Deltapine Smooth Leaf Research Articles

Assessing Cotton Genotypes for Resistance to Aphis gossypii (Hemiptera: Aphididae).

Aphis gossypii Glover (Hemiptera: Aphididae) is a polyphagous species frequently associated with the presence of sooty mold and viruses lethal to plants. The purpose of this work was to characterize possible resistance categories of cotton genotypes against A. gossypii. Initially, a preliminary test was carried out with 78 genotypes, 15 of which were selected for infestation ability assays and the determination of the cumulative aphid-day rates. Posteriorly, these genotypes were also evaluated through antixenosis and antibiosis assays. The genotypes FM 910, FM 966 LL, Mocó, Gossypium hirsutum var. punctatum L. (Malvaceae), Variedade Reba = BTK-12, Deltapine, Hi-Bred, Acala 4-42, IAC PV010-1664, IAC 21, Reba B-50 PR and FMT 709 inhibited the aphid colonization. In the infestation ability assay, G. hirsutum punctatum, IAC PV010-1664 and Acala 4-42 were the least infested. In a multiple-choice assay, Deltapine Smooth Leaf and Variedade Reba = BTK-12 were significantly less infested, suggesting antixenosis. In the antibiosis assay, Gossypium arboreum L. (Malvaceae) 1 showed the lowest number of nymphs, number of nymphs per adult per day and, number of nymphs at 10 d after the birth of the first nymph in addition to reducing the reproductive period, nymphal survival, adult longevity and, developmental time. In the FM 910, the number of nymphs produced per day and, at 10 d after the birth of the first nymph decreased, which also indicated resistance. The results obtained here are unprecedented and can be explored in breeding programs to develop insect-resistant cotton cultivars.

Oviposition by Heliothis armigera and H. punctigera (Lepidoptera: Noctuidae) on Okra Leaf and Smooth-Leaf Cotton

This study compared oviposition by Heliothis armigera (Hübner) and H. punctigera (Wallengren) on four cotton cultivars: a smooth-leaf cultivar (‘Deltapine Smooth Leaf’) and a genetically similar hirsute cultivar (‘Deltapine 16’), an okra leaf cultivar (‘Coker 201 Okra Leaf’) and a near-isogenic normal-leaf cultivar (‘Coker 201 Normal Leaf’). In the glasshouse, ‘Deltapine Smooth Leaf’ plants received the lowest number of eggs and ‘Coker 201 Normal Leaf’ the highest. In the field, ‘Deltapine Smooth Leaf’ had the fewest eggs and ‘Coker 201 Okra Leaf’ the most. Both Heliothis species exhibited similar oviposition on different structures on each cultivar for each plant growth stage. Most eggs were laid on mature leaves. In the glasshouse, the lower leaf surface received more eggs than the upper; the upper surface received more eggs in the field. Terminal buds received the fewest eggs in the glasshouse, but in the field, egg numbers on terminal buds, bracts, stems, petioles, and stipules were similar. Analysis of the relative effect of the okra leaf and smooth-leaf traits on oviposition indicates higher oviposition on the okra leaf than on the smooth-leaf plants, although trichome density might in part be responsible for some of the differences.

Effect of Mercerization on the Relation Between Single Fiber Mechanical Properties and Fine Structure for Different Cotton Species

Five G. barbadense species obtained from Egypt (Dendara, and Gizas 75, 76, 77, and 80), one American G. barbadense cotton (Pima S-5), and one American G. hirsutum cotton (Deltapine Smooth Leaf) were studied. Mercerization appeared to decrease the crystallinity of the G. hirsutum cotton more than that of the G. barbadense types. The mercerization treatment also appeared to have swollen the G. hirsutum fibers by a greater amount. The large increase in breaking load of the Deltapine Smooth Leaf cotton, which occurred on mercerization, may be due to the lower crystallinity and smaller crystallite lengths induced in these fibers by this treatment. The breaking load of the G. barbadense fibers either increased by smaller amounts than that obtained with the G. hirsutum sample or it fell. Mercerization appeared to reduce the brittleness of the Egyptian G. barbadense varieties; however, the changes were small and with Dendara, insignificant. For Pima S-5, brittleness did not change, and with Deltapine Smooth Leaf, the apparent increase in brittleness was insignificant. Mercerization appeared to improve the flex lives of the Giza 76, Giza 80, Pima S-5, and Deltapine Smooth Leaf samples, but the evidence for an increase was not as strong in the case of Giza 75, Giza 77, and Dendara. Mercerized Gizas 76 and 77 appeared to have the shortest flex lives of all the mercerized G. barbadense samples tested.

Antixenosis of Smooth Leaf Cotton to the Ovipositional Response of Tobacco Budworm1

Cottons (Gossypium spp.) ranging from glabrous (Smooth leaf) to Pilose were compared to determine their effects on I he ovipositional response of the tobacco budworm moth, Heliothis virescens (F.). The numbers of trichome branches/cm on the margin, midrib, secondary vein, and petiole., and in an area of the lamina of young fully expanded cotton leaves were positively correlated with the number of eggs laid on cotton plants. Tobacco budworm moths laid fewer eggs on leaves of cottons with no more or fewer trichome branches than those found on ‘Deltapine Smooth Leaf’ than on the normally pubescent cultivar ‘Stoneville 213’ or on the densely pubescent (Pilose) line. Stoneville 213, a pubescent near‐isoline, and a Smooth leaf near‐isoline (Sm2) in Stoneville 213 background, were tested in solid and mixed plantings. Significantly fewer eggs were laid on the Smooth leaf cotton than on the pubescent cottons whether or not the tobacco budworm had a choice of hosts. In a laboratory test, bond paper, synthetic net, rayon, cheesecloth, and muslin fabric were compared in no‐choice and freechoice tests as ovipositional surfaces. Those with textures that had fibers with the highest numbers of loose ends (cheesecloth and muslin) were preferred by tobacco budworm females.

Genotype × environment interactions and evaluation of cotton cultivars*

Stoneville 7A and Deltapine Smooth Leaf, bred in the Mississippi delta, were the highest yielders among a small group of medium-staple United States cultivars compared over three seasons and three sites in the Ord River valley (15° 39´S.), north-western Australia. Significant cultivar x year interactions existed for lint yield, lint percentage, boll weight, micronaire and Pressley strength, and significant cultivar x site x year interactions occurred for lint yield, lint percentage and staple length. Significant cultivar x site interactions occurred only for lint yield and Pressley strength. From the expected standard errors of cultivar means an evaluation procedure involving sampling for seed cotton yield over 3 years at each of six sites and two replications, but sampling for other agronomic and fibre quality attributes only at one site, was suggested. This procedure should result in standard errors of 5% or less of the mean values for all attributes. Consistency and stability of cultivar behaviour was assessed by simple rank methods, and Finlay and Wilkinson's joint regression method. The consistency of performance was such that a high probability of choosing the top yielders successfully would have attended early selection. ______________________ * The field work reported in this paper was carried out by the senior author when he was a member of the Division of Land Use Research, CSIRO.

The effect of planting date on the yield and some fibre properties of cotton in the Namoi Valley

The effect of planting dates between September 30 and November 30 on the yield and some fibre properties of two cotton cultivars has been studied over three seasons. The yield of the commercial cultivar (Deltapine Smoothleaf) fell by an average of 20 kg ha-1 day-1 delay in planting after October 20, earlier planting dates having equal yields, producing a plateau effect. The yield of an early maturing cultivar (Short Sympodial) fell linearly by 11 kg ha-1 day-1 delay in planting. Planting dates after mid-October had an adverse effect on micronaire in the commercial cultivar, but lint length and strength were not affected. Thus maximum yield and micronaire for plantings after mid-October came from the early cultivar. Tolerance to low temperature is an important factor in cultivar earliness, and accounts for the performance of Short Sympodial in these experiments. The number of days from first flower to first frost was as reliable as growing degree days in explaining yield variation within a cultivar

Oscillations in Stomatal Conductance

It is supposed that oscillations in stomatal conductance are associated with the dynamic properties of the loop in which rate of evaporation affects, through physiological processes, the aperture of stomata and stomatal aperture in turn affects rate of evaporation. It is therefore predicted that their occurrence must be influenced by the magnitude of what is termed environmental gain: the sensitivity of rate of evaporation to change in leaf conductance to vapor transfer. Two methods of manipulating gain, and their effects on stomatal behavior in cotton (Gossypium hirsutum L. cv. Deltapine Smooth Leaf), are described. In the first, gain was increased by decreasing ambient humidity; in the second, it was made zero by regulating ambient humidity to keep rate of evaporation constant despite changes in conductance. The results are in accord with the supposition.

Analysis of the Exponential Growth Equation1

Solutions for growth equations that estimate dry matter from photosynthetic, respiratory, and photosynthetic area variables were tested by using field data for cotton (G. hirsutum L. var. ‘Deltapine Smoothleaf’). The equations based on assumptions of exponential leaf area expansion and exponential extraction of light by leaves fitted the data test. A leaf area expansion function that depends upon morphogenetic variables should improve the fit.

MODERATE‐TERM WATER STRESSES AND ASSOCIATED CHANGES IN SOME PHOTOSYNTHETIC PARAMETERS IN COTTON

SUMMARYCotton plants (Gossypium hirsutum L., var Deltapine smoothleaf) were subjected to 1‐ or 2‐week periods of mild water stress using an osmotic soil cell. The treatments were severe enough to affect seriously several photosynthetic parameters, while good night‐time recovery of plant water‐potential minimized effects on development and leaf expansion.Most measurements were made soon after rewatering, owing to very high stomatal resistances in the stressed plants. The stressed plants had lower rates of potential photosynthesis and lower rates of actual photosynthesis (at normal ambient CO2 concentrations) than the controls. Both stomatal and intracellular resistances and the corresponding ‘photosynthetic limitations’ were greater in the stressed plants than the controls. Most of these parameters showed fairly complete recovery 24 hours after rewatering. Parallel changes were observed in the activities of carbonic anhydrase, ribulosediphosphate carboxylase and 14C fixation by leaf slices, all of which were lower in the stressed plants.Although activities of all the processes studied showed parallel changes, there was evidence that the major factor causing reduced photosynthesis in the stressed plants was stomatal closure. There was some evidence that the photosynthetic system adjusted itself to water stress over the periods studied.

Behavior of the Boll Weevil on Frego Bract Cotton123

In a detailed study of the behavior of Anthonomus grandis Bobeman in frego bract and ‘Deltapine Smoothleaf’ (DPSL) cotton, 2.5 times as many weevils were trappped in or around the DPSL as around the frego bract cotton. Also, boll weevils moved somewhat more in frego than in DPSL cotton, since about ½ as many introduced weevils were recovered in frego as in DPSL. In DPSL, 64% of the weevils recovered were found in squares, only 20% were recovered in squares on frego cotton. Both overwintered, and current-generation on female weevils deposited about twice as many eggs per hour in the DPSL as in the frego bract cotton.

Intra-varietal variability and response to single plant selection inGossypium hirsutumL.: I. Phenotypic variability

SummaryPopulations of spaced plants of each of the four American upland cotton varieties Deltapine Smooth Leaf, Rex Smooth Leaf, Pope, and Rex and one African upland variety, Bar 7/8, were grown in the 1965–6 wet season at Kimberley Research Station, in the Ord River valley, Western Australia. The number of bolls, boll weight, lint percentage, seed cotton yield, lint yield, micronaire value, mature height, and morphological type were recorded for each plant.For all varieties the range of each attribute was wide; for example, for a typicalvariety, boll weight ranged from 3·0 to 7·8 g, lint percentage from 30·5 to 43·5%, micronaire value from 3·3 to 5·9 units, and mature height from 78 to 195 cm.The most variable varieties judged on coefficients of variation were those maintained at the station for the longest period without selection while the most recent accession was the least variable.Frequency distributions for all attributes in each population departed significantly from normality: the majority showed both significant skewness and kurtosis. Positive skewness shown for the yield parameters seed-cotton yield, lint yield, boll number and boll weight in all varieties suggested there was scope for improvement by selection. Negative skewness for lint percentage was found in three varieties, suggesting previous intense selection for this trait. The coefficient of variation of lint percentage with one variety (Deltapine Smooth Leaf) was considerably less than that recorded 30 years earlier for its predecessor D x PL 11 A.Covariance adjustments to seed cotton yield of individual plants, based on various hypotheses of the relationship between a plant's yield and that of its neighbours failed to give reductions of consequence in the variability of yield. It was concluded that inter-plant influences were far more complex than the models assumed.

Agronomic Potential of Nectariless Cotton

AbstractWe compared three BC6F4 nectariless strains of cotton (Gossypium hirsutum L.) with their recurrent parent varieties for yield, yield components, and fiber properties at six environments in 1971. A slight decrease (4.3%) in yield for nectariless ‘Stoneville 7A’ and a slight increase (3.8%) in yield for nectariless ‘Deltapine Smooth Leaf’ was detected. Nectaried and nectariless ‘Dixie King’ did not differ in yield. Nectariless strains, especially Deltapine Smooth Leaf tended to mature earlier. Slight but inconsistent differences in yield components of nectariless and nectaried strains were detected. Nectariless cottons tended to have shorter fibers.Significant genetic variability within BC6F3 nectariless populations of Stoneville 7A was detected, indicating that we were not working with isogenic nectariless varieties. Selection within BC5 nectariless Stoneville 7A resulted in yield improvement equal to that of nectaried Stoneville 7A. Fiber properties between nectaried and nectariless strains were essentially the same.The nectariless trait reduced boll rot. While the results from large field test were inconclusive, there were fewer tarnished plant bugs, fleahoppers, and less bollworm damage in nectariless cotton. Two predatory insects, lady beetles and big‐eyed bugs, were not affected by the presence or absence of nectaries.We detected no strong deleterious associations of nectariless and agronomic performance. This trait appears to have a good potential for insect and boll rot suppression in the Mississippi Delta.

Temperature Dependence of Photosynthesis in Cotton

Cotton plants (Gossypium hirsutum L., var. Deltapine Smooth Leaf) were grown under controlled environmental conditions over a range of day/night temperatures from 20/15 to 40/35 C. Their photosynthetic characteristics were then measured over a comparable temperature range. Net photosynthesis tended stongly to be greatest, and intracellular resistance to CO(2) transport to be lowest, when the measurement temperature corresponded to the daytime growth temperature, suggesting pronounced acclimation of the plants to the growth temperature. The preferred growth temperature was close to the 25/20 C regime, since net photosynthesis of these plants, regardless of measurement temperature, was higher and intracellular resistance lower, than in plants from any other regime.Ribulose diphosphate carboxylase activity per unit leaf area was highest in plants grown at 25/20 C, but did not show pronounced changes with growth temperature. Glycolate oxidase activity decreased and NADH-malate dehydrogenase activity tended to increase with increasing growth temperature. In contrast, changes in carbonic anhydrase activity with growth temperature showed a general similarity to changes in photosynthetic rate. This may suggest that the "chemical resistance" component of the intracellular resistance bears a relationship to the amount of carbonic anhydrase in the leaf.

Influence of Mulches on the Growth and Development of Cotton Grown on Verticillium‐infested Soil1

AbstractSoil surface mulches of asphalt, asphalt + white paint, cotton burs, and no‐mulch or check were compared in a field experiment involving cotton (Gossypium hirsutum L.) grown on verticillium wilt‐infested soil to determine if resulting changes in soil temperature could influence wilt incidence. Mean soil temperature, dry weight of seedling cotton plants, and seed cotton yield at first harvest were significantly reduced by the cotton bur mulch. The mulch from cotton burs, even though associated with a lowered soil temperature, however, was also associated with a lowered wilt incidence in the ‘Deltapine Smooth Leaf’ cultivar. The more wilt‐susceptible and earliermaturing cultivar, ‘Rex Smoothleaf,’ gave no mulch response as measured by wilt incidence. Covariance analyses indicated that the yield differences in seed cotton at first harvest were largely a function of differential seedling growth rates as measured by seedling dry weights.

Estimation of the Transport and Carboxylation Components of the Intracellular Limitation to Leaf Photosynthesis

A model is presented which enables gas exchange data to be used to partition the intracellular resistance to leaf photosynthesis into carboxylation and transport components. A basic assumption is that the over-all kinetics of the carboxylation reaction fit the Michaelis-Menten equation.The model was tested for cotton (Gossypium hirsutum L., var. Deltapine Smoothleaf), where photorespiration was suppressed by using gas mixtures containing less than 1.5% oxygen. It was concluded that the transport resistance formed the major component of the intracellular resistance for the plants studied. However, in some cases the major intracellular factor limiting photosynthesis, at an ambient CO(2) concentration of 600 ng cm(-3), was the carboxylation system, which was close to saturation.

Constituents of the cotton bud

The investigation of the alcohol fraction of the essential oil of cotton ( Gossypium hirsutum L. var. Deltapine Smoothleaf) with an integrated gas-liquid chromatography-mass spectrometry system resulted in the identification of 17 additional alcohols and β-ionone. Tentative assignments were made for 4 other alcohols. None of these has previously been reported in cotton.

Canopies of Deltapine Smoothleaf and Pima S-2 Cotton Plants1

Entomologists are frequently confronted with the task of estimating the area of the canopy of a crop to determine the degree of interception of insecticides, pathogens, and other biological agents when the control agents are applied aerially. These data are also necessary for estimates of the shading of the soil surface when models are to be used to predict the temperatures of the soil surface and the upper subterranean strata from more easily measured parameters such as air temperature, shading, cloud cover, solar radiation, and other factors associated with the coefficient of diffusivity of soil (K. Foster, Research Associate, and R. E. Fye, unpublished data). The results of a preliminary study to determine means of estimating the canopy coverage of cotton are discussed here.

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel. III. The Bet-She'an Valley

SUMMARYThe effects of moisture stress during various stages of the development of two varieties of upland cotton (Acala 4–42 and Deltapine Smoothleaf) were studied in two irrigation experiments in the Bet-She'an valley, where summer temperatures were high and evapotranspiration in the fully irrigated treatments was up to 8–10 mm./day in July and August. Optimum time for first irrigation in the Bet-She'an valley was two or three weeks before flowering and six or seven irrigations, if timed to prevent moisture stress, were sufficient to give high yields and good lint quality. Lint yield ranged from 270 kg./ha. in non-irrigated to 2000 kg./ha. in the fully irrigated treatments in 1966.

Identification and Quantitative Analysis of the Volatile Substances Emitted by Maturing Cotton in the Field

When atmosphere from cotton plants (Gossypium hirsutum L., var. Deltapine Smoothleaf) was condensed by passing it over the expansion coil of an air conditioner and three 1-hour collections per day (early morning, noon, and late afternoon) were made, the total essential oils were found to consist of 50 to 60% beta-bisabolol (I(k) 1660) and gamma-bisabolene (I(k) 1550) and 30 to 40% geraniol (I(k) 1250), myrtenal (I(k) 1328), nerolidol (I(k) 1520), and beta-caryophyllene oxide (I(k) 1590). As the plant matured, trans-2-hexanol was produced in concentrations of 7 to 27%. Before fruiting, beta-bisabolol made up as much as 60% of the total essential oil transpired by the plants, and as the concentration of beta-bisabolol increased, that of gamma-bisabolene decreased.

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel I. The Coastal Plain Region

SUMMARYEffects of moisture stress during different stages of cotton development were examined in two experiments when temperatures were mild and evapotranspiration less than 6 mm./day. Two varieties of upland cotton, Acala 4–42 and Deltapine Smoothleaf, were affected similarly. Moisture stress at the beginning of flowering reduced growth rate and the numbers of flowers and bolls. During the second half of the flowering period it reduced the percentage of boll retention, boll number, boll weight, seed index, lint index and lint length. Stress during boll development had similar effects and caused earlier maturity. Lint yield was reduced significantly by moisture stress during each of the periods but tensile strength of lint was not affected. Three irrigations, if properly timed so that no appreciable moisture stress occurred, were sufficient for high yields and good quality of lint, and the first could be postponed until after flowering began without any loss in yield.