assessed under lowland reproductive stage stress at Raipur in eastern India and under upland reproductive stage drought stress at IRRI. The selection under severe stress (in both upland and lowland trials) resulted in greater gains under similar stress levels (yield reduction of 65% or greater under stress) in evaluation experiments than did selection under non-stress conditions, with no yield reduction under non-stress conditions. We observed similar H of grain yield under stress and non-stress conditions, indicating direct selection for yield under drought will be effective under both lowland and upland drought stresses. None of the secondary traits (panicle exsertion, harvest index, leaf rolling, leaf drying) included in our study showed a higher estimate for H than grain yield under stress. Secondary traits as well as indirect selection for grain yield under non-stress situation were predicted to be less effective in improving yield under drought in both lowland and upland ecosystem than direct selection for grain yield under the respective stress situations. The low, but positive values observed for genetic correlation (rG) between yield under stress and non-stress indicated that it is possible to combine drought tolerance with high-yield potential but low values also indicated that selection for grain yield needs to be carried under stress environments. The study also indicated that under lowland drought stress, the use of highly drought-tolerant donors, as parents in crosses to high yielding but susceptible varieties resulted in a much higher frequency of genotypes combining high-yield potential with tolerance than did crosses among elite lines with high-yield potential but poor tolerance. Breeding strategies that use drought-tolerant donors and that combine screening for yield under managed drought stress with screening for yield potential are likely to result in the development of improved cultivars for drought-prone rainfed rice producing areas. 相似文献
3.
选取我国当前生产上大面积推广应用的籼稻恢复系明恢86和蜀恢527作为轮回亲本,以籼稻品种爷驼崽为供体亲本构建了2个BC2F4群体,在河北廊坊田间正常土壤正常施肥(对照)、贫瘠土壤正常施肥和贫瘠土壤低磷胁迫这三种处理下进行产量及相关性状的表型评价。同时,在北京温室采用水培法进行苗期耐低磷鉴定。在廊坊检测到49个产量及相关性状主效QTL,这些QTL对表型变异的贡献率为6.7%~16.5%;其中有25个(51.0%)QTL的有利等位基因来自供体亲本爷驼崽。在北京检测到影响耐低磷相关性状(根长、根系干质量、根冠比、地上部分干质量和总干质量)的主效QTL 48个,这些QTL对表型变异的贡献率为7.7%~16.6%;其中有21个(43.8%)QTL的有利等位基因来自供体亲本爷驼崽。多达79.6%的QTL能在廊坊环境两个或两个以上处理下被检测到,特别是与每穗总粒数、结实率和千粒重有关的QTL,不仅能稳定的表达,并且它们在不同处理下具有比较一致的效应。在检测到的所有QTL中,有8个染色体区段在两种环境的低磷胁迫条件下被同时检测到,其中与第12染色体RM511(Bin12.4)紧密连锁的位点,同时控制每穗实粒数、每穗总粒数、根长、根系干质量、地上部分干质量和总干质量等6个性状。 相似文献
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《Field Crops Research》2002,73(2-3):169-180
Drought frequently reduces grain yield of rainfed lowland rice. A series of experiments were conducted in drought-prone northeast Thailand to study the magnitude and consistency of yield responses of diverse, rainfed lowland rice genotypes to drought stress environments and to examine ways to identify genotypes that confer drought resistance. One hundred and twenty-eight genotypes were grown under non-stress and four different types of drought stress conditions. The relationship of genotypic variation in yield under drought conditions to genetic yield potential, flowering time and flowering delay, and to a drought response index (DRI) that removed the effect of potential yield and flowering time on yield under stress was examined.Drought stress that developed prior to flowering generally delayed the time of flowering of genotypes, and the delay in flowering was negatively associated with grain yield, fertile panicle percentage and filled grain percentage. Genotypes with a longer delay in flowering time had extracted more water during the early drought period, and as a consequence, had higher water deficits. They were consistently associated with a larger yield reduction under drought and in one experiment with a smaller DRI. Genotypes, however, responded differently to the different drought stress conditions and there was no consistency in the DRI estimates for the different genotypes across the drought stress experiments. The results indicate that with the use of irrigated-control and drought test environments, genotypes with drought resistance can be identified by using DRI or delay in flowering. However, selections will differ depending on the type of drought condition. The inconsistency of the estimates in DRI and flowering delay across different drought conditions reflects the nature of the large genotype-by-environment interactions observed for grain yield under various types of drought in rainfed lowland conditions. 相似文献
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Yaduru Shasidhar Murali T.Variath Manish K.Vishwakarma Surendra S.Manohar Sunil S.Gangurde Manda Sriswathi Hari Kishan Sudini Keshavji L.Dobariya Sandip K.Bera Thankappan Radhakrishnan Manish K.Pandey Pasupuleti Janila Rajeev K.Varshney 《作物学报(英文版)》2020,(1):1-15
Foliar fungal diseases(rust and late leaf spot)incur large yield losses,in addition to the deterioration of fodder quality in groundnut worldwide.High oleic acid has emerged as a key market trait in groundnut,as it increases the shelf life of the produce/products in addition to providing health benefits to consumers.Marker-assisted backcrossing(MABC)is the most successful approach to introgressing or pyramiding one or more traits using traitlinked markers.We used MABC to improve three popular Indian cultivars(GJG 9,GG 20,and GJGHPS 1)for foliar disease resistance(FDR)and high oleic acid content.A total of 22 BC3F4 and 30 BC2F4 introgression lines(ILs)for FDR and 46 BC3F4 and 41 BC2F4 ILs for high oleic acid were developed.Recurrent parent genome analysis using the 58 K Axiom_Arachis array identified several lines showing upto 94%of genome recovery among second and third backcross progenies.Phenotyping of these ILs revealed FDR scores comparable to the resistant parent,GPBD 4,and ILs with high(~80%)oleic acid in addition to high genome recovery.These ILs provide further opportunities for pyramiding FDR and high oleic acid in all three genetic backgrounds as well as for conducting multi-location yield trials for further evaluation and release for cultivation in target regions of India. 相似文献
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Satoshi Hayashi Akihiko Kamoshita Junko Yamagishi Anuchart Kotchasatit Boonrat Jongdee 《Field Crops Research》2009
Large within-field variation in rice growth often causes production loss in broadcast-seeded (BC) rainfed lowland rice. The spatial variability of direct-seeded rainfed lowland rice was evaluated in 2004, 2005, and 2007 in on-station experiments at Ubon Ratchathani, northeast Thailand, in relation to soil water content and weed infestation, by adopting semivariogram and block kriging, including comparisons among BC with harrowing (BCH; no weeding), BC with no harrowing (BCNH; no weeding), and row-seeded (RS; interrow weeding once) fields. BCH and BCNH were also compared in 11 farmers’ fields in 2006 and 2007, to assess the effect of harrowing on rice growth and weed infestation. During most of the rice growing periods, flooded and non-flooded portions existed simultaneously in the fields, with different proportions among years and among seeding methods in the on-station experiment. BCH and BCNH rice had large within-field variation in seedling density, heading date, shoot dry matter, grain yield, harvest index, panicle density, and filled spikelet per panicle, as well as in weed infestation, measured by a quick visual estimation. Many of the measured variables (except mean soil water content in RS in 2007, seedling density in BCH in 2005 and 2007, shoot dry matter in BCH and BCNH in 2007, and panicle density in BCH in 2007) were spatially dependent (i.e., data from nearby locations were most similar) by geostatistical analysis. Analysis of correlations using the 420 data sets of BCH plots in 2005 and BCH, BCNH, and RS plots in 2007 revealed a positive correlation between soil water content and grain yield and negative correlations between weed infestation and soil water content and grain yield. Compared with BCH, in 2007 BCNH had much lower grain yield because of lower soil water content after establishment and more weed infestation. BCH had higher grain yield than BCNH in weedy fields in the farmers’ fields experiment. RS with interrow weeding resulted in a smaller coefficient of variation, smaller sill value, and higher grain yield than BCH, due to less weed infestation and a higher proportion of flooded water. These results indicated that reducing the spatial variability in rice growth requires careful field preparation, such as harrowing to level the soil surface and to reduce the uneven distribution of standing water and the variability in soil water content, combined with effective crop and weed management (i.e., harrowing and row-seeding). This is the first study that examined spatial variability in the growth of direct-seeded rice as a function of soil water content and weed infestation in a rainfed lowland environment. 相似文献
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Weiling YuanShaobing Peng Cougui CaoParminder Virk Danying XingYunbo Zhang Romeo M. VisperasRebecca C. Laza 《Field Crops Research》2011,121(1):168-174
Selection for yield per se has greatly contributed to yield improvement in many crops. It is expected that selection based on plant traits is more effective in increasing crop yield potential. This study was conducted to compare the effectiveness of trait-based and yield-based selection in increasing rice yield and to determine whether lines with ideotype traits have the potential to express higher yield under optimal crop management conditions. Lines were selected based on plant traits or on grain yield measured in a breeder's replicated yield trial. The main target traits for selection were plant height, leaf and panicle morphology, grain size, total dry weight, and grain-filling percentage. Yield performance of trait-based selection was compared with that of yield-based selection in an agronomic trial with optimum crop management for three seasons. Trait-based selection increased leaf area index and total dry weight but reduced spikelet number per m2 and harvest index compared with yield-based selection. Consequently, selection based on plant traits did not increase grain yield compared with selection based on yield per se. In one of the three seasons, yield of trait-based selection was significantly lower than that of yield-based selection. Among all tested breeding lines, maximum yield was produced by yield-based selection and minimum yield came from trait-based selection. These results suggest that lines with ideotype traits did not express higher grain yield than lines selected based on yield per se under optimal crop management conditions, and yield-based selection was as effective in increasing rice grain yield as trait-based selection in the late generations of the breeding cycle. 相似文献
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The low and unstable yields of rainfed lowland rice in Central Java can be attributed to drought, nutrient stress, pest infestation or a combination of these factors. Field experiments were conducted in six crop seasons from 1997 to 2000 at Jakenan Experiment Station to quantify the yield loss due to these factors. Experimental treatments—two water supply levels (well-watered, rainfed) in the main plots and five fertilizer levels (0-22-90, 120-0-90, 120-22-0, 120-22-90, 144-27-108 kg NPK ha−1) in the subplots—were laid out in a split-plot design with four replications. Crop, soil, and water parameters were recorded and pest infestations were assessed.
In all seasons, rice yield was significantly influenced by fertilizer treatments. Average yield reduction due to N omission was 42%, to K omission 33–36%, and to P omission 3–4%. Water by nutrient interactions did not affect rice yield and biomass production. In two of the three dry seasons, an average of 20% of the panicles were damaged by pests and estimated yield loss from pests was 56–59% in well-watered and well-fertilized treatments. In one out of six seasons, yields under rainfed conditions were 20–23% lower than under well-watered conditions. Drought, N and K deficiencies, and pest infestation are the major determinants for high yields in rainfed environments in Jakenan. Supplying adequate nutrient and good pest control are at least as important as drought management for increasing crop productivity of rainfed rice-growing areas in Central Java. The relative importance of drought, nutrient and pest management may vary in other rainfed areas. Yield constraints analysis should be systematically carried out to identify appropriate management strategies. 相似文献
10.
不同年份水稻产量性状的QTL分析 总被引：7，自引：1，他引：6
分别于2005年和2006年利用热研2号（粳稻）和密阳23（籼稻）为亲本构建的含111个家系的F6和F7重组自交系群体,对单株穗数、每穗颖花数、每穗实粒数、结实率、千粒重和单株产量6个性状进行了QTL分析。两年共检测到分布于7条染色体上的19个QTL,其中2005年检测到10个,2006年检测到14个,两年相同的QTL 5个。大多数性状之间具有显著的表型相关性,相关性较强的性状之间具有较多共同或紧密连锁的QTL。检测到3个控制产量性状的QTL区域存在一因多效或紧密连锁,其中第8染色体上RM5556-RM331区域两年同时检测到控制每穗颖花数、每穗实粒数以及单株产量的QTL。这些QTL为通过分子标记辅助选择提高水稻产量提供了有用信息。 相似文献
11.
System of rice intensification (SRI) is a water-saving agro-technique being popularized in Southern Asia including India. A particular key practice in SRI, reduced water application (no continuous flooding), needs to be more farmer-friendly for its mass adoption under traditional and non-traditional cultivation. A field experiment was conducted maintaining different water regimes throughout the crop season (vegetative as well as reproductive stages) by scheduling irrigation applications at 1, 3, or 5 days after disappearance of ponded water (DADPW), using two different plant spacings and two different varieties. With an increase in the period of water stress, tiller production was increased significantly (P ≤ 0.05) and found to be maximum under prolonged stress, i.e., 5 days after disappearance of ponded water (5 DADPW). Increased tiller production did not result in yield increments, but yield-contributing parameters (panicle weight, grain weight per panicle, filled grain percentage, and test weight) were confirmed as critical determinants of yield. Plant nutrient (NPK) uptake was reduced under stress conditions, but the translocation of phosphorus and potassium from sources to sink was increased significantly in this study. Nutrient utilization efficiency was also enhanced under mild (3 DADPW) to prolonged (5 DADPW) water stress conditions. No significant reduction in yield was recorded under mild water stress, and this resulted in increased water productivity; however, significant yield loss was observed under prolonged water stress (5 DADPW). 相似文献
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可持续发展农业和有机栽培越来越受到人们的关注。以常规香稻品种19香为试验材料,研究了有机栽培条件下不同机械种植方式（DD,旱插秧机旱插秧;DW,水插秧机旱插秧;D,机械旱直播;CK,常规水插秧）对香稻品种产量、品质及香气的影响。结果表明,与CK相比,DD处理水稻有效穗数、每穗粒数、结实率、千粒重和产量均无明显差异,D处理水稻产量显著下降;DD、DW和D处理的水稻香气合成关键基因BADH2表达受到抑制,从而明显提高了稻米香气,其中,DD处理香气物质（2-乙酰-1-吡咯啉）含量最高。综上所述,旱插秧机旱插秧适宜作为有机栽培条件下机械种植方式。 相似文献
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Reena Sellamuthu Gui Fu Liu Chandra Babu Ranganathan Rachid Serraj 《Field Crops Research》2011,124(1):46-58
Drought is a major constraint for rice production and yield stability in rainfed ecosystems, especially when it occurs during the reproductive stage. Combined genetic and physiological analysis of reproductive-growth traits and their effects on yield and yield components under drought stress is important for dissecting the biological bases of drought resistance and for rice yield improvement in water-limited environments. A subset of a doubled haploid (DH) line population of CT9993-5-10-1-M/IR62266-42-6-2 was evaluated for variation in plant water status, phenology, reproductive-growth traits, yield and yield components under reproductive-stage drought stress and irrigated (non-stress) conditions in the field. Since this DH line population was previously used in extensive quantitative trait loci (QTLs) mapping of various drought resistance component traits, we aimed at identifying QTLs for specific reproductive-growth and yield traits and also to validate the consensus QTLs identified earlier in these DH lines using meta-analysis. DH lines showed significant variation for plant water status, reproductive-growth traits, yield and yield components under drought stress. Total dry matter, number of panicles per plant, harvest index, panicle harvest index, panicle fertility, pollen fertility, spikelet fertility and hundred grain weight had significant positive correlations with grain yield under drought stress. A total of 46 QTLs were identified for the various traits under stress and non-stress conditions with phenotypic effect ranging from 9.5 to 35.6% in this study. QTLs for panicle exsertion, peduncle length and pollen fertility, identified for the first time in this study, could be useful in marker-assisted breeding (MAB) for drought resistance in rice. A total of 97 QTLs linked to plant growth, phenology, reproductive-growth traits, yield and its components under non-stress and drought stress, identified in this study as well as from earlier published information, were subjected to meta-analysis. Meta-analysis identified 23 MQTLs linked to plant phenology and production traits under stress conditions. Among them, four MQTLs viz., 1.3 for plant height, 3.1 for days to flowering, 8.1 for days to flowering or delay in flowering and 9.1 for days to flowering are true QTLs. Consensus QTLs for reproductive-growth traits and grain yield under drought stress have been identified on chromosomes 1 and 9 using meta-QTL analysis in these DH lines. These MQTLs associated with reproductive-growth, grain yield and its component traits under drought stress could be useful targets for drought resistance improvement in rice through MAB and/or map-based positional analysis of candidate genes. 相似文献
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S.M. Haefele S.M.A. Jabbar J.D.L.C. Siopongco A. Tirol-Padre S.T. Amarante P.C. Sta Cruz W.C. Cosico 《Field Crops Research》2008
Water and nutrient availability are two major constraints in most rice-based rainfed shallow lowland systems of Asia. Both stresses interact and contribute to the low productivity and widespread poverty in this environment. The objective of this study was to improve the understanding of interaction between the two factors and to identify varietal characteristics beneficial for productivity in a water- and nutrient-limited rice environment. For this purpose, we screened 19 rice genotypes adapted to different rice environments under two water and two nutrient treatments during the wet season of 2004 and 2005 in southern Luzon, Philippines. Across all genotypes tested and in comparison with the irrigated control, rainfed conditions reduced grain yield of the treatment without N application by 69% in 2004 and by 59% in 2005. The mean nitrogen fertilizer response was highest in the dryer season of 2004 and the rainfed treatment, indicating that water stress had no effect on fertilizer response. Nitrogen application reduced the relative yield loss to 49% of the irrigated treatment in 2004 and to 52% of the irrigated treatment in 2005. Internal efficiency of N (IEN) and recovery efficiency of applied N (REN) were significantly different between genotypes, but were not affected by water availability (REN) or by water and nutrient availability (IEN). In contrast, grain yield and total N uptake were affected by cultivar, N and water availability. Therefore, germplasm for rainfed environments should be screened under conditions of limited and good nitrogen and water supplies. The four best cultivars, CT6510-24-1-2, IR55423-01, IR72, and IR57514-PMI5-B-1-2, performed well across all treatments and both years. Except for IR72, they were all characterized by medium height, medium duration, high early vigor, and a moderate level of drought tolerance. This combination of characteristics seems to enable the optimal use of limited water and nutrient resources occurring in many shallow rainfed lowlands. We also concluded that moderate drought stress does not necessarily affect the response to moderate N rates, provided that drought does not induce high spikelet sterility and that fertilizer N is properly managed. 相似文献
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稻麦周年不同秸秆还田方式对水稻产量及品质的影响 总被引：1，自引：0，他引：1
为探明淮北地区稻麦周年不同秸秆还田方式与模式对水稻产量及稻米品质的影响,通过大田大区试验,比较分析了在正常水肥管理下不同秸秆还田方式（旋耕、耕翻）与模式（双季秸秆均不还田、双季秸秆均还田、稻季秸秸秆还田、麦季秸秆还田）处理组合下优香粳的产量和品质。两年结果均显示,耕翻不还田处理下产量最低,在耕翻条件下,秸秆还田增产效应较为显著。产量构成分析表明,多数指标在秸秆还田方式与模式间均存在显著和极显著水平互作, 2020年试验穗质量、穗长、每穗粒数、一次枝梗数、二次枝梗数等指标在不同还田模式之间达到显著或极显著差异,均表现出秸秆还田处理优于不还田处理的趋势,耕翻条件下结实率明显高于旋耕处理。2020年不同处理间在垩白粒率、碱消值、直链淀粉含量、透明度以及RVA值间均存在显著或极显著差异。耕翻条件下垩白粒率明显低于旋耕。耕翻条件下直链淀粉含量稻还田、麦还田处理明显高于不还田处理,说明秸秆还田在一定程度上增加了直链淀粉含量,使得米饭不至过于软黏。RVA数据显示,旋耕不还田和耕翻麦还田处理下数值最优。说明还田模式的不同可能会影响到稻米的食味品质。 相似文献
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通过不同基蘖肥及穗肥施用量试验,研究在高产、品质及高产品质均衡条件下浙禾香2号的叶片含氮量、籽粒外观品质、营养品质及产量表现。结果表明,浙禾香2号倒4叶叶片含氮量随着基蘖肥用量提高而提高,倒1叶叶片含氮量随穗肥用量变化而变化;同样施氮量,穗肥用量对叶片含氮量影响更大;基蘖肥低氮条件下,不同处理营养品质及外观品质没有显著性差异,基蘖肥纯氮0.12 t/hm2以上,减施穗肥可以降低垩白粒率和蛋白质含量,提高直链淀粉含量;氮肥（纯N）0~0.24 t/hm2范围内,产量随施肥量的增加而提高,穗肥的施用对产量的影响较大,但减施穗肥能明显提高食味值。综合考虑品质与产量,浙禾香2号穗肥施用量以0.045 t/hm2为宜。 相似文献
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于2019年在浙东单季稻区2种不同类型土壤中开展了不同减氮模式下甬优1540产量和氮素利用率差异的田间试验。结果表明,与人工撒施肥处理相比,机械侧深施处理每穗粒数显著提高,稻谷平均增产3.0%~8.2%;氮肥减量20%（192 kg/hm2）,撒施条件下会导致水稻一定程度减产,但侧深施方式下可以保证水稻稳产并大幅提高氮肥利用率,平均产量达11.8 t/hm2,氮肥当季回收率、农学利用率和偏生产力分别达36.9%、15.0 kg/kg和61.7 kg/kg。因此,在浙东地区籼粳杂交稻甬优1540宜推广应用氮肥减量侧深施模式,肥料可为基肥和穗肥2次施用。 相似文献
19.
Identifying physiological traits associated with improved drought resistance in winter wheat 总被引：1，自引：0，他引：1
The association of specific target traits for drought resistance (early flowering, high accumulation of stem water soluble carbohydrate (WSC) reserves, presence of awns and high green flag-leaf area persistence) with yield performance under late-season drought was analyzed utilizing two doubled-haploid (DH) populations derived from crosses between Beaver × Soissons and Rialto × Spark in two seasons 2000/2001 and 2001/2002. The aim was to quantify associations between target traits and yield responses to drought, and to prioritize traits for drought resistance. Flowering time variation had a neutral effect on the absolute yield loss under drought, suggesting there may be a trade-off between water-saving behaviour in the shorter pre-flowering period with early flowering and a reduced capacity to access water associated with a smaller rooting system. The presence of awns also had a neutral effect on yield loss under drought amongst lines of the Beaver × Soissons population. The potential advantages of awns for increasing water-use efficiency and sensible heat transfer responsible for a cooler canopy appeared to be of less significance under moderate droughts in the UK than under severe droughts in other regions worldwide. The value of large stem soluble carbohydrate reserves for drought environments alone could not be confirmed in the UK environment. Stem WSC was positively associated with grain yield under both irrigation and drought. The genetic trait which showed the clearest correlation with the ability to maintain yield under drought was green flag-leaf area persistence. Averaged across years, the positive phenotypic correlation of this trait with yield under drought amongst DH lines of the Beaver × Soissons population (r = 0.49; p ≤ 0.001) indicated the potential use of this trait as a selection criterion for yield under drought. It is suggested that screens for this trait including marker-assisted selection would have value in future breeding programmes aimed at improving yields in high yielding, rainfed environments, but where drought can also be a problem, such as the UK. 相似文献
20.
In order to study selection indices for improving rice grain yield, a cross was made between an Iranian traditional rice (Oryza sativa L.) variety, Tarommahalli and an improved indica rice variety, Khazar in 2006. The traits of the parents (30 plants), F1 (30 plants) and F2 generations (492 individuals) were evaluated at the Rice Research institute of Iran (RRII) during 2007. Heritabilities of the number of panicles per plant, plant height, days to heading and panicle exsertion were greater than that of grain yield. The selection indices were developed using the results of multivariate analysis. To evaluate selection strategies to maximize grain yield, 14 selection indices were calculated based on two methods (optimum and base) and combinations of 12 traits with various economic weights. Results of selection indices showed that selection for grain weight, number of panicles per plant and panicle length by using their phenotypic and/or genotypic direct effects (path coefficient) as economic weights should serve as an effective selection criterion for using either the optimum or base index. 相似文献