Genetic analysis of coleoptile length and diameter in wheat

2004 ◽  
Vol 55 (7) ◽  
pp. 733 ◽  
Author(s):  
G. J. Rebetzke ◽  
R. A. Richards ◽  
X. R. R. Sirault ◽  
A. D. Morrison
Keyword(s):  
Genetic Control ◽  
Genotypic Variation ◽  
Soil Surface ◽  
Strongly Correlated ◽  
Coleoptile Length ◽  
Dwarfing Gene ◽  
Diallel Mating Design ◽  
Different Temperatures ◽  
Australian Wheat ◽  
Temperature Interaction

Lack of moisture near the soil surface commonly delays sowing, reducing grain yields of Australian wheat (Triticum aestivum) crops. Deep sowing would allow growers to make use of soil moisture lying below the drying topsoil, but the short coleoptiles of semidwarf wheats reduce emergence when sowing at depths greater than 5 cm. Selection of longer, thicker coleoptiles would help in improving emergence in hard or crusted soils, or when deep sowing, yet little is known of genetic control of coleoptile size in wheat. A diallel mating design was generated from crosses between 12 Australian and overseas wheats, and assessed for coleoptile size at different temperatures (11, 15, 19, and 23°C). Repeatabilities for coleoptile diameter and length were moderate to high on an entry-mean basis (R2 = 0.48 and 0.77, respectively), reflecting large genotype and small genotype × temperature interaction variances. Genotypic variation among parents translated into large and significant (P < 0.01) differences among F1 progeny (94–142 mm and 1.56–1.84 mm for length and diameter, respectively). General (GCA) and specific combining ability (SCA), and reciprocal effects were significant (P < 0.01) for length and diameter. Baker’s GCA/SCA ratio was high (0.62–0.77) for coleoptile length but intermediate for diameter (0.38–0.64), indicating strong additive genetic control for length. Further, GCA effects and parental means were strongly correlated (r = 0.81–0.91, P < 0.01) indicating parent length to be a useful predictor of progeny performance. Coleoptile lengths for progeny derived from Rht8, Rht9, and Rht12 dwarfing gene donors were generally shorter (c. –7 to –13%) but were still an average 47% longer than coleoptiles of Rht-B1b and Rht-D1b controls. The genetic correlation for coleoptile length and diameter was small (rg = –0.25 ± 0.15n.s.) suggesting that the two traits are genetically independent. Development of wheats with longer, thicker coleoptiles should be readily achieved in selection among partially inbred families from crosses targetting improved establishment.

Direct seeding of black spruce in northwestern Ontario: Seedbed relationships

1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa
Keyword(s):  
Seedling Establishment ◽  
Black Spruce ◽  
Mineral Soil ◽  
Soil Surface ◽  
Direct Seeding ◽  
First Year ◽  
Strongly Correlated ◽  
Seedling Mortality ◽  
Northwestern Ontario ◽  
Seedbed Preparation

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination

scholarly journals QTL mapping of genotype–environment interaction for fitness in Drosophila melanogaster

1998 ◽  
Vol 71 (2) ◽  
pp. 133-141 ◽  
Author(s):  
JAMES D. FRY ◽  
SERGEY V. NUZHDIN ◽  
ELENA G. PASYUKOVA ◽  
TRUDY F. C. MACKAY
Keyword(s):  
Environmental Heterogeneity ◽  
Natural Populations ◽  
Antagonistic Pleiotropy ◽  
Environment Interaction ◽  
Standard Medium ◽  
Fitness Effects ◽  
Genotype Environment Interaction ◽  
Different Temperatures ◽  
Temperature Interaction ◽  
Ri Lines

A fundamental assumption of models for the maintenance of genetic variation by environmental heterogeneity is that selection favours alternative alleles in different environments. It is not clear, however, whether such antagonistic pleiotropy is common. We mapped quantitative trait loci (QTLs) causing variation for reproductive performance in each of three environmental treatments among a set of 98 recombinant inbred (RI) lines derived from a cross between two D. melanogaster laboratory strains. The three treatments were standard medium at 25°C, ethanol-supplemented medium at 25°C, and standard medium at 18°C. The RI lines showed highly significant genotype–environment interaction for the fitness measure. Of six QTLs with significant effects on fitness in at least one of the environments, five had significantly different effects at the different temperatures. In each case, the QTL by temperature interaction arose because the QTL had stronger effects at one temperature than at the other. No evidence for QTLs with opposite fitness effects in different environments was found. These results, together with those of recent studies of crop plants, suggest that antagonistic pleiotropy is a relatively uncommon form of genotype–environment interaction for fitness, but additional studies of natural populations are needed to confirm this conclusion.

Emergence, stand establishment and vigour of deep-sown Australian and CIMMYT wheats

2006 ◽  
Vol 46 (9) ◽  
pp. 1167 ◽  
Author(s):  
S. Gooding ◽  
T. L. Botwright Acuña ◽  
P. N. Fox ◽  
L. J. Wade
Keyword(s):  
Sandy Loam ◽  
Field Site ◽  
Red Clay ◽  
Coleoptile Length ◽  
Sowing Depth ◽  
Stand Establishment ◽  
Early Vigour ◽  
Australian Wheat ◽  
Seedling Characteristics ◽  
Rapid Emergence

The short coleoptile of the majority of released Australian wheat cultivars, is well-documented to increase time to emergence and reduce stand establishment. We examined the effect of seeding depth on coleoptile length and seedling characteristics of 36 CIMMYT wheats, bred for their ability to emerge from deep sowing, relative to 14 Australian cultivars in controlled and field environments. Coleoptile length of one of the CIMMYT lines, Berkut, exceeded that of Vigour 18 when grown in the dark in a controlled environment. In a second experiment in controlled conditions, this time with a regular day/night cycle, seedlings of 4 CIMMYT and 4 Australian cultivars emerged from 5 and 8 cm sowing depths, but only 50% of the Australian wheats emerged from 11 cm, compared with 100% for the CIMMYT wheats. In a third experiment, 6 cultivars were sown at depths of 5, 8 and 11 cm at 2 field sites with different soil types (a sandy loam duplex and a red clay) at Kukerin, Western Australia. Field site and sowing depth interacted for emergence time, stand establishment and coleoptile length, with higher values of each at the clay site. The first internode elongated at both field sites, but to a lesser extent on the clay soil, where the response was only observed with deep sowing. CIMMYT wheats Parus/Pastor and Berkut were notable for rapid emergence, a long sub-crown internode and coleoptile, and above-average leaf area in controlled and field environments, in comparison with Australian cultivars. These lines hold promise as genetic sources of improved stand establishment and early vigour in wheats for use in Australia and similar environments.

Effects of environmental factors on germination and emergence ofAmaranthus retroflexus

Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 505-510 ◽  
Author(s):  
R. Ghorbani ◽  
W. Seel ◽  
C. Leifert
Keyword(s):  
Seed Germination ◽  
Control Strategies ◽  
Germination Rate ◽  
Soil Surface ◽  
Dry Weight ◽  
Amaranthus Retroflexus ◽  
Nitrogen Supply ◽  
Biological Weed Control ◽  
Detailed Knowledge ◽  
Different Temperatures

Detailed knowledge about the environmental conditions required for weed seed germination and establishment in soil is an important prerequisite for the development of integrated and biological weed control strategies. Germination and establishmentof Amaranthus retroflexuswere studied at different temperatures, planting depths, soil types, nitrogen supply, and water potentials. The minimum temperature for seed germination was > 5 C; maximum germination occurred between 35 and 40 C. At temperatures between 25 and 35 C, an additive effect on germination rate was observed when temperature and water availability were increased. For all soils tested, the percentage emergence of seeds placed on the soil surface and 4 cm deep was significantly lower than seeds placed between 0.5 and 3 cm. Emergence in the four sandy soils was generally greater than in the two heavier soils included in the study. There was a highly significant interaction between seed depth and soil type. Plant growth was also greatest in the lighter soils. Plant height, number of leaves, leaf area, fresh and dry weight, and nitrogen and carbon percentage in plant tissues ofA. retroflexusincreased significantly with increasing soil nitrogen supply.

scholarly journals The Effect of Temperature, Light and Calcium Carbonate on Seed Germination and Radicle Growth of the Polycarpic Perennial Galium cracoviense (Rubiaceae), a Narrow Endemic Species From Southern Poland

2015 ◽  
Vol 57 (1) ◽  
pp. 70-81 ◽  
Author(s):  
Jeremi Kołodziejek ◽  
Jacek Patykowski
Keyword(s):  
Calcium Carbonate ◽  
Endemic Species ◽  
Soil Surface ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Radicle Growth ◽  
Southern Poland ◽  
Narrow Endemic ◽  
Before And After ◽  
Different Temperatures

Abstract Germination responses of Galium cracoviense Ehrend. (Rubiaceae), a narrow endemic species from southern Poland, were tested in light and dark conditions at three constant temperatures (5, 10, or 22°C), before and after cold-wet stratification. Additionally, seeds were germinated under different calcium carbonate (CaCO3) concentrations (1, 5, 10, 15, 20, or 25 mM/L CaCO3) at 22°C in light. The high germination capacity of seeds incubated at different temperatures, shortly after collection, already suggested the absence of dormancy in this species. Thus, the seeds are ready to germinate immediately in the field when water resources are available and the temperature is adequate. Light was a significant factor for G. cracoviense; more seeds germinated in light than in darkness at all temperatures tested. Cold stratification decreased germination especially at higher temperatures. The light requirement for G. cracoviense germination ensures their successful germination on or near the soil surface, and in cracks and crevices in limestone, when temperature and edaphic conditions are favourable. Seeds of this species show temperature enforced dormancy throughout the winter. Germination was significantly affected by calcium carbonate. Non-germinated seeds germinated well after being transferred from higher CaCO3 concentrations to distilled water. The results indicate that the seeds of this species can endure CaCO3 stress without losing their viability and start germination once CaCO3 concentration is reduced. It can be concluded that the seeds of this species require lower Ca2+ ion concentration, moderate temperatures and the presence of light to germinate.

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 Resistance to Meloidogyne enterolobii and Meloidogyne incognita in Cultivated and Wild Cowpea

HortScience ◽  
2021 ◽  
Vol 56 (4) ◽  
pp. 460-468
Author(s):  
Rocheteau Dareus ◽  
Antonio Carlos Mota Porto ◽  
Mesfin Bogale ◽  
Peter DiGennaro ◽  
Carlene A. Chase ◽  
...  
Keyword(s):  
Meloidogyne Incognita ◽  
Genotypic Variation ◽  
Geographic Origin ◽  
Nematode Species ◽  
Strongly Correlated ◽  
Industrialized Countries ◽  
Sources Of Resistance ◽  
Mini Core Collection ◽  
Meloidogyne Enterolobii ◽  
The University

Cowpea [Vigna unguiculata (L.) Walp] is a multipurpose crop that provides nutrients for human and livestock diets, as well as regulates and supports ecosystem services. In developing countries, cowpea is exploited as a dual-purpose crop for its grain and fodder; it is cultivated primarily for grain and as a cover crop in industrialized countries. However, root-knot nematodes (RKNs) (Meloidogyne spp.) represent a threat to cowpea production worldwide. Thus, we screened the University of California, Riverside (UC-Riverside), cowpea mini-core collection for resistance to Meloidogyne incognita Kofoid and White (Chitwood) and M. enterolobii Yang and Eisenback to verify the potential of this collection to be used for improving RKN resistance in cowpeas. Both screenings showed significant genotypic variation and medium/high broad-sense heritability (H2) estimates for most traits, and several traits were also strongly correlated. For the M. incognita screening, 86.1% of accessions showed some level of resistance based on gall score (≤3), and 77.7% based on reproduction index (RI) (25 ≤ RI ≤ 50), whereas only 10.4% and 29.8% of accessions were resistant to M. enterolobii based on gall score (≤3) and RI (25 ≤ RI ≤ 50), respectively. These results demonstrate the greater virulence of M. enterolobii than M. incognita in cowpea, and that geographic origin of germplasm was not linked to sources of resistance. Among cultivars, only US-1136 showed resistance against both nematode species, whereas 12 wild/landrace germplasms exhibited resistance to M. incognita and M. enterolobii, and can be exploited for breeding resistant cowpeas.

scholarly journals Inheritance of Resistance to Colletotrichum gloeosporioides and C. acutatum in Strawberry

2019 ◽  
Vol 109 (3) ◽  
pp. 428-435 ◽  
Author(s):  
Raymond L. Jacobs ◽  
Tika B. Adhikari ◽  
Jeremy Pattison ◽  
G. Craig Yencho ◽  
Gina E. Fernandez ◽  
...  
Keyword(s):  
Genetic Control ◽  
Colletotrichum Gloeosporioides ◽  
Leaf Tissue ◽  
Crown Rot ◽  
Valuable Insight ◽  
Inheritance Of Resistance ◽  
Additive Variance ◽  
Diallel Mating Design ◽  
Crown Tissue ◽  
Sib Families

Information on the inheritance of resistance to Colletotrichum gloeosporioides and C. acutatum hemibiotrophic infections (HBI) in strawberry leaf tissue and the genetic control of anthracnose crown rot (ACR) in crown tissue are relatively unknown. Six parental genotypes were crossed in a half-diallel mating design to generate 15 full-sib families. HBI and ACR experiments were conducted concurrently. Both seedlings and parental clones were inoculated with 1 × 106 conidia/ml of C. gloeosporioides or C. acutatum. Percent sporulating leaf area, wilt symptoms, and relative area under the disease progress curve were calculated to characterize resistance among genotypes and full-sib families. Low dominance/additive variance ratios for C. acutatum HBI (0.13) and C. gloeosporioides ACR (0.20) were observed, indicating additive genetic control of resistance to these traits. Heritability estimates were low for C. acutatum HBI (0.25) and C. gloeosporioides HBI (0.16) but moderate for C. gloeosporioides ACR (0.61). A high genetic correlation (rA = 0.98) between resistance to C. acutatum HBI and C. gloeosporioides HBI was observed, suggesting that resistance to these two Colletotrichum spp. may be controlled by common genes in strawberry leaf tissue. In contrast, negative genetic correlations between ACR and both HBI traits (rA = −0.85 and −0.61) suggest that resistance in crown tissue is inherited independently of resistance in leaf tissue in the populations tested. Overall, these findings provide valuable insight into the genetic basis of resistance, and the evaluation and deployment of resistance to HBIs and ACR in strawberry breeding programs.

EFFECT OF CULTIVAR, TRADITIONAL CORM PRE-TREATMENT AND WATERING ON SPROUTING AND EARLY GROWTH OF ENSET (Ensete ventricosum) SUCKERS

2014 ◽  
Vol 51 (2) ◽  
pp. 232-243 ◽  
Author(s):  
L. M. KARLSSON ◽  
A. L. DALBATO ◽  
T. TAMADO ◽  
Y. MIKIAS
Keyword(s):  
Soil Surface ◽  
Leaf Length ◽  
Strongly Correlated ◽  
Ensete Ventricosum ◽  
Livelihood Security ◽  
Drought Tolerant ◽  
Local Soil ◽  
Soil Preparation ◽  
Management Techniques ◽  
Pre Treatment

SUMMARYEnset [Ensete ventricosum (Welw.) Cheesman (Musaceae)] is a multi-purpose and drought-tolerant crop, traditionally grown in Ethiopia. Food from enset has nutritive values similar to potato; it could improve food and livelihood security for many in larger geographical areas. Agronomical advice is needed which requires increased knowledge of management techniques. The purposes of this study were to (i) compare traditional corm pre-treatments when planting for sucker production, (ii) compare all six officially released cultivars regarding sprouting and (iii) investigate the effect of watering on newly buried corms. Emergence rate and number and characteristics of sprouts were recorded. Corms, from 63 two year old plants, were buried in local soil supplied with cow manure in Wolaita Sodo, Ethiopia. Emergence was recorded daily. After nine months, including one rainy season, all suckers (totally 4405) were harvested and individually recorded. Regardless of cultivar, minimum time to emergence was 50 days. Sprouts from split parent corms emerged earlier than from entire. Emergence occurred from 100% of corms, number of sprouts was strongly correlated to cultivar: average 28–106. The cultivars responded similarly to corm splitting: the more pieces the corm was split into, the more sprouts per parent corm. Average pseudostem diameter of the seven largest per parent corm: 8–10 cm for all cultivars, leaf length: 3.1–3.7 m, remaining 2700 smaller suckers: diameter 3 cm (SD 1.8). Watering decreased the average time to emergence and levelled out the differences between pre-treatments. The traditional belief is that watering as well as manure on corm cause rotting; manure is therefore usually put on the soil surface. On the contrary, full emergence and unexpected large suckers may be a result of careful soil preparation with manure applied on corm directly; watering resulted in an even emergence and growth. In conclusion, vegetative propagation of enset is efficient, but methods used and agronomical advice can be improved.

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