优质高产甜糯玉米杂交种泸玉糯1号的选育及栽培要点

泸玉糯1号是用甜质自交系泸97-23和糯质自交系渝9741分别作母本和父本组配而成的杂交种.甜糯结合、皮薄、口感好,一般产鲜果穗13047.0 kg/hm²左右.播种至采收鲜果穗的生育期为82～85 d.属黄白相间粒,甜糯结合大穗型玉米。     

灌浆结实期高温胁迫对糯玉米子粒产量和叶片光合特性的影响

以苏玉糯5号和渝糯7号为材料,研究灌浆结实期高温胁迫对子粒充实、叶片光合特性和产量的影响。结果表明,高温胁迫下灌浆后期粒重增速缓慢,穗粒数减少,产量降低。高温胁迫使花后5 d光合速率下降,胞间CO₂浓度、气孔导度和蒸腾速率上升。随灌浆进程推进光合参数逐渐降低,高温胁迫处理下降幅较高,是粒重降低并造成产量损失的关键因素。与苏玉糯5号相比,渝糯7号在高温胁迫处理下光合参数降幅较低,光合速率和胞间CO₂浓度中后期较高,受高温胁迫影响较小。     

高产优质糯玉米杂交种鄂白糯1号的选育

鄂白糯1号糯质玉米杂交种是湖北省种子集团有限公司用自选糯质自交系EN6535为母本、EN6597为父本杂交选育而成。其产量高,外观品质和蒸煮品质优良,一般每667m^2产鲜果穗1200kg左右、干子粒650kg左右。综合抗性强,保绿度好。2009年通过河北省审定,品种审定号为：冀审玉2009013号。     

CO2浓度升高对玉米叶片光合生理特性的影响

以沈糯3号为研究材料,利用开顶式气室(OTCs)法研究了二氧化碳(CO₂)浓度升高处理下,玉米叶片叶绿素含量、光合生理特性及其子粒产量的变化,揭示CO₂浓度升高对玉米光合生理特性及子粒产量的影响机理。结果表明,在整个生育期内,与对照相比,高浓度CO₂处理下,玉米叶片叶绿素a、叶绿素b及叶绿素(a+b)的含量增加,而叶绿素a/b的值则先升高后降低;在整个处理期间,净光合速率均高于对照(p>0.05),升高幅度为12.6%～71.1%,气孔导度低于对照(p>0.05),其降低幅度为2.9%～18.8%。处理至抽雄期和灌浆期,胞间CO₂浓度分别增加152%和161%,均极显著高于对照(p<0.01);蒸腾速率的变化较小。高浓度CO₂处理下,玉米穗粒数和穗粒重均明显高于对照(p<0.05)。CO₂浓度升高在一定程度上促进了玉米的光合作用,从而使玉米子粒产量增加。     

优质高产糯玉米杂交种宿糯1号的选育及栽培技术

宿糯1号糯玉米杂交种是用自选糯质自交系SN21作母本,SN22作父本杂交选育而成。产量高,皮薄,口感好,一般产鲜果穗12 750.0 kg/hm2左右,干子粒7 875.0 kg/hm2。综合抗性强,保绿度好。     

掖单22超高产群体光合生理指标的研究

对夏玉米掖单22超高产群体光合生理指标的研究结果表明：掖单22产量水平达到13500kg/hm²,适宜密度为75000株/hm²左右,产量结构为75000穗/hm²左右,穗粒数480左右,千粒重380g左右,经济系数0.52。群体叶面积发展动态为花前快、花后稳、蜡熟后衰减缓,最大叶面积系数(LAI)5.5左右,成熟期保持2.5左右;总光合势(LAD)330万m²·ｄ/hm²开花至成熟期的光合势占总光合势的65%;群体光合速率(CAP)全生育期平均6.5gCO₂/m²·h开花期高峰值10gCO₂/m²·h左右;净同化率(NAR)全生育期平均7.8g/m²·ｄ左右;干物质积累总量26000kg/hm²以上,开花期至成熟期干物质积累量占总量的60%左右;干物质生产率平均250kg/hm²·d以上。     

加甜型糯玉米的选育研究初报

采取部分基因修饰的方法,用不同的隐性基因纯合体杂交,使部分糯子粒被甜基因修饰而增甜,选育出又甜又糯的加甜型糯玉米--甜糯玉米.选育实践表明,正确筛选及鉴定目标甜、糯基因是自交系选育的关键技术.重庆及西南地区甜糯玉米选育应以选择su₁、sh₂等修饰基因,采取单基因修饰的方式,选育甜糯比例为1:3的加甜型糯玉米为主。     

玉米子粒色素稳定性比较研究

用比色法对两种玉米子粒花色苷色素的色谱及稳定性进行研究。结果表明：西星赤糯1号玉米子粒色素最大吸收峰为506 nm,酸性条件下为酒红色;黑包公鲜玉米子粒色素的最大吸收峰为528 nm,酸性条件下为玫瑰红色。两种玉米子粒花色苷色素对室内散射光、温度(20℃～60℃)、食盐、蔗糖、葡萄糖、维生素C、柠檬酸、乙酸、防腐剂苯甲酸钠(C₇H₅NaO₂)以及Mg²⁺、Zn²⁺、Mn²⁺、Ca²⁺、K⁺、Na⁺均表现稳定,对室外自然光、氧化剂H₂O₂(30%)、还原剂亚硫酸钠(Na₂SO₃)以及Fe3+、Fe2+、Cu2+表现不稳定。     

玉米杂交种产量性状与产量的灰色关联度分析

本文通过对10个玉米单交种9个数量性状与子粒产量的灰色关联度分析，结果表明，玉米杂交种产量与各产量性状的关联度大小顺序为：叶数r₁＞抽丝期r₂＞行粒数r₃＞株高r₄＞穗位高r₅＞穗长r₆＞穗粗r₇＞百粒重r₈＞穗行数r₉．说明，玉米杂交种产量主要取决于与其关联度较高的叶数、抽丝期、行粒数、株高等主要性状．为高产     

增密、少耕与化控耦合对玉米产量及光合特性的影响

利用长期定位试验,设置密度(D₁：60 000株/hm²,D₂：90 000株/hm²)、耕法(T₁：少耕,T₂：常规耕作)与化控(R₁：喷化控剂,R₂：喷清水)三因素试验,分析不同处理玉米产量及其形成过程和冠层光合特性。结果表明,D₁条件下,T₁R₁处理子粒产量、穗粒数较T₂R₂处理显著增加27%～40.5%、19.6%～27.3%;D₂条件下,T₁R₁处理子粒产量、穗粒数较T₂R₂处理显著增加22.9%～24.9%、14%～21.3%。少耕和化控处理显著影响植株冠层结构,降低了玉米的植株高度、穗位系数、上部叶片的叶面积,提高了植株上层和中层叶向值及上部冠层的透光率;少耕和化控处理提高了叶片单位面积光能的吸收(ABS/CS0)、捕获(TR0/CS0),在高密度条件下表现明显差异。综上,在密植条件下,少耕和化控耦合优化了玉米密植群体冠层结构,增强了对光能的截获、吸收与传递能力,最终显著增加子粒产量。     

The effect of row spacing on alfalfa seed and forage production under irrigated Mediterranean agricultural conditions

We evaluated the effect of row spacing on seed and forage yields in alfalfa (Medicago sativa L.) using combined seed and forage production plots, in an irrigated Mediterranean agricultural environment. We compared three row distances (20, 40 and 60 cm) in two cultivars at a seed rate of 25 kg ha^?1 over a period of 4 years. We measured the seed yield and yield components as well as forage production. The 4‐year average revealed an overall clean seed yield of 367 kg ha^?1 declining over time, without significant differences in row distances. The number of shoots per square metre differed significantly as a function of row spacing, with averages of 357, 226 and 172 shoots m^?2 for row widths of 20, 40 and 60 cm respectively. The row spacing did not affect the number of racemes per shoot (23·1), the number of pods per raceme (7·2), the number of seeds per pod (6·5) or the thousand seed weight (1·667 g). The average forage production was 20·1, 18·5 and 17·9 Mg DM ha^?1 for row distances of 20, 40 and 60 cm, respectively, with higher yields associated with smaller row distances. Our data demonstrate that row spacing >20 cm does not confer any advantage to the production of alfalfa seed under irrigated Mediterranean agricultural conditions and that close spacing can significantly increase forage yields in the same environment.     

Physiological age index: a new,simple and reliable index to assess the physiological age of seed potato tubers based on haulm killing date and length of the incubation period

Chronological and physiological age of seed tubers have major impacts on potato yields. This paper presents a new, simple and reliable physiological age index (PAI) that considers and reconciles the effects of chronological and physiological age. PAI calculation is based on the haulm killing date of the seed crop (T₀) and the end of the incubation period of seed tubers, measured under standardized conditions. The PAI formula is T₁/T₂, where T₁ is the time from haulm killing date (T₀) to possible planting date and T₂ the time from T₀ to the end of the incubation period. The PAI expresses physiological ageing of seed potato tubers within a range from 0 (for physiologically young) to 1 (old) tubers. To test the PAI existing data were re-evaluated and re-elaborated and specific experiments regarding seed origin and storage conditions for different cultivars were performed during 1994–1999. The PAI proved useful in assessing differences due to differences in growing conditions, cultivar, haulm killing, seed origin and storage system, and pre-planting treatments. For example, for cv. Spunta 6 days after haulm killing the PAI was 0.025 and after 100-storage days the PAI was 0.56, 0.52 and 0.49 for seed tubers stored in heaps in the field, at relatively high temperatures, natural diffuse light and a cold (4°C) and ventilated store, respectively. The PAI is related to ground cover duration and yield of the future crop. For a PAI of 0.55 tuber yield was 55 t ha⁻¹, while for a PAI of 0.80 tuber yield was 40 t ha⁻¹. The PAI is easy to measure, non-invasive, objective, reproducible and reliable and could be used for modelling purposes to describe performance of seed tubers.     

测土配方施肥对水稻生长发育及产量形成的影响

以当地优质稻南粳5718和糯稻99-25为供试材料,根据试验地土壤养分状况,采取减氮增磷增钾的措施,即在基肥中减少氮肥,增加磷钾肥,并在追肥中降低氮肥投入,来研究测土配方施肥技术对当地水稻增产的途径和方法。结果表明,测土配方施肥技术能够通过促进水稻分蘖,提高成穗数,其中南粳5718高峰苗较常规施肥处理增加8.02%,有效茎蘖数增加5.26%,穗数增加4.89%;糯稻99-25高峰苗较常规施肥处理增加10.12%,有效茎蘖数增加4.32%,穗数增加2.34%。测土配方施肥可以提高抽穗期的叶面积指数(增幅19.47%),强化水稻的光合能力。在不影响穗粒数和结实率的情况下,测土配方施肥可以增加水稻千粒质量,从而最终提高产量。     

THE EFFECTS OF DEFOLIATION ON EMERGENT ANNUAL GRASS SWARDS UNDER SIMULATED GRAZING

For three weeks after emergence, micro-swards of Lolium rigidum were defoliated to a height and at a frequency which represented a range of set stocking rates of less than, similar to, and more than 7–8 sheep/ha as based on the results of Greenwood and Arnold (6) and referred to as D₁, D₂ and D₃ respectively. The effects of these defoliation regimes on the growth and development of emergent swards were evaluated according to their effect on increments of DM from plant parts, rate of appearance of leaves and tillers, concentration of soluble carbohydrates, and on the uptake and concentration of inorganic nutrients. Defoliation began five days after emergence, when the dry weight of the shoot was 3g/m². After 20 days of treatment, 6±7 g/m² of DM had been removed from D₁, 5±5 g/m² from D₂ and 51 g/m² from D₃; and the dry weight of shoot remaining was 13, 7 and 4±5 g/m² on D₁, D₂ and D₃ respectively. The effect of defoliation on dry weight of plant parts increased in severity in the order leaf 1, stem+sheaths, leaf 2, roots, leaf 3, tiller 1, tiller 2, leaf 4. Average relative growth rate of the sward was reduced from 17% per day on D₁ to 13% per day on D₃. There was no necrosis of root tissue. Emergence of the later leaves and of the tillers was retarded by up to three days by more frequent defoliation. Alcohol-soluble carbohydrates in the root fell from over 6% to about 1±5% on all treatments. Uptake of N. P and K was limited by increasing intensity of defoliation and because concentrations of those elements were not greatly affected, the limitation could be ascribed mainly to the effects of defoliation on plant size. The plausibility of the technique for the experimental simulation of grazing of emergent annual grass swards in Western Australia is discussed. It is concluded that for set-stocking rates of less than about 12 sheep/ha, grazing, while reducing DM production just after emergence, is unlikely to produce severe physiological stresses in the sward.     

Studies on β-carotene and lycopene content in the fruits of lycopersicon esculentum mill. X L. Chilense dun. Hybrids

Data are reported from breeding work in the progeny of the cross (L. chilense x Ace)F₁ x Ace as a result of which stabilized lines have been obtained with different β-carotene/lycopene ratio. In some lines possessing very good morphological and economic properties the fruits contained up to 8–9 mg% of β-carotene and were also distinguished by high vitamin C content (about 50 mg%). No determinate plants with high β-carotene content in the fruits were observed. It is suggested that the same B factor determining high β-carotene content inL. hirsutum is present inL. chilense. Therefore, it is in close relation with the sp⁺ gene in the sixth chromosome.     

Yield components,dry matter,LAI and LAD of soybeans in Northeast China

Pod and seed number are the most important yield components of soybean [Glycine max (L.) Merr.]. Leaf area index (LAI), leaf area duration (LAD) and dry matter accumulation during the reproductive period strongly influence yield components. Our objectives were: to investigate if differences in yield components exist among genotypes differing in both yield and maturity; and to examine the dynamics of dry matter accumulation, LAI, and LAD during the reproductive period for the high-yielding genotypes. Sixteen soybean genotypes within three maturity groups were grown in Hailun, China in a randomized complete block design with three replications, across 2 years. Maturity groups were selected to differ by approximately 7 days in mean days to R₇ (5% of pods are mature pod color). Dry matter accumulation, LAI, and LAD were measured at R₂, R₄, R₅, and R₆ stages, respectively in each year. Yield, yield components and harvest index were determined at maturity. Late maturity genotypes had higher yield than early ones. Majority of the seed yield and components were positioned in the middle and upper part of the plant. Both pod number and seed number were higher in high-yield genotypes in each group. Seed number per pod contributed to increased yield in the high rainfall year but was not related to the variation in yield of the genotypes evaluated. Significant variations were found for LAI, LAD and dry matter within each maturity group. Higher accumulation of dry matter, higher LAI and LAD during reproductive stages were found to be closely related to high-yield genotypes in each group. No relationship was found between harvest index (HI) and seed yield.     

杂交玉米引种高产栽培试验研究

通过对9313、3333、3119等7个玉米杂交种的引种高产栽培试验研究,筛选出适宜我市自然条件下春玉米种植的高产玉米杂交种3个.实践证明我市春玉米每667m²可突破吨粮大关,为发展永州玉米生产提供科学依据。     

Relationships and influence of yield components on spaced-plant and sward seed yield in perennial ryegrass

Adequate seed production is essential for cultivar success in perennial ryegrass turf and forage industries, but improvement is limited by the complexity of yield components and low-rank correlations between selection and production environments. This study examined seed yield components among 20 perennial ryegrass entries in both spaced plantings (selection environment) and swards (production environment) at two locations in Minnesota. Competitive (23 plants/m²) and non-competitive (3 plants/m²) spaced-plant nurseries were tested. Competitive spaced-plant total yield was highly correlated with sward yield (r_s = 0.64 and 0.66, p < 0.01) at both locations, whereas the non-competitive environment showed no correlation. Structural equation modelling (SEM) was used to explore the indirect and direct relationship of fall vegetative growth, winterkill, and yield components on total seed yield in all environments. Fertile tiller number (spikes plant⁻¹/m⁻²) exhibited both strong direct and indirect influence on total seed yield in all environments. However, the importance of fertile tiller number in the SEM was reduced with increased plant competition. The SEM showed that both weight per spike and seed yield per spike influenced total yield in spaced plants; however, neither consistently predicted total sward yield. The ratio of these two traits (g seed spike⁻¹/g spike⁻¹) gave an index of fertility that was easy to measure and had a superior correlation with sward yield at two locations (r_s = 0.81 and 0.54, p < 0.05) when spaced plants were under competition. Results suggest that increasing competition in spaced plantings and selecting for spike fertility may more accurately identify superior plant material compared to lower competition environments.     

Effect of green-belly stink bug,Dichelops furcatus (F.) on wheat yield and development

The green belly stink bug, Dichelops furcatus (F.) (Hemiptera: Heteroptera: Pentatomidae) is a pest of corn and soybean in southern Brazil. It also occurs on wheat, but information on its damage to this crop is limited. To determine the need for sustainable IPM programs, the impact of this bug on wheat production should be determined. Studies were conducted in the screenhouse with 1, 2 and 4 bugs caged for 16 days on single plants, cv. ‘BRS Parrudo’. During the vegetative period (plants ca. 25 cm tall), all infestation levels significantly reduced plant height and ear head length, but did not reduce grain yield. Feeding damage caused tissue necrosis on leaves. During the booting stage, grain yield was significantly reduced with 2 and 4 bugs per plant; ear heads were small, discolored and abnormally developed. In 2013 and 2014 field trials, plants were infested for 18 days with 2, 4 and 8 bugs per m² at vegetative, booting, and milky grain stage. At these infestation levels, there was no significant reduction in grain yield. There was a significant decrease in the number of normal seedlings resulting from seeds exposed to 8 bugs per m² at the milky grain stage. Results suggest that, in general, there is no need to control D. furcatus on wheat, unless numbers are ≥8 bugs per m² during reproductive period.     

Population density studies with Russet Burbank I. Yield/stem density models

Two reciprocal polynomial models were used to quantify yield/stem density relationships in the Russet Burbank cultivar y^?θ = α + β? and y^?1 = β₀ + β₁? + β₂?² where y = yield per plant; ? = stems m^?2 and β₀, β₁, β₂ and α, β, and θ are fitted parameters. The use of a systematic design allowed characterisation of the yield/density response surface over a wide range of densities (1.8 to 20.0 plants m^?2) without involving experiments of impractical size. The effect of both seed size (30, 40, 50, 60 gm) and type (cut or whole) on the relationship was studied. Both models provided excellent statistical fits for marketable yield data, while the former model gave a similar fit for total yield data. The form of the relationship was not influenced either by seed size or type. Total yield was asymptotically related to stem density while marketable yield was parabolically related.