Super Okra Leaf Research Articles

Canopy Hyperspectral Reflectance of Redroot Pigweed versus Okra and Super Okra Leaf Cotton

Redroot pigweed (Amaranthus retroflexus L.) is a nuisance weed that affects cotton (Gossypium hirsutum L.) growth and yield worldwide. Being able to distinguish redroot pigweed from cotton would help producers and crop consultants better implement strategies used to suppress and control it. Hyperspectral reflectance properties of weed and crop canopies have been used to differentiate between them. Currently, no information is available on the application of hyperspectral data to distinguish redroot pigweed from cotton with different leaf shapes. Positive results will further support the exploration of remote sensing technology for distinguishing redroot pigweed from cotton. The objectives were to compare canopy hyperspectral reflectance of redroot pigweed to canopy hyperspectral reflectance of okra and super okra leaf cotton and to identify regions of the spectrum in which differences exist in their reflectance properties. Hyperspectral reflectance measurements of redroot pigweed and cotton were obtained with a spectroradimeter on May 6 and June 27, 2019. Plants grown in a greenhouse were used for this study. One-hundred and sixty-two 10-nm bands (400 - 2350 nm spectral range) were evaluated with analysis of variance (p ≤ 0.05) and Dunnett’s test (p ≤ 0.05) to determine the wavebands that were useful for separating redroot pigweed from okra leaf and super okra leaf cotton. The following bands were consistent in distinguishing redroot pigweed and okra leaf cotton on both dates: 420 nm, 510 - 650 nm, 690 - 740 nm, and 2000 - 2010 nm; whereas, 400 - 500 nm, 1480 - 1780 nm, and 1990 - 2350 nm were identified for both dates for separating redroot pigweed from super okra leaf cotton. Commercial imaging systems used on ground-based or airborne platforms can be easily tuned into the spectral bands listed in this study, thus providing managers with a tool to use for identifying redroot pigweed in cotton production systems.

Comparing Canopy Hyperspectral Reflectance Properties of <i>Palmer amaranth</i> to Okra and Super-Okra Leaf Cotton

Palmer amaranth (Amaranthus palmeri S. Wats.) is a major weed problem of cotton (Gossypium hirsutum L.) production systems in the southern United States. Hyperspectral remote sensing has shown promise as a tool for crop weed discrimination, and there is a growing interest in using this technology for identifying weeds in cotton production systems. Information is lacking on differentiating Palmer amaranth from cotton with an okra leaf structure based on canopy hyperspectral reflectance properties. Two greenhouse studies were conducted to compare canopy hyperspectral reflectance profiles of Palmer amaranth to canopy hyperspectral reflectance profiles of okra and super-okra leaf cotton and to identify optimal regions of the electromagnetic spectrum for their discrimination. Ground-based hyperspectral measurements of the plant canopies were obtained with a spectroradiometer (400 - 2350 nm range). Analysis of variance (ANOVA, p ≤ 0.05), Dunnett’s test (p ≤ 0.05), and difference and sensitivity measurements were tabulated to determine the optimal wavebands for Palmer amaranth and cotton discrimination. Results were inconsistent for Palmer amaranth and okra leaf cotton separation. Optimal wavebands for distinguishing Palmer amaranth from super-okra leaf cotton were observed in the shortwave infrared region (2000 nm and 2180 nm) of the optical spectrum. Ground-based and airborne sensors can be tuned into the shortwave infrared bands identified in this study, facilitating application of remote sensing technology for Palmer amaranth discrimination from super-okra leaf cotton and implementation of the technology as a decision support tool in cotton weed management programs.

The variability of cotton accessions (Gossypium Hirsutum L.) with different leaf forms under non-irrigated conditions

30 specimens of cotton with different leaf forms from Australia were evaluated under non-irrigated conditions at the VIR Budionnovsk experiment station in Stavropol region Australian samples during the first three years of trials were significantly later-ripening than the local standard POSS-2, but in the last 2 years only the Super Okra leaf genotypes were a little later-ripening. On agronomical traits most studied Australian accessions exceed the POSS-2 standard (by length of fibres — 30–32 vs. 25–27 mm, by turnout — 38–40 vs. 34–36 %, by boll weight 5.6–5.8 vs 5.1–4.6 g), and may be used as sources of these features in breeding. Analysis of variability of traits in groups with different leaves form shows that the samples with Okra leaf are close to group varieties with typical leaf form in terms of variability character, but Super Okra leaf varieties vary greatly in terms of productivity and duration of the germination-maturity period. Research has shown that in dry years Super Okra leaf genotypes exceeded the normal leaf accessions, including standard ones, on productivity which is associated with a lower need for moisture plants with smaller leaves area. It is important to use such varieties, adapted to drought, in breeding of cotton in the Stavropol region, as there is currently a progressive climate aridization in this zone. Refs 24. Figs 7. Tables 4.

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

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.

Regional evaluation of cotton cultivars in eastern Australia, 1974-85

In 1974, a district cotton cultivar trial was initiated to assess the yield and fibre quality of promising cultivars in all major Australian cotton growing areas over 1 or more years. A nearly 5-fold range in site yields (595-2451 kg/ha) occurred across locations and years. Yields were usually higher in the last 6 years of the trial (overall mean 1688 kg/ha) than in the first half (overall mean 1223 kg/ha). Queensland sites (except Theodore) were lower yielding than average, while New South Wales sites (except Warren) were higher yielding. Deltapine cultivars from the U.S.A. have been the dominant commercial cultivars during 1974-85, and in the first 9 years of the trials USA. or Australian-bred Deltapine types produced the highest overall lint yields. Since 1982, Australian-bred Siokra lines have been the highest yielding with their resistance to bacterial blight apparently being an important factor in their performance. The rate of genetic gain in lint yield, as assessed from the overall year means and the mean yield of the 2 control cultivars (Deltapine 16 and Namcala) grown in all 12 years of the trials, was 2.3% per year. These yield increases were also accompanied by improvements in fibre strength and micronaire value in some of the recently developed lines or cultivars. A number of genotypes with mutant traits associated with host plant resistance to insect pests were compared with their near-isogenic counterparts. Superokra leaf yielded 6% less than normal leaf, nectariless yielded similarly to nectaried, and glabrous yielded similarly to delta-smooth pubescence. Frego bract yielded less in 1 comparison but in 2 others was similar to the normal counterpart, while glabrous and frego bract together led to reduced yields. Intra-varietal selection was shown to produce useful gains in yield between 3 to 6.5%.

Effect of Early Season Square Removal on Three Leaf Types of Cotton1

In certain environments, reduced leaf‐open canopy cottons (Gossypium hirsutum L.) allow more light penetration and air circulation within their canopies than do normal leaf types. However, too much reduction in canopy can reduce overall productivity and economic yield. Removal of floral buds (squares) early in the season has been shown to result in larger plant size. Square removal was carried out in the field (fine‐silty, mixed, thermic, Aquic Fragiudalf soil type) on normal, okra, and super okra leaf type near‐isogenic lines of a ‘Stoneville 213’ background cotton for 3 and 6 weeks to determine i) if improved yield could be obtained in one or both open canopy types by enlarging the canopy and ii) if delaying fruit set produced differential responses in these leaf types. Results would form a basis for development of a boll weevil (Anthonomus grandis Boh.) trap crop system using exogenous chemicals to effect square abscission. Removal of squares increased plant height, leaf area index (LAI) and number of sympodial branches. The super okra leaf type produced the greatest responses to square removal. Fruit set was more rapid and occurred during a shorter interval for all leaf types undergoing square removal for 3 weeks, but the greatest response was obtained from super okra. Comprehensive analysis in 1983 indicated the rapid fruit set was due primarily to more sympodia fruiting simultaneously. The 3‐week treatment was more consistent in this response than the 6‐week treatment because of the generally shorter horizontal and vertical flowering intervals. Economic yield of normal and okra leaf types was generally not improved by square removal, whereas the super okra leaf type in the 3‐week square removal treatment produced an average 23.5% greater lint yield than its control. Differences in lint percentage were significant between treatments in 1981 with significant leaf type by treatment interactions in 1983. The data indicate that the super okra leaf type had the most consistent responses to 3 weeks of manual square removal. These results imply that this leaf type would produce the best response to exogenous chemical abscission of squares and the greatest chance of recovery from early season insect pressure.

Influence of Leaf Morphology on Lint Yield of Cotton—Enhancement by the Sub Okra Trait1

Sub okra leaf (L14) is a trait in cotton (Gossypium hirsutum L.) which displays greater indentation of sinus and more lobing than does normal leaf (l). This study was initiated because previous research on the influence of this trait for lint yield or its components had been reported. In 1981, 48 populations descending from 24 crosses were initiated to compare the influence of this trait on yield relative to that of normal and two other mutant leaf types. The populations developed were from crosses of eight normal with three mutant leaf types of cotton. The eight normal leaf cultivars and strains wee ‘Deltapine 26’, ‘Deltapine 5540’, ‘Stoneville 825’, ‘SC‐I’, ‘DES 422’, ‘Tamcot CAMD‐E’, MD 69, and DES 2–10. The mutant leaf types were La 1363Lsne, La 500C, and HYC 79‐6 which possessed the super okra (L1), okra (L0), and sub okra (L14) leaf traits, respectively. Tw o populations were produced from each cross, i.e., one normal and one homozygous for the mutant leaf type. In 1982, the 48 F3 populations were grown in replicated experiments at three locations near Stoneville, Miss. Mean lint yield ranged from 870 to 1175 kg/ha for the three locations and from 927 to 1099 kg/ha for the eight sources of normal leaf types. No interactions with the eight sources of normal types were detected with environments, mutant leaf source types, or normal vs mutant types. Super okra populations averaged 95 kg/ha (8.8%) less lint yield than their corresponding normal populations. No differences in lint yield of okra vs normal leaf populations were detected, averaging 1053 and 1055 kg/ha, respectively. In contrast, lint yield of sub okra was significantly higher, averaging 47 kg/ha (4.8%) more than its corresponding normal populations. The yield superiority of sub okra over normal at the three locations ranged from 18 to 83 kg/ha. This investigation indicates a potential increase in the lint yield of cotton grown in the Mississippi Delta through the incorporation of the sub okra leaf trait.

Carbon Source‐Sink Relationships within Narrow‐Row Cotton Canopies1

Cotton (Gossypium hirsutum L.) is an indeterminate crop in which vegetative and reproductive sinks compete for photosynthetic assimilates. The objective of this study was to evaluate the carbon source sink relationship in cotton canopies with differing leaf types grown under narrow‐row culture and to determine if measurement of specific leaf weight (SLW) can be used as a simplified evaluation of photosynthetic rate within cotton canopies. Three near‐isogenic lines of ‘Stoneville 7A’ (normal, okra, and superokra) cotton which differed in blade area/leaf were grown in narrow‐row culture at a plant density of 10 plants m‐2. During the 3rd (29 July) and 5th (13 August) weeks of flowering, whole plants were exposed to 14CO2 and evaluated at three height intervals (0 to 30 cm, 30 to 55 cm, and above 55 cm) for leaf area index (LAI), 14CO2 uptake, and biomass distribution. Okra and superokra leaf types generally had higher 14CO2 uptake within the canopy on a leaf area basis, but lower LAI than normal leaf plants. Uptake of 14CO2 among leaf types on a land area basis was different only on 13 August in the top interval where the ranking was normal > okra > superokra. By 13 August, the top interval accounted for 81, 77, and 69% of the canopy 14Cassimilate production, but contained only 29, 28, and 32% of the fruit dry weight for normal, okra, and superokra leaf plants, respectively. Mutant leaf types had a larger percentage of dry weight as fruit and less as leaves and petioles compared to normal leaf plants. This study suggests that vegetative growth is favored at the expense of reproductive growth due to high LAI at the top of normal leaf canopies when grown in narrow‐row culture. However, the mutant leaf types tend to have less biomass resulting in only equivalent yields to normal leaf plants when grown under full‐season culture. Significant correlation coefficients between C uptake and SLW ranged between 0.72 and 0.89 depending upon time of SLW measurement and sampling date, but were not altered by leaf type. Use of SLW is a simple method for estimating photosynthetic activity of leaves within cotton canopies.

Mutants of Gossypium hirsutum: Effect on Pink Bollworm in Arizona12

Several mutants in upland cotton, Gossypium hirsutum L., sustained less seed damage from pink bollworm (PBW), Pectinophora gossypiella (Saunders), than the check cultivars ‘Deltapine 16’, ‘Deltapine 61’, ‘Stoneville 7A’, and ‘Stoneville 213’. These mutants were as follows: glabrous, early-maturing, high-terpenoid (gossypol and related compounds), Okra-leaf and Super Okra-leaf. Earlier studies had shown that glabrous, nectariless, glabrous-nectariless, and highly pubescent mutants, and an upland cotton of complex background (AET-5), had sustained less seed damage than the check cultivars. Cottons having as much as or more seed damage than checks were Red plant, late-maturing, glandless, and frego-bract, and also strains carrying exotic cytoplasms from 6 other Gossypium spp. Practically all the cottons tested that showed resistance to PBW were earlier maturing and yielded less lint than the check cultivars. Exceptions were: ‘Westburn M’, slightly earlier, with significantly lower seed damage, and with a slightly lower lint yield the 1st season but a significantly higher yield the 2nd season; ‘DES 56’, significantly earlier, with slightly lower seed damage, and with a comparable lint yield the 1st season, and a significantly higher lint yield the 2nd season; and Stoneville 7A Okra-leaf, significantly earlier, with significantly less seed damage, and with slightly lower lint yields. No single character reduced seed damage sufficiently to be adequate for PBW control.

The superokra leaf gene and short-season cotton breeding

The performance of superokra leaf backcross progenies was compared with their normal leaf recurrent parent in two experiments in two successive seasons at Narrabri Research Station in the Namoi River Valley of New South Wales. The first experiment used standard 1 m row spacing and the second both standard and twin-row spacing (two rows sown 25 cm apart on 1 m beds). Other varietal comparisons including short-season and standard types, and normal and superokra leaf types were also made. The mean yield of 220 superokra progenies was 8.4% less than their recurrent parent in the first experiment. The mean yield of 14 of these was 1.2% greater in the second experiment. The superokra leaf progenies were earlier maturing and had a higher lint percentage. Strength and fineness of the progenies compared with the parent varied between experiments. Although mean staple length of the superokra leaf progenies was shorter than the recurrent parent it was demonstrated that selection for longer staple without yield sacrifice was feasible in the backcross population. All short season varieties tested had deficiencies of yield or quality compared with desired standards. The normal leaf Tamcot SP-37 and the superokra leaf M8 variety appeared to have the best combination of earliness and other attributes. There were no significant variety interactions with row spacing. Further study is needed to clarify the usefulness of the superokra leaf gene, because of quality deficiencies and apparent greater instability of varietal performance associated with the gene.

Effect of Leaf Shape and Plant Population on Rate of Fruiting Position Appearance in Cotton1

AbstractRate of appearance of fruiting positions in cotton (Gossypium hirsutum L.) is an important component of earliness. The objective of this research was to evaluate the influence of leaf type (size) and population density on rate of fruiting position appearance along branches of individual plants. Normal, okra, and superokra leaf cotton plants were grown in rows 51 cm apart in irrigated basins at 11.2 and 18.5 plants/m2 in 1973, and 10.0 and 20.0 plants/m2 in 1974. Fruiting positions reaching anthesis were tagged daily. Rate of appearance was determined by observing the number of days between successive fruiting branches (sympodial plastochron) and the number of days between first fruiting positions of successive fruiting branches (monopodial plastochron). Plants grown in high population densities generally had larger sympodial and monopodial plastochrons (longer time intervals between appearance of fruiting positions) than plants in the low population. Okra and superokra plants had smaller monopodial plastochron and larger ratios of sympodial to monopodial plastochrons than normal leaf plants. Sympodial plastochron increased from early to mid‐season and then declined. Monopodial plastochrons increased from early season to plateau values at mid‐season. The seasonal changes in plasto‐chrons did not appear to be related to changes in temperature. This study shows that both leaf type and population density affect rate of fruiting position appearance and earliness in cotton but changes in temperature found in fields may have little effect on plastochrons.

CARBON SOURCE FOR DEVELOPING BOLLS IN NORMAL AND SUPEROKRA LEAF COTTON*

SUMMARYNarrow‐row field experiments were conducted to investigate the importance of leaves near developing bolls as a source of assimilate in normal and superokra leaf cotton (Gossypium hirsutum L.) plants. A small plexiglass chamber was used to enclose individual leaves which were pulsed with 14CO2 for 5 min. Leaves were labelled when sink bolls were 10 days old. Despite much smaller leaves at each position (averaging 42% of normal leaf size) the superokra leaves exported similar amounts of 14C‐assimilate to the primary boll as did normal plant leaves. Primary sympodial bolls of superokra and normal leaf plants received 37 and 41% of their 14C‐assimilate from subtending leaves, respectively, 38% from the secondary sympodial leaf, and 28.2 and 21.5%, respectively, from the main stem leaf. Although the leaf subtending the boll of superokra plants was much smaller than the subtending normal leaf, the amount of assimilate provided to the boll was 88% of the normal leaf. The differences in assimilate export to a given boll may not be as important in causing fruit abortion in superokra cotton as expected from leaf size considerations.

Canopy Photosynthesis and Transpiration of Cotton as Affected by Leaf Type1

Cotton (Gossypium hirsutum L.) plants with okra or superokra leaves have several agronomic characteristics which could make them better adapted to narrow‐row culture than plants with normal leaves. This study was conducted to investigate the effect of these leaf types on canopy photosynthesis and transpiration of narrow‐row cotton. A portable, open‐chamber system was used in plant communities grown at high and low densities. In 1973 the three leaf types (normal, okra, and superokra) had dissimilar genetic background with the okra and superokra leaf lines being similar in appearance and leaf area. Maximum leaf area index (LAI) these canopies was approximately 2.8 compared to 4.6 for normal leaf plants. Near‐isogenic lines were used in 1974. Although morphologically distinctive, the okra and normal isolines had maximum LAIs of approximately 5.2, compared with 3.5 for the superokra leaf isoline. Apparent photosynthesis was positively associated with LAI, although correlation coefficients were low (0.23 to 0.54). Plant population had little effect on canopy photosynthesis. When data were averaged across populations, normal leaf plants had CO2 exchange rates 20 and 29% higher than superokra leaf plants in 1973 and 1974, respectively. Okra leaf plants were intermediate. Leaf type effects on transpiration were small and inconsistent during the 2 years. Although differences in photosynthesis to transpiration ratios statistically nonsignificant, the trend was normal>okra> superokra. Thus, the okra leaf types do not appear to be associated with improved efficiency of water use.

Herbicide, Leaf Type, and Row Spacing Response in Cotton

Near isogenic strains of okra, super okra and normal leaf cotton (Gossypium hirsutum L.) were grown in rows spaced 25, 50, and 100 cm apart and were sprayed with various combinations of trifluralin (α,α,α,trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and fluometuron [1,1-dimethyl-3-(α,α,α,-trifluoro-m-tolyl)urea]. Neither row spacing nor leaf type had any effect on early season weed control. Late season control was better with normal and okra leaf types than with the super okra leaf type. Weed control was significantly better with additional postemergence application of herbicides than with only preplant and preemergence applications. Although the cotton varied in opening date with herbicide programs there was no difference in total yield.

Effects of the superokra leaf gene on cotton growth, yield, and quality

No significant lint or seed cotton yield differences were found between a normal leaf cultivar of cotton and its near-isogenic superokra leaf counterpart in three experiments over three seasons at Kimberley Research Station in north-western Australia. There were also no significant interactions for lint yield of the two lines with variations in inter-row spacing and nitrogen application. Differences in quality between the two were also slight and of no commercial importance. The superokra leaf gene, however, caused earlier maturity and decreased production of leaf and stem tissue. Biologically superokra leaf was more efficient, with a greater production of seed cotton per unit of leaf tissue than for the normal leaf. Superokra leaf led to increased difficulty of weed control in conventional 1-metre cotton culture, but it appeared a desirable factor to transfer to cultivars bred for narrow-row high density cotton.

Effects of Super Okra Leaf Shape on Boll Rot, Yield, and Other Characters of Upland Cotton, Gossypium hirsutum L.1

The effects of the super okra leaf shape on boll rot. yield, plant and fiber characters of Upland cotton, Gossypium hirsutum L., were investigated at three locations in Louisiana. Near isogenic populations of super okra leaf and normal leaf on each of three varietal backgrounds were used.Super okra leaf shape, as an average of varieties and locations, caused a significant reduction in boll rot, yield, fiber length, and total leaf surface area in comparison with normal leaf cotton. Super okra leaf shape caused an increase in earliness, lint percentage, fruiting rate, and micronaire value, but had no effects or inconsistent effects on boll size, fiber length uniformity, fiber strength, and fiber elongation. The interactions of variety ✕ leaf shape and location ✕ leaf shape were significant for some of the characters studied.A mixed population of super okra leaf and normal leaf plants in a 1:1 ratio was investigated. The mixed leaf population was found to have no advantage over the pure populations of the contrasting leaf shapes.