Showing papers on "Cultivar published in 1993"

Transgenic sorghum plants via microprojectile bombardment.

Abstract: Transgenic sorghum plants have been obtained after microprojectile bombardment of immature zygotic embryos of a drought-resistant sorghum cultivar, P898012. DNA delivery parameters were optimized based on transient expression of R and C1 maize anthocyanin regulatory elements in scutellar cells. The protocol for obtaining transgenic plants consists of the delivery of the bar gene to immature zygotic embryos and the imposition of bialaphos selection pressure at various stages during culture, from induction of somatic embryogenesis to rooting of regenerated plantlets. One in about every 350 embryos produced embryogenic tissues that survived bialaphos treatment; six transformed callus lines were obtained from three of the eight sorghum cultivars used in this research. Transgenic (T0) plants were obtained from cultivar P898012 (two independent transformation events). The presence of the bar and uidA genes in the T0 plants was confirmed by Southern blot analysis of genomic DNA. Phosphinothricin acetyltransferase activity was detected in extracts of the T0 plants. These plants were resistant to local application of the herbicide Ignite/Basta, and the resistance was inherited in T1 plants as a single dominant locus.

Response of tomato cultivars to salinity

Abstract: The responses of five tomato cultivars (L. esculentum Mill) of different degrees of salt tolerance were examined over a range of 0 to 140 mM NaCl applied for 3 and 10 weeks. Judged by both Na and Cl accumulations and maintenance of K, Ca and Mg contents with increasing salinity, the most tolerant cultivars (Pera and GC-72) showed different responses. The greater salt tolerance of cv Pera was associated with a higher Cl and Na accumulation and a lower K content in the shoot than those found in the other cultivars, typical of a halophytic response to salinity. However, the greater salt tolerance of cv GC-72 was associated with a retention of Na and Cl in the root, restriction of their translocation to the shoot and maintenance of potassium selectivity under saline conditions. The salt tolerance mechanisms that operated in the remaining cultivars were similar to that of cv GC-72, as at first they excluded Na and Cl from the shoots, accumulating them in the roots; with longer treatment, the ability to regulate Na and Cl concentrations in the plant was lost only in the most salt sensitive cultivar (Volgogradskij), resulting in a massive influx of both ions into the shoot. The salt sensitivity of some tomato cultivars to salinity could be due to both the toxic effect of Na and Cl ions and nutritional imbalance induced by salinity, as plant growth was inversely correlated with Na and Cl contents and directly correlated with K and Ca contents. This study displays that there is not a single salt tolerance mechanism, since different physiological responses among tomato cultivars have been found.

Rapid Assessment of the Adulteration of Virgin Olive Oils by Other Seed Oils Using Pyrolysis Mass Spectrometry and Artificial Neural Networks

Abstract: Curie-point pyrolysis mass spectra were obtained from a variety of extra-virgin olive oils, prepared from various cultivars using several mechanical treatments Some of the oils were adulterated (according to a double-blind protocol) with different amounts of seed oils (50-500 ml of soya, sunflower, peanut, corn or rectified olive oils per litre of mixed oil) Canonical variates analysis indicated that the major source of variation between the pyrolysis mass spectra was due to differences between the cultivars rather than whether the oils had been adulterated However, artificial neural networks could be trained (using the back-propagation algorithm) successfully to distinguish virgin oils from those which had been adulterated

Effectiveness of adult-plant resistance in reducing grain yield loss to powdery mildew in winter wheat

Abstract: We studied the effectiveness of adult-plant resistance (APR) in protecting grain yields in winter wheat grown in Virginia under varying levels of intensity of powdery mildew (caused by Blumeria graminis f. sp. tritici) obtained with different fungicide treatments in field experiments in two crop years. Mildew severity was assessed at three to four plant growth stages, and the data were used to calculate mean mildew severity (MMS) and area under the mildew disease progress curve. The susceptible cultivar Saluda had an average MMS of 5.3%. MMS and grain yield for Saluda were significantly negatively correlated in both years, and yield loss averaged 13.4% in untreated plots relative to full-season control plots (.)

Durable Resistance to Rice Blast Disease

Abstract: Observations of low-level infection by virulent populations of Magnaporthe grisea on traditional upland rice cultivars, reveal the existence of durable resistance. Its analysis demonstrates that it is a partial resistance. Resistant cultivars show an adult plant resistance; they limit the number and the size of lesions, that have the lowest capacity of sporulation. This partial resistance is of a polygenic nature. Segregating lines are usually screened for the total effect of the partial resistance components. One of the main problems in screening for durable resistance is the interaction between segregating lines having different race-specific major resistance genes in addition to different levels of partial resistance, and a blast population heterogeneous in virulence. Specific methods of breeding for partial polygenic resistance are proposed for pedigree selection and recurrent selection methods.

Genetics of adult plant resistance to stripe rust in ten spring bread wheats

Abstract: Nine Mexican spring bread wheat (Triticum aestivum L.) cultivars derived from CIMMYT germplasm and the U.S. spring wheat cultivar Wheaton were susceptible to the Mexican Puccinia striiformis pathotype 14E14 in seedling growth stage, but displayed different levels of adult plant resistances to the same pathotype when tested in the field. One hundred and eighteen random F2 plant derived F3 and F5 lines from the crosses of these ten adult plant resistant wheats and susceptible cultivar Jupateco 73S were evaluated in the field. The moderate adult plant resistance of Penjamo 62, Lerma Rojo 64, Nacozari 76, Tesia 79, and Wheaton was under monogenic genetic control and was attributed to the adult plant stripe rust resistance gene Yr18. The moderate resistances of Cleopatra 74, Zaragoza 75, and Apache 81 were also monogenic, but gene Yr18 was absent. Pavon 76 carried two partially effective additive genes; and the adult plant resistance of Tonichi 81 was based on additive interaction involving Yr18 and two additional partially effective genes. Tonichi 81 does not carry any seedling resistance gene, however, the adult plant resistance is highly effective worldwide. This resistance, designated as the Yr18 complex, is of a durable nature. The partial adult plant resistance of Pavon 76 has also remained durable in Mexico and other countries where it is grown.

Apple cultivar variations in response to heat treatment and minimal processing

Abstract: Eleven apple cultivars were subjected to heat treatments at various times and temperatures. Susceptibility to browning during heat treatment and after heat treatment was evaluated. Changes in firmness, respiration rate, soluble solids and acidity of slices prepared with heat treated apples were measured. Incidence of browning was dependent upon cultivar and heating temperature; Liberty, Monroe, RI Greening and Rome were very susceptive, while McIntosh, NY 674 and Empire were less susceptive. Golden Delicious and Delicious showed relative strong tolerance to heat. Apples that received heat treatment at 45 o C produced slices with less browning and firmer texture compared to non-treated apples. The positive effect of heat treatment might help produce high quality minimum processed fruits

Resistance to leaf rust in 26 Mexican wheat cultivars

Abstract: CIMMYT germplasm derived wheat (Triticum aestivum L.) cultivars are grown on a large area worldwide. The status of leaf rust Puccinia recondita Roberge ex Desmaz. f. sp. tritici resistance in various cultivars is unknown. In this study, designated Lr genes were postulated in 26 cultivars released in Mexico between 1950 and 1989 by inoculating their seedlings with 14 pathotypes of diverse avirulence-virulence combinations. The adult plant resistance was evaluated with two currently predominant pathotypes during 1991-1992 crop cycle at Ciudad Obregon in northwest Mexico. Additionally, the probable presence of Lr13 and Lr34 was identified by determining the presence of linked genes Ne2 and Ltn, respectively (.)

Timing of reproductive abortions in relation to cell division, water content, and growth of pea seeds

Abstract: Pod number is the most explicative component of the yield variability of pea (Pisum sativum L.). To understand the processes that determine pod number, the timing of reproductive abortion, seed development, and growth were studied. Cultivar Solara was grown in nonstressed conditions during three successive years, in 1988 and 1990 in a glasshouse in 7-L pots with 4 or 5 plants per pot, and in 1989 in the field with 50 plants m -2 (.)

Corn Growth Following Cover Crops: Influence of Cereal Cultivar, Cereal Removal, and Nitrogen Rate

Abstract: Rye (Secale cereale L.) cover crops often delay development and reduce yield of corn (Zea mays L.). A 3-yr study (1982-1984) was conducted to investigate the influence of flour rye cultivars and one wheat (Triticum aestivum L.) cultivar, rate of N application in the spring, and removal of above-ground cereal phytomass on growth and development of corn. Experiments were carried out at the Elora Research Station, Ontario, in a split-plot design, with two N levels (145 and 220 kg ha −1 ) and five cereal cultivars as main plots, and cereal phytomass removal or retention as sub-plots. Cereal cultivars were planted in September after corn harvest and corn was planted in the spring [...]

Gas Exchange Differences and Comparative Anatomy among Cotton Leaf-type Isolines

Abstract: Photosynthesis rate could be a selection criterion for plant breeders, especially if lines with superior photosynthesis could be identified and coupled with those lines with suitable partitioning of photosynthate between reproductive and vegetative growth. Establishing why certain lines may differ in photosynthetic rate could provide additional tools for selection. Photosynthesis and leaf anatomy of the youngest fully expanded leaf in field plots of the super okra, okra, and normal leaftype isolines of the cotton (Gossypium hirsutum L.) genotype ‘MD 65− 11’, which differ in leaf size and degree of Iobing, were compared with the normal leaf genotype ‘DPL 50’. Super okra and okra averaged 24 and 22% greater leaf CO₂-exchange rates (CER), respectively, than the normal leaf isoline in both 1989 and 1990. These differences were associated primarily with greater specific leaf weight (SLW) and leaf chlorophyll concentration of the super okra and okra leaf types. Water use efficiency [WUEg = CER/leaf stomatal conductance (gₛ)] was and 40% greater for super okra and okra, respectively, during 1990 compared to normal leaf. Leaves of the super okra and okra isolines were 42% thicker than normal leaf which contributed to this greater SLW. The relative tissue percentage of various cell types and mesophyil surface area per unit leaf volume did not differ among genotypes. Rubisco concentrations per unit stroma area were similar among chloroplasts of the different genotypes. Genotypic differences in CER are likely due to a greater concentration of photosynthetic apparatus per unit leaf area caused by leaf thickness differences, however the possibility of differences in the rate of dark respiration or photores piration cannot be discounted.

Soybean cultivar 9202709

Abstract: A novel soybean cultivar, designated 9202709, is disclosed. The invention relates to the seeds of soybean cultivar 9202709, to the plants of soybean 9202709 and to methods for producing a soybean plant produced by crossing the cultivar 9202709 with itself or another soybean variety. The invention further relates to hybrid soybean seeds and plants produced by crossing the cultivar 9202709 with another soybean cultivar.

Genotypic differences in phosphorus efficiency of wheat

Abstract: In an attempt to evaluate whether breeding and selection for high yielding capacity did change the P requirements of modern wheat cultivars, the response of two wheat cultivars to different levels of P supply was investigated. A traditional cultivar (“Peragis”) and a modern cultivar (“Cosir”) were cultivated in a C-loess low in available P and high in CaCO3 in 120 cm high PVC pots. Shoot and root growth at different developmental stages was compared. The grain yield of the modern cultivar Cosir was higher at limiting and non-limiting P supply and, therefore, this cultivar can be considered as more P-efficient than the traditional cultivar. From the results it can be concluded that the main factors contributing to the higher P efficiency of the modern cultivar are (i) efficient use of assimilates for root growth characteristics which enhance P acquisition: smaller root diameter, and longer root hairs, (ii) efficient remobilization of P from vegetative plant organs to the grains, and (iii) lower P requirement for grain yield formation because of lower ear number per plant but higher grain number per ear.

Genetic improvement of spring barley cultivars grown in eastern Canada from 1910 to 1988

Abstract: Spring barley is an important feed crop in eastern Canada, and the development of high-yielding, high grain protein cultivars is desirable. This study was conducted to assess the impact of breeding on the yield and protein aspects of cultivar development, and to identify related changes in plant characteristics which may have been altered over time. A 3-year field experiment was conducted to evaluate twenty six-rowed spring barley genotypes representing the majority of cultivars developed from 1910 to 1988 for eastern Canada. The yields of barley cultivars released from 1935 to 1988 increased at a rate of about 0.03 t ha-1 yr-1, and showed no evidence of having reached a plateau. Increases in yield were associated with higher total dry matter production and harvest index, reduced plant height and increased lodging resistance. No consistent change in main stem or tiller yield components was observed. Grain protein concentration decreased progressively with time, especially with the newer cultivars. Reduction in grain protein concentration was not associated with lower protein content on a per grain basis, but rather with an increase in the amount of non-structural carbohydrate per grain. Total plant and grain N accumulation showed positive trends with time. No trends were observed for N harvest index, apparent post-heading N uptake, N retranslocation, and retranslocation efficiency. Thus, while the newer cultivars accumulated more total and grain N, proportional N partitioning to the grain was not altered.

F2 Hybrids of Host Plant Germplasm and Cotton Cultivars: I. Heterosis and Combining Ability for Lint Yield and Yield Components

Abstract: Although pest-resistant cotton (Gossypuim hirsutum L.) germplasm is available, it is generally not equal to adapted cultivars and other elite germplasm in yield. Cotton F 2 hybrids could provide a means to combine beneficial traits of high-yielding adapted cultivar (elite) germplasm with those of pest-resistant germplasms. In the F 2 heterosis and combining ability were studied for lint yield and the primary yield component boll number as well as for the secondary yield components of lint percentage and boll weight (.)

Contrasting the Tolerance of Wild and Domesticated Tomatoes to Herbivory: Agroecological Implications

Abstract: Application of plant life-history theory to strategies for breeding crop plants for sustainable agriculture remains relatively unexplored. We determined the relative tol- erance of wild and domesticated tomatoes to simulated herbivory and evaluated plant characteristics that may contribute to tolerance. Wild and domesticated tomatoes were subjected to different levels of defoliation ranging from 0 to 70%. Single defoliation events at lower levels (15-30%) did not significantly affect total fruit mass produced in either wild or domesticated tomatoes. Increased defoliation resulted in significant reductions in total fruit mass per plant and mean mass per fruit. Reduction in fruit output by the cultivar was -3 times greater than the wild tomato for the first 8 wk of fruit production, whereas the loss in seasonal fruit production by the cultivar was 1.7 times greater than the wild tomato. We concluded that domestication of tomatoes may have decreased their relative tolerance to herbivory. Possible mechanisms for decreased tolerance include differences in leaf area index, light capture curves, and the relative allocation pattern to vegetative growth vs. reproductive structures. Optimization of potential life-history trade-offs between tol- erance to herbivory and maximum fruiting abilities are proposed for cultivars of sustainable agriculture.

Nitrogen Fertilization of Cotton Cultivars of Differing Maturity

Abstract: Management of N nutrition of cotton (Gossypium hirsutum L.) is one of the most critical aspects of successful cotton production, but growth and yield responses of individual cotton cultivars to N fertilization is relatively unknown. The objective of this research was to evaluate the responses of three cotton cultivars (Arkot 518, Stoneville 453, and Deltapine 90) to soil-applied N fertilization rates. The study was conducted for 3 yr on a Hebert silt loam soil (fine-silty, mixed, thermic Aeric Ochraqualf). Few significant (α = 0.05) cultivar × N rate interaction differences were found, although main effects of the N treatments and the cultivars were evident. The most pronounced responses of the cotton were found as an effect of the N-fertilization treatments [...]

Strawberry plant called `Camarosa`

Abstract: `Camarosa` is a short-day (June bearing) cultivar similar to `Chandler` (U.S. Plant Pat. No. 5,262) but with greater total productivity, substantially greater early productivitiy, larger fruit, firmer fruit, and is a more vigorous plant.

A field comparison of conventional suckers with tissue culture banana planting material over three crop cycles

Abstract: A randomized block split-plot experiment was established at Burgershall Research Station, eastern Transvaal to compare three cultivars (Williams, Dwarf Cavendish and Grand Nain) and three types of planting material (conventional 2 kg pared suckers, 200 and 500 mm high, tissue cultured plants rooted in bags). In the first crop cycle (P), tissue culture (TC) plants were up to 300 mm taller than conventional suckers (CON) at flowering. Over all three cultivars, TC plants yielded 56 t ha-1 annum“1 which was 20.4% higher than CON plants, due to larger bunches and a shorter cycle to harvest. Cvs Williams and Grand Nain yielded similarly at 54 t ha-1 annum-1 which was 9% more than ‘Dwarf Cavendish’ over all planting materials. There were 30 (1.76%) distinct somaclonal variants in the plantation of 1,700 plants. In the second crop cycle (Rl), there was a significant carry-over effect with TC plants, as shown by the increased vigour and size of the first ratoon followers selected on TC mother plants. Such TC follo...

Research achievements in plant resistance to insect pests of cool season food legumes

Abstract: Plant resistance to at least seventeen field and storage insect pests of cool season food legumes has been identified. For the most part, this resistance was located in the primary gene pools of grain legumes via conventional laboratory, greenhouse, and field screening methods. The use of analytical techniques (i.e., capillary gas chromatography) to characterize plant chemicals that mediate the host selection behavior of pest insects offers promise as a new, more rapid way to differentiate between insect-resistant and susceptible plant material. Examples of research achievements in mechanisms of resistance and host-plant resistance within the context of integrated control programs are discussed. Accelerating the development and subsequent releases of insect-resistant cultivars to pulse farmers requires more involvement from interdisciplinary teams of plant breeders, entomologists, plant pathologists, plant chemists, molecular biologists, and other scientists.

Nitrogen Fertilizer and Cultivar Effects on Yield and Nitrogen-Use Efficiency of Grain Amaranth

Abstract: Knowledge of fertility requirements or nitrogen-use efficiency of amaranth (Amaranthus spp.) cultivars is limited. The objectives of this research were to determine the response of grain amaranth to applied N, P, and K, and to determine the effect of cultivar and fertilizer N on nitrogen-use efficiency. Two field experiments were conducted. In the first, five rates of N, P, and K were applied in a central composite design with the cultivar Plainsman grown in five environments. In a second experiment, six amaranth cultivars, Amont, K266, K283, Plainsman, K432 and D136, were grown in three environments with five N rates (0, 45, 90, 135, and 180 kg N ha −1 ) []

Identification of powdery mildew resistance genes in common wheat (Triticum aestivum L). II. French cultivars

Abstract: Des genes majeurs de resistance a l'agent de l'oidium du ble Erysiphe graminis f sp tritici ont ete recherches chez 35 cultivars francais de ble, et quelques-uns de leurs parents. Les cultivars ont ete testes avec un ensemble d'isolats differentiels presentant des interactions specifiques sur chaque lignee hote. Les resultats ont ete completes par des observations cytologiques et par une analyse des genealogies. Dix huit cultivars ont montre des reactions de sensibilite. Les autres forment 9 groupes possedant 1 ou 2 genes de resistance. Des 5 genes de resistance connus presents chez les cultivars etudies, Pm2 apparait le plus frequemment (chez 5 cultivars) suivi de Pm4b et Pm6 (chacun present chez 4 cultivars], Pm5 (3 cultivars) et Pm8 (2 cultivars) [...]