scholarly journals Leafminer Resistance in Spinach

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1716-1719 ◽  
Author(s):  
Beiquan Mou
Keyword(s):  
Leaf Area ◽  
Field Experiments ◽  
Spinacia Oleracea ◽  
Plant Biomass ◽  
Rank Order ◽  
Field Tests ◽  
Genotypic Differences ◽  
Plant Weight ◽  
Unit Leaf Area ◽  
Unit Leaf

Leafminer (Liriomyza spp.) is a major insect pest of many important agricultural crops, including spinach (Spinacia oleracea). Genetic variability in leafminer resistance has not been studied for spinach. The purposes of the present experiments were to evaluate differences in leafminer damage among spinach genotypes, to compare results obtained from insect cage and field experiments, and to study the association among different resistant traits. We screened 345 accessions of the U.S. spinach collection for leafminer resistance in an outdoor insect cage and putative resistant genotypes were further tested in the cage and in the field over 2 years. Although no genotype was immune to leafminers, significant genotypic differences were found for leafminer stings per unit leaf area, mines per plant, and mines per 100 g plant weight. PI 274065 had the lowest sting density, whereas PI 174385 showed the fewest mines per unit plant weight among genotypes in the field. Rank order of stings per square centimeter leaf area did not significantly change for the genotypes in the cage and field tests, and the sting results from different tests were also highly correlated, suggesting that a cage test could be used to screen germplasm for fewer leafminer stings, and sting density is a reliable trait for the selection of leafminer feeding nonpreference. Stings per unit leaf area were not correlated with mines per plant or per 100 g plant weight, which suggests that feeding nonpreference does not necessarily mean oviposition–nonpreference for a spinach genotype and these two traits can be improved independently. Stings per square centimeter leaf and mines per 100 g plant weight had little correlation with plant weight in cage and field tests, suggesting that leafminer sting and mine densities are not associated with plant biomass, and it is possible to improve and combine the leafminer resistance and yield traits in a spinach cultivar. From these findings, the genetic improvement of spinach for leafminer resistance seems feasible.

scholarly journals Screening and Breeding for Leafminer Resistance in Spinach

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1114D-1115
Author(s):  
Beiquan Mou
Keyword(s):  
Leaf Area ◽  
Recurrent Selection ◽  
Spinacia Oleracea ◽  
Insect Pest ◽  
Germplasm Collection ◽  
Leaf Miner ◽  
Genotypic Differences ◽  
Plant Weight ◽  
Unit Leaf Area ◽  
Unit Leaf

Leaf miner(Liriomyza spp.) is a major insect pest of many important vegetable crops, including spinach (Spinacia oleracea). Chemical control is not long lasting, and it is well documented that leafminers can develop a high degree of resistance to insecticides. Resistant varieties remain the most economical means of insect control. The purposes of the present experiments were to evaluate differences in spinach genotypes to leafminer damage, to compare results obtained from insect cages and from the field, and to study the association among different resistant traits. We screened 345 spinach genotypes from the USDA germplasm collection and 441 genotypes from CGN (Holland) and IPK (Germany) spinach collections for leafminer resistance in an outdoor insect cage and in the field. Significant genotypic differences were found for leafminer stings per unit leaf area, mines per plant, and mines per 100 g of plant weight. The sting result from the field was highly correlated (r = 0.770) with the result from the insect cage, demonstrating that a cage test could be used to screen for leafminer resistance in the field. Mines per plant were not correlated with plant weight, suggesting that leafminer flies did not lay their eggs randomly and oviposition-nonpreference occurred in these plants. Stings per unit leaf area was not correlated with mines per plant or per 100 g plant weight, which suggests that feeding-nonpreference does not necessarily mean oviposition-nonpreference for a spinach genotype and these two traits can be improved independently. These findings suggest that genetic improvement of spinach for leafminer resistance is feasible. A phenotypic recurrent selection method is used to increase the level of leafminer resistance in spinach.

Genotypic, intraplant, and environmental variation in stomatal frequency and size in wheat

1993 ◽  
Vol 73 (3) ◽  
pp. 671-678 ◽  
Author(s):  
H. Wang ◽  
J. M. Clarke
Keyword(s):  
Leaf Area ◽  
Rank Order ◽  
Triticum Aestivum L ◽  
High Light Intensity ◽  
Genotypic Differences ◽  
Stomatal Frequency ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Triticum Spp ◽  
Number Of Leaves

Stomatal characteristics are of interest in physiological studies and in the development of cultivars to improve productivity or stress resistance. In wheat (Triticum spp.) previous studies show contradictory results for intraplant variation in stomatal frequency and size. Our objective was to investigate the effects of genotype, environment and intraplant variation on stomatal frequency, size and the total stomatal area per unit leaf area in tetraploid (T. turgidum L. var. durum) and hexaploid (T. aestivum L.) wheat, and to assess requirements of sample size and allocation for determining genotypic differences. Significant variation was found in stomatal frequency within leaves (position on leaf and between surfaces), among leaf positions within plants, and with leafage in both wheat species. To obtain consistent genotypic differences, fully expanded leaves from the same plant position should be taken, and frequency counts should be made on the same leaf surface and at a constant position within leaves. Although stomatal frequency was negatively correlated with stomatal size, the total stomatal area per unit leaf area usually increased with increasing stomatal frequency. Stomatal frequency increased under dry or high light intensity environments. There were no significant changes in genotype rank order for stomatal frequency in different environments. Increasing the number of leaves sampled had a greater impact on precision of determination of stomatal frequency than increasing the number of microscope fields counted within leaves. Key words: Stomata, Triticum aestivum L., T. turgidum L. var. durum

scholarly journals Retention and the Kinetics of Uptake and Export of Foliage-applied, Labeled Boron by Apple, Pear, Prune, and Sweet Cherry Leaves

1995 ◽  
Vol 120 (1) ◽  
pp. 28-35 ◽  
Author(s):  
G.A. Picchioni ◽  
S.A. Weinbaum ◽  
P.H. Brown
Keyword(s):  
Leaf Area ◽  
Sweet Cherry ◽  
Foliar Application ◽  
Surface Characteristics ◽  
Genotypic Differences ◽  
Retention Capacity ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Leaf Retention ◽  
Kinetics Of Uptake

Leaf retention, uptake kinetics, total uptake (per unit leaf area), export kinetics, and the total export of foliage-applied, labeled B (]0B-enriched boric acid) were determined for apple (Malus domestics Borkh.), pear (Pyrus communis L.), prune (Prunus domestics L.), and sweet cherry (P. avium L.). Foliar uptake of labeled B by shoot leaves was 88% to 96% complete within 24 hours of application. More than 50% of the B retained on shoot leaf surfaces following application was absorbed and exported within 6 hours of application. Genotypic differences in shoot leaf surface characteristics among the species tested greatly influenced the amount of solution retained per unit leaf area. Leaf retention capacity was the primary determinant of the quantity of B absorbed by and exported from shoot leaves following foliar application. On average, apple shoot leaves retained, absorbed, and exported at least twice as much labeled B per unit leaf area as prune and pear shoot leaves and three to four times as much as sweet cherry shoot leaves. The sink demand of nearby, mature apples did not affect the export of labeled B when applied to adjacent spur leaves, but the fruit imported 16% of their total B from the applied solution during a 10-day period. Despite extensive documentation for the immobility of B accumulated by leaves naturally (e.g., from the soil), the B accumulated by leaves following foliage application was highly mobile in all four species tested.

Acrolein Reduces Biomass and Seed Production of Potamogeton pectinatus in Irrigation Channels

2004 ◽  
Vol 18 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Diego J. Bentivegna ◽  
Osvaldo A. Fernández ◽  
María A. Burgos
Keyword(s):  
Plant Growth ◽  
Field Experiments ◽  
Plant Biomass ◽  
Treatment Plant ◽  
Irrigation District ◽  
Potamogeton Pectinatus ◽  
Individual Plant ◽  
Plant Weight ◽  
The Third ◽  
Irrigation Channels

Chemical weed control with acrolein has been shown to be a lower cost method for reducing submerged plant biomass of sago pondweed in the irrigation district of the Lower Valley of Rio Colorado, Argentina (39°10′S–62°05′W). However, no experimental data exist on the effects of the herbicide on plant growth and its survival structures. Field experiments were conducted during 3 yr to evaluate the effect of acrolein on growth and biomass of sago pondweed and on the source of underground propagules (i.e., rhizomes, tubers, and seeds). Plant biomass samples were collected in irrigation channels before and after several herbicide treatments. The underground propagule bank was evaluated at the end of the third year. Within each treatment, plant biomass was significantly reduced by 40 to 60% in all three study years. Rapid new plant growth occurred after each application; however, it was less vigorous after repeated treatments. At the end of the third year at 3,000 m downstream from the application point, plant biomass at both channels ranged from 34 to 3% of control values. Individual plant weight and height were affected by acrolein treatments, flowering was poor, and seeds did not reach maturity. After 3 yr, acrolein did not reduce the number of tubers. However, they were significantly smaller and lighter. Rhizomes fresh weight decreased by 92%, and seed numbers decreased by 79%. After 3 yr of applications, operational functioning of the channels could be maintained with fewer treatments and lower concentrations of acrolein.

Stomatal Development During Leaf Expansion in Tobacco and Sunflower

1975 ◽  
Vol 23 (2) ◽  
pp. 253 ◽  
Author(s):  
HM Rawson ◽  
CL Craven
Keyword(s):  
Leaf Area ◽  
Stomatal Density ◽  
Stomatal Development ◽  
Developmental Patterns ◽  
Full Size ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Wide Range ◽  
Young Leaves ◽  
Different Levels

Changes in stomatal density and size were followed in tobacco and sunflower leaves expanding from 10% of final area (10% Amax) to Amax under different levels of radiation. Lower radiation increased final leaf area, reduced stomatal densities, and increased area per stoma but had little effect on stomatal area per unit leaf area at Amax. In very young leaves (20% Amax) there was a wide range in the sizes of individual stomata, some stomata being close to full size, but by Amax differences were small. The possible relationship between the developmental patterns described and photosynthesis is briefly discussed.

Effect of Interspecific Interference, Light Intensity, and Soil Moisture on Soybean (Glycine max), Common Cocklebur (Xanthium strumarium), and Sicklepod (Cassia obtusifolia) Water Uptake

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 534-540 ◽  
Author(s):  
Ronald E. Jones ◽  
Robert H. Walker
Keyword(s):  
Soil Moisture ◽  
Light Intensity ◽  
Leaf Area ◽  
Water Uptake ◽  
Root Weight ◽  
Pressure Potential ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Shoot Weight ◽  
The Relationship

Greenhouse and growth chamber experiments with potted plants were conducted to determine the effects of interspecific root and canopy interference, light intensity, and soil moisture on water uptake and biomass of soybean, common cocklebur, and sicklepod. Canopy interference and canopy plus root interference of soybean with common cocklebur increased soybean water uptake per plant and per unit leaf area. Root interference with soybean decreased common cocklebur water uptake per plant. Canopy interference of soybean with sicklepod increased soybean water uptake per unit leaf area, while root interference decreased uptake per plant. Combined root and canopy interference with soybean decreased water uptake per plant for sicklepod. Soybean leaf area and shoot weight were reduced by root interference with both weeds. Common cocklebur and sicklepod leaf area and shoot weight were reduced by root and canopy interference with soybeans. Only common cocklebur root weight decreased when canopies interfered and roots did not. The relationship between light intensity and water uptake per unit leaf area was linear in both years with water uptake proportional to light intensity. In 1991 water uptake response to tight was greater for common cocklebur than for sicklepod. The relationship between soil moisture level and water uptake was logarithmic. Common cocklebur water uptake was two times that of soybean or sicklepod at −2 kPa of pressure potential. In 1991 common cocklebur water uptake decreased at a greater rate than soybean or sicklepod in response to pressure potential changes from −2 to −100 kPa.

Carbon Isotope Discrimination and Gas Exchange in Coffea arabica During Adjustment to Different Soil Moisture Regimes

1992 ◽  
Vol 19 (2) ◽  
pp. 171 ◽  
Author(s):  
FC Meinzer ◽  
NZ Saliendra ◽  
C Crisosto
Keyword(s):  
Soil Moisture ◽  
Gas Exchange ◽  
Leaf Area ◽  
Coffea Arabica ◽  
Carbon Isotope Discrimination ◽  
Total Leaf Area ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Moisture Regimes ◽  
Area Basis

Although carbon isotope discrimination (Δ) has been reported to decline in plants growing under reduced soil moisture, there is little information available concerning the dynamics of adjustments in Δ and gas exchange following a change in soil water availability. In this study Δ, photosynthetic gas exchange, and growth were monitored in container-grown coffee (Coffea arabica L.) plants for 120 days under three soil moisture regimes. At the end of 120 d, total leaf area of plants irrigated twice weekly was one half that of plants irrigated twice daily, although their assimilation rates on a unit leaf area basis were nearly equal throughout the experiment. This suggested that maintenance of nearly constant photosynthetic characteristics on a unit leaf area basis through maintenance of a smaller total leaf area may constitute a major mode of adjustment to reduced soil moisture availability in coffee. Intrinsic water-use efficiency (WUE) predicted from foliar Δ values was highest in plants irrigated weekly, intermediate in plants irrigated twice weekly and lowest in plants irrigated twice daily. When instantaneous WUE was estimated from independent measurements of total transpiration per plant and assimilation on a unit leaf area basis, the reverse ranking was obtained. The lack of correspondence between intrinsic and instantaneous WUE was attributed to adjustments in canopy morphology and leaf size in the plants grown under reduced water supply which enhanced transpiration relative to assimilation. Values of Δ predicted from the ratio of intercellular to ambient CO2 partial pressure determined during gas exchange measurements were not always consistent with measured foliar Δ. This may have resulted from a patchy distribution of stomatal apertures in plants irrigated weekly and from a lag period between adjustment in gas exchange and subsequent alteration in Δ of expanding leaves. The importance of considering temporal and spatial scales, and previous growth and environmental histories in comparing current single leaf gas exchange behaviour with foliar Δ values is discussed.

Photosynthetic Acclimation of Alocasia macrorrhiza (L.) G. Don

1988 ◽  
Vol 15 (2) ◽  
pp. 107 ◽  
Author(s):  
WS Chow ◽  
L Qian ◽  
DJ Goodchild ◽  
JM Anderson
Keyword(s):  
Charge Density ◽  
Leaf Area ◽  
Cell Walls ◽  
Surface Charge Density ◽  
Leaf Tissue ◽  
O2 Evolution ◽  
Palisade Cell ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Growth Irradiance

The photosynthetic acclimation of Alocasia macrorrhiza (L.) G. Don, a species naturally occurring in deep shade in rainforests, has been studied in relation to a wide range of controlled irradiances during growth (~3-780 �mol photons m-2 s-1 of fluorescent or incandescent light, 10 h light/ 14 h dark). At the maximum growth irradiances, the light- and CO2-saturated rates of O2 evolution per unit leaf area were ~4 times as high as at low irradiance, and approached those of glasshouse-grown spinach. Growth at maximum irradiances reduced the quantum yield of O2 evolution only slightly. Changes in the anatomy of leaf tissue, the ultrastructure of chloroplasts and the composition of chloroplast components accompanied the changes in photosynthetic functional characteristics. At low growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the distal periclinal cell walls and had large granal stacks, and the destacked thylakoids had a very low surface charge density. In contrast, at higher growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the anticlinal cell walls; they had small granal stacks, large stromal space, and a high surface charge density on the destacked thylakoids. The number of chloroplasts per unit section length increased with growth irradiance. Ribulosebisphosphate carboxylase activity per unit leaf area increased markedly with irradiance. Photosystem II, cytochrome f and latent ATPase activity per unit chlorophyll increased to a lesser extent. While the chlorophyll a/chlorophyll b ratio increased substantially with growth irradiance, the chlorophyll content per unit leaf area declined slightly. Our results show that coordinated changes in the structure of leaf tissue, and the organisation and composition of chloroplast components are responsible for Alocasia being capable of acclimation to high as well as low irradiance.

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