Rice growth and yield as affected by the whorl maggot Hydrellia philippina Ferino (Diptera: Ephydridae)

Grain yields of rice cultivars IR36 and IR40 artificially infested with Hydrellia philippina flies were compared with those of non-infested plants in two screenhouse and four field tests. Infestation rates as high as 800 flies per 49 plants resulted in 82% of the leaves damaged but did not reduce grain yields of either IR36 or IR40. Larval feeding decreased plant height and increased number of panicle-bearing tillers of IR36. Maturity of damaged plants was delayed 7–10 days.     

Potato (Solanum tuberosum L.) cultivar response to bentazon and crop oil

Bentazon [3-(l-methylethyl)-(1H)-2,l,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was applied at two rates to nine potato cultivars in the field, with or without a crop oil, to plant foliage at two different heights. Seven days after application of bentazon, foliar injury ranged from 0 to 36 percent depending on rate, cultivar, and plant height at the time of application. Of nine cultivars tested, Russet Burbank was the most susceptible to injury and Red LaSoda the least susceptible. A bentazon application rate of 1.12 kg a.i./ha, compared to a rate of 0.84 Kg a.i./ha, resulted in a biologically insignificant increase in foliar injury of two to four percent and a significant increase in weed control. The addition of crop oil to bentazon did not result in an increase of foliar injury, but increased the percentage of weeds controlled approximately two-fold. With one exception, application of bentazon to plants 8–15 cm in height resulted in less foliar injury than application to plants 20–30 cm in height. Application of bentazon to larger plants resulted in lower yield and quality. For most cultivars, the application of bentazon (1.12 kg/ha a.i.) and crop oil (2.3 L/ha) to 8 to 15 cm-tall potato plants resulted in no appreciable loss in potato tuber yield, while controlling 74–85 percent of broadleaf weeds.     

中美德系玉米品种的耐密性对深松耕作措施的响应分析

采取耕作方式×种植密度×品种三因素裂区试验,深松40 cm和旋耕15 cm耕作条件,在9.0万株/hm~2和10.5万株/hm~2种植密度下,对中系郑单958和登海618、美系先玉335和华美1号、德系KX3564和KWS2564不同血缘玉米品种的地上部形态、生理及产量构成指标进行对比分析。结果表明,深松可降低增密后玉米净光合速率、LAI、SPAD值和单株生产能力的下降幅度,缓解株型的变化,提高玉米的耐密性。我国玉米品种的耐密性对深松耕作响应与美系和德系玉米品种存在差异,深松耕作与旋耕相比,华美1号、KX3564、KWS2564、先玉335增加种植密度后,其穗位叶叶倾角、净光合速率、LAI、SPAD值下降缓慢,产量、耐密系数显著提高,其耐密适应性对深松耕作的响应度高于郑单958、登海618。     

Fumigants,rates, and application methods affecting Verticillium wilt incidence and potato yields

A three year comparison was made among fumigants, rates and placement for control ofVerticillium albo-atrum (microsclerotial type). Fumigants were placed in the soil by (i) row method [one shank with duck-foot tool attached to give two bands of fumigant 9 inches (22.8 cm) deep and 9 inches apart (4.5 inches = 11.4 cm from center of a 36-inch row = 91.44 cm)], (ii) deep shank method [one shank in center of a 36-inch row, 18–20 inches (45.7–50.8 cm) deep], (iii) and by the standard broadcast method (four shanks spaced 9 inches deep and 9 inches apart per 36-inch row). The row and deep shank methods were no more effective than the broadcast method when the fumigant rate was equal (calculated on an acre basis and not on the actual portion of the row treated by the method of application). Fewer wilted plants and increased yields (120–160 hundredweight per acre = 134–179 quintals per hectare) were found in plots treated with (i) DD + Picfume (4:1), (ii) Telone + Picfume (4:1), (iii) Telone C, (iv) Terr-o-cide 30, (v) Terr-o-cide 30D and (vi) Vorlex at 25 gal per acre (233.8 liters per hectare) for all years tested. Yield was increased in plots treated at 12.5 gal per acre (116.9 liters per hectare) in 1968 and 1970, but not in 1969. Rates below 12.5 gal per acre were not effective in increasing yield and there was no advantage to applying fumigants above 25 gal per acre. All the six fumigants were equally effective in their control.     

Planting date effects on flowering,seed yield,and oil content of rape and crambe cultivars

Both crambe (Crambe abyssinicia, Hochst) and rape (Brassica napus L. and Brassica rapus L.) are cool season crops, thus they may have potential as irrigated, winter rotational crops in the low deserts of the southwestern United States and northern Mexico. Currently, no information is available on the effects of fall planting date on the production of these crops. The objectives of this study were (1) to determine the effects of fall planting date on flowering patterns, seed yield, and oil content of crambe and two species of rape, and (2) to determine the suitability of rape and crambe as rotational crops for the low deserts of the southwestern United States. Nine cultivars of rape and one cultivar of crambe were planted at the Maricopa Agricultural Center on three dates in November and December of 1995 and four dates from October through December of 1997 on a variable Mohall sandy loam soil (fine-loamy, mixed hyperthermic, Typic Haplargid). Five of the rape cultivars were B. napus types and the remaining four were B. rapus. One was an industrial rape (R-500) and the other eight were Canola types. Seed yield, oil concentration, and seed weight were determined. In 1996, the percent of plants flowering was observed visually on a periodic basis. In 1998, detailed imaging of flowering was done periodically using a digital camera. Planting date affected water application by controlling the length of the growing season. Our plants were taller, oil content was higher, seed weights were comparable, days to flowering were more than doubled, and seed yields were lower than plants from spring plantings in the Northern Great Plains. In both years of the study, the highest yields were obtained when rape and crambe were planted in November, which would fit well with cotton harvest dates. Lodging was a serious problem in rape. Crambe was sensitive to frost and could fail in some years. Only R-500 matured early enough to be used in rotation with current cotton cultivars. In addition to the onset of flowering, the automated method for estimating flowering was able to detect differences between Brassica species and cultivars and to measure the duration of flowering. Each species had a distinctive flowering pattern. Planting dates also affected the pattern and efficiency of flowering. Reproductive efficiency appeared to change with planting date and in general, October and November planting dates produced seed with higher oil content and seed weights than December planting dates.     

High Temperature Modifies Resistance Performances of Rice Varieties to Brown Planthopper,Nilaparvata lugens(Stl)

To investigate the effect of temperature on the resistance characteristics of rice varieties with different resistance genes to brown planthopper(BPH),Nilaparvata lugens(Stl),the resistances of IR26(Bph1)and IR36(bph2)to BPH population in Hangzhou,China were monitored in greenhouse during September in 2007 and 2008 by using the standard seedling screening techniques(SSST)developed by the International Rice Research Institute(IRRI).Furthermore,the changes in resistance of IR26 and IR36 to BPH,soluble sugar and oxalic acid contents in 25-day-old rice plants of susceptible variety TN1 and resistant varieties IR26 and IR36 were detected at five temperatures(22℃,25℃,28℃,31℃ and 34℃).IR26 completely lost resistance both in greenhouse and at the five tested temperatures.IR36 still had moderate resistance at natural temperature,but its resistance decreased gradually when the temperature increased from 25℃ to 34℃,and fully lost its resistance at 31℃ and 34℃.The highest durable resistance of IR26 and IR36 were recorded at 25℃.The soluble sugar content in plants of the three tested rice varieties increased with temperature increase,and the oxalic acid content increased with the temperature increase at first,maximized at 25℃,and then declined.Two-way ANOVA indicated significant effects of temperature and rice variety on contents of soluble sugar and oxalic acid in rice plants.     

A detached-leaf method to evaluate late blight resistance in potato and tomato

We developed a detached leaf method for evaluating potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.) germplasm for reactions toPhytophthora infestans, the causal organism of late blight. Primary leaves from the third to the sixth node of potato plants, and the fourth to sixth node of tomato plants were excised at the stem. Their petioles were inserted into 14 mm × 100 mm floral aqua tubes containing 9 ml of sterilized distilled water. The leaves in the aqua tubes were placed with abaxial sides down on galvanized metal hardware cloth (12.5 × 12.5 mm mesh). A 12.5 mm sensi-disc containing 50μl of 2 × 10⁴ zoospores was placed in the centers of the terminal leaflet and the second leaflet pair of the potato leaf. A single disc was placed on the center of the tomato leaf. The supporting hardware cloth was placed 2.5 cm above distilled water (2.5 cm deep) in 31 cm × 17 cm × 8 cm clear plastic boxes with tight fitting lids. Leaves on intact tomato and potato plants were inoculated in a similar manner and placed in a mist chamber. Lesion growth was determined 4, 5, and 6 days following inoculation. There were no significant differences in reactions to isolates ofP. infestans on detached and intact leaves of potato cultivars Green Mountain and Kennebec and the tomato cultivar Bonnie Best.     

Potato Plants Grown from Minitubers are Delayed in Maturity and Lower in Yield,but are not at a Higher Risk of <Emphasis Type="Italic">Potato virus Y</Emphasis> Infection than Plants Grown from Conventional Seed

Potato virus Y (PVY) is the most important virus in North American seed potato (Solanum tuberosum L.) production. Planting virus-free minitubers in place of field-grown seed, which usually has a low PVY incidence, reduces initial PVY inoculum in the field. However, plants grown from minitubers are smaller and emerge later than those grown from conventional seed, which could make them more likely to become infected with PVY. We tested the effects of seed type of three potato cultivars (Dark Red Norland, Goldrush, and Red La Soda) on PVY incidence, tuber yield, and flowering time. The incidence of PVY in plants grown from minitubers did not differ from that of plants grown from conventional seed. Minituber-grown plants produced lower tuber yields than plants grown from conventional seed. Plants from minitubers also emerged and flowered later, but this did not increase their incidence of PVY. Cultivar-specific differences were observed in tuber yield and flowering times, suggesting that this variation may influence PVY incidence more than seed type.     

半矮秆大豆窄行密植超高产栽培产量性状及产量结构研究

采用3个基因型品种,2种栽培模式,设置3个处理,研究半矮秆大豆窄行密植超高产栽培技术产量性状及产量结构,旨在为超高产大豆研究与应用提供技术依据.结果表明:在窄行、密植、高肥水条件下,B45处理由于采用半矮秆品种植株矮、底荚低、秆强不倒,虽然单株荚数、粒数显著低于对照,但由于密度增加,群体荚数、粒数显著增加.每节位平方米荚数、粒数分别达到145.1个和411.7个,分别较对照增加78.8～84.0个和254.2～258.0个,顶荚部位荚、粒数分别占总数的21.3%和22.5%.产量极显著高于对照处理,2008年在760 m2面积上,大豆产量达到4 895.7 kg·hm-2.     

Evaluation of various methods of weed control for increasing rhubarb yields

Four herbicides, monthly handweeding and a 15 cm deep straw mulch were evaluated for weed control during 1982 to 1987 on rhubarb (Rheum rhabarbarum L. ≡ R. rhaponticum L. ‘Victoria Red’). The straw-mulched plots produced larger plants, provided higher yields and had fewer weeds than all other treatments during the five years of these field trials. Yields in 1987 were 29·42, 17·65 and 13·06 tonnes/hectare for straw, handweeded and herbicide treatments, respectively. Monthly handweeding produced large plants and high yields, but required much more hand labour than mulching, making straw mulch the most cost-effective treatment. The four herbicides evaluated (glyphosate, fluazifop, sethoxydim and propyzamide) provided weed control for up to 1 month and would require reapplication during the growing season.     

The effects of plant arrangement and density on intercropped beans (Phaseolus vulgaris) and maize I. Traits related to dry matter and seed productivity

In traditional agricultural practice in the tropics, climbing beans (Phaseolus vulgaris L.) and maize (Zea mays L.) are commonly grown together in hills (relatively widely spaced clumps of plants) rather than in rows. Density of planting is also low in many cases (average 3 plants per m² each of beans and maize in Colombia). Three experiments were conducted at CIAT in Cali, Colombia, to compare planting systems. Planting in hills significantly reduced lodging of the maize in two out of three experiments. Higher bean density also tended to reduce maize lodging due to an anchoring effect of the climbing stems. Maize yields were reduced by planting in hills in two out of three experiments, but tended to increase slightly with bean density. Bean yield was also reduced by planting in hills but increased with density up to 9 plants per m², associated with a reduction in node number per plant, especially on the branches. Bean harvest index was increased by planting in hills, but reduced by higher bean density. Bean cultivars significantly affected maize yield, which was negatively related to bean plant height and node number. The best-yielding bean cultivar (G2525) had a well-developed climbing main stem; it gave 53% greater yield than G4017, which had well-developed branches. There were no significant interactions of bean cultivars with spacing or density. Increased bean density, either in hills or in rows, had beneficial effects both on bean and maize yields, the latter mainly due to reduced lodging. Reducing the spacing between hills and increasing bean density has potential for increasing the total productivity of this cropping system.     

不同锌效率水稻基因型及其杂种一代幼苗生长和抗氧化酶活性对Zn2+活度的反应

  为了解水稻耐低锌能力基因型差异的生理机制及F1杂种的耐低锌能力以提高水稻锌效率,解决水稻锌缺乏问题,选用耐低锌基因型水稻IR8192、IR36,锌敏感基因型水稻Ce 64、IR26及杂交后代IR36×IR8192、IR36×IR26和Ce 64×IR26为材料,进行低锌(pZn2+ 11.0)和正常锌(pZn2+ 9.7)营养液培养。结果表明：1)亲本和F1幼苗的株高,叶鞘高,地上部和地下部干质量及锌含量,叶片的叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量在pZn2+ 11.0与pZn2+ 9.7条件下的相对值可作为耐低锌基因型水稻的筛选指标;2)在低锌条件下所有亲本及F1各项指标变化趋势相同,但IR8192、IR36、IR36×IR8192、IR36×IR26的叶绿素含量、SOD酶活性降幅较小,POD、CAT、APX活性升幅较大,MDA含量升幅较小,表明上述基因型水稻的耐低锌能力更强。 低锌胁迫下POD、CAT、APX活性增强,可以更有效地清除活性氧,SOD活性则最先下降;3)除根长、APX活性外,在低锌条件下,IR36×IR8192、IR36×IR26各项指标变化幅度均表现出超亲优势,而Ce 64×IR26则表现出偏中亲优势,推测水稻的耐低锌特性主要受基因的显性效应控制,并存在基因的叠加效应,可以通过耐低锌亲本间的杂交获得具有更强耐低锌能力的水稻基因型。     

Confirmation of the Productivity of the Stored Seeds of Wheat and Two-Rowed Barley

Summary

To confirm the excellence in productivity of the stored seeds of wheat and two-rowed barley, we examined the growth characters and productivity of the plants developed from the seeds stored at 5°C and 40% relative humidity for various periods but showed a 80% or higher germination percentage, in comparison with those of newly harvested seeds (new seeds). The cultivars of stored seeds were identified by the random amplified polymorphic DNA (RAPD) method. There were no differences in the morphological characters of the seedlings 3 months after emergence between the new seeds and the old seeds (stored for 2 years and 5 months) or the very old seeds (stored for 10 years and 5 months or 16 years and 5 months). On the other hand, there was a positive correlation between the top dry weight at 3 months after emergence and 1,000-grain weight of the seed. In the plants from the old seeds, no significant differences from those from new seeds were observed either in the mean heading date, maturing date, culm lengths, ear length, yield components, grain yield or inspection-grade. On the other hand, in the plants from the very old seeds, the mean heading date, maturing date, culm lengths, yield components and grain yield were significantly different from those in the new seeds in some cultivars. The results of RAPD analysis showed that the band pattern of the very old seeds was the same as that of the new seed in each cultivar. We concluded that the seeds of wheat and two-rowed barley stored for 2 years and 5 months with a germination percentage of higher than 80% are practically useful, showing normal growth characters and productivity. However, it should be noted that some cultivars had inferior grain yield after the seed storage for over 10 years.     

温度对水稻抗褐飞虱特性的影响

 为研究温度对水稻抗褐飞虱特性的影响,于2007年和2008年应用苗期集团筛选法（SSST）在杭州地区的自然条件下测定了抗性水稻品种IR26和IR36对田间褐飞虱的抗性,同时比较了不同温度（22℃、25℃、28℃、31℃和34℃）下IR26和IR36对褐飞虱的抗性、可溶性糖和草酸含量的变化。自然条件下,IR26已完全失去对杭州种群褐飞虱的抗性,而IR36仍具中等抗性。在25℃到34℃的范围内随着温度升高,IR26对褐飞虱抗性减弱,但22℃条件下抗性比25℃更弱。IR36在温度升高的条件下对褐飞虱的抗性总体呈降低趋势,在31℃和34℃下也已完全失去对褐飞虱的抗性。在22~25℃条件下,IR26和IR36的持抗期均在25℃下最长,分别为9 d和11 d。3个品种稻株中的可溶性糖含量均随温度升高而增加,而草酸含量则随温度升高先增加后下降,在25℃时为最大值。不同温度下及不同水稻品种之间稻株内可溶性糖和草酸的含量均有显著差异。     

Differential susceptibility of potato cultivars to four herbicides

Greenhouse and field studies were conducted to evaluate the susceptibility of six potato (Solatium tuberosum L.) cultivars to injury by four herbicides. The White Rose cultivar was the most susceptible to injury, especially from metribuzin {4-amino-6-tert-butyl-3-(methylthio)-s-triazin-55 (4H) one}, and linuron {3-(3,4-dichlorophenyl)-l-methoxy-l-methyl-urea}. Injury was attenuated by decreasing the rate of herbicide in the range of 4.5 to 0.5 kg/ha (4 to 0.5 1b/A) and by increasing the seed piece size. Injury seemed to be associated with soil texture and was greater in a sandy loam than in a sandy clay loam soil. Greenhouse studies provided valuable leads on cultivar susceptibility to herbicides but reductions in foliar weight of 15 to 20% are required to justify any suspicion that field injury will occur.     

Competitiveness of rice (Oryza sativa L.) cultivars against Echinochloa crus-galli (L.) Beauv. in water-seeded production systems

Developing more competitive rice cultivars could help improve weed management and reduce dependency on herbicides. To achieve this goal, an understanding of key traits related to competitiveness is critical. Experiments were conducted at Gelemen and Bafra districts of Samsun province in Turkey between 2008 and 2009 to measure the competitiveness of rice cultivars against Echinochloa crus-galli, a problematic weed in rice fields. Five rice cultivars (Osmancık, Kızılırmak, Karadeniz, Koral and Neğiş) and five E. crus-galli densities (0, 5, 10, 20, and 30 plants m⁻²) were used. Koral produced significantly more tillers than the other cultivars irrespective of E. crus-galli densities and reduced E. crus-galli tiller production by about 29.5% at Gelemen and 15.8% at Bafra at the highest weed density. E. crus-galli interference reduced rice height and there was a density dependent relationship. Koral was the most competitive cultivar; it maintained high biomass accumulation in early growth stages and suffered smaller reductions in plant height in the presence of E. crus-galli, compared to the other cultivars. In the absence of weed competition, Koral and Neğiş produced the highest yields at both locations. Stepwise regression analyses of the combined data from both years showed tillering capacity, early growth crop biomass, and plant height were critical traits related to competitiveness. These traits should be considered by plant breeders in their efforts to develop rice cultivars with enhanced competitiveness against weeds. Development of such cultivars could substantially reduce herbicide and labor inputs for rice production.     

苏北垦区豆田杂草生长为害习性

苏北垦区豆田杂草分属15科,36属,41种,恶性杂草有稗,苍耳等9种。在大豆整个生育期间通常出现1～2个萌发高峰,主要集中在6月中旬～7月下旬。杂草种子于8～10月成熟。种子在土壤中的埋深及出苗期,直接影响杂草的出苗和繁殖。杂草与大豆的相互竞争,以在大豆播种一个月后最为剧烈。0～2cm和6～25cm耕层中贮葳的杂草种子最多。     

Variation in Seed Shape and Husk Color in Japanese Native Cultivars of Common Buckwheat (Fagopyrum esculentum Moench)

Abstract

The variation in seed shape and husk color was investigated in 56 Japanese native cultivars of common buckwheat. Analysis of variance revealed highly significant differences among the cultivars in seed shape characteristics and husk colors. The 1000-seed weight (1000-SW) ranged widely, from 20.4 to 39.0 g, among the cultivars. The cultivars collected from the Kanto region of the mainland had a large length and width of seed and heavy 1000-SW. On the other hand, the cultivars from the Chugoku and Shikoku regions of Japan had a small length and width of seed. The length and width of seeds showed a high positive correlation. The cultivars with a high 1000-SW showed a slight difference between length and width of seed and were typically the triangular type in seed shape. The length/width ratio (L/W) depended on the width rather than the length of seed, though both were negatively correlated with the L/W. Highly positive correlations were found among the L*, a* and b* husk color value. The L* showed a highly positive correlation with growth duration, and the husk color of the cultivars became more deep black as growth duration decreased. The husk color of the cultivars from the Kyushu region (long growth duration) was grayish brown, but that of the cultivars from Nagano Pref. (the shortest growth duration) was characterized as typically deep black. The cultivars collected at lower latitude regions tended to have a lighter color of husk than those from higher latitude regions. The cultivars from the Tohoku region showed a smaller variation for seed size characteristics and 1000-SW, and the cultivars from the Kyushu region showed a smaller variation for husk color.     

An evaluation on intensity of infection of Pseudocercospora leaf spot disease of cowpea cultivars (Vigna unguiculata L. Walp), with respect to infector rows, dates of inoculation and cultivars, grown under field conditions in Northeast Thailand

This investigation was carried out at the Experimental Farm, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand to evaluate intensity of infection of Pseudocercospora Leaf Spot disease of cowpea cultivars, grown under field conditions with the use of Yasothon soil series (Oxic Paleustults). The experimental design used was a strip split plot design with four replications. The experiment consisted of three factors, i.e., with and without infector rows (Factor A), with and without inoculation and inoculated dates, i.e. none inoculation, inoculated at days 15 and 30 after sowing of seeds in main plots (Factor B) and three cowpea cultivars of KVC7, KKU25 and IT81D-1228-14-1 (Factor C). The results showed that the use of infector rows of cowpea plants (KKU25) being sown at 15 days before sowing seeds of cowpea cultivars in main plots gave a similar intensity of disease as those infector rows being sown at 30 days before sowing seeds of cowpea cultivars in main plots but significantly higher than without infector rows. Pathogenic disease being inoculated to the cowpea plants at 15 days after the sowing of seeds in main plots gave significantly higher intensity of disease than none inoculation. The establishment of infector rows at 15 days ahead of the sowing of seeds in main plots together with an inoculation of the disease at 15 days after the sowing of seeds in main plots gave the best results in evaluating amount of the infected disease. Thus infector rows surrounded the main plots are required whenever trials on disease evaluation are taken place.     

稻瘟病菌体细胞色素的变异性及其突变体

 利用紫外光诱变，从来自菲律宾田间的一个具有广谱毒性的流行菌株PO6-6中获得一些浅黄色素突变株，并检测了它侵染水稻的频率；同时对利用浅黄色的表现型来研究体细胞变异的可能性进行了探讨。在所测试的13个浅黄色素突变株中，有6个能使水稻产生病斑，在品种CO39、IR50，IR36上能重新分离到浅黄色素突变株。由此表明，某些浅黄色的突变株具有侵染水稻的能力， 它们没有通常的黑色素合成。从一些浅黄色突变株引起的病斑上获得的单孢培养菌中，野生菌株(Wild type)色素的频率范围为10％～100％。由浅黄色突变株引起的病斑中也可重新获得白色的变异物。在室内培养试验中，出现色素变异的频率未超出l10^-3 ～10^-4 的范围。用一个浅黄色突变株和野生类型的分离菌株进行的相互接种中，从品种IR50的病斑上分离的单孢中，浅黄色菌株占绝对优势。在一次实验中， 由浅黄色素培养菌所引起的一个病斑中，同时获得了浅黄色和灰黑色的培养菌。这些结果表明，体细胞色素的变异也许表现在与寄主植物之间的互作。