scholarly journals Genetic Variance Estimates for Maize Yield, Grain Moisture, and Stalk Lodging for Doubled-Haploid and Conventional Selfed-Line Hybrids

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 138
Author(s):  
Ronald P. Mowers ◽  
David J. Foster
Keyword(s):  
Doubled Haploid ◽  
Genetic Variance ◽  
Maize Yield ◽  
The Other ◽  
Parent Population ◽  
Maize Hybrid ◽  
Grain Moisture ◽  
Dh Lines ◽  
Variance Estimates ◽  
Stalk Lodging

An experiment was conducted to compare estimated genetic variance for maize doubled haploid (DH) with conventional twice-selfed (S2)-line hybrids. Starting with a 4-parent population, at least 160 lines were derived using both of these methods and crossed with two inbred testers. For both inbred testers, maize hybrid grain yield and stalk lodging had higher estimated genetic variances for DH than for S2. For one of the testers, estimated grain moisture genetic variance was higher for DH, but not for the other. The DH hybrid yield distributions on both testers were flatter and had more entries in tails compared with S2 distributions. With complete homozygosity of DH lines and the subsequent increased genetic variance among lines, the expected response to yield selection is higher for DH than for S2 line hybrids.

General and specific combining ability of in vitro doubled haploid maize lines in the field

2010 ◽  
Vol 58 (2) ◽  
pp. 167-177
Author(s):  
T. Spitkó ◽  
L. SÁgi ◽  
J. Pintér ◽  
C. Marton ◽  
B. Barnabás
Keyword(s):  
Doubled Haploid ◽  
Combining Ability ◽  
Field Performance ◽  
Control Line ◽  
Regeneration System ◽  
Sample Number ◽  
Maize Hybrids ◽  
Grain Moisture ◽  
Dh Lines

The breeding of hybrid maize now has a history of over 100 years. In 1908, George H. Shull was the first to report on the high yields, great uniformity and homogeneity of hybrids derived from a cross between two inbred lines. Following this discovery, consistent self-fertilisation over a period of six to eight generations was found to be an extremely efficient method for developing maize lines. From the mid-1970s, however, with the elaboration of the monoploid ( in vivo ) and microspore culture ( in vitro ) techniques, it became possible to develop homozygous lines within a year.With the help of an efficient plant regeneration system based on anther culture, large numbers of doubled haploid (DH) lines can be produced. In the course of the experiments the seed of DH plants selected over several years was multiplied and crossed with Martonvásár testers, after which the hybrids were included in field performance trials in three consecutive years (2005–2007). The aim was to determine whether the field performance of hybrids developed in this way equalled the mean yield of standards with commercial value. The data also made it possible to calculate the general (GCA) and specific (SCA) combining ability of the parental lines, indicating the usefulness of the parental components in hybrid combinations and expressing the extent to which a given line contributes to yield surpluses in its progeny.A total of 52 maize hybrids were evaluated in the experiments in terms of yield and grain moisture content at harvest. The combinations, resulting from crosses between 12 DH lines, one control line developed by conventional inbreeding and four testers, were found to include hybrids capable of equalling the performance of the standards, and four DH lines were identified as improving the yield level of their progeny. As the experiment was carried out on a very small number of genotypes, the results are extremely promising and suggest that, if the range of genotypes used to develop DH lines is broadened and the sample number is increased, it will be possible in the future to find maize hybrids, developed with in vitro DH parental components, that surpass the performance of commercial hybrids.

scholarly journals Comparison of methods for obtaining doubled haploids of carrot

2017 ◽  
Vol 86 (2) ◽  
Author(s):  
Waldemar Kiszczak ◽  
Urszula Kowalska ◽  
Agata Kapuścińska ◽  
Maria Burian ◽  
Krystyna Górecka
Keyword(s):  
Plant Regeneration ◽  
Doubled Haploid ◽  
Aspartate Aminotransferase ◽  
Doubled Haploids ◽  
The Other ◽  
Plant Production ◽  
Comparison Of Methods ◽  
Anther Cultures ◽  
Induction Stage ◽  
Main Factor

Doubled haploid lines of carrot can be obtained through androgenesis in anther cultures and in isolated microspore cultures. The two methods were compared using three carrot cultivars (‘Kazan F1’, ‘Feria F1’, and ‘Narbonne F1’) at the androgenesis induction stage, during plant regeneration from embryos, and during acclimatization of androgenetic plants as well as their characterization. It was found that cultivar was the main factor affecting the efficiency at each stage of plant production in both anther and isolated microspore cultures. The efficiency of androgenesis in anther cultures of ‘Feria F1’ was considerably higher in comparison with isolated microspore cultures, and more plants were obtained from the embryos of androgenesis-cultured plants. In ‘Kazan F1’ and ‘Narbonne F1’, more acclimatized androgenetic plants were produced from anther cultures. Ploidy assessment of acclimatized plants of ‘Narbonne F1’ showed that the majority of the plants in the population derived from anther cultures had a doubled chromosome (DH) set. On the other hand, the majority of plants obtained from isolated microspore cultures were haploids. When assessing homozygosity, it was found among plants obtained in anther cultures that the percentage of homozygotes for phosphoglucose isomerase (PGI) and aspartate aminotransferase (AAT) depended on the cultivar. In contrast, the majority of plants derived from isolated microspore cultures were homozygous regardless of cultivar.

In vitro and in vivo screening for cold tolerance in winter × spring wheat-derived doubled haploids following the wheat × maize system

2007 ◽  
Vol 55 (3) ◽  
pp. 273-282
Author(s):  
S. Sharma ◽  
H. Chaudhary
Keyword(s):  
Grain Yield ◽  
Cold Tolerance ◽  
Spring Wheat ◽  
Doubled Haploid ◽  
Tetrazolium Chloride ◽  
Cold Tolerant ◽  
Dh Lines ◽  
Ttc Test

Seventy-eight doubled haploid (DH) lines, derived from 21 elite and diverse winter × spring wheat F 1 hybrids, following the wheat × maize system, were screened along with the parental genotypes under in vitro and in vivo conditions for cold tolerance. Under in vitro conditions, the 2,3,5-triphenyl tetrazolium chloride (TTC) test was used to characterize the genotypes for cold tolerance. Based on the TTC test, only one doubled haploid, DH 69, was characterized as cold-tolerant, seven DH and five winter wheat parents were moderately tolerant, while the rest were susceptible. Analysis of variance under in vivo conditions also indicated the presence of sufficient genetic variability among the genotypes (DH lines + parents) for all the yield-contributing traits under study. The correlation and path analysis studies underlined the importance of indirect selection for tillers per plant, harvest index and grains per spike in order to improve grain yield. It was also concluded that selection should not be practised for grain weight per spike as it would adversely affect the grain yield per plant. When comparing the field performance of the genotypes with the in vitro screening parameters, it was concluded that in addition to the TTC test, comprising a single parameter, other physiological and biochemical in vitro parameters should be identified, which clearly distinguish between cold-tolerant and susceptible genotypes and also correlate well with their performance under field conditions.

Quantitative inheritance studies in sugar-cane. I. Estimation of variance components

1971 ◽  
Vol 22 (1) ◽  
pp. 93 ◽  
Author(s):  
DM Hogarth
Keyword(s):  
Factorial Design ◽  
Variance Components ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
The Other ◽  
Quantitative Inheritance ◽  
Genetic Determination ◽  
Nested Design ◽  
Dominance Genetic Variance ◽  
Estimation Of Variance

Two experiments in quantitative genetics were conducted, one based on a nested design in lattice squares and the other on a factorial design in a balanced lattice. Lattice designs were found to be suitable for genetic experiments if a large number of crosses was involved, but posed some problems in partitioning the sum of squares for treatments. The factorial design was considered preferable to the nested design, although neither design permitted estimation of epistatic variances which, therefore, were assumed to be negligible. Additive genetic variance was found to be more important than dominance genetic variance for most characters. However, most estimates of genetic variance lacked precision in spite of the use of large, precise experiments, which illustrated the difficulty in obtaining estimates of variance components with adequate precision. The validity of assumptions made for these analyses is discussed. The effect of competition was studied and estimates of heritability and degree of genetic determination were determined.

Growth and yield of doubled haploid lines of oilseed Brassica rapa

1998 ◽  
Vol 78 (4) ◽  
pp. 537-544 ◽  
Author(s):  
D. B. Dewan ◽  
G. Rakow ◽  
R. K. Downey
Keyword(s):  
Brassica Rapa ◽  
Seed Yield ◽  
Doubled Haploid ◽  
Field Tests ◽  
Field Evaluation ◽  
Growth And Yield ◽  
Consistent Performance ◽  
Delayed Flowering ◽  
Dh Lines ◽  
Number Of Seeds

The production of doubled haploid (DH) lines of Brassica rapa could be an efficient procedure for the development of inbred parents for hybrid production. A total of 162 B. rapa DH lines were evaluated in field tests at Saskatoon, Canada, in single row, replicated tests and 10 DH lines were tested in four-row plot, multilocation, replicated tests. Seed of DH lines was produced by bud selfing in the greenhouse. Approximately one-fifth of all DH lines tested were chlorophyll deficient, presumably due to the expression of recessive alleles. Inbreeding depression was evident in low seed and biological yields, low number of seeds per pod and delayed flowering. Seed yield of DH lines was positively associated with the number of seeds per pod, early flowering and a long pod-filling period. One DH line was equal in yield to its donor population (DP), suggesting that dominance deviation was the genetic basis for high seed yield in this species. The consistent performance of DH lines over years and locations indicated that DH lines may be selected after 1 year of evaluation for combining ability testing. Higher yielding DH lines of B. rapa must be selected before they can be used as parents for hybrid development. Key words: Brassica rapa, doubled haploid, field evaluation

Changes in stored-wheat ecosystems infested with two combinations of insect species

1980 ◽  
Vol 58 (9) ◽  
pp. 1524-1534 ◽  
Author(s):  
N. D. G. White ◽  
R. N. Sinha
Keyword(s):  
Carbon Dioxide ◽  
Sitophilus Oryzae ◽  
The Other ◽  
Rhyzopertha Dominica ◽  
Cryptolestes Ferrugineus ◽  
Oryzaephilus Surinamensis ◽  
Stored Wheat ◽  
Seed Damage ◽  
Grain Moisture ◽  
Multiple Species

The consequences of infestation of bulk-stored wheat by multiple species of insects were determined for 60 weeks at 30 ± 2 °C. Eight 204-L drums containing wheat at 15.5% moisture content were used as three distinct systems: (I) Control system (two drums), insect free; (II) RST system (three drums), infested with the grouping of Rhyzopertha dominica F., Sitophilus oryzae (L.), and Tribolium castaneum (Herbst); and (III) COT system (three drums), infested with the grouping of Cryptolestes ferrugineus (Stephens), Oryzaephilus surinamensis (L.), and T. castaneum. At triweekly intervals carbon dioxide, oxygen, temperature, grain moisture, seed damage, grain weight, dust weight, fat acidity values (FAV), seed germination, microflora, and the numbers of insects and the mite Tarsonemus granarius Lindquist were measured. Seeds died by week 15 and bacterial infection on them increased in all systems. The seed FAVs in the RST system peaked by week 30 and then declined steadily while these values were increasing continuously in the Control and levelling off in the COT systems. Insects multiplied exponentially for 6–15 weeks and then declined sharply or maintained oscillating populations; Sitophilus and Oryzaephilus were unable to survive in the presence of the other insects.

Sex Differences in Genetic Determinants of Craniofacial Variations - A Study Based on Twin Kinships

1998 ◽  
Vol 47 (1) ◽  
pp. 31-41 ◽  
Author(s):  
K. Sharma
Keyword(s):  
Sex Differences ◽  
Genetic Variance ◽  
Mean Value ◽  
Regression Coefficients ◽  
Genetic Determinants ◽  
Heterogeneity Of Variance ◽  
Variance Ratios ◽  
Ear Height ◽  
The Mean ◽  
Variance Estimates

AbstractRace, sex, nutritional status and cultural factors affect craniofacial morphogenesis. Out of these, sex is a major factor in craniofacial differentiation, because it can be stronger in one ethnic group and weaker in another. In this study, sex differences in genetic variance and heritability of 13 craniofacial traits are investigated. The study is based on a sample of 45 MZ and 101 DZ twin pairs and their 125 singleton siblings, 104 fathers and 103 mothers in 146 families drawn from an urban population of Chandigarh. Results of t'-tests for equality of the means reveal association of zygosity with the mean value of bigonial diameter in female twins and for none in males. Heterogeneity of variance is observed in about 50% traits in females as compared to 15% in males. This invalidates conventional within-pair genetic variance estimates for these traits. The revised genetic variance ratios are higher on an average in males than in females. However, there is greater MZ environmental covariance in male twins than their female counterparts. Family data indicate higher maternal effect for ear height, nasal height and frontal breadth, while greater paternal effect is seen in cranial traits. Sex-wise midparent-child regression coefficients show greater heritability in daughters for nasal traits and bigonial breadth, while sons show higher genetic component for head size measures.

Association of Twin Zygosity With the Mean and Variance of Tooth Size

1979 ◽  
Vol 28 (3) ◽  
pp. 211-223 ◽  
Author(s):  
Rosario H. Yap Potter ◽  
Pao-lo Yu ◽  
Joe C. Christian
Keyword(s):  
Genetic Variance ◽  
T Test ◽  
Tooth Size ◽  
F Test ◽  
Sex Influence ◽  
Mean And Variance ◽  
The Mean ◽  
Variance Estimates

To search for an association of twin zygosity with tooth size, 56 dental variables measured from 65 pairs of twins (43 MZ, 22 DZ) were studied. Results of the t′ test for equality of the means showed no association of zygosity with any of the variables in males or in females. Results of the F′ test for homogeneity of total variances between zygosities showed evidence for unequal total variances in 15 variables in males and 13 in females. Sex influence was further noted on the association of zygosity with the variance of tooth size. Where total variances were unequal, genetic variance estimates differed when only the within-pair mean squares were used and when combined estimates designed to be unbiased by differences in environmental variances were used.

Sign in / Sign up

Export Citation Format

Share Document