Genetic Control Of Plant Height Research Articles

Genetic control of plant height in corn lines in diallel crosses

The article presents the results of a study of corn hybrids cultivated in diallelic crosses (p(p+1)/2) according to the trait “plant height”. The experiment included 11 self-pollinated lines (method 2, model 1) and 55 hybrids. As a result of the research, the height of plants in parental lines and F1 hybrids was determined (a total of 3960 measurements were made), the effects of TCA and SCA dispersion, the level of heterosis were calculated, and the genetic components that control the manifestations of the studied trait were determined. The highest plant heights were in the lines SPK 13, SPK 14, SPK 17, SPK 21. Relatively high group average values of plant heights of hybrids were found with the lines SPK 14, SPK 18, SPK 17, SPK 16. A high effect of TCA and a high dispersion of SCA were determined in the line SPK 14. High effects of SCA were detected in combinations with the lines SPK 14, SPK 12, SPK 16. True heterosis of more than 20% was determined in 45 hybrids in 2017 and in 9 hybrids in 2018. Adequacy of the additive-dominant model in 2017. obtained by excluding the lines SPK 13, SPK 14, SPK 15, SPK 17 from the calculations. In 2018, the non-allelic effect of genes was not determined. The experiment established that control of plant height in the model population was carried out by at least 5 genes or groups of genes in 2017 and 9 genes in 2018.

BREEDING AND GENETIC FEATURES OF SOYBEAN VARIETIES BASED ON THE MANIFESTATION OF TRAITS IN F1 HYBRIDS IN TOPCROSSES

Further increase in gross soybean production requires the introduction of new varieties with an optimal combination of elements of the crop structure. Hybridization in soybeans is the main effective method of creating new varieties. Increasing the efficiency of hybridization in obtaining heterotic offspring is possible when using parental forms with high combinational ability in crosses. In the study, a two-tester analysis of topcrosses of soybean varieties differing in economically valuable traits was used. Based on the results of the combinational ability assessment, the value of soybean varieties was determined by the elements of the yield structure. Heterotic combinations in first-generation hybrids were identified, from which it is more likely to select highly productive forms in later hybrid populations F2-F4. The high effects of ZKZ and SCZ on plant height in varieties Medea, Kyivska 97, Sawyer 2-95 and KiVin tester; on the height of lower bean attachment in varieties Sawyer 2-95, Ustia, Kharkivska skoroglya and KiVin tester; on the number of productive nodes - in varieties Kyivska 97 and Goverla tester; by the number of beans per plant - in varieties Sawyer 2-95, Kyivska 97 and tester Goverla; by the number of seeds per plant - in varieties Medea, Kyivska 97 and tester KiVin; by the weight of 1000 seeds - in varieties Sawyer 2-95, Kyivska 97 and tester Goverla; by the weight of grain per plant - in varieties Sawyer 2-95, Kyivska 97 and tester Goverla. It was found that additive effects of genes were predominant in the genetic control of plant height and lower bean attachment, elements of yield structure and grain weight per plant, but there is a smaller influence of non-additive effects. The manifestation of true heterosis (dominance in 100% of cases) in hybrids (F1) was found in crosses with both testers for the number of productive nodes, number of beans and seeds per plant, and grain weight per plant.

INHERITANCE OF PLANT HEIGHT IN EINKORN WHEAT BY RESULTS OF SEGREGATION ANALYSIS

The genetic control of plant height – important trait associated with yield – is practically not studied in diploid wheats. In this paper, using reciprocal crosses between two Triticum monococcum accessions – var. monococcum (UA0300311) and var. nigricultum (UA0300282) in autumn and spring sowing, inheritance of the plant height is studied. The sowing period significantly affects the expression of einkorn plant height. Data from the generations P1, P2, F1, F2 were used for segregation analysis. For a combination of UA0300311 × UA0300282, the optimal models for plant height inheritance are: at autumn sowing – one main gene with a negative complete dominant effect, its additive effect is –8.05; at spring sowing – one main gene with an additive-dominant effect, its additive effect is –24.51. For the reciprocal combination UA0300282 × UA0300311, at autumn sowing, the optimal model of plant height was one main gene with an equal additive-dominant effect, it additive effect is 10.94; at spring sowing – one main gene with a negative complete dominant effect, its additive effect is –18.37. The heritability was in all cases from 96.52% to 99.70%. The high dispersion of the trait in the second hybrid generation suggests that the studied parental forms differ not only in the main gene, as follows from the results of segregation analysis, but also in the system of modifier genes with a weak effect.

The miR166 mediated regulatory module controls plant height by regulating gibberellic acid biosynthesis and catabolism in soybean.

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play critical roles in regulating plant growth and development. Here, we used Short Tandem Target Mimic (STTM) technology to generate soybean (Glycine max (L.) Merr.) miRNA knockdown lines and identify miRNAs that regulate plant height, a key agronomic trait that affects yield. STTM166 successfully silenced miR166 in soybean and upregulated the expression of miR166 target genes, such as ATHB14-LIKE. The miR166 knockdown lines (GmSTTM166) displayed a reduced plant height phenotype. Moreover, GmSTTM166 plants contained lower levels of bioactive gibberellic acid (GA3) than wild-type plants, and application of exogenous GA partially rescued the dwarf phenotype of GmSTTM166. Knockdown of miR166 altered the expression of genes involved in GA biosynthesis and catabolism. Further analysis revealed that ATHB14-LIKE directly represses transcription of the GA biosynthesis genes GmGA1 and GmGA2, while activating transcription of the GA catabolic gene GIBBERLLIN 2 OXIDASE 2 (GmGA2ox2). Collectively, these results reveal a pivotal role for miR166 in the genetic control of plant height in soybean, thereby providing invaluable insights for molecular breeding to improve soybean yield.

Genome-wide association study dissects the genetic control of plant height and branch number in response to low-phosphorus stress in Brassica napus.

Oilseed rape (Brassica napus) is one of the most important oil crops worldwide. Phosphorus (P) deficiency severely decreases the plant height and branch number of B. napus. However, the genetic bases controlling plant height and branch number in B. napus under P deficiency remain largely unknown. This study aims to mine candidate genes for plant height and branch number by genome-wide association study (GWAS) and determine low-P-tolerance haplotypes. An association panel of B. napus was grown in the field with a low P supply (P, 0 kg ha-1) and a sufficient P supply (P, 40 kg ha-1) across 2 years and plant height and branch number were investigated. More than five million single-nucleotide polymorphisms (SNPs) were used to conduct GWAS of plant height and branch number at two contrasting P supplies. A total of 2127 SNPs were strongly associated (P < 6·25 × 10-07) with plant height and branch number at two P supplies. There was significant correlation between phenotypic variation and the number of favourable alleles of associated loci on chromosomes A10 (chrA10_821671) and C08 (chrC08_27999846), which will contribute to breeding improvement by aggregating these SNPs. BnaA10g09290D and BnaC08g26640D were identified to be associated with chrA10_821671 and chrC08_27999846, respectively. Candidate gene association analysis and haplotype analysis showed that the inbred lines carrying ATT at BnaA10g09290Hap1 and AAT at BnaC08g26640Hap1 had greater plant height than lines carrying other haplotype alleles at low P supply. Our results demonstrate the power of GWAS in identifying genes of interest in B. napus and provided insights into the genetic basis of plant height and branch number at low P supply in B. napus. Candidate genes and favourable haplotypes may facilitate marker-based breeding efforts aimed at improving P use efficiency in B. napus.

Identification and Fine-Mapping of Quantitative Trait Loci Controlling Plant Height in Central European Winter Triticale (×Triticosecale Wittmack).

The quantitatively inherited trait plant height is routinely evaluated in triticale breeding programs as it substantially influences lodging and disease susceptibility, is a main contributor to biomass yield, and is required to improve hybrid seed production by fine-tuning plant height in the female and male parental pools in hybrid breeding programs. In this study, we evaluated a panel of 846 diverse Central European triticale genotypes to dissect the genetic architecture underlying plant height by genome-wide association mapping. This revealed three medium- to large-effect QTL on chromosomes 5A, 4B, and 5R. Genetic and physical fine-mapping of the putative QTL revealed that the QTL on chromosome 5R most likely corresponds to Ddw1 and that the QTL on chromosome 5A is likely to be Rht12. Furthermore, we observed a temporal trend in registered cultivars with a decreasing plant height during the past decades, accompanied by an increasing use of the height-reducing alleles at the identified QTL. In summary, our results shed new light on the genetic control of plant height in triticale and open new avenues for future improvement by breeding.

Deciphering the Genetic Architecture of Plant Height in Soybean Using Two RIL Populations Sharing a Common M8206 Parent.

Plant height (PH) is an important agronomic trait that is closely related to soybean yield and quality. However, it is a complex quantitative trait governed by multiple genes and is influenced by environment. Unraveling the genetic mechanism involved in PH, and developing soybean cultivars with desirable PH is an imperative goal for soybean breeding. In this regard, the present study used high-density linkage maps of two related recombinant inbred line (RIL) populations viz., MT and ZM evaluated in three different environments to detect additive and epistatic effect quantitative trait loci (QTLs) as well as their interaction with environments for PH in Chinese summer planting soybean. A total of eight and 12 QTLs were detected by combining the composite interval mapping (CIM) and mixed-model based composite interval mapping (MCIM) methods in MT and ZM populations, respectively. Among these QTLs, nine QTLs viz., QPH-2, qPH-6-2MT, QPH-6, qPH-9-1ZM, qPH-10-1ZM, qPH-13-1ZM, qPH-16-1MT, QPH-17 and QPH-19 were consistently identified in multiple environments or populations, hence were regarded as stable QTLs. Furthermore, Out of these QTLs, three QTLs viz., qPH-4-2ZM, qPH-15-1MT and QPH-17 were novel. In particular, QPH-17 could detect in both populations, which was also considered as a stable and major QTL in Chinese summer planting soybean. Moreover, eleven QTLs revealed significant additive effects in both populations, and out of them only six showed additive by environment interaction effects, and the environment-independent QTLs showed higher additive effects. Finally, six digenic epistatic QTLs pairs were identified and only four additive effect QTLs viz., qPH-6-2MT, qPH-19-1MT/QPH-19, qPH-5-1ZM and qPH-17-1ZM showed epistatic effects. These results indicate that environment and epistatic interaction effects have significant influence in determining genetic basis of PH in soybean. These results would not only increase our understanding of the genetic control of plant height in summer planting soybean but also provide support for implementing marker assisted selection (MAS) in developing cultivars with ideal plant height as well as gene cloning to elucidate the mechanisms of plant height.

Quantitative trait loci associated with short inter-node length in soybean.

Manipulating the genetic control of plant height is essential in soybean breeding to increase yield through the enlargement of the plant size while preventing lodging. A Japanese soybean germplasm, Y2, has distinctively shorter inter-node lengths than those of recently developed Japanese cultivars and is expected to provide new variation to prevent lodging. A quantitative trait loci (QTL) analysis for plant height-related traits was conducted using F2 individuals derived from a cross between the elite Japanese cultivar Fukuyutaka and Y2. A major QTL for average inter-node length (AIL) and plant height was identified on chromosome 13 and named qSI13-1 (QTL for short inter-node on chromosome 13). The Y2 allele of qSI13-1 was partially dominant for plant height. qSI13-1 exhibited no effect on either days to flowering or number of main stem nodes. The AILs and plant heights of the near-isogenic lines containing the Y2 allele of qSI13-1 in the genetic background of Fukuyutaka were significantly less than those of Fukuyutaka. No significant differences between the near-isogenic lines and Fukuyutaka were observed for seed yield and flowering date, indicating that qSI13-1 will be useful in developing cultivars with short plant heights without having negative effects on yield potential and days to flowering.

Genetic analysis of agro-morphological traits in promising hybrids of sunflower (Helianthus annuus L.)

The main objective underlying sunflower breeding programs is to develop high-yielding productive F1 hybrid cultivars. This study was conducted to investigate the genetic control of some agro-morphological traits of new sunflower F1 hybrids. For this purpose, fourteen inbred lines of sunflower were crossed with three male sterile inbred lines. Their hybrids (14 hybrids) were then evaluated against three control cultivars. The data thus obtained were analyzed using the nested model (North Carolina Design І) as a completely randomized block design (CRBD) with four replications. Analysis of variance showed that the hybrids were significantly different in all the traits studied, except for head and stem diameters. From among the hybrids evaluated, Cms19 × Rn1-81 was found to have the highest seed yield and oil content. Cluster analysis classified the hybrids into four different groups. Genetic analysis showed that days to maturity, seed weight, and oil content (%) were under the additive gene action. Breeding strategies based on selection could be suggested for the improvement of these traits. Head angle, head diameter, seed yield, and oil yield were under the dominance gene action; breeding based on hybridization methods is, therefore, proposed for these traits. Finally, both additive and dominance gene actions were observed to play important roles in the genetic control of plant height and stem diameter.

Genetic control of plant height in European winter wheat cultivars.

Plant height variation in European winter wheat cultivars is mainly controlled by the Rht - D1 and Rht - B1 semi-dwarfing genes, but also by other medium- or small-effect QTL and potentially epistatic QTL enabling fine adjustments of plant height. Plant height is an important goal in wheat (Triticum aestivum L.) breeding as it affects crop performance and thus yield and quality. The aim of this study was to investigate the genetic control of plant height in European winter wheat cultivars. To this end, a panel of 410 winter wheat varieties from across Europe was evaluated for plant height in multi-location field trials and genotyped for the candidate loci Rht-B1, Rht-D1, Rht8, Ppd-B1 copy number variation and Ppd-D1 as well as by a genotyping-by-sequencing approach yielding 23,371 markers with known map position. We found that Rht-D1 and Rht-B1 had the largest effects on plant height in this cultivar collection explaining 40.9 and 15.5% of the genotypic variance, respectively, while Ppd-D1 and Rht8 accounted for 3.0 and 2.0% of the variance, respectively. A genome-wide scan for marker-trait associations yielded two additional medium-effect QTL located on chromosomes 6A and 5B explaining 11.0 and 5.7% of the genotypic variance after the effects of the candidate loci were accounted for. In addition, we identified several small-effect QTL as well as epistatic QTL contributing to the genetic architecture of plant height. Taken together, our results show that the two Rht-1 semi-dwarfing genes are the major sources of variation in European winter wheat cultivars and that other small- or medium-effect QTL and potentially epistatic QTL enable fine adjustments in plant height.

Dissection of the genetic architecture underlying the plant density response by mapping plant height-related traits in maize (Zea mays L.).

Plant height is one of the most heritable traits in maize (Zea mays L.). Understanding the genetic control of plant height is important for elucidating the molecular mechanisms that regulate maize development. To investigate the genetic basis of the plant height response to density in maize, we evaluated the effects of two different plant densities (60,000 and 120,000 plant/hm(2)) on three plant height-related traits (plant height, ear height, and ear height-to-plant height ratio) using four sets of recombinant inbred line populations. The phenotypes observed under the two-plant density treatments indicated that high plant density increased the phenotypic performance values of the three measured traits. Twenty-three quantitative trait loci (QTLs) were detected under the two-plant density treatments, and five QTL clusters were located. Nine QTLs were detected under the low plant density treatment, and seven QTLs were detected under the high plant density treatment. Our results suggested that plant height may be controlled mainly by a common set of genes that could be influenced by additional genetic mechanisms when the plants were grown under high plant density. Fine mapping for genetic regions of the stable QTLs across different plant density environments may provide additional information about their different responses to density. The results presented here provide useful information for further research and will help to reveal the molecular mechanisms related to plant height in response to density.

Multiparental mapping of plant height and flowering time QTL in partially isogenic sorghum families.

Sorghum varieties suitable for grain production at temperate latitudes show dwarfism and photoperiod insensitivity, both of which are controlled by a small number of loci with large effects. We studied the genetic control of plant height and flowering time in five sorghum families (A–E), each derived from a cross between a tropical line and a partially isogenic line carrying introgressions derived from a common, temperate-adapted donor. A total of 724 F2:3 lines were phenotyped in temperate and tropical environments for plant height and flowering time and scored at 9139 SNPs using genotyping-by-sequencing. Biparental mapping was compared with multiparental mapping in different subsets of families (AB, ABC, ABCD, and ABCDE) using both a GWAS approach, which fit each QTL as a single effect across all families, and using a joint linkage approach, which fit QTL effects as nested within families. GWAS using all families (ABCDE) performed best at the cloned Dw3 locus, whereas joint linkage using all families performed best at the cloned Ma1 locus. Both multiparental approaches yielded apparently synthetic associations due to genetic heterogeneity and were highly dependent on the subset of families used. Comparison of all mapping approaches suggests that a GA2-oxidase underlies Dw1, and that a mir172a gene underlies a Dw1-linked flowering time QTL.

Genetic Analysis of Salt Tolerance in Safflower (Carthamus tinctorius L.)

Aim: The mode of agronomic traits inheritance was investigated in safflower (Carthamus tinctorius L.) in salt stress as a new report in this study. Place and Duration of Study: This experiment was carried out in Agricultural Research Farm of Shahid Bahonar University at Ekhtiarabad, Kerman, Iran, in 2011 -2012. Methodology: Five generation including P1, P2, F1, F2 and F3 that derived from the cross of IL.111 (salt sensitive) × Mex.22-191 (salt tolerance) were used in a randomized complete block design with two replications. Results: According to generation mean analysis, different types of gene action was obtained for studied traits. The additive model [d] was fitted for branches/plant, seeds/capsule and seed yield/plant. The simple additive dominance model [d, h] was fitted for number of seeds/plant. Also, dominance× dominance epistasis [l] was added to fit the model as [d, h, l] for capsule/plant and dry weight/plant. The genetic model of [d,h,i] and [d, i] was fitted for genetic control of plant height and seed weight, respectively. Conclusion: Obtained results could be suitable for designing of breeding strategies to Research Article Annual Research & Review in Biology, 4(1): 337-346, 2014 338 improve seed yield of safflower in salt stress.

Mutations in an AP2 Transcription Factor-Like Gene Affect Internode Length and Leaf Shape in Maize

BackgroundPlant height is an important agronomic trait that affects yield and tolerance to certain abiotic stresses. Understanding the genetic control of plant height is important for elucidating the regulation of maize development and has practical implications for trait improvement in plant breeding.Methodology/Principal FindingsIn this study, two independent, semi-dwarf maize EMS mutants, referred to as dwarf & irregular leaf (dil1), were isolated and confirmed to be allelic. In comparison to wild type plants, the mutant plants have shorter internodes, shorter, wider and wrinkled leaves, as well as smaller leaf angles. Cytological analysis indicated that the leaf epidermal cells and internode parenchyma cells are irregular in shape and are arranged in a more random fashion, and the mutants have disrupted leaf epidermal patterning. In addition, parenchyma cells in the dil1 mutants are significantly smaller than those in wild-type plants. The dil1 mutation was mapped on the long arm of chromosome 6 and a candidate gene, annotated as an AP2 transcription factor-like, was identified through positional cloning. Point mutations near exon-intron junctions were identified in both dil1 alleles, resulting in mis-spliced variants.ConclusionAn AP2 transcription factor-like gene involved in stalk and leaf development in maize has been identified. Mutations near exon-intron junctions of the AP2 gene give mis-spliced transcript variants, which result in shorter internodes and wrinkled leaves.

Genetic control of plant height in combinations of crossing hexaploid spring triticale with R/D chromosome substitution

An analysis of the plant height of F1−F3 hybrids in combinations of crossing hexaploid spring triticale with R/D chromosome substitution shows that dwarfism of the six studied variety accessions is determined by the alleles of three recessive and one semidominant genes.

Genetic control of dwarfism in hexaploid triticale (Triticosecale wittm.)

The genetic control of plant height has been studied in hexaploid forms of triticale (2n = 42) with genomic structure AABBRR. Thirty-four specimens from the world collection of triticale at the Vavilov All-Russian Research Institute of Plant Breeding with plant heights from 70 to 180 cm have been used in the study. The hybrid analysis of the first, second, and third generations, as well as backcross offsprings, has demonstrated that the given trait is characterized by different modes of inheritance: dominance of dwarfism, dominance of tallness, and intermediate inheritance. It has been found that triticale cultivars of middle and large height differ from short ones in alleles of one or two major genes.

Inheritance of reduced height in sunflower

Breeding to improve stem strength is a major objective of researchers of sunflower (Helianthus annuus L.). This study was undertaken to investigate genetic factors controlling reduced plant height and increased stem diameter in three sources of sunflower, DDR, Donsky, and Donskoi 47, crossed with a conventional height line, HA 89. As these two characters may lead to improved standability, knowledge of their inheritance will assist researchers in utilizing proper breeding methods. Estimates of additive, dominance, and epistatic genetic effects controlling reduced height indicated that the additive component was most important in two of the three crosses with the additive and epistatic component nearly equal in the third cross. Breeding efforts to reduce height of sunflower hybrids utilizing these lines in crosses could be effective due to the magnitude of additive effects. The dominance component of genetic effects controlling stem diameter was the most important for two crosses, with both dominance and additive components important for the third cross. Epistasis was present, but minor, for controlling stem diameter. The high relative importance of the dominance component indicates that testcross evaluation of lines in early generations could identify lines for producing increased stem diameter in hybrids. Even though the three sources of sunflower with reduced height were different in morphologic and agronomic characteristics, they had similar genetic control of plant height and stem diameter. Each could be utilized in a breeding program to develop lines with reduced height and larger stem diameter.

GENES FOR DWARFNESS IN WHEAT, TRITICUM AESTIVUM L

The genetic control of plant height was studied in crosses of four spring wheats involving the standard height variety Ramona 50 and short-statured selections Olesen, D6301, and D6899. Data from parent, F(1), F(2), and F(3) populations indicated that four independently segregating loci account for most of the differences among the four varieties. Two major genes of a highly recessive nature condition reduced height in Olesen and the Norin 10 derivative D6301. Olesen also carries a third dwarfing gene which is partially dominant in its effects over genes for tallness. This gene, or a gene that acts in a similar manner, is also present in the standard height variety Ramona 50. Dwarfing in D6899, a derivative of Tom Thumb, is controlled primarily by a single gene with mainly additive effects which is not present in any of the other three varieties.Genetic components estimated from generation means (parental, F(1), F(2), F(3), and backcross) indicated that additive gene effects were the major component of variation in four of the six crosses, and of similar magnitude to dominance effects in another cross. The primary source of genetic variation in the cross Olesen x D6899 was due to epistasis with both additive x additive and dominance x dominance effects of major importance. The results of the generation mean analyses were consistent with the models for major-gene control of plant height based on segregation patterns.