Rice plant growth and yield: foliar application of plasma activated water

Plasma activated water(PAW)was prepared for 10 min to be applied one tofive times as a foliar spray to rice plants,to investigate plant growth,yield and the concentrations of total soluble protein and sugar in the rice grains produced.The results reveal that(1)the plant height,stem diameter,dry weight,chlorophyll and total carotene concentrations were improved by∼15%,∼25%,∼24%,∼47%and∼45%,respectively,with respect to control,(2)defense mechanisms of the plants treated with PAW were improved,(3)concentrations of total soluble protein and sugar were enhanced in the rice grains of PAW treated plants and(4)yield was increased by∼14%.

Chromatin-remodeling factor OsINO80 is involved in regulation of gibberellin biosynthesis and is crucial for rice plant growth and development

The phytohormone gibberellin（GA） plays essential roles in plant growth and development. Here,we report that OsINO80, a conserved ATP-dependent chromatin-remodeling factor in rice（Oryza sativa）, functions in both GA biosynthesis and diverse biological processes. OsINO80-knockdown mutants, derived from either T-DNA insertion or RNA interference, display typical GA-deficient phenotypes, including dwarfism, reduced cell length, late flowering, retarded seed germination and impaired reproductive development. Consistently, transcriptome analyses reveal that OsINO80 knockdown results in downregulation by more than two-fold of over 1,000 genes, including the GA biosynthesis genes CPS_1 and GA_3ox_2, and the dwarf phenotype of OsINO80-knockdown mutants can be rescued by the application of exogenous GA3. Chromatin immunoprecipitation（Ch IP） experiments show that OsINO80 directly binds to the chromatin of CPS1 and GA_3ox_2 loci. Biochemical assays establish that OsINO80 specially interacts with histone variant H_2A.Z and the H_2A.Z enrichments at CPS_1 and GA_3ox_2 are decreased in OsINO80-knockdown mutants. Thus, our study identified a rice chromatin-remodeling factor,OsINO80, and demonstrated that OsINO80 is involved in regulation of the GA biosynthesis pathway and plays critical functions for many aspects of rice plant growth and development.

Advanced Backcross QTL Analysis for the Whole Plant Growth Duration Salt Tolerance in Rice(Oryza sativa L.)

Salinity is a major factor limiting rice yield in coastal areas of Asia. To facilitate breeding salt tolerant rice varieties, the wholeplant growth duration salt tolerance（ST） was genetically dissected by phenotyping two sets of BC2F5 introgression lines（ILs） for four yield traits under severe natural salt stress and non-stress filed conditions using SSR markers and the methods of advanced backcross QTL（AB-QTL） analysis and selective introgression. Many QTLs affecting four yield traits under salt stress and nonstress conditions were identified, most（〉90%） of which were clustered in 13 genomic regions of the rice genome and involved in complex epistasis. Most QTLs affecting yield traits were differentially expressed under salt stress and non-stress conditions. Our results suggested that genetics complementarily provides an adequate explanation for the hidden genetic diversity for ST observed in both IL populations. Some promising Huanghuazhan（HHZ） ILs with favorable donor alleles at multiple QTLs and significantly improved yield traits under salt stress and non-stress conditions were identified, providing excellent materials and relevant genetic information for improving rice ST by marker-assisted selection（MAS） or genome selection.

Mining Applicable Elite Alleles of Growth Duration, Plant Height and Panicle Number per Plant by Conditional QTL Mapping in Japonica Rice

Unconditional and conditional QTL mapping were conducted for growth duration (GD), plant height (PH) and effective panicle number per plant (PN) using a recombinant inbred line (RIL) population derived from a cross between two japonica rice varieties Xiushui 79 and C Bao. The RIL population consisted of 254 lines was planted in two environments, Nanjing and Sihong, Jiangsu Province, China. Results showed that additive effects were major in all of QTLs for GD, PH and PN detected by the two methods, and the epistatic effects explained a small proportion of phenotypic variation. No interactions were detected between additive QTL and environment, and between epistatic QTL pairs and environment. After growth duration was adjusted to an identical level, RM80-160bp was detected as an applicable elite allele for PN, with an additive effect of 0.71. When effective panicle number per plant was adjusted to an identical level, RM448-240bp was detected as an applicable elite allele for GD, with an additive effect of 4.64. After plant height was adjusted to an identical level, RM80-160bp was detected as an applicable elite allele for PN, with an additive effect of 0.62, and RM448-240bp was detected as an applicable elite allele for GD, with an additive effect of 3.89. These applicable elite alleles could be used to improve target traits without influencing the other two traits.

Plant Growth Promoting Rhizobacteria as Biological Control Agent in Rice

The use of agrochemical products to combat diseases in crops has adverse effects on the environment and human health. Plant growth promoting rhizobacterium (PGPR) has been increasingly proposed as an eco-friendly alternative in agriculture. PGPRs have beneficial effects not only in promoting plant growth but also have shown their potential as biological control agent, being able to inhibit plant pathogens. Here, we investigated the use of PGPR Paraburkholderia sp. strain SOS3 to provide disease protection in rice (Oryza sativa L.). The antagonistic activity of SOS3 against five fungal pathogens of rice was assessed by dual culture on plates and on rice seedlings. The results showed that on plate assay, SOS3 inhibits the growth of Curvularia lunata, Rhizoctonia solani, Pyricularia oryzae, Helminthosporium oryzae, and Fusarium moniliforme by 17.2%, 1.1%, 8.3%, 32.5%, and 35.4%, respectively. When inoculated on rice seeds, SOS3 promotes seed germination and significantly reduces disease symptoms in plants infected with R. solani. These results suggest that SOS3 has a great potential to be used in rice agriculture to combat the “Sheath Blight” disease.

Mining Elite Alleles of Growth Duration and Productive Panicle Number per Plant by Association Mapping with Conditional Phenotypic Value in Japonica Rice

To provide genetic information and materials for breeding hybrid japonica rice with wide adaptability and strong competitive advantage of yield, elite alleles and their carrier varieties of growth duration （GD） and productive panicle number per plant （PN） were detected. A natural population composed of 94 japonica varieties was phenotyped for the GD, PN and plant height （PH） in two environments. The conditional phenotypic data were transferred by the linear model method in software QGAStation 1.0, and association mapping based on the unconditional and conditional phenotype values of GD and PN was analyzed by using general linear model in software TASSEL. A total of 34 simple sequence repeat （SSR） marker loci associated with GD and PN were detected in the two environments. Among them, 15 were associated with GD, and 19 were associated with PN. Four elite alleles of RM8095-120bp, RM7102-176bp, RM72-170bp and RM72-178bp were associated with GD, and their carrier varieties were Hongmangshajing, Nipponbare, Hongmangshajing and Nannongjing 62401, respectively. These elite alleles from the carrier varieties can shorten GD by 2.03-9.93 d when they were introduced into improved materials. RM72-182bp associated with PN was an elite allele, and its carrier variety was Xiaoqingzhong. It can increase PN by three when introduced into improved materials. Moreover, these elite alleles can be used to improve target traits without influencing another two traits.

Effect of plant growth regulator on rate of twin seedlings of rice with polyembryony

Rice with polyembryony characterized bytwin seedlings is a good genetic tool for apomixisresearch.A study on the effect of five plantgrowth regulators(IAA,KT,GA,2,4-D and6-BAP)on rate of twin seedlings in 3 rice varie.ties with polyembryony(Shuang 3,Shuang 13and Lu 52)was conducted.The results showed

Enhancement of Growth and Grain Yield of Rice in Nutrient Deficient Soils by Rice Probiotic Bacteria

Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly manner.In this study,rice associated bacteria were isolated and assessed for mineral phosphate solubilization and indole-3-acetic acid(IAA) production activity in vitro.Six promising strains,which were tentatively identified as phylotaxon Pseudochrobactrum sp.(BRRh-1),Burkholderia sp.(BRRh-2),Burkholderia sp.(BRRh-3),Burkholderia sp.(BRRh-4),Pseudomonas aeruginosa(BRRh-5 and BRRh-6) based on their 16 S rRNA gene phylogeny,exhibited significant phosphate solubilizing activity in National Botanical Research Institute phosphate growth medium,and BRRh-4 displayed the highest phosphate solubilizing activity,followed by BRRh-5.The p H of the culture broth declined,resulting in increase of growth rate of bacteria at p H 7,which might be due to organic acid secretion by the strains.In presence of L-tryptophan,five isolates synthesized IAA and the maximum IAA was produced by BRRh-2,followed by BRRh-1.Application of two most efficient phosphate solubilizing isolates BRRh-4 and BRRh-5 by root dipping(colonization) of seedling and spraying at the flowering stage significantly enhanced the growth and grain yield of rice variety BRRI dhan-29.Interestingly,application of both strains with 50% of recommended nitrogen,phosphorus and potassium fertilizers produced equivalent or higher grain yield of rice compared to the control grown with full recommended fertilizer doses,which suggests that these strains may have the potential to be used as bioinoculants for sustainable rice production.

Comparison of Effect of Brassinosteroid and Gibberellin Biosynthesis Inhibitors on Growth of Rice Seedlings

Brassinosteroid（BR） and gibberellin（GA） are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to investigate the roles of BR and GA in growth of rice seedlings. Yucaizol, a specific inhibitor of BR biosynthesis, and Trinexapac-ethyl, a commercially available inhibitor of GA biosynthesis, were used. The effect of Yucaizol on rice seedlings indicated that Yucaizol significantly retarded stem elongation. The IC_（50） value was found to be approximately 0.8 μmol/L. Yucaizol also induced small leaf angle phenocopy in rice seedlings, similarly to BR-deficient rice, while Trinexapac-ethyl did not. When Yucaizol combined with Trinexapac-ethyl was applied to the rice plants, the mixture of these two inhibitors retarded stem elongation of rice at lower doses. Our results suggest that the use of a BR biosynthesis inhibitor combined with a GA biosynthesis inhibitor may be useful in the development of new technologies for controlling rice plant height.

Efficacy of Bacillus subtilis MBI 600 Against Sheath Blight Caused by Rhizoctonia solani and on Growth and Yield of Rice

Rice sheath blight disease （ShB）, caused by Rhizoctonia solani, gives rise to significant grain yield losses. The present study evaluated the efficacy of Integral, the commercial liquid formulation of Bacillus subtilis strain MBI 600, against rice ShB and for plant growth promotion. In greenhouse studies, four log concentrations of Integral （from 2.2×10^6 to 2.2×10^9 cfu/mL） were used as seed treatment （ST）. After 25 d, seedlings were dipped （SD） into Integral prior to transplanting. At 30 d after transplanting （DAT）, leaf sheaths were inoculated with immature sclerotia of the pathogen. At 45 DAT, a foliar spray （FS） with Integral was applied to some treatments. The fungicide control was 50% carbendazim at 1.0 g/L, and a nontreated control was also included. Overall, there were 10 treatments, each with five replications. ShB severity was rated at 52 DAT, and seedling height and number of tillers per plant were rated at 60 DAT. In 2009, two field trials evaluated Integral at 2.2×10^8 and 2.2×10^9 cfu/mL. Integral was applied as ST, and seedlings were produced in a nursery bed. After 32 d, seedlings were treated with Integral as SD and transplanted into 10 m^2 blocks. Foliar sprays were given at 45 and 60 DAT. There were seven treatments, each with eight replications arranged as a factorial randomized complete block design. At 20 DAT, the plots were broadcast inoculated with R. solani produced on rice grains. Seedling height before transplanting, ShB severity at 90 DAT, and grain yield at harvest were recorded. Integral at 2.2×10^9 cfu/mL provided significant increase of seedling heights over other treatments under greenhouse conditions. The Integral treatments of ST ＋ SD ＋ FS at 2.2×10^9 cfu/mL significantly suppressed ShB over other treatments. In field studies, Integral provided significant increase of seedling height in nursery, and number of tillers per plant, compared with the control. ShB severity was significantly suppressed with higher concentrations of Integral compared to lower concentrations. Grain yield were the highest at an Integral concentration of 2.2×10^9 cfu/mL. Overall, Integral significantly reduced ShB severity, enhanced seedling growth, number of tillers per plant and grain yield as ST ＋ SD ＋ FS at the concentration of 2.2×10^9 cfu/mL under the conditions evaluated.

Effect of Growing Conditions of Rice Donor Plants on Anther Culture in Vitro

An experiment was conducted to find the effect of three types of donor plants growing conditions （growth chamber, open space ＋ growth chambers and open space） on callus induction and subsequent plant regeneration and productive shoot regeneration from the anthers culture in vitro of four rice hybrid （1-2, 2-1, 7-1, 13-3） developed by Primorsky Scientific Research Institute of Agriculture. Five variants of N6 medium （N6-I, N6-2, N6-3, Mix-l, N6-4） were used as basal medium. Mean value of callus induction frequency on three types of conditions ranged from 5.68% to 9.44% and the difference was non-significantly. In general, callus derived from donor plants grown on condition of open space ＋ growth chambers showed significantly better performances for plant regeneration （0.23 green regenerants on anther and 3.77 green regenerants on callus） and productive shoot regeneration （0.06 productive regenerants on anther and 0.56 productive regenerants on callus）. Favourable conditions for donor plant growth in open space positively affect on callus induction and regenaration. It is possible to get assured results on many hybrids, but not the highest. In growth chamber, frequency of callus induction can be the maximal only on some samples, few hybrids are resulted in deficiency of callus induction.

Characterization of Growth and Light Utilization for Rice Genotypes with Different Tiller Angles

Tiller angle is very important for plant architecture and canopy structure in rice （Oryza sativa L.）. Physiological and ecological characteristics of three rice genotypes with different tiller angle habits were compared in the paper. DI508, a genotype with changing tiller angle during the growth, has semi-erect tillers at early tillering stage, similar to genotype M09, and had erect tillers at late stage, similar to genotype 9308. In terms of dry biomass per plant, DI508 was consistently higher than those of M09 and 9308 throughout the growth. It was also a distinct difference of leaf area per plant that DI508 was larger than two others. From booting stage, DI508 and 9308 maintained higher photosynthetic ability of the topmost three leaves, while M09 showed rapid decline in photosynthesis during grain filling. It may be concluded that the genotype DI508 with dynamic tiller angle habit has a comprehensive advantage of fast growth and high weed competition at early stage and slow decline in photosynthesis at late stage.

干湿交替灌溉与植物生长调节剂对水稻光合特性及内源激素的影响

为探明干湿交替灌溉与植物生长调节剂(plant growth regulators, PGRs)对水稻光合特性、内源激素及产量的影响。采用盆栽与大田相结合方式,以龙粳31为试验材料,设置轻干湿交替灌溉(MI)和重干湿交替灌溉(HI)2种灌溉处理,于分蘖盛期和剑叶展叶期喷施已酸二乙氨基乙醇酯(diethylaminoethylcaproate,DA)、6-苄氨基腺嘌呤(6-benzylaminoadenine,BA)和BA(分蘖盛期)+DA(剑叶展叶期)3种PGRs,并设置清水对照,探究干湿交替灌溉、PGRs及互作下干物质积累、光合特性、内源激素及产量差异。结果表明,与HI相比, MI显著增加了抽穗后叶面积、叶面积指数、SPAD值及净光合速率,提高了剑叶与籽粒IAA、GA3和ZR含量,降低了ABA含量,增加了干物质积累及茎鞘物质转运能力,并在改善节间性状基础上增加了结实率、每穗粒数及粒重,增产5.30%(盆栽)和5.11%(大田)。与CK相比,喷施BA+DA显著提高了抽穗后剑叶净光合速率、干物质积累及茎鞘物质转运能力,提高了剑叶与籽粒IAA、GA3和ZR含量,增加了千粒重、结实率、收获指数、每穗粒数和粒重,增产6.60%(盆栽)和6.05%(大田),其次是BA。干湿交替灌溉与PGRs互作对叶面积指数、内源激素含量、每穗粒数及千粒重存在显著影响,其中MI×(BA+DA)处理更有助于维持抽穗后绿叶功能持续期,提高叶片SPAD值、叶面积、叶面积指数和净光合速率,增强干物质积累及茎鞘物质转运能力,提高叶片与籽粒IAA、GA3和ZR含量,促进同化物向籽粒输出,并在稳定穗数基础上增加了千粒重、每穗粒数和粒重,提高了结实率和收获指数,实现产量较其他处理及CK增幅3.17%~12.57%(盆栽)和3.14%~11.55%(大田),而HI×(BA+DA)处理可实现MI×CK产量效果。综上所述,干湿交替灌溉配合喷施BA+DA可作为本区域水稻高产高效生产环节中的一种节水化控栽培组合措施。

Involvement of Antioxidative Defense System in Rice Seedlings Exposed to Aluminum Toxicity and Phosphorus Deficiency

Plants growing in acid soils may suffer both phosphorus （P） deficiency and aluminum （Al） toxicity.Hydroponic experiments were undertaken to assess the single and combination effects of Al toxicity and low P stress on seedling growth,chlorophyll and proline contents,antioxidative response and lipid peroxidation of two rice genotypes （Yongyou 8 and Xiushui 132） differing in Al tolerance.Al toxicity and P deficiency both inhibited rice seedling growth.The development of toxic symptoms was characterized by reduced chlorophyll content,increased proline and malondialdehyde contents in both roots and leaves,and increased peroxidase and superoxide dismutase activities in roots,but decreased in leaves.The stress condition induced more severe growth inhibition and oxidative stress in Yongyou 8,and Xiushui 132 showed higher tolerance to both Al toxicity and P deficiency.P deficiency aggravated Al toxicity to plant growth and induced more severe lipid peroxidation.

Silicon Mediated Arsenic Reduction in Rice by Limiting Its Uptake

This study was planned to examine the effects of exogenous silicon supply on growth parameters and arsenic accumulation level in rice. The experiment was conducted in the wire house of Saline Agriculture Research Centre, Institute of Soil and Environmental Science, University of Agriculture Faisalabad. The study was comprised of treatments viz: control;(100 μM Arsenic);(200 μM Arsenic);(5 mM Silicon);(5 mM Silicon + 100 μM Arsenic) and (5 mM Silicon + 200 μM Arsenic). Results revealed that maximum shoot fresh weight, shoot dry weight, root fresh weight and root dry weight were observed in (5 mM Si) solution. In the same way, maximum number of tillers was also recorded in (5 mM Si) solution;while silicon application failed to alleviate arsenic concentration of rice genotype.

Potential of System of Rice Intensification (SRI) to Contribute to the Policy Objectives: Paradigm of Three-Tier Approach in Southern Telangana—A Case Study of Narayanpet

A programme effort for SRI impact assessment has been undertaken in 20 project villages in the Narayanpet block. The villages have been pooled under four clusters, for which quantitative and qualitative analyses have been carried out on water usage, input cost, plant growth, farmer group collectivization, gross and net returns of SRI, and conventional paddy cultivation. The result shows that significant water saving was achieved for SRI, i.e., 8586 m3∙ha−1 under tubewell irrigation over conventional. This approximation has served as an auxiliary to the number of pumping hours and number of irrigation days that have been reduced for SRI. Less utilisation of water and distance maintained in SRI has benefited in reducing the biotic and abiotic stress caused by snails and nutrient deprivation, respectively. The total yield for a sampled number of SRI farmers has been found to have a 22% increase for the total expenditure difference of Rs. 6153, i.e., 13% less than conventional paddy farmers, which highly impacts the SRI farmers’ net income, i.e., 69% more than the conventional returns. The SRI method has a lower labour deployment of 8 people/ha than the conventional method, which requires 16 people/ha with a constant price of Rs 250/person. Input cost saving in these two categories has ranked top and has fetched maximum production efficiency among the others. The seed cost at a fixed price of 32 Rs/kg was significantly (87%) reduced for SRI as 8 kg per ha was required rather than the conventional that required 62 kg/ha. Social benefits were listed based on the qualitative analysis and were transformed using the theory of planned behaviour.

不同外源物质及喷施时期对滩涂水稻穗部性状、产量及品质的影响

以南粳5055为供试品种,于2021年在江苏滩涂地区(土壤盐分1.11~1.26 g/kg)开展田间试验,研究不同外源物质及喷施时期(2次:分蘖期、孕穗期和3次:分蘖期、孕穗期、灌浆期)对滩涂水稻穗部性状及产量、品质的影响。试验设置7个处理,即喷施清水(CK)、禾稼春喷施2次(L1-2)、碧护喷施2次(L2-2)、萘乙酸喷施2次(L3-2)、禾稼春喷施3次(L1-3)、碧护喷施3次(L2-3)和萘乙酸喷施3次(L3-3)。结果表明,喷施外源物质具有提高水稻产量的效果,与CK相比,L2-2、L2-3、L3-2和L3-3分别显著提高产量17.69%、17.80%、11.62%和13.42%,L1-2和L1-3则分别提高产量6.66%和7.09%,但差异不显著;喷施外源物质对稻米品质影响不大。喷施外源物质对水稻有效穗数和结实率均没有明显影响,但显著增加实粒数;L1-2、L2-2、L1-3和L3-3处理显著增加每穗粒数,L2-2和L2-3处理显著增加千粒重。喷施外源物质对水稻一次枝梗的枝梗数、总粒数、实粒数和结实率没有显著影响,而对二次枝梗的枝梗数、总粒数、实粒数及结实率均有不同程度的增加效果,且二次枝梗对每穗粒数的贡献率普遍提高。对同一种外源物质而言,喷施2次和喷施3次对水稻产量、穗部性状的影响没有显著差异。碧护喷施处理提高水稻产量主要是由每穗粒数、每穗实粒数和千粒重提高引起的,萘乙酸喷施处理提高水稻产量主要是每穗粒数、每穗实粒数提高引起的,而每穗粒数的提高主要与二次枝梗数及二次枝梗的总粒数和实粒数增加有关。因此,今后在滩涂地区种植水稻,可通过在分蘖期和孕穗期喷施外源叶面肥或植物生长调节剂来改善穗粒结构特别是二次枝梗性状,达到增产增收的目的。

植物生长调节剂对优质粳稻产量、品质与光合特性的影响

为探究植物生长调节剂对优质粳稻光合特性、产量与品质的影响,以绥粳18、垦稻12和三江6为试验材料,研究剑叶展开期喷施脱落酸(ABA)、6-苄氨基腺嘌呤(6-BA)、己酸二乙氨基乙醇酯(DA-6)、亚精胺(Spd)、3-吲哚丁酸(IBA)、3,5-二硝基水杨酸(SA)、油菜素内酯(BL)、玉米素(ZT)、三十烷醇(TRIA)、茉莉酸甲酯(MeJA)和N6-呋喃甲基腺嘌呤(KT)对水稻产量、品质和光合特性的影响。结果表明:与对照(CK)相比,喷施BL提高了抽穗后水稻干物质积累和茎鞘物质转运能力,增加了每穗粒重、千粒重、结实率和粒叶比,两年平均增产7.61%;喷施6-BA有利于延长抽穗期至蜡熟期绿叶面积持续期,改善抽穗后光合特性,增加每穗粒数、每穗粒重、千粒重和粒叶比,两年平均增产6.40%;而喷施DA-6、ZT、ABA、Spd、IBA、SA和KT的增产效果存在品种和年份间稳定性差异。在品质上,喷施DA-6和ZT提高了精米率和整精米率,改善了稻米外观品质。综上,剑叶展开期喷施BL和6-BA有利于供试品种增产,而喷施DA-6和ZT则更有利于稳产或增产前提下提质。

多粘类芽胞杆菌新菌株X-11及其对番茄和水稻的促生效应

【目的】从小麦(Triticum aestivum L)根际筛选到了一株细菌菌株(编号X-11),为该菌株在植物促生上应用提供依据。【方法】结合形态特征、生理生化特性、16S rDNA序列及基因组测序对其进行了鉴定,并测定其对番茄(Solanum lycopersicum)和水稻(Oryza sativa)的促生效应。【结果】该菌株菌落圆形、半透明、凸起、黏稠;菌体杆状,形成芽胞,革兰氏阴性;具有固氮,还原硝酸盐,产吲哚、分泌铁载体及分解有机磷的功能。基于16S rDNA序列比对将X-11菌株归类为多粘类芽胞杆菌种群,基于非冗余蛋白数据库的基因比对表明其与最近缘菌株基因相似率55.7%,证明其为一个新菌株。X-11菌液浸种显著增加了番茄发芽率和胚根伸长度,灌根(R)及灌根结合叶面喷施(R+L)显著提高了番茄叶片中过氧化物酶(POD)活性,R+L处理使超氧化物歧化酶(SOD)活性提高了34.58%。水稻1叶1心期施用X-11菌液,根长增加了6.8%;立针期或1叶1心期施用X-11菌液,使秧苗SOD活性分别提高了90.4%和51.8%。【结论】X-11被鉴定为多粘类芽胞杆菌新菌株,是多种功能的植物根际促生菌,在植物促生方面具有开发应用潜力。

水稻籼粳中间型杂交组合若干性状的遗传效应分析

【目的】水稻籼粳亚种间杂交具有强大的杂种优势已成为当前水稻育种关注的焦点,本研究旨在为籼粳交水稻育种实践以及水稻关键性状的遗传研究提供理论依据。【方法】按照NC-II不完全双列杂交方式,选择14个亲本材料并配组48个杂交组合,采用植物数量性状的加性-显性遗传模型(A-D模型)分析生育期、株高与粒形相关性状等共计5个农艺性状的遗传效应、杂种优势及性状之间的相关性。【结果】籼粳亚种间杂交稻生育期、株高、粒长、粒宽及长宽比等的加性方差分量占遗传主效应比率(V_(A)/V_(P))比值分别为69.2%、 74.2%、 58.9%、66.0%和63.5%。广义遗传率(H^(2)B)和狭义遗传率(H^(2)N)的变幅分别为59.0%~99.6%和69.2%~98.9%,均达显著或极显著水平,主要受加性效应控制,且受环境影响小,在育种上早期选择有效。大多数的籼粳亚种间杂种一代的生育期、株高和粒形性状均呈负向中亲优势和负向超亲优势,杂交后代的生育期缩短、株高降低,长宽比介于双亲之间。籼粳亚种间杂交稻生育期是一个独立遗传的品种特性,株高与粒形具呈显著正相关。【结论】在籼粳交育种上应关注生育期、株高,粒形等性状间的协调,有效利用杂种优势,培育强优势亚种间杂交稻新组合。