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A new system was developed and tested for efficient use of irrigation and rainfall for furrow irrigation of grain sorghum (Sorghum bicolorL. Moench). The design uses a limited water supply to irrigate a larger area than could be fully irrigated and thus reduces the area in dryland sorghum where a farmer produces both. A 600‐m long field was divided into three water management sections. The upper half of the field was managed as fully irrigated. The next one‐fourth was a “tail‐water‐runoff” section that utilized furrow runoff from the fully irrigated section. The lower one‐fourth was designated a “dryland” section, retaining and utilizing any runoff generated either by irrigation or rainfall from the wetter, fully irrigated, or tailwater‐runoff sections. Furrow dams were placed about every 3 to 4 m throughout the length of the field after planting. However, these were washed out by the irrigation water over the distance the water advanced down the furrows. The remaining furrow dams on the lower part of the field stopped rainfall runoff and prevented any water from leaving the field. As the profile soil water was depleted on the drier lower field sections, shrinkage cracks developed that helped to absorb rainfall and prevent rainfall runoff. Seeding rates were reduced down the field from 6 kg/ha on the fully irrigated section to 3 kg/ha on the tailwater section, to 1.5 kg/ha on the dryland section. Nitrogen applications were also reduced on the tailwater and dryland sections to correspond with anticipated yield levels. The three irrigation treatments were 5‐cm water applied to every furrow; 3.75‐cm water applied to alternate furrows; and 2.5‐cm water applied to every third furrow between crop rows in a two‐row planted, and one row left out, skip‐row system. These treatments were compared with conventional furrow irrigation without dams involving tail‐water runoff. Five irrigations were applied at 14‐day intervals, regardless of seasonal rainfall. The extent that the field was irrigated depended on the rainfall. The fixed 14‐day irrigation schedule and 12‐hour sets reduced management requirements and facilitated the potential for automation of graded furrow water application, without the farmer having to be concerned about tailwater runoff from the end of the field. For 1979, a year with near average rainfall, the system successfully prevented runoff from both irrigation and rainfall.

Abstract: LarvalAlosa pseudoharengus may be distinguished from larvalA. aestivalis by differences in the relative termination of the vent. The number of myomeres between the insertion of the dorsal fin and the vent is diagnostic. The mean number is 8.0 inA. pseudoharengus and 11.8 inA. aestivalis. Also of use in distinguishing between larvae of the two species are the number of preanal myomeres, the regression of the distance from snout to vent on standard length, the regression of the distance from vent to tail on standard length. Methods of distinguishing larvalA. pseudoharengus andA. aestivalis from commonly associated species in the Chesapeake Bay region are discussed.

A field study was conducted to determine nutrient concentration and dry matter and nutrient accumulation patterns in grain sorghum [Sorghum bicolor(L.) Moench] plants and to determine the effects of plant water stress on these parameters. Grain sorghum hybrid ‘Pioneer 8311’ was grown under five irrigation treatments to givestress periods varying in timing and duration. Samples were collected at weekly intervals from plants grown with and without stress from (i) early boot until early grain filling, (ii) heading until late grain filling, (iii) early grain filling until near physiological maturiy, and (iv) from early boot until mid‐grain filling. Plants were partitioned into component parts for dry matter estimation and analysis for N, P, K, Ca, Mg, and NO3. Plant water stress reduced N and P concentrations in leaves and increased N concentration in stalks and heads, but did not affect NO3−N, K, Ca, and Mg concentrations. In unstressed plants, dry matter accumulation proceeded at a near constant rate from about 40 days after planting until physiological maturity. Nutrient accumulation rates tended to be near‐constant from 40 days after planting until flowering and then slowed somewhat. At flowering, plants had accumulated 59, 77, 72, 90, 88, and 65% of their total dry matter N, P, K, Ca, and Mg, respectively. Plant water stress reduced dry matter and nutrient accumulation. Nitrogen and P were affected more than K, Ca, and Mg.

A field study was conducted to evaluate effects of plant water stress at different stages of growth on grain and forage yields and yield components of grain sorghum [Sorghum bicolor(L.) Moench]. Irrigated grain sorghum was subjected to various periods of plant water stress beginning at (i) early boot, (ii) heading, and (iii) early grain filling. Unstressed sorghum yielded 7,410 kg grain/ ha. Stress periods of 13 to 15 days [average afternoon leaf water potentials (LWP) −15.8 to −20.3 bars] did not reduce grain yields but, 27− to 28‐day stress periods (average afternoon LWP, −21.7 bars) beginning at early boot or heading stages reduced yields 27%. However, a 27‐day stress period (average afternoon LWP, −22.7 bars) beginning at early grain filling reduced yields only 12%. Thirty.five and 42‐day stress periods (average afternoon LWP, −22.9 and −24.0 bars), beginning at boot stage reduced yields 43 and 54%, respectively. Yield reductions from stress initiated at early boot stage resulted from both reduced seed size and seed numbers. When stress was imposed at heading or later, only seed size was reduced. Forage yields were not affected by 27‐ to 28‐day stress periods but were reduced by stress periods imposed at early boot stage and extended for 35 or 42 days.

Major variability occurs in yield response of irrigated winter wheat (Triticum aestivumL. em Thell.) to water deficits and irrigation in the Southern High Plains. Evaluation of plant growth and development and yield components are needed to better understand water relations and to develop and test growth and yield models. The study was conducted to evaluate the effects of three planting dates, four to six water deficit treatments during stages of plant development, and two short wheats, ‘TAM W‐101’ and ‘Vona,’ differing in yield components. Planting dates were early (15 September), normal (12 October), and late (7 November). Water deficits were established by withholding irrigation and were terminated at selected plant stages by applying irrigation to level border plots. The study was conducted on a slowly permeable Torrertic Paleustoll (Pullman clay loam). We evaluated development stages, tillering, plant water potential, grain and dry matter yields, and yield components of heads per m2spikelets per head, grain per spikelet, grain weight and number per m2. Early to normal planting, as compared with late planting (i) advanced the dates of phenological development, (ii) lengthened the time in the vegetative period, (iii) lengthened the time from floral initiation to inflorescence, (iv) increased tillering during vegetative growth and tiller senescence during jointing, and (v) increased dry matter and grain yields. Plant water deficits reduced yields by increasing tiller and stem senescence, which reduced harvested heads, and by reducing grain numbers (spikelets per head and grain per spikelet). Vona produced more secondary tillers and grains per head, but tiller‐stem senescence and smaller grain size resulted in harvested head numbers and grain yield similar to those of TAM W‐101. High yields (5,580 kg/ha) were associated with adequate fall‐tillering and irrigation during spring vegetative growth that minimized stress‐associated tiller‐stem senescence and reduction in spikelets per head. TAM W‐101 was more resistant than Vona to severe desiccation and tillerstem senescence under severe water deficits. A fall irrigation applied before winter dormancy delayed the need for a spring irrigation until jointing. Irrigation just before a period of above average rainfall did not affect yields. Yields comparisons of TAM W‐101 and Vona indicate that similar high yields can be produced by varieties having large differences in seed size and number per m2, suggesting that specific yield components may not be closely correlated with high yield potential.

Effective screening techniques for drought resistance would be beneficial in a winter wheat (Triticum aestivumL.) breeding program. Several greenhouse and field screening techniques were evaluated for abilily to differentiate drought resistance in five cultivars reputed to differ in drought resistance and yield: Scout 66, Sturdy, TAM W‐101, TAM 105, and TAM 108. Grain yield for droughtstressed and irrigated conditions was determined in field trials on Pullman clay loam soil (fine, mixed, thermic Torrertic Paleustoll). Yield ranking, both irrigated and drought stressed, was: TAM 108 ≧ TAM 105 > TAM W‐101 = Scout 66 ≧ Sturdy. Drought susceptibility index (S) values were: 0.55, 0.57, 0.59, 0.63, and 0.63, for Scout 66, TAM 105, TAM W‐101, Sturdy, and TAM 108, respectively. These values indicate that Scout 66 has the greatest yield stability in drought, while Sturdy and TAM 108 have the least. Screening techniques that were unsuitable because they did not differentiate cultivars were germination in mannitol, rooting depth, leaf conductance, and canopy temperature. Seedling root length appeared unsuitable because of limited cultivar differentiation and high labor requirement. Seedling survival after desiccation was the most suitable technique for screening large populations. Water loss of excised leaves and leaf water potential (Ψ) are labor intensive but would be informative screening techniques for parental material and advanced lines. Water loss of excised leaves was correlated with S (least loss = lowest S). High yield was associated with low Ψ, which may be associated with high ability to retain green leaves in drought

Transmitter release at adrenergic synapses is accompanied by release of chromogranin proteins, which are contained in synaptic vesicles. To determine if a similar phenomenon occurs at the neuromuscular junction, correlated release of acetylcholine (ACh) and protein was investigated using in vitro neuromuscular preparations (phrenic nerve-diaphragm muscle of the rat and mouse, sciatic nerve-sartorius muscle of Rana pipiens and R. catesbeiana). Nerve stimulation of curare-paralyzed preparations increased the rate of efflux of Lowry-reactive material relative to control values. Stimulus-specific responses outlasted the period of neural stimulation. Stimulus-induced release of Lowry-reactive material was correlated with ACh release since it was Ca2+ dependent and Mg2+ antagonized. Conditions that potentiate spontaneous ACh release also significantly increased the rate of efflux of Lowry-reactive material. Most of the Lowry-reactive material released with ACh is not a secretory product of synaptic vesicles because the amount released exceeds the contents of synaptic vesicles that undergo exocytosis. It is concluded that ACh release from the neuromuscular junction is accompanied by release of proteinaceous material that is not entirely derived from synaptic vesicles.

Due to a wide range of irrigated and dryland production systems and highly variable weather, planting date of winter wheat (Triticum aestivumL.) grown in the Southern High Plains varies from August to November. A 2‐yr field study was conducted at Bushland, TX, to evaluate planting date effects on soil water extraction and grain yield. ‘TAM 107’ wheat was planted in late August to simulate a grazed production system, early October to represent an optimum date for grain production, and early November on preirrigated Pullman clay loam soil (fine mixed thermic Torrertic Paleustoll) and grown to maturity without further irrigation. Gravimetric soil water content to 3.6 m depth was determined at the beginning and end of winter dormancy and at anthesis. Water extraction prior to winter dormancy occurred to a depth of 1.8, 0.9, and 0.15 m for the early, normal, and late planting dates, respectively. Depth of water extraction at anthesis was 2.4, 2.4, and 1.2 m for the three dates. The fraction of total preanthesis soil water extraction that occurred during a critical 60‐d period immediately prior to anthesis was 0.22, 0.59, and 0.91 for the early to late planting dates, respectively. Planting in August greatly increased depth and amount of soil water extraction prior to winter dormancy; however, water deficits in the spring contributed to low head density and grain yield. Wheat planted in early October extracted as much soil water as the August planting by anthesis and produced high grain yield. Wheat planted in early November rooted only one‐half as deep, extracted two‐thirds as much water, and yielded two‐thirds as much grain as the October planting date. In conclusion, planting in August as compared with October did not increase soil water extraction at anthesis and grain yield was reduced because the period of major soil water extraction was shifted from spring to fall. Planting in November reduced grain yield because of insufficient rooting to fully extract soil water from below 1.2 m.

This report describes the age, growth, and reproductive biology of the spiny dogfish Squalus acanthias off the northeastern U.S. Analysis of growth rings on dorsal fin spines yielded yon Bertalanffy growth coefficients (K) and asymptotic total lengths (L8) of K = 0.1481, L8= 82.49 cm for males, and K = 0.1057, L8= 100.5 cm for females. Median lengths and ages at maturity were 79.9 cm and 12.1 years for females and 59.5 cm and 6.0 years for males. The average number of young for females at the modal size range (90–94 cm) was 5.8; litter size ranged from 1 to 15 embryos every 2 years. Received March 12, 1984 Accepted March 12, 1985

A Limited Irrigation‐Dryland (LID) farming system for the conjunctive use of rainfall and limited irrigation of graded furrows was developed and field tested. The unique feature of the LID system is that it actually adjusts, during the crop growing season, the amount of land irrigated since more land can be irrigated during above‐average rainfall years with a limited amount of irrigation water than during below‐average years. The design used a limited water supply to irrigate a larger area than could be conventionally irrigated. A graded furrow field, 600 m long on a 0.3 to 0.4% slope was divided into three water management sections. The upper half of the field was managed as “fully irrigated.” The next one‐fourth was managed as a “tailwater runoff” section that utilized furrow runoff from the fully irrigated section. The lower one‐fourth was managed as a “dryland” section capable of utilizing runoff from either rainfall or irrigation on the wetter sections. The system was field tested for 3 years with grain sorghum (Sorghum bicolor(L.) Moench) on a Pullman clay loam (fine, mixed, thermic family of Torretic Paleustolls). Seasonal rainfall values were 224 mm in 1979, 103 mm in 1980, and 424 mm in 1981 as compared to the average of about 250 mm. The LID system was successful in increasing the utilization efficiency of irrigation water. Irrigation water added to a field can be transpired, evaporated, percolated, lost as runoff, or left stored in the soil after harvest. The LID system tended to reduce all losses other than transpiration. When 125 mm or 185 mm of irrigation water were added with the LID system, the evapotranspiration by grain sorghum was increased by an almost equal amount. This increased grain yield an average of 154 kg/ha for each 10 mm added irrigation, compared to 92 kg/ha for each 10 mm under conventional irrigation practices.

Populations of 100,000 plants per acre produced highest grain yields. Increased row width reduced yields significantly as expressed by the regression Ŷ = 117.11 − 0.72X, where Y is in bushels per acre and ✕ is inches. A significant interaction was found between plant spacing and irrigation water management but not between plant spacing and fertility level. Seasonal moisture use or efficiency was not affected significantly by plant spacing.

During seedling to crown root stages daily dry matter production was 30 to 50 pounds per acre and N uptake about 1 pound; both were increased only slightly by N fertilizer. During crown root through flowering stages increased growth and N uptake rates were further increased by irrigation and N fertilization, ranging from 240 to 340 pounds and from 4 to 6 pounds, respectively. Maximum production and N uptake occurred between soft and hard dough stages.

Grain yields were curvilinearly related to the number of irrigations, depletion of soil moisture, and increments of applied N. Evapotranspiration was related to number of irrigations and to available soil moisture. Plant growth response to applied N increased evapotranspiration slightly. Irrigation and applied N both increased the efficiency of water use. Maximum efficiency occurred at a yield level below maximum production.

Presents letters to the editor referencing articles and topics discusses in previous issues. "Career Matchmakers," which focused on the importance of relationships between companies and career centers; "Helping Executive Black Women Succeed," which discussed programs that offer assistance for African American women executives; "Blind Investment," which discussed the impact of financial analysis on a management's valuation of human capital.