Variation in south Asian wheat germplasm for seedling drought tolerance traits

2009 ◽  
Vol 7 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Umesh R. Rosyara ◽  
Amrit A. Ghimire ◽  
Sushil Subedi ◽  
Ram C. Sharma
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Wheat Breeding ◽  
Dwarfing Genes ◽  
Seedling Vigour ◽  
Coleoptile Length ◽  
Wide Range ◽  
Dry Conditions ◽  
Breeding Programmes ◽  
Positive Correlations

Higher seedling vigour and greater coleoptile length are important for early establishment of wheat crops and subsequently higher grain yield in many dry environments. Seedling vigour includes those seed properties that determine the potential for rapid, uniform emergence and development of normal seedlings under a wide range of field conditions. Genotypes with the widely used gibberellic acid (GA)-insensitive dwarfing genes Rht-B1b and Rht-D1b have good partitioning and grain yield under optimal conditions, but may perform poorly under stressed conditions due to poor crop establishment. Breeding programmes are in search of GA-sensitive dwarfing genes that do not affect seedling vigour under dry conditions. This study evaluated 40 genotypes currently used in wheat breeding programmes of south Asia for seedling vigour-related traits in greenhouse and field experiments during 2006–2007 at IAAS, Rampur, Nepal. Wide variation in coleoptile length, seedling vigour, as well as sensitivity to GA was observed. Among the genotypes studied, there were positive correlations among coleoptile length, leaf width and plant height. Genotypes, SW89-5193, SW89-5422/NL251 and SW89-5422, were found to have longer coleoptile, higher seedling vigour and response to GA application. This shows a promise for their further applications in the breeding programmes.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

scholarly journals Evidence for improved pollen viability as the mechanism for film antitranspirant mitigation of drought damage to wheat yield

2016 ◽  
Vol 67 (2) ◽  
pp. 137 ◽  
Author(s):  
Minuka M. Weerasinghe ◽  
Peter S. Kettlewell ◽  
Ivan G. Grove ◽  
Martin C. Hare
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Pollen Viability ◽  
Wheat Yield ◽  
Spray Application ◽  
Grain Number ◽  
Climatic Zones ◽  
Boot Stage ◽  
Wide Range ◽  
Drought Damage

Application of film antitranspirant to wheat during late stem extension reduces drought damage to yield, but the mechanism is unknown. Field experiments under rain shelters were conducted over 3 years to test the hypothesis that film antitranspirant applied before meiosis alleviates drought-induced losses of pollen viability, grain number and yield. The film antitranspirant di-1-p-menthene was applied at third-node stage, and meiosis occurred at the early boot stage, with a range of 11–16 days after spray application in different years. Irrigated, unsprayed plots were included under the rain-shelters, and pollen viability, measured in 2 years in these plots, averaged 95.3%. Drought reduced pollen viability to 80.1% in unirrigated, unsprayed plots, but only to 88.6% in unirrigated plots treated with film antitranspirant. Grain number and yield of irrigated plots, measured in all years, were 16 529 m–2 and 9.55 t ha–1, respectively, on average. These were reduced by drought to 11 410 m–2 and 6.31 t ha–1 in unirrigated, unsprayed plots, but only to 12 878 m–2 and 6.97 t ha–1 in unirrigated plots treated with film antitranspirant. Thus compared with unirrigated, unsprayed plots, antitranspirant gave a grain yield benefit of 0.66 t ha–1. Further work is needed to validate the pollen viability mechanism in different climatic zones and with a wide range of cultivars.

Distribution of dwarfing genes (Rht-B1b and Rht-D1b) in Martonvásár wheat breeding materials

2011 ◽  
Vol 59 (3) ◽  
pp. 249-254 ◽  
Author(s):  
G. Gulyás ◽  
Z. Bognár ◽  
L. Láng ◽  
M. Rakszegi ◽  
Z. Bedő
Keyword(s):  
Triticum Aestivum ◽  
Molecular Markers ◽  
Plant Height ◽  
Wheat Breeding ◽  
Minor Role ◽  
Dwarfing Genes ◽  
Breeding Programmes ◽  
A Minor ◽  
Positive Results ◽  
Marker Information

A total of 266 Martonvásár (Mv) wheat (Triticum aestivum L.) accessions, including varieties and advanced lines, were examined using the “Perfect” molecular markers to detect the Rht-B1b (formerly Rht1) and Rht-D1b (formerly Rht2) semi-dwarfing genes. The gene Rht-B1b was detected in a total of 221 (83.5%) accessions. The Rht-D1b allele was found in fewer accessions. Overall 24 genotypes (9%) contained this allele. The analysis of the development date of the genotypes revealed that the introduction of the dwarfing genes into Martonvásár breeding programmes started in the early 1970s, and they were widely utilized from the 1980s. The Rht-B1b allele was the main source for reducing plant height, while the Rht-D1b allele played only a minor role in the Martonvásár breeding programme.Characterizing accessions using various molecular markers allows us to create a database offering relevant marker information about genotypes. Such a database could be very helpful for selection, allowing breeders to include varieties giving positive results in specific breeding programmes.

Host suitability of different wheat lines to Pratylenchus thornei under naturally infested field conditions in Turkey

Nematology ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 557-571 ◽  
Author(s):  
Abdelfattah A. Dababat ◽  
Fouad Mokrini ◽  
Salah-Eddine Laasli ◽  
Şenol Yildiz ◽  
Gül Erginbas-Orakci ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Conditions ◽  
Nematode Reproduction ◽  
Pratylenchus Thornei ◽  
Wide Range ◽  
Infested Field ◽  
Breeding Programmes ◽  
Moderate Resistance ◽  
Wheat Lines ◽  
Moderately Resistant

Summary The root-lesion nematode, Pratylenchus thornei, attacks a wide range of crops and causes significant reductions in global grain production. Breeding programmes are currently restricted to using parents with moderate resistance to P. thornei as cereal cultivars with complete resistance are yet to be identified. This study evaluated 484 of CIMMYT’s spring wheat accessions for resistance to P. thornei of which 56 lines were pre-identified as resistant under controlled growth room conditions. These lines were further evaluated for their resistance and tolerance reactions under field conditions, where 14 accessions maintained their resistance and 16 were moderately resistant against P. thornei. Four lines gave excellent resistant and tolerance reactions to P. thornei. The relationship between the nematode reproduction factor (Pf/Pi) and wheat grain yield in field experiments fits a linear regression model. These findings could be useful for improving P. thornei resistance in wheat.

scholarly journals Effect of gibberellin-sensitive Rht18 and gibberellin-insensitive Rht-D1b dwarfing genes on vegetative and reproductive growth in bread wheat

2020 ◽  
Author(s):  
Ting Tang ◽  
Tina Botwright Acuña ◽  
Wolfgang Spielmeyer ◽  
Richard A Richards
Keyword(s):  
Dry Matter ◽  
Green Revolution ◽  
Dominant Gene ◽  
Early Growth ◽  
Wheat Breeding ◽  
Dwarfing Genes ◽  
Coleoptile Length ◽  
Backcross Population ◽  
Wheat Improvement ◽  
Vegetative And Reproductive Growth

Abstract Gibberellin (GA)-insensitive dwarfing genes Rht-B1b and Rht-D1b that are responsible for the ‘Green Revolution’ have been remarkably successful in wheat improvement globally. However, these alleles result in shorter coleoptiles and reduced vigour, and hence poor establishment and growth in some environments. Rht18, on the other hand, is a GA-sensitive, dominant gene with potential to overcome some of the early growth limitations associated with Rht-B1b and Rht-D1b. We assessed progeny from both a biparental and a backcross population that contained tall, single dwarf, and double dwarf lines, to determine whether Rht18 differs from Rht-D1b and hence verify its value in wheat improvement. Progeny with Rht18 had an almost identical height to lines with Rht-D1b, and both were ~26% shorter than the tall lines, with the double dwarf 13% shorter again. However, coleoptile length of Rht18 was 42% longer than that of Rht-D1b. We detected no differences in time to terminal spikelet and anthesis, and few differences in stem or spike growth. Both dwarfing genes diverted more dry matter to the spike than tall lines from prior to heading. No differences were detected between Rht18 and Rht-D1b that could prevent the adoption of Rht18 in wheat breeding to overcome some of the limitations associated with the ‘Green Revolution’ genes.

Gibberellic acid-sensitive dwarfing genes reduce plant height to increase kernel number and grain yield of wheat

2000 ◽  
Vol 51 (2) ◽  
pp. 235 ◽  
Author(s):  
G. J. Rebetzke ◽  
R. A. Richards
Keyword(s):  
Gibberellic Acid ◽  
Grain Yield ◽  
Plant Height ◽  
Harvest Index ◽  
Genotypic Variation ◽  
Genotypic Differences ◽  
Dwarfing Genes ◽  
Kernel Number ◽  
Coleoptile Length ◽  
Reduced Height

The Norin-10 dwarfing genes, Rht-B1b (Rht1) and Rht-D1b (Rht2), have been used to reduce plant height and increase grain yield in wheat breeding programs worldwide. Other dwarfing genes are available to reduce plant height of wheat but little is known of their effects on grain yield. A set of random, F5-derived wheat lines containing either minor genes for reduced plant height, or major gibberellic acid (GA) sensitive Rht8 and Rht9 dwarfing genes, were obtained from 3 different populations. Environment mean yields ranged from 2.5 to 4.6 t/ha. Genotypic variation was large and significant (P < 0.05) for plant height, grain yield and its components, and kernel number and size. Approximately 30% of lines were as short as variety Hartog, while kernel number per m2, harvest index, and grain yield of the shortest GA-sensitive lines were not significantly different (P < 0.05) from the commercial semidwarf checks Janz or Hartog. Furthermore, genotypic differences in plant height were genetically correlated (rg) with variation in kernel number (rg = −0.76*), harvest index (−0.71*), and grain yield (−0.62*). These correlated effects were confirmed with retrospective selection for height and were consistent with reported height effects of Rht-B1b and Rht-D1b dwarfing genes on kernel number and harvest index in wheat. Plant height differences among GA-sensitive lines were independent of variation in seedling characteristics (r2 = 0.01–0.02 n.s.), while a number of reduced-height lines produced 50% longer coleoptiles and greater seedling biomass than Janz. These studies demonstrate a correlation between the shorter height of GA-sensitive dwarfing genes and increased grain yield, and suggest their potential for improving wheat establishment through greater coleoptile length and early vigour.

Enhancement of dwarf wheat germplasm with high-yield potential derived from induced mutagenesis

2016 ◽  
Vol 16 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Hongchun Xiong ◽  
Huijun Guo ◽  
Yongdun Xie ◽  
Linshu Zhao ◽  
Jiayu Gu ◽  
...  
Keyword(s):  
Yield Components ◽  
Field Experiments ◽  
Wheat Breeding ◽  
Grain Weight ◽  
Yield Potential ◽  
High Yield ◽  
Dwarfing Genes ◽  
Biosynthetic Genes ◽  
Specific Pcr ◽  
1000 Grain Weight

AbstractThe dwarfing wheat (Triticum aestivum L.) breeding has promoted a dramatic increase in yields. Since the utilized dwarfing genes in wheat are very limited, identification of novel dwarfing genes is necessary for improving the genetic diversity of wheat. In this study, more than 300 dwarfing wheat lines from induced mutation were screened by kompetitive allele-specific PCR and gibberellin (GA) treatment. The 17.49% of Rht-D1b and 1.37% of Rht-B1b dwarfing mutants were identified in this mutant group. Additionally, Rht-D1b mutants showed more effective in reduction of plant height and higher 1000-grain weight comparing with that of Rht-B1b mutants. By combing with comparison of yield components and expression profile of GA biosynthetic genes with wild-type, the GA-responsive mutant dm15 without directly involvement in GA metabolism, significantly increased 1000-grain weight but no change of other yield components in two locations of field experiments. Meanwhile, another elite mutant dm11 with change of GA biosynthetic genes expression was also identified. These mutants will be promising candidates for dwarfing wheat breeding.

scholarly journals The effect of climatic factors on production of spring wheat quantity to quality ratio in southern Finland

1990 ◽  
Vol 62 (3) ◽  
pp. 227-236 ◽  
Author(s):  
Jari Peltonen ◽  
Tuomo Karvonen ◽  
Erkki Kivi
Keyword(s):  
Grain Yield ◽  
Spring Wheat ◽  
Field Experiments ◽  
Climatic Factors ◽  
Wheat Yield ◽  
Grain Filling ◽  
Effect Of Temperature ◽  
Total Precipitation ◽  
Factors Affecting ◽  
Dry Conditions

Interrelationships between climatic factors and spring wheat yield and quality were examined with 21 years field experiments. The formation of gluten was less at dry conditions (total precipitation under 50 mm) and total precipitation exceeded 130—140 mm. The optimum daily temperature for gluten production was some 15—17°C during grain filling. The gluten content decreased if daily minimum and maximum temperatures exceeded 11—12°C and 21—22°C, respectively. The effect of temperature and rainfall were not, however, significant in early maturing varieties. The climatic factors and grain yield did not correlate. Grain yield and protein yield had strong positive relationship, which was perhaps a consequence of supply and utilization of nitrogen. It is concluded that climatic factors affecting yield to quality ration in wheat may be excessive rains before heading and high temperature during grain filling. Interaction between weather and nitrogen are discussed to optimize correct timing of nitrogen fertilization for amount and quality of economic wheat yield.

scholarly journals Phenotypic characterization of wheat landraces from mid and far western districts of Nepal

2015 ◽  
Vol 4 (4) ◽  
pp. 32-44
Author(s):  
Sangharash Raj Dangi ◽  
Ramesh Raj Puri ◽  
Nutan Raj Gautam
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Phenotypic Variability ◽  
Block Design ◽  
Wheat Breeding ◽  
Phenotypic Characterization ◽  
Improvement Program ◽  
Wide Range ◽  
Wheat Landraces

The study was conducted to evaluate phenotypic variation in one hundred and sixty six wheat landraces from mid and far western districts of Nepal. They were sown in randomized complete block design with two replications at National Wheat Research Program in 2014/15. The observed traits were analyzed using descriptive statistics and multivariate analysis using MINITAB v. 14. The results showed a wide range of phenotypic variability in observed parameters. The results also showed that the highest value of the standard deviation from mean (Sd) was for grain yield (±290.10) followed by plant height (±7.21). Among the traits the lowest deviation from mean (Sd) was for thousand grain weight TGW (±2.68). Wheat landraces grouped in four clusters depending on similarity of the studied traits. The results in this cluster, showed that days to maturity ranged from 97 to111 days, TGW ranged from 16 to17 gm, plant height ranged from 76 to 85 cm, and grain yield ranged from 2800 to 3000 Kg ha-1. Wheat landraces under study are grouped depending on specific traits useful for wheat improvement program. Results of this study can be supportive to detect wheat landraces within species with similar traits. In addition it can be useful for sampling in successive studies and parental selection in wheat breeding program.International Journal of Environment Vol.4(4) 2015: 32-44

scholarly journals WAPO-A1 is the causal gene of the 7AL QTL for spikelet number per spike in wheat

2021 ◽  
Author(s):  
Saarah Kuzay ◽  
Huiqiong Lin ◽  
Chengxia Li ◽  
Shisheng Chen ◽  
Daniel Woods ◽  
...  
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Apical Region ◽  
Genome Wide Association Studies ◽  
Causal Gene ◽  
Spikelet Number ◽  
Grain Number Per Spike ◽  
A Genome ◽  
Wide Range ◽  
Spikelet Number Per Spike

Improving our understanding of the genes regulating grain yield can contribute to the development of more productive wheat varieties. Previously, a highly significant QTL affecting spikelet number per spike (SNS), grain number per spike (GNS) and grain yield was detected on chromosome arm 7AL in multiple genome-wide association studies. Using a high?resolution genetic map, we established that the A-genome homeolog of WHEAT ORTHOLOG OF APO1 ( WAPO-A1 ) was a leading candidate gene for this QTL. Using mutants and transgenic plants, we demonstrate in this study that WAPO-A1 is the causal gene underpinning this QTL. Loss-of-function mutants wapo-A1 and wapo-B1 showed reduced SNS in tetraploid wheat, and the effect was exacerbated in wapo1 combining both mutations. By contrast, spikes of transgenic wheat plants carrying extra copies of WAPO-A1 driven by its native promoter had higher SNS, a more compact spike apical region and a smaller terminal spikelet than the wild type. Taken together, these results indicate that WAPO1 affects SNS by regulating the timing of terminal spikelet formation. Both transgenic and wapo1 mutant plants showed a wide range of floral abnormalities, indicating additional roles of WAPO1 on wheat floral development. Previously, we found three widespread haplotypes in the QTL region (H1, H2 and H3), each associated with particular WAPO-A1 alleles. Integrating results from this study and previous findings, we show that the WAPO-A1 allele in the H1 haplotype (115-bp deletion in the promoter) is expressed at significantly lower levels in the developing spikes than the alleles in the H2 and H3 haplotypes, resulting in reduced SNS. Field experiments also showed that the H2 haplotype is associated with the strongest effects in increasing SNS and GNS (H2>H3>H1). The H2 haplotype is already present in most modern common wheats, so it might be particularly useful in durum wheat where H2 is rare.

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