Plant Type Traits Research Articles

Screening and Expression Characteristics of Plant Type Regulatory Genes in Salix psammophila

Salix psammophila is an important tree species adapted to sand-fixing afforestation in arid areas, and its different plant type characteristics can have different ecological functions. To identify the genes affecting the plant type of S. psammophila, this study used RT-qPCR and RNA-seq technology to establish a method for screening the candidate genes of the S. psammophila plant type based on the correlation coefficient of the crown–height ratio. We then screened out the gene combination that can best control the expression of the S. psammophila plant type. The results show the following: (1) The expression levels of the FHY1 and TAC2 genes were positively correlated with the crown–height ratio, whereas those of the ATX1, RFK1, PYL1, ABF2, SPA2, TB1, ZFP4, and LAZY1b genes were negatively correlated with the crown–height ratio. (2) The ATX1 + FHY1 gene combination had the greatest influence on the plant type traits of S. psammophila, and the correlation between the gene combination and the crown–height ratio reached 0.74. (3) The double- gene combination screening method improved the screening efficiency and accuracy, as well as the sensitivity and specificity, indicating certain universality. This strategy can be used for the determination of other plants or other traits, providing a theoretical basis for the directional breeding of forest trees.

Integrating hormones and transcriptome to explore the formation of dwarf and lateral buds in Capsicum

Plant type in pepper is an important morphological characteristic and reproductive basis, among which dwarfing and lateral buds are important traits of plant type. Significantly, the integrated analysis of metabonomics and transcriptome data helps to elucidate the key metabolites and genes in the formation of plant-type traits, which is helpful to understand the formation of target traits. However, relevant studies on pepper are still lacking. In the current study, three pepper cultivars with significant differences in the two traits were used, then, RNA-seq of stem tissues was performed based on a sequencing platform, and HPLC-LC-MS was used for metabolite determination. The results showed that the low content of key cytokines, gibberellin and high content of auxin may be the important factors causing plant dwarfing. Meanwhile, jasmonic acid may be an important metabolic factor affecting the trait of branches. Moreover, combined with metabolic pathway analysis and transcription factor analysis, a total of 131 candidate genes were obtained, which were involved in metabolite synthesis and affect the formation of two important plant-type traits. These findings provide data support for metabolic and molecular basis of trait formation and give guiding significance for the improvement of rational plant type.

Detection of Hub QTLs Underlying the Genetic Basis of Three Modules Covering Nine Agronomic Traits in an F2 Soybean Population

Deciphering the genetic basis underlying agronomic traits is of importance for soybean improvement. However, covariation, modulated by genetic correlations between complicated traits via hub QTLs, commonly affects the efficiency and accuracy of soybean improvement. The goals of soybean improvement have nearly all focused on agronomic traits, including yield, plant type traits, and seed-related traits especially. To decipher the hub QTLs of yield, plant type, and seed, nine pertinent traits of an F2 population (181 plants) derived from a cross between KeXin No.03 and JiDou 17, which were different in multiple traits such as plant height, seed protein, and 100-seed weight, were investigated with a high-density genetic map covering 2708.63 cM. A highly significant negative phenotypic correlation (−0.95) was found between seed protein (Pro) and seed oil (Oil). A total of 35 final QTLs after combining the ones closely linked physically were identified for eight traits explaining from 0.10% to 24.63% of the phenotypic variance explained (PVE) using composite interval mapping (CIM) and inclusive composite interval mapping (ICIM) procedures, and 13 QTLs were novel genes. A genomic region on chromosome 14 (qPro14, qOil14.2, and qSw14) was associated with three seed-related traits based on the relationship within and among the three trait modules. In addition, four genomic regions were detected as hub QTLs which linked to the seed-related module and plant-type model, including the E loci (E1 and E2). From the QTL results, 31 candidate genes were annotated, including the verified genes E1, E2, and QNE1, and they were grouped into three categories of biological processes. These results illustrate the genetic architecture as correlations among various soybean traits, and the hub QTLs should provide insights into the genetic improvement of complex traits in soybean.

Maize plant architecture trait QTL mapping and candidate gene identification based on multiple environments and double populations

BackgroundThe plant architecture traits of maize determine the yield. Plant height, ear position, leaf angle above the primary ear and internode length above the primary ear together determine the canopy structure and photosynthetic efficiency of maize and at the same time affect lodging and disease resistance. A flat and tall plant architecture confers an obvious advantage in the yield of a single plant but is not conducive to dense planting and results in high rates of lodging; thus, it has been gradually eliminated in production. Although using plants that are too compact, short and density tolerant can increase the yield per unit area to a certain extent, the photosynthetic efficiency of such plants is low, ultimately limiting yield increases. Genetic mapping is an effective method for the improvement of plant architecture to identify candidate genes for regulating plant architecture traits.ResultsTo find the best balance between the yield per plant and the yield per unit area of maize, in this study, the F2:3 pedigree population and a RIL population with the same male parent were used to identify QTL for plant height (PH), ear height (EH), leaf angle and internode length above the primary ear (LAE and ILE) in Changchun and Gongzhuling for 5 consecutive years (2016–2020). A total of 11, 13, 23 and 13 QTL were identified for PH, EH, LAE, and ILE, respectively. A pleiotropic consistent QTL for PH overlapped with that for EH on chromosome 3, with a phenotypic variation explanation rate from 6.809% to 21.96%. In addition, there were major consistent QTL for LAE and ILE, and the maximum phenotypic contribution rates were 24.226% and 30.748%, respectively. Three candidate genes were mined from the three consistent QTL regions and were involved in the gibberellin-activated signal pathway, brassinolide signal transduction pathway and auxin-activated signal pathway, respectively. Analysis of the expression levels of the three genes showed that they were actively expressed during the jointing stage of vigorous maize growth.ConclusionsIn this study, three consistent major QTL related to plant type traits were identified and three candidate genes were screened. These results lay a foundation for the cloning of related functional genes and marker-assisted breeding of related functional genes.

Correlation analysis of the transcriptome and metabolome reveals the role of the flavonoid biosynthesis pathway in regulating axillary buds in upland cotton (Gossypium hirsutum L.).

Flavonoids are involved in axillary bud development in upland cotton. The phenylpropanoid and flavonoid biosynthesis pathways regulate axillary bud growth by promoting the transport of auxin in upland cotton. In cotton production, simplified cultivation and mechanical harvesting are emerging trends that depend on whether the cotton plant type meets production requirements. The axillary bud is an important index of cotton plant-type traits, and the molecular mechanism of axillary bud development in upland cotton has not yet been completely studied. Here, a combined investigation of transcriptome and metabolome analyses in G. hirsutum CCRI 117 at the fourth week (stage 1), fifth week (stage 2) and sixth week (stage 3) after seedling emergence was performed. The metabolome results showed that the total lipid, amino acid and organic acid contents in the first stalk node decreased during axillary bud development. The abundance of 71 metabolites was altered between stage 2 and stage 1, and 32 metabolites exhibited significantly altered abundance between stage 3 and stage 2. According to the correlation analysis of metabolome and transcriptome profiles, we found that phenylpropanoid and flavonoid biosynthesis pathways exhibit high enrichment degrees of both differential metabolites and differential genes in three stages. Based on the verification of hormone, soluble sugar and flavonoid detection, we propose a model for flavonoid-mediated regulation of axillary bud development in upland cotton, revealing that the decrease in secondary metabolites of phenylpropanoid and flavonoid biosynthesis is an essential factor to promote the transport of auxin and subsequently promote the growth of axillary buds. Our findings provide novel insights into the regulation of phenylpropanoid and flavonoid biosynthesis in axillary bud development and could prove useful for cultivating machine-harvested cotton varieties with low axillary buds.

Transcriptome analyses provide insights into the homeostatic regulation of axillary buds in upland cotton (G. hirsutum L.)

BackgroundThe axillary bud is an important index of cotton plant-type traits, and the molecular mechanism of axillary bud development in upland cotton has not yet been reported. We obtained a mutant (designated mZ571) with a high-budding phenotype in axillary bud development from the low-budding phenotype variety G. hirsutum Z571 (CCRI 9A02), which provided ideal materials for the study of complex regulatory networks of axillary bud development. In this study, RNA sequencing was carried out to detect gene expression levels during three stages of axillary buds in Z571 (LB, low budding) and mZ571 mutant (HB, high budding).ResultsA total of 7162 DEGs were identified in the three groups (HB-E vs. LB-E, HB-G1 vs. LB-G1, HB-G2 vs. LB-G2), including 4014 downregulated and 3184 upregulated DEGs. Additionally, 221 DEGs were commonly identified in all three groups, accounting for approximately 3.09% of the total DEGs. These DEGs were identified, annotated and classified. A significant number of DEGs were related to hormone metabolism, hormone signal transduction, and starch and sucrose metabolism. In addition, 45, 22 and 9 DEGs involved in hormone metabolic pathways and 67, 22 and 19 DEGs involved in hormone signal transduction pathwayspathway were identified in HB-E vs. LB-E, HB-G1 vs. LB-G1, and HB-G2 vs. LB-G2, respectively, suggesting that endogenous hormones are the primary factors influencing cotton axillary bud growth. Hormone and soluble sugar content measurements revealed that mZ571 exhibited higher concentrations of zeatin, gibberellins and soluble sugar in all three stages, which confirmed that these hormone metabolism-, hormone signal transduction- and starch metabolism-related genes showed interaction effects contributing to the divergence of axillary bud growth between mZ571 and Z571.ConclusionsOur results confirmed the importance of endogenous hormones and sugars in the development of axillary buds, and we found that mZ571 plants, with a high-budding phenotype of axillary buds, exhibited higher endogenous hormone and sugar concentrations. Overall, we present a model for the emergence and development of cotton axillary buds that provides insights into the complexity and dynamic nature of the regulatory network during axillary bud emergence and development.

QTL mapping analysis of maize plant type based on SNP molecular marker

In this study, the elite maize inbred line (Zheng683-1) was used as a recurrent parent and the four maize inbred lines (ZPH1388, ZPH5, Dong 237 and Chang 7-2) were used as donor parents. The four F1 hybrids were produced by crossing between them and were continued backcrossing to the recurrent parent to produce four BC3F1s. The BC3F1 were pollinated by selfing four generations to generate the recombinant inbred lines (BC3F5) that showed variation in plant height, ear height, leaf angle. There were 53 lines for Zheng683-1 x ZPH1388, 53 lines for Zheng683-1 x ZPH5, 48 lines for Zheng683-1 x Dong237 and 61 lines for Zheng683-1 x Chang 7-2. The four populations were genotyped by using SNP marker and identified the QTLs of targeted traits by using QTL IciMapping V4.1 software and stepwise regression analysis. The main results are as follows:1. 19 additive QTLs and 2 dominant QTLs about plant height were detected in four introgression lines, and 7, 4, 5, 5 QTLs related plant height in ZPH1388-IL, ZPH5-IL, Dong237-ILand Chang7-2-IL. Among the 21 plant height QTLs, the largest contribution to phenotypic variation was QTLqPHa12 from Dong237-IL population, which evaluated 43.44% of the phenotypic variation of plant height . Followed by qPHa3 from ZPH1388-IL, the phenotypic contribution rate was 20% 2. Sixteen QTLs related ear height were detected in the population of the 4 introgression lines, of which there were 15 additive and 1 dominant QTLs. In addition, 9, 3, and 4 QTLs were detected in ZPH1388-IL, ZPH5-IL and Dong237-IL respectively. Among the 16 ear height QTLs, the largest contribution to phenotypic variation was QTL (qEHa1) from the ZPH1388 IL, which recorded the phenotypic variation of ear height by 26.01%. Next the phenotype contribution rates were 22.05% and 21.46%, respectively for qEHa13 and qEHa15 from Dong237-IL. Fourteen QTLs related leaf angle was detected in the population of the introgression lines, of which there were 5 additive QTLs and 9 dominant QTLs. Moreover, 2, 9, and 3 QTLs were detected in ZPH1388-IL, ZPH5-IL, Dong237-IL, respectively. Among the 14 leaf angle QTLs, the largest contribution to phenotypic variation was QTL (qLAa4) from the Dong237-IL then qLAa3 from ZPH5-IL, detecting the phenotypic variation of leaf angle of 28.56% and 24.08%, respectively.The results showed that the QTL locus was characterized by uneven chromosome distribution. The chromosome 1, 2, 5, and 7 are the regions with the QTL concentrated distribution of plant type traits. The QTL of plant type also showed QTL concentrated distribution in some regions of chromosomes. For example, there are three QTLs about plant height and ear height in the region of chromosome bin1.02, three QTLs about plant and ear heights, as well as leaf angle in the region of chromosome bin 2.02. These areas are QTL enrichment region (or the hot spots) of the pleiotropic gene loci related the plant type and ear traits.

New plant type trait characterization and development of core set among indica and tropical japonica genotypes of rice

AbstractThis study was conducted to characterize new plant type (NPT) traits among 650 genetically diverse rice genotypes of tropical japonica and indica and to establish an initial core set for NPT traits. Analysis of variance revealed highly significant differences among the genotypes for all the traits assessed except flag length and width and leaf angles. Dendrogram categorized the genotypes into five distinct duration groups. Genotypes viz., Pumphamah, IRGC5097, IRGC37015, IRGC43741, IRGC50448, IRGC53089, IRGC39111, IRGC18021, Haorei Machang, IRGC44069, IRGC8269, Thangmoi, IRGC33130 and IRGC29772 were identified as possessing strong culm. Long panicles with a length of more than 35 cm were found in IRGC8269, IRGC9147, IRGC14694, IRGC19642, IRGC27435, IRGC39111, IRGC31051, IRGC26011and IRGC25892. Ideal leaf angle of NPT genotypes of 5°, 10° and 20° of flag leaf, 1st and 2nd leaves was not found in any genotype but with a combination of 5°, 10° and 10° was observed in IRGC63102 and IRGC66644. NPT flag leaf length and width of 50 and 2 cm, respectively, was seen in ‘Kemenya Kepeu’ and ‘IRGC29772’. High grain number of more than 350 was observed in IRGC53089, IRGC31063 and Azhoghi. A total of 72 genotypes were found with a combination of one or more ideal plant type traits of which, hierarchical cluster analysis based on genetic distances selected 32 as NPT core set. This core set will serve as an ideal genetic resource for breeding programs aimed at NPT development.

Relation of Plant Type Traits with Fiber Yield and Quality in the Crossing Population of Mechanical-Harvested Cotton

Relation of Plant Type Traits with Fiber Yield and Quality in the Crossing Population of Mechanical-Harvested Cotton

Chromosome mapping, molecular cloning and expression analysis of a novel gene response for leaf width in rice

Genetic analysis revealed that narrow leaf, small panicle, thin and slender stems as well as low fertility rate of an Indica rice variety were recessive traits and controlled by a single gene. Applying map-based cloning strategy, a novel narrow leaf gene, which was named nal11 was delimited to an interval of 58.3 kb between the InDel markers N10 and InD5016. There are 9 genes in the mapping interval, and only a heat shock DNAJ protein encode gene (Os07g09450) has a specific G to T SNP, which was occurred at the last base of the second exon of Os07g09450 in ZYX. 5′ and 3′ RACE result shown that there were two transcripts in NAL11, and the SNP in nal11 leads to a variable shear of mRNA. In addition, this type of mRNA alternative splicing together with a stop codon closely followed the SNP which caused termination of translation destroyed the DNAJ domain of nal11’s product. These results suggested that the heat shock DNAJ gene was most likely to be the candidate gene of nal11. The results of RT-PCR and real-time PCR further verified that the SNP in the ZYX-nal11 gene affects mRNA splicing pattern. Phenotype of ZYX may be caused by a statistically significant reduction in the total number of small veins in leaf, size and number of small vascular bundles and cells in stems, similar to several previous reported mutations. The basic molecular information we provide here will be useful for further investigations of the physiological function of the heat shock DNAJ gene, which will be helpful in better understanding the role of the DNAJ family in regulation of plant type traits such as leaf width of rice.

Mapping a major QTL responsible for dwarf architecture in Brassica napus using a single-nucleotide polymorphism marker approach

BackgroundKey genes related to plant type traits have played very important roles in the “green revolution” by increasing lodging resistance and elevating the harvest indices of crop cultivars. Although there have been numerous achievements in the development of dwarfism and plant type in Brassica napus breeding, exploring new materials conferring oilseed rape with efficient plant types that provide higher yields is still of significance in breeding, as well as in elucidating the mechanisms underlying plant development. Here, we report a new dwarf architecture with down-curved leaf mutant (Bndwf/dcl1) isolated from an ethyl methanesulphonate (EMS)-mutagenized B. napus line, together with its inheritance and gene mapping, and pleiotropic effects of the mapped locus on plant-type traits.ResultsWe constructed a high-density single-nucleotide polymorphism (SNP) map using a backcross population derived from the Bndwf/dcl1 mutant and the canola cultivar ‘zhongshuang11’ (‘ZS11’) and mapped the dwarf architecture with the down-curved leaf dominant locus, BnDWF/DCL1, in a 6.58-cM interval between SNP marker bins M46180 and M49962 on the linkage group (LG) C05 of B. napus. Further mapping with other materials derived from Bndwf/dcl1 narrowed the interval harbouring BnDWF/DCL1 to 175 kb in length and this interval contained 16 annotated genes. Quantitative trait locus (QTL) mappings with the backcross population for plant type traits, including plant height, branching height, main raceme length and average branching interval, indicated that the mapped QTLs for plant type traits were located at the same position as the BnDWF/DCL1 locus.ConclusionsThis study suggests that the BnDWF/DCL1 locus is a major pleiotropic locus/QTL in B. napus, which may reduce plant height, alter plant type traits and change leaf shape, and thus may lead to compact plant architecture. Accordingly, this locus may have substantial breeding potential for increasing planting density.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0865-6) contains supplementary material, which is available to authorized users.

Population Characteristics of High‐Yielding Rice under Different Densities

To explore the common characteristics of high‐yield rice (Oryza sativa L.) production and the influence of transplanting density on yield, field experiments were conducted in eight ecological zones with local popular high‐yield rice varieties in China in 2009. This study revealed that different ecological types of rice exhibit robust differences in growth stage, yield composition, source, sink, grain/leaf ratio, plant type traits, and dry matter (DM) accumulation and partitioning. The different ecological types of rice displayed the following common features: (i) grain yield was correlated with sink such that larger sink was always associated with larger yield; (ii) DM accumulation before and after the heading stage showed large variation in contribution to yield regardless of DM accumulation enhancement, especially for postheading accumulation, which was beneficial for increasing yield; and (iii) under the suitable seedling population (36 seedlings m−2 or 25 seedlings m−2), wide rows with narrow within‐row plant spacing was conducive for building high‐yield populations. Overall, transplanting density and ecological site both have significant effects on rice yield, source‐sink relationship, and DM accumulation.Core Ideas Yield was closely correlated with sink such that larger sink was always associated with higher yield. The dry matter accumulation before and after the heading stage had enormous variation in contribution to yield regardless of the dry matter accumulation enhancement, especially the yield of postheading accumulation, which was beneficial for increasing yield. Under the suitable seedling population, wide rows and narrow within‐row plant spacing was conducive for building high‐yield populations to improve the yield.

Analysis of combining ability in white seeded genotypes of maize (Zea mays L.)

The present investigation consisted of 45 hybrids alongwith 18 parents and four checks viz., Arawali Makka-1, Mahi Kanchan, Navjot and PEHM-2 a total 67 entries was conduted during Kharif 2002 in Randomised Block Design having three replications. The data were recorded on fourteen traits to study general and specific combining ability effects. In general inbred lines L 1 , L 3 , L 11 and L 15 were considered good general combiner for yield and yield contributing traits as well as for quality traits. Among the testers, the tester T 2 was considered good general combiner for maturity traits, plant type traits, harvest index and starch content. Majority of the hybrids exhibited significant positive values for yield and yield contributing traits as well as quality traits. Thereby, indicating that for these traits the genes with positive effects were dominent. The variance due to lines was of greater magnitude than that of testers for most of the traits. The ratio of 6 2 sca/6 2 gca indicated prependerance of non-additive variance for most of the traits. Parental lines L 1 , L 3 , L 11 and L 15 were found to be good general combiners for grain yield per plant as well as for other traits. Hybrid L 12 x T 1 exhibited maximum significant positive sca effects for grain yield per plant. While the hybrid L 2 x T 1 exhibited highest estimates of significant positive sca effects for starch content. In general, there is a close association between sca effects, relative heterosis and per se performance for grain yield per plant was observed among the best hybrid identified on the basis of sca effects.

Comparisons of plant-type characteristics and yield components in filial generations of Indica × Japonica crosses grown in different regions in China

Ideotype breeding plays a significant role in increasing rice yields. A number of representative plant-type models have been developed based on environmental conditions and yield potential. Identifying the effects of the ecological environment on plant-type models will provide insight into rice ideotype breeding, and will be useful to optimize cultivation management. The aim of this study was to analyze the effects of different ecological conditions on plant-type traits and yields, and to identify the relationships between plant-type models and yield components in different ecological environments. Two populations of filial generations Indica×Japonica rice were grown in Liaoning, Sichuan, Shanghai, and Guangdong in 2012. The grain yield showed a downward trend from high latitude to low latitude. The traits of the plant-types differed markedly among the four regions. Plant height was significantly greater in Sichuan and Liaoning than in Shanghai and Guangdong. Based on panicle length, the four regions were ranked as follows (longest panicle length to shortest) Shanghai>Sichuan>Guangdong>Liaoning. For flag leaf length, the ranking order was as follows (longest to shortest): Shanghai>Guangdong>Sichuan>Liaoning; for flag leaf width (widest to narrowest): Sichuan>Liaoning>Shanghai>Guangdong. The flag leaf angle was larger in Liaoning and Guangdong than in Shanghai and Sichuan. Panicle curvature was significantly influenced by genetic factors. The long-flag-leaf, curved-panicle type with characteristics of the super hybrid plant-type model showed significant vigor in Guangdong, Sichuan, and Shanghai. The short-flag-leaf, erect-panicle plant-type was more adaptable to the environmental conditions in Liaoning. There were strong correlations between some plant-type traits and yield components. However, the strengths and directions of the correlations were not completely consistent because of the different populations in different ecological environments. In ideotype breeding practice, the criteria should be regionalized based on local climatic and cultivation conditions. Such breeding should consider not only traits of “space”, but also specific geoecotypes.

Characteristics of Plant Type Traits and Subspecies Characteristics in F 2 Generations of Cross between Indica and Japonica Rice under Different Ecological Regions

Two F2 populations,one derived from the cross between Wanlun 422(indica) and Shennong 265(japonica) named as F2-A,the other derived from the cross between Luhui 99(indica) and Shennong 265(japonica) named as F2-B,were grown in Liaoning and Sichuan to analyze the effect of ecological environments on subspecies characteristics and their relationships with plant type traits.The result showed that subspecies characters in F2 generations were continuously varied in different environ-ments.Two populations were generally normal distribution in Sichuan,but obviously indica-like in Liaoning.The effects of en-vironment on six traits of Cheng's index were incompletely consistent.The ecological conditions had a significant effect on plant type traits.The plant height and panicle curvature increased significantly,but the panicle length,flag leaf length,flag leaf width,and leaf angle decreased in Sichuan.Plant height in different subspecies had no obvious regularity in different regions.Flag leaf length was longer in indica(H) than in other types,but flag leaf angle had no significant difference in different subspecies and environments.Flag leaf width was changed with the cross combinations.Generally,panicle length reduced,but panicle curvature increased progressively from indica(H) to japonica(K) type.The subspecies characteristics were certainly related with plant type traits,but the correlation between them was not consistent in different cross combinations and environments.

Establishment of a Quantitative Evaluation Method of Rice Plant Type Using P-type Fourier Descriptors

To evaluate rice plant type precisely at the seedling stage, we established a quantitative evaluation method using an image analysis. P-type Fourier descriptors, which could apply an “open-curve”, were used for the plant type, and the coefficients were summarized as the scores of principal components (PCs) by principal component analysis. At the same time, “conventional plant type traits”, leaf blade length, leaf blade angle and inter-leaf-blade length, were measured by traditional plant type measurement methods. Based on the PC scores, the plant type for each PC was reconstructed by inverse Fourier transformation and the morphological characteristics were evaluated. To examine whether our method could appropriately identify the characteristics of the varieties, we discriminated the varieties using the PC scores by support vector machines. The varieties were also discriminated using the conventional traits of plant type. The results indicated that both traits had equal discrimination efficiency. In addition, the combination of conventional traits and scores had the highest discrimination efficiency. The relationship between the PC scores and conventional traits was examined by multiple regression analysis. The PC scores were not correlated with size-related traits. From these results, our research clarified that a plant type evaluation method using P-type Fourier descriptors could evaluate rice plant type precisely combined with conventional methods.

Clustered QTL for source leaf size and yield traits in rice (Oryza sativa L.)

Improvement of plant type plays an important role in super-high yield breeding in rice (Oryza sativa L.). In the present study, a set of backcross recombinant inbred lines derived from a cross of 9311 and Zhenshan97, both elite indica hybrid parents, were developed to identify quantitative trait loci (QTL) for flag leaf size, panicle and yield traits. Forty-seven QTL for 14 traits were detected in common in the two environmental trials, of which nine genomic regions contained clustered QTL affecting plant type traits and yield traits. Four co-localized QTL on chromosomes 1, 6, 7 and 8 involving QTL for flag leaf size (flag leaf length, width and area) contained the QTL for yield traits such as panicle weight (PW) and secondary branch number (SBN), and in all cases alleles from 9311 increased source leaf size and were associated with increased sink size and yield (SBN and PW). Using a subset of overlapping substitution lines for the QTL region on chromosome 1, the QTL were validated and narrowed into a 990 kbp interval (RM3746–RM10435) with pleiotropic effects on flag leaf size, PW, SBN and spikelet number per panicle. These QTL clusters with large effects on source leaf size and yield-related traits provide good targets for marker-assisted breeding for plant type improvement and high-yield potential in rice.

Relationship Between Plant Type and Grain Quality of Japonica Hybrid Rice in Northern China

Abstract Plant type and grain quality are two major aspects in rice breeding. Using canonical correlation analysis and canonical redundancy analysis, the relationship between plant type traits and rice grain quality traits was studied with 100 crosses derived from 10 sterile lines × 10 restorer lines. There was a complex relationship between parts of the traits of the two aspects. The angle of the 2 nd leaf from the top and single panicle weight played important roles in plant type system and amylose content and grain length in grain quality system. The angle of the 2 nd leaf from the top, plant height and single panicle weight had a great effect on grain quality traits, and amylose content, brown rice rate and translucency were easily influenced by plant type traits. Selection index model indicated that japonica hybrid rice in Northern China with good quality was characterized by broad flag leaf and 2 nd leaf from the top, narrow and short 3 rd leaf from the top, low plant height, short culm, long and more panicles and low single panicle weight.

Gene mapping of brachytic stem and its effects on yield-related traits in soybean

Plant height, determinate growth habit, and brachytic stem are 3 major plant-type traits of soybean. In this report, a population of 151 recombinant inbred lines (RILs) derived from the cross of Bogao (high stature, indeterminate growth habit, and normal stem) and Nannong 94-156 (short stature, determinate growth habit, and brachytic stem) was used to map genes and quantitative trait loci (QTLs) for 3 plant-type traits and to reveal the effects of brachytic stem on yield-related traits including seed yield, apparent biological yield, apparent harvest index, plant height, and days to maturity. The results indicated that brachytic stem (sb) and determinate growth habit (dt1) were mapped on linkage groups B2 and L, respectively. Two major QTLs related to plant height were detected and mapped on linkage group L near dt1, and 0.6 cM above the Sb locus on linkage group B2 across 2 years. These 2 QTLs explained 15.1% and 52.7% of the phenotypic variation, and decreased plant height by 9.2 and 17.6 cm, respectively. It was found that only one QTL was detected and mapped on linkage group L near dt1 across 2 years. Lines with brachytic stem had shorter plant height, lower biomass, yield, and harvest index, and essentially no differences in days to maturity when compared with normal stem lines.

Molecular Marker‐Assisted Dissection of Genotype × Environment Interaction for Plant Type Traits in Rice (Oryza sativa L.)

A doubled haploid (DH) population of 123 lines from IK64/Azucena was used to analyze the genotype × environment (GE) interaction for eight plant type traits in rice (Oryza sativa L.). The total genetic effects were partitioned into genetic main effects and GE interaction effects. These two kinds of predicted effects were used in mapping quantitative trait loci (QTLs). Four to nine QTLs affecting different plant type traits were detected. Results indicated that all common QTLs detected in both environments were controlled by genetic main effects and some also by GE interaction effects. Some genomic regions identified significant QTL in only one environment; some also showed genetic main effects. Those QTLs with genetic main effects could be used in marker‐assisted selection across environments. For some other map regions, QTLs were controlled by only GE interaction effects without genetic main effects. Those QTLs could be included in marker‐assisted selection only for specific environments. In most cases, the pairs of traits with a high genetic correlation shared more common QTL regions than those pairs of traits with a lower genetic correlation.