The effect of Dwarfing Genes on the Expression of Heterosis for Grain Yield in F1 Hybrid Wheat

1989 ◽  
pp. 49-61 ◽  
Author(s):  
M. D. Gale ◽  
A. M. Salter ◽  
W. J. Angus
Keyword(s):  
Grain Yield ◽  
Dwarfing Genes ◽  
Hybrid Wheat ◽  
F1 Hybrid

Heterosis, overdominance for grain yield, and alpha-amylase activity in F1 hybrids between near-isogenic Rht dwarf and tall wheats

1997 ◽  
Vol 129 (4) ◽  
pp. 371-378 ◽  
Author(s):  
J. E. FLINTHAM ◽  
W. J. ANGUS ◽  
M. D. GALE
Keyword(s):  
Grain Yield ◽  
Amylase Activity ◽  
Single Gene ◽  
Preharvest Sprouting ◽  
Alpha Amylase ◽  
F1 Hybrids ◽  
Dwarfing Genes ◽  
Heterozygous Condition ◽  
Reduced Height ◽  
Continuous Range

The Rht-B1b, Rht-D1b and Rht-B1c alleles for reduced height in wheat (the Norin 10 and Tom Thumb dwarfing genes previously known as Rht1, Rht2 and Rht3) were exploited in combinations to generate a near-continuous range of plant heights, from 53 cm to 123 cm, amongst near-isogenic homozygotes and F1 hybrids. Pleiotropic yield effects of Rht genes were measured in both homozygous (intravarietal) and heterozygous (intervarietal) genetic backgrounds. Heterosis due to overdominance of Rht genes was detected among intravarietal hybrids. The effects of heterozygosity at other genetic loci (mean dominance) were determined, independently of Rht effects, from comparisons between intravarietal and intervarietal F1 hybrids.Genotypes of intermediate plant heights gave maximum yields, in agreement with other trials of the homozygous lines, so that heterosis (hybrid exceeding best parent) for Rht yield effects was observed in crosses between tall and dwarf isogenic pairs. This heterosis combined additively with increased mean weight per grain in intervarietal crosses, generating the highest overall grain yields in hybrids with semi-dwarf stature in heterozygous genetic backgrounds. The Rht-B1c allele showed single-gene overdominance for grain yield, also the production of alpha-amylase in ripening grains of Maris Huntsman was effectively inhibited in the Rht-B1a/c intravarietal hybrid. The Rht-B1c allele thus offers advantages for both grain yield and grain quality in the heterozygous condition and should be considered as an alternative to the conventional semi-dwarfing genes Rht-B1b and Rht-D1b for F1 varieties in environments conductive to preharvest sprouting.

scholarly journals Competition among wild rice, landrace, improved cultivar and F1 hybrid rice

2018 ◽  
Vol 18 ◽  
pp. 29-40
Author(s):  
Bal Krishna Joshi ◽  
Sanjaya Gyawali ◽  
Surya Narayan Sah ◽  
Rewati Raman Chaudhary
Keyword(s):  
Grain Yield ◽  
Wild Rice ◽  
Growth Period ◽  
Oryza Rufipogon ◽  
Panicle Length ◽  
F1 Hybrid ◽  
Panicle Number ◽  
Growing Environment ◽  
Different Response ◽  
Competition Environment

Four genotypes, namely Oryza rufipogon, F1 of IR68888A/Chaite-6, Chaite-6 and Ratodhan were grown in crop and competition environment at Rampur, Nepal to study the effect of genotypes mixture on the characters. Univariate, multivariate and correlation methods of analysis were applied. Seven characters namely panicle length, panicle number, grain yield, harvest index, internode length and leaf width showed significantly different response in crop and competition environment. The performance of cultivar was poor in competition environment than hybrid and wild rice. Hybrid and wild rice showed longer panicle length in competition environment. Significant reduction in panicle number was found in cultivars. The pattern of tiller number over the growth period showed that the competition started after 50 days of seeding. Grain yield of cultivars was significantly reduced in competition environment. Considering the most important characters, hybrid was best competitor and local landrace (Ratodhan) was poorest competitor. Significant variations in culm characters were not found between two environments but leaf characters varied significantly. Highest increment in plant height was found in F1 grown in competition than crop environment. Relationship between characters was affected by growing environment. Among 162 pairs of characters r-value of six and 36 pairs were highly significant different from zero in crop and competition environment respectively. Multivariate analysis indicates that growing environment does not suppress the genetic characters. Competition among the tested genotypes exists even in the recommended spacing. Competition should be studied in detail planting at different spacing.

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.

Levels of heterosis for yield and quality in an F1 hybrid wheat

1985 ◽  
Vol 36 (4) ◽  
pp. 545 ◽  
Author(s):  
OW Boland ◽  
JJ Walcott
Keyword(s):  
Side Effects ◽  
Hybrid Wheat ◽  
Seeding Rate ◽  
Yield Performance ◽  
F1 Hybrid ◽  
Flour Protein ◽  
Yield And Quality ◽  
Expected Values ◽  
Milling Yield ◽  
Yield Trials

A newly released F1 hybrid wheat (Hybrid Titan) was compared with its parents and three commercial check cultivars in yield trials over 16 site years. Mid-parent heterosis varied considerably (100-127%) over the sites and averaged 111%. However, high-parent and high-check cultivar heterosis levels were much lower (99-119%), most likely a consequence of the low yield of the male parent. A concurrent seeding rate trial showed that lower levels of heterosis resulted if the seeding rate of the hybrid was reduced below that of the parent and check cultivars. Quality tests performed on the harvested grain showed some characters deviating considerably from expected values. The most significant of these were lower milling yield, flour protein content, and water absorption. The T. timopheevi nucleo-cytoplasmic system for producing hybrid wheat was implicated as having likely side effects on yield performance and quality. The study emphasized the need for both parents to be high-yielding and to have good combining ability for both yield and quality.

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.

scholarly journals Influence of different types of sterile cytoplasms (A3, A4, 9E) on the combining ability of CMS lines of sorghum

2020 ◽  
Vol 24 (6) ◽  
pp. 549-556
Author(s):  
O. P. Kibalnik ◽  
L. A. Elkonin
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Combining Ability ◽  
F1 Hybrids ◽  
Thermal Coefficient ◽  
Negative Effects ◽  
F1 Hybrid ◽  
Positive Effects ◽  
Different Types ◽  
Dry Seasons

Investigation of the effect of the cytoplasm on the combining ability (CA) of lines with cytoplasmic male sterility (CMS) is of considerable interest in terms of understanding the genetic functions of the cytoplasm and for practical purposes to create hybrids with improved economically valuable traits. In order to investigate the effect of different types of sterile cytoplasm (A3, A4, 9E) on CA in sorghum, we studied the manifestation of a number of biological and agronomic traits in 54 F1 hybrid combinations obtained using iso-nuclear CMS lines with the nuclear genome of the line Zheltozernoye 10, differing only in the types of sterile cytoplasm (A3, A4 and 9E). Eighteen varieties and lines of grain sorghum developed at the Russian Research and Project-technological Institute of Sorghum and Maize were used as paternal parents. The CA was determined by the topcross method. F1 hybrids and their parents were grown in 2015–2017 in conditions of insufficient (2015–2016: HTC (hydro-thermal coefficient) = 0.32–0.66), or good water availability conditions (2017: HTC = 1.00). On average, for three years of testing, a positive effect of the 9E cytoplasm on the general combining ability (GCA) (0.63) and negative effects of the A3 and A4 cytoplasms (–0.32 and –0.31) for the inflorescence length were noted. In dry seasons, significant positive effects of the 9E cytoplasm on GCA for the length of the largest leaf, and positive effects of the A3 cytoplasm on GCA for the plant height, and negative effects of the A4 cytoplasm on GCA for these traits were observed. No differences were observed during the wet season. The type of CMS did not affect the GCA for the width of the largest leaf and grain yield. The dispersion of specific combining ability (SCA) in the dry seasons was significant for the following traits: leaf length, plant height, panicle length and width, and grain yield, the 9E cytoplasm had the highest SCA dispersion, whereas the A4 cytoplasm had the smallest one. The data obtained indicate that different types of sterile cytoplasm of sorghum make a different contribution to CA under conditions of drought stress.

scholarly journals Correlation of yield and heterosis of maize hybrids and their parental lines with genetic distance based on SSR markers

Genetika ◽  
2012 ◽  
Vol 44 (2) ◽  
pp. 399-408 ◽  
Author(s):  
Snezana Mladenovic-Drinic ◽  
Marija Kostadinovic ◽  
Danijela Ristic ◽  
Milan Stevanovic ◽  
Zoran Camdzija ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Distance ◽  
Ssr Markers ◽  
F1 Hybrids ◽  
F1 Hybrid ◽  
Maize Hybrids ◽  
Average Value ◽  
Parental Inbred ◽  
The Mean ◽  
Parental Lines

The yield, grain yield heterosis and genetic distance based on SSR markers were analyzed in eight maize hybrids and their parental lines. The mean grain yield of all F1 hybrids was 11.37 tha-1. The F1 hybrid from the crosses between L4xL6 gave the highest grain yield of 12.12 tha-1. For the mid parent heterosis (MPH) grain yields of the F1 hybrids, the data showed the average value of 164.25%, and ranged from 136.72% (L4xL6) to 218.07% (L8xL2), and for better parent heterosis (BPH) from 100.70% (H4) to 212.60% (H2), averaged 137.36%. The average genetic distance among parental inbred lines of analyzed hybrids was 0.58 with a range from 0.55 to 0.61. The GD showed a positive correlation with the grain yield of the F1 hybrids (0.22), as well as with MPH and BPH, with the values of 0.12 and 0.45, respectively.

scholarly journals Exploitation of Hybrid Vigor for Identification of Promising Sorghum F1 Hybrid for High Grain Yield and Resistance to Sorghum Midge

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Massaoudou Hamidou ◽  
Oumarou Souleymane ◽  
Mahamadou Salifou ◽  
Malick N. Ba ◽  
Issoufou Kapran ◽  
...  
Keyword(s):  
Grain Yield ◽  
Grain Sorghum ◽  
Hybrid Vigor ◽  
Cereal Crop ◽  
F1 Hybrid ◽  
The World ◽  
Improvement Programs ◽  
Parental Lines ◽  
Sorghum Production ◽  
Better Than

Sorghum is the second most grown cereal crop in Niger. However, sorghum production in the country is dominated by indigenous cultivars with low productivity. Productivity in grain sorghum has been achieved in developing countries around the world using hybrids. This study was conducted to evaluate heterosis in F1 sorghum hybrids for grain yield and resistance to midge. Fifty F1 sorghum hybrids were evaluated for grain yield and resistance to midge. Variation for grain yield, midge resistance, and flowering time was observed. The magnitude of better parent heterosis for grain yield and resistance to midge varied significantly among hybrids. Four hybrids combined high better parent heterosis for both grain yield and resistance to midge while eight hybrids were better than their better parent for resistance to midge. These hybrids performed well for grain yield and/or resistance to midge. Therefore, the parental lines involved in these hybrids can be advanced for commercial hybrids production or used in sorghum improvement programs.

scholarly journals Comparative Genetic Effect of Dwarfing Genes on Yield and Yield Contributing Traits in Bread Wheat (Triticum aestivum L.)

2014 ◽  
Vol 18 (2) ◽  
pp. 49-55
Author(s):  
MA Jahan ◽  
MS Hossain ◽  
M Khalekuzzaman ◽  
MM Hassan
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Plant Height ◽  
Bread Wheat ◽  
Yield Components ◽  
Genetic Effect ◽  
Triticum Aestivum L ◽  
High Yield ◽  
Strong Positive Correlation ◽  
Dwarfing Genes

Norin 10 based dwarfing genes (Rht1 and Rht2) have been widely exploited for increasing the grain yield in bread wheat (Triticum aestivum L.) by improving partitioning of assimilates to grain. Eight semi-dwarf wheat genotypes having either Rht1 or Rht2 dwarfing genes were compared with a tall control named, Kheri (rht) having no dwarfing genes were evaluated at Rajshahi University, Bangladesh for yield and yield contributing traits. Significant differences in grain yield and yield components were observed in genotypes under study showing the effects of dwarfing genes. Genotype Seri 82 (Rht1) and Kanchan (Rht2) had medium plant height of 75.73 and 72.22 cm respectively, highest number of tillers/plant (7.33 and 7.67), highest number of spikes/plant (6.33 and 6.67) resulted the highest grain yield per plant. Because the dwarfing genes not only provide lodging tolerance but also perhaps pleiotropically affected high yield by allowing more tillers to survive. Number of tillers/plant and number of spikes/plant showed very strong positive correlation with grain yield per plant in all the genotypes. Kheri (rht) with highest plant height (95.17cm) reduced number of tillers/plant (4.00) and spikes/plant (3.67) had the lowest grain yield per plant (3.85g). Aghrani possessed significantly the highest number of grains/spike with medium grain yield/plant (5.94g). The degree of relationship varied from genotype to genotype.DOI: http://dx.doi.org/10.3329/pa.v18i2.18075 Progress. Agric. 18(2): 49 - 55, 2007

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