Highest Leaf Yield Research Articles

Artemisinin, Related Sesquiterpenes, and Essential Oil inArtemisia annuaDuring a Vegetation Period in Vietnam

The active principle of ARTEMISIA ANNUA L., artemisinin, is currently being developed to a registered antimalarial drug. For production purposes, plants with a high artemisinin content are required. We followed the development of the artemisinin content and of the biosynthetically related sesquiterpenes artemisinic acid, arteannuin B, and artemisitene in A. ANNUA plants, during a vegetation period in Vietnam, where this species is indigenous. In addition, the essential oil content and composition were studied. Samples of leaves, buds, flowers, or post-bloom flowers and fruits were taken at different stages: vegetative (5, 6, and 8 months old), at mass formation of buds (9 months), at full bloom (10 months), and post-bloom (10S months). The highest artemisinin content (0.86% dry wt) was present in the leaves of 5 months-old plants. At this stage also the highest leaf yield was found. Subsequently, the artemisinin content gradually dropped. At the age of 5 months the highest artemisinic acid and arteannuin B contents, 0.16 and 0.08% dry wt, respectively, were found as well. Artemisitene was present at all stages of development, ranging from 0.002 to 0.09% dry wt. With 1.9% v/w, the essential oil content was maximal just before flowering and was composed of 55% monoterpenes and 45% sesquiterpenes. At all other stages (0.4 - 1.0% v/w oil) this ratio was ca. 30%/70%. The main components of the oil were camphor and germacrene-D.

An Irrigation Scheduling Model for Turnip Greens

An irrigation scheduling model for turnip (Brassica rapa L.) was validated using a line-source irrigation system in a 2-year field trial. The model used a water balance, a variable root length, and a crop factor function of plant age (i). Evapotranspiration was computed daily as class A pan evaporation times a crop factor [CF(i) = 0.365 + 0.0154i-0.00011i2]. Irrigation according to the model maintained soil water tension at <25 kPa at a 30-cm depth. When rainfall amounts were less than water use, leaf yields responded quadratically to irrigation rates, from 0% to 160% of the model rate, and the highest leaf yield with the lowest water applications corresponded to the model rate. Therefore, this model could replace the “feel or see” methods commonly used for scheduling irrigation of leafy vegetables grown in the southeastern United States.

An evaluation of the production potential of six tropical grasses under grazing. 1. Yield and yield components, growth rates and phenology

Fertilised pastures of 4 varieties of Setaria sphacelata (var. splendida and cvv. Nandi, Narok and Kazungula), pangola grass (Digitaria eriantha ssp. pentzii) and kikuyu grass (Pennisetum clandestinum cv. Whittet) were grazed rotationally over a 3-year period at Beerwah, south-eastern Queensland. Each variety was grazed on a 5-weekly rotation by 2 leaders for 7 days; a follower herd including 2 testers grazed the regrowth for 7 days. The numbers of followers were subjectively adjusted weekly, depending on feed available. The experiment was designed to provide adequate quantities of forage of maximum potential quality to the leaders throughout the year. There were large and frequently consistent differences between the grasses in yield and its various components, leafiness, leaf and forage density, rate of development of leaf dry matter, and time and intensity of flowering under the management system imposed. Of particular interest were the high leaf yield of Narok, high overall yield of Narok and var. splendida, low rate of development of leaf area index of pangola grass and kikuyu grass, and high forage density of kikuyu grass. These differences might be expected to have an effect on pasture quality, carrying capacity and optimal management strategy.

Effects of bicarbonate, phosphorus, iron EDDHA, and nitrogen sources on soybeans grown in calcareous soil

Abstract Hawkeye soybeans (Glycine max L.), an iron‐efficient cultivar when grown in calcareous Hacienda loam soil low in P and available Fe, did not respond to P, FeEDDHA, NH4+‐N or NO‐ 3‐N when applied singly nor to Fe + P together; but did give yield response for N + P + Fe applied together. Addition of HCO3 ‐ with N + P + Fe decreased yields by about 10% and decreased Fe in shoots also by 10%. The NH4+ source of N gave 12% higher leaf yield without HCO3 ‐ and 11% higher with HCO3 ‐ than did nitrate N. Bicarbonate alone caused severe damage to the Hawkeye soybeans, while P alone had little effect. In contrast, P was very damaging with less effect from HCO3 ‐ with iron‐inefficient PI‐54619–5–1 soybeans from a companion study. Addition of Fe decreased Zn and Mn concentrations in leaves, while addition of both Fe and P decreased Zn concentration even more. Bicarbonate contributed additionally to low Zn in leaves with treatments of Fe and Fe + P. These Fe‐efficient Hawk‐eye soybeans were less impaired by N...

Cytoplasmic channels and chromatin migration in mulberry.

Cytomixis was observed in triploid mulberry. The cause of this has been attributed to initial hybrid nature of tetraploid and triploid. The cytomixis involved many cells at a time and was observed in all the stages of meiosis, contrary to the common belief that only earlier stages are favourble. In some cases two different stages of meiosis were also involved in cytomixis. Cytomixis resulted in other abnormalities like anucleate cells, cells with more or less chromosome number, multinucleolate cells, unusually large cells, triads, pentads and hexads. Cytomixis leads to sterility in mulberry resulting in higher leaf yield and nutritiveness, useful for silkworm feeding.

Agronomic, Chemical, Physical, and Visual Characteristics of Hand‐Suckered vs. Maleic Hydrazide‐Treated Flue‐Cured and Burley Tobaccos1

AbstractRemoval of the developing inflorescence (topping) in tobacco (Nicotiana tabacumL.) production will result in higher leaf yield and increased alkaloid content. Unfortunately, topping will remove axillary bud (sucker) inhibition. To achieve the higher yields and alkaloid content growers must control the development of suckers through manual or chemical means. Because hand‐suckering is a menial task, the use of maleic hydrazide (MH) rapidly became the cultural practice to control sucker growth, but its use was severely questioned by the industry. The Regional Tobacco Growth Regulator Committee was established in 1963 to evaluate tobacco treated with various experimental chemical sucker‐controlling agents as alternatives to MH. Regional committee test data accumulated from 1963 through 1981 by federal and state researchers were used to compare cured leaf from MH‐treated plants with hand‐suckered plants, the control treatments. Yield and value per hectare were higher from the use of MH while dollars per 100 kg were the same for both kinds of treatments in both classes of tobacco. Tobacco leaf experts were able to visually differentiate between MH‐treated and hand‐suckered flue‐cured but not burley tobaccos. Chemical analyses indicated that percent total alkaloids and percent total ash were less in MH‐treated flue‐cured and burley tobaccos. Alkalinity of water soluble ash increased from MH treatment. Total volatile bases minus nicotine (as ammonia) decreased significantly in flue‐cured tobacco from MH treatment while the increase found in burley from MH treatment was not. Maleic hydrazide treatment significantly increased per cent reducing sugars in flue‐cured tobacco, but had no effect on percent total N in burley. Physical analyses indicated that values for filling capacity were significantly lower and equilibrium moisture content significantly higher in MH‐treated tobaccos.

TOPPING CUM VARIETAL EVALUATION IN TOBACCO

Field experiments conducted at the Agricultural Research Station, Tamil Nadu Agri. University, Bhavanisegar during Rabi seasons of 1980-81. and 81-82 revealed that topping the tobacco crop by leaving 12 leaves per plant has given the highest leaf yield. Among the varieties studied variety. 1. 64 performed better than varieties 1, 115, HV, 67-18 and Vazhaikkappal in respect of leaf yield.

Atriplex hortensis L. as a leafy vegetable, and as a leaf protein concentrate plant

The quality ofAtriplex hortensis L. (Mountain Spinach) as a leafy vegetable, forage crop, and plant for production of leaf protein/nutrient concentrate was investigated. The plant can substitute or supplementSpinacia oleracea L. as a leafy vegetable, due to similar chemical composition and a higher leaf yield. The whole plant, as a meal, is similar toMedicago sativa L. in chemical composition. It could be suitable for cultivation in dry areas. By wet-fractionation of the plant a leaf protein concentrate can be obtained. The concentrate is well composed, and should lack anti-nutritive substances present in the whole plant.

The effect of plant structure on the intake of tropical pasture. III.* Influence of fertilizer nitrogen on the size of bite harvested by Jersey cows grazing Setaria anceps cv. Kazungula swards

The effect of fertilizing Setaria anceps cv. Kazungula swards with nitrogen on the size of bite harvested by cattle was determined and the influence of sward canopy structure upon bite size was investigated in two experiments. The first experiment measured the effect of nitrogen at 0, 40, 60 and 100 kg/ha on 6-week regrowth, and the second measured the effect at 50 and 100 kg/ha on 4- and 6-week regrowths of both unfertilized swards and others which had received 350 kg nitrogen per hectare in each of the previous three years. The mean bite size of cows grazing immature (4-week) regrowths increased linearly with increasing applications of nitrogen, averaging 0.29, 0.33 and 0.37 g organic matter (OM) per bite on the 0, 50 and 100 kg/ha treatments respectively. Swards which allowed the largest bites to be prehended had the highest leaf yields and the highest leaf bulk densities. The mean bite size on 6-week regrowths was lower (0.28 g OM/bite) than on 4-week regrowths (0.33 g OM/bite). Cows selected leaf from the upper layers of the swards, and inaccessibility of leaf resulting from a high stem and inflorescence content prevented animals from taking larger bites. In both experiments high levels of nitrogen fertilizer advanced the maturity of 6-week regrowths, and the bite size of cows grazing these pastures did not increase beyond the level recorded at intermediate nitrogen levels. It was concluded that fertilizer nitrogen increases dry matter and leaf yields, particularly in the uppermost layers of the sward, allowing cows to harvest large bites of immature herbage. A higher stem and inflorescence content in heavily fertilized swards can result in inaccessibility of leaf when mature herbage is grazed. ________________ *Part II, Aust. J. Agric. Res., 24: 821 (1973).