播期对四川小麦分蘖发生、消亡及成穗特性的影响

为探讨四川小麦分蘖发生、消亡与成穗规律,了解穗数形成的制约因子,在四川两个典型小麦生态区(川西平原区和川中丘陵区),以主推品种川麦104(春性)和半冬性品种川农30为材料,通过定点调查茎蘖动态,以及定株调查分蘖发生、消亡时间和叶位,研究过早播(10月16日)、早播(10月23日)、适播(10月30日)、晚播(11月6日)下小麦的分蘖成穗特性。结果表明,四川小麦分蘖发生一般持续50d左右,分蘖发生数量少且低位分蘖缺位多。平原区(温江点)小麦第1叶位分蘖发生率为61%~80%,丘陵区(仁寿点)为13%~60%;第2叶位分蘖发生率在两生态点分别为63%~98%和45%~83%;第3、第4叶位以及二级分蘖很少发生。川麦104单株分蘖数(1.4~2.4个)显著低于川农30(1.6~2.9个)。四川小麦分蘖消亡持续时间长,从拔节一直持续到开花,分蘖消亡率高达50%以上,花后也还有8.0%~19.4%的分蘖消亡,其中川麦104分蘖消亡各期(拔节-孕穗、孕穗-抽穗、抽穗-开花)比较均衡,川农30分蘖消亡集中在孕穗-抽穗阶段(占总消亡率的43.9%)。四川小麦分蘖成穗率低,平原区和丘陵区分别为27.7%~48.8%和9.0%~19.4%,其中平原区第1、2叶位分蘖成穗率分别为65.0%和50.2%,丘陵区分别34.8%和24.4%。10月23日左右是利于丘陵区小麦分蘖成穗、高产的适宜播期,平原区还可提前到10月16日左右。     

Performance of double cropping and relay intercropping for black soybean production in small-scale farms

We investigated the soybean productivity of double cropping and relay intercropping in farmer’s fields for three years using two black soybean cultivars of Kurozukin and Tanbaguro, which are used for the first and second crop, respectively. Kurozukin is the early maturing cultivar for vegetable soybean harvest and Tanbaguro is the late-maturing cultivar for the harvest of vegetable soybean and seeds. The yield of the first crop (Kurozukin) was similar to the mono cropping regardless of cropping patterns. However, the yield of the second crop (Tanbaguro) was affected by cropping patterns. The yield of Tanbaguro in double cropping was prone to decrease by late sowing. The late sowing was induced by the late sowing and late harvesting of Kurozukin because of the low temperature in April and the large amount of precipitation in rainy season, respectively. In relay intercropping that Tanbaguro was sown between the rows of Kurozukin at about one month before the harvest of Kurozukin, the yield of Tanbaguro was similar to the mono cropping and the competition with Kurozukin was not observed. Thus, the land equivalent ratio value of double cropping was lower than that of relay intercropping. These results suggest that relay intercropping is more useful cultivation system than double cropping to increase the annual soybean production.     

Grain Yield of Sorghum Cultivars in a Double Cropping System

Abstract

Field experiments were conducted at the experimental field of Kyushu University, northern Kyushu in 1996 and 1997 to investigate the possibility of a double cropping of sorghum using early maturity cultivars. The effects of sowing date (early or late) and the cultivar on the yield were also examined. On the average, grain yield from double cropping was 556 g m^?2 in 1996 and 746 g m^?2 in 1997. Sowing date greatly influenced the major traits of the summer crop, but not significantly those in the spring crop, except for the days to heading. Late summer sowing decreased grain yield as much as 41.9%, decreased 100-grain weight by 22.4% and extended days to heading. Early sowing, early in April and late in July or early in August, is recommended for spring and summer crops, respectively, in a double cropping system to obtain a high grain yield. SA 403, D12, C8, C9, D5 C10-1 F₄ line and D5 × C8 (F₁ hybrid) were considered to be suitable for a double cropping system.     

播期推迟对冬小麦产量形成和籽粒品质的调控效应

为了明确推迟播期对小麦产量形成和品质的影响,选用2个冬小麦品种(轮选987和京冬8号),在大田条件下研究了播期推迟对小麦群体动态、物质积累、产量构成和籽粒品质的调控效应.结果表明,播期推迟能显著降低小麦冬前分蘖数,促进春季分蘖的发生和成穗,提高分蘖成穗率.播期对小麦植株干物质积累的影响存在基因型差异.播期推迟引起小麦产量构成因素的变化,进而导致籽粒产量下降,且京冬8号出现显著下降时对应的播期早于轮选987.播期推迟后小麦籽粒中的淀粉含量呈下降趋势,蛋白质含量呈上升趋势,同时二者的主要组成成份也随之改变.因此,冀东地区选用轮选987且适当早播(10月5日播种)可以获得高产;推迟播期至10月10日则籽粒品质提高,但要注意加强小麦生育后期的田间管理,防止粒重明显降低.     

Irrigated cotton in the tropical dry season. III: Impact of temperature,cultivar and sowing date on fibre quality

Depending on sowing month, temperatures during boll growth in the tropical dry season are potentially sub- or supra optimal for the fibre quality parameters length and strength. The aims of this research were to: (1) measure the effect of sowing date on the quality of fibre from cotton grown during the dry season as this was not known; (2) use the range in temperature created by varying sowing date in the dry season, to derive relationships with gin turnout, the fibre quality parameters length, strength and micronaire. Over three seasons, two Gossypium hirsutum (upland) cultivars and one Gossypium barbadense cultivar were sown from March to June at the Ord River (15.5°S), Western Australia. For the highest yielding sowing months of March and April, fibre length and strength were at or below market preference due to relatively low temperatures and solar radiation during early fibre development. Fibre micronaire achieved market preference at all sowing months due to favourable late season temperatures and radiation. It is likely that current G. barbadense cultivars will have short fibre when grown in the dry season. For fibre length and gin turnout quadratic responses (p < 0.05) to weighted minimum temperature were fitted for each cultivar, where the optimum minimum temperature was 18–20 and 16–17 °C, respectively. The cultivar differences in fibre properties observed here suggest that wider screening may identify G. hirsutum cultivars with suitable fibre length and strength in the dry season. It was demonstrated by weighting of temperatures for the contribution of the cohort of bolls pollinated each day; the variation in crop fibre quality and gin turnout in the field due to temperature can be predicted.     

种植抗虫品种和减量使用杀虫剂的白背飞虱可持续治理技术的田间试验

采用田间虫情和天敌数量调查、水稻产量与千粒重测定和水稻生产实际收益比较的方法,在浙江富阳和重庆秀山两地进行了种植抗虫品种和减量使用杀虫剂的白背飞虱可持续治理技术的田间试验.设使用杀虫剂2次和农户管理(使用杀虫剂4～5次)两个处理,无杀虫剂作为对照.试验结果表明,抗虫品种嘉花1号在各种杀虫剂处理中,白背飞虱成、若虫数量最低(0.9～3.3只/株),是感虫品种中香1号无杀虫剂处理的0.12%.无杀虫剂处理的蜘蛛数量分别是农户管理和杀虫剂2次处理的2.8～5.5倍和1.6～4.1倍.在同样的杀虫剂处理条件下,抗虫和耐虫品种的稻谷损失量和损失率较感虫品种明显地低.水稻生产的实际收益比较显示,无杀虫剂处理,种植嘉花1号可以增收1.13%～15.91%.因此,稻农种植抗虫或耐虫品种,减量使用杀虫剂至2次或不使用杀虫剂,充分利用蜘蛛等天敌的控制作用,完全能够有效地抑制白背飞虱种群的发生和发展,获得与常规杀虫剂用量(4～5次)相仿或更高的收益.     

Wheat quality and productivity as affected by varieties and sowing time in Haryana, India

Of the wheat grown in North-West India the majority is consumed as traditional Indian flat bread (chapatti). Chapatti quality is important to consumers and people are willing to pay more for better quality wheat flour, but farmers do not specifically target quality outcomes as the majority of their wheat is sold with no segregation. For farmers the main objective is to harvest maximum yields, but in the last decade productivity growth for wheat yields has slowed in the areas where the wheat is grown in a double cropping pattern. Nutrient depletion and temperature-related stress are possible causes for this decline in productivity growth. Farmers meanwhile are looking to opportunities to maintain profitability and, with consumers willing to pay a higher price for better chapatti wheat, an opportunity exists for farmers to manage their wheat to improve both the yield as well as quality of wheat. In this paper we evaluate management practices that best achieve high yield and better chapatti quality, and assess the temperature environment for the winter wheat growing season. A step-wise analysis of the long-term temperature trend for sites in NW India showed that mean annual temperature has increased by 0.7-1.0 °C during the last decade. Field experiments with wheat varieties (C-306, WH-283, DBW-17, PBW-343, PBW-502, PBW-550, Raj-3765 and WH-1025) were conducted at farmers’ fields under 4 different sequential cropping rotations for the 2007-08 and 2008-09 winter seasons in Haryana (India). C-306 and WH-283 are varieties with excellent chapatti quality but are lower yielding by 15-26% than the more widely grown varieties such as PBW-343 and PBW-502. The replicated experiments involved three sowing times, these being an early sowing (late October to early November, timely sowing (mid November) and a late sowing (early December). A differential response of varieties was observed to sowing time with the yield of C-306 better whereas that of WH-283 and Raj-3765 was poor in early sown conditions. The varieties DBW-17, PBW-343 and PBW-502 were the highest yielding wheat with similar performance under early as well as timely sowing. All the varieties had lowest yield in December sowing. In general, late sowing had lower thousand grain weight but higher protein content. Of the quality measure grain hardness was the only attribute with a consistent positive correlation with chapatti quality. The chapatti score was higher for varieties C-306 and WH-283 compared to the other varieties but grain hardness and chapatti score was not much affected by sowing time. With all varieties included in the analysis there was no correlation between protein and chapatti score, but within an individual variety usually higher protein resulted in a higher chapatti score. There was no association of grain test weight or sedimentation value with chapatti score. From the results shown here it is evident that farmers will be able to manage with variety choice and timely sowing to obtain chapatti quality without losing grain yield benefits.     

优质稻核心种质黄华占及其衍生系统理想模式研究

 为了构建优质稻核心种质黄华占及其衍生系统理想模式,指导黄华占及其衍生系统品种的进一步遗传改良,2007年早季和晚季在广州进行大田试验,设计随机区组试验考查黄华占及其衍生品种的综合农艺性状,整合黄华占及其衍生品种在南方稻区省级水稻区试结果,构建黄华占及其衍生系统理想模式。黄华占及其衍生系统的早季产量与每穗总粒数和倒2叶长呈显著正相关,相关系数分别为0.716和0.825;与每株有效穗数呈显著负相关,相关系数为-0.795。早季总粒数因子增加1个单位,产量增加3.17个单位。晚季产量与千粒重呈显著正相关,相关系数为0.734;食味品质与剑叶长、倒2叶长、倒3叶长呈显著正相关,相关系数分别为0.798、0.794和0.831。晚季剑叶宽因子减少1个单位,产量增加2.06个单位。广州地区优质稻核心种质黄华占及其衍生系统理想模式早晚季有所不同,早季应注重选育大穗、长穗、较长上3叶的株（品）系;在晚季应注重较高千粒重和较窄上3叶的株（品）系。     

杂交水稻氮肥施用技术研究

通过不同氮肥施用法对杂交水稻群体、穗粒结构及产量的效应分析，表明重前施肥法能获得较多 的有效穗，但每穗粒数较少、粒重软低．适当降低前期用肥量，增加保花肥、粒肥的施用，可提高成穗率，增加千 粒重，从而提高产量．     

不同播量对机械精量直播水稻产量及其物质生产的影响

以杂交晚粳稻甬优8号、常规粳稻武运粳19为材料,在机械化精量直播方式下,研究了不同播量对其产量及物质生产的影响。结果表明,每667 m2播种量甬优8号1.5~2.2 kg、武运粳19号2.2~3.0 kg处理的产量最高;其群体均能于有效分蘖临界叶龄期够苗,拔节期达高峰苗,且数量适宜,最终成穗率较高(75%左右);最大叶面积指数均出现在孕穗期,数值适宜;抽穗后干物质积累多,成熟期生物学产量高。     

Effects of two mixtures of perennial ryegrass cultivars with contrasting heading dates, and differing in spring-grazing frequency and silage harvest date, on characteristics of silage from first-cut swards

This experiment quantified the effects of: (i) heading date of perennial ryegrass, (ii) grazing frequency in spring and (iii) date of silage harvest, on the ensilability of herbages harvested for silage, and on the conservation and estimated nutritive value of the resultant silages. Replicated field plots with two perennial ryegrass mixtures (intermediate‐ and late‐heading cultivars) were subjected to three spring‐grazing regimes (no grazing, grazing in late March and grazing in both late March and late April) and were harvested on four first‐cut harvest dates between 20 May and 21 June. Herbage from each of the four replicates of these 24 treatments was precision‐chopped and ensiled unwilted and with no additive in laboratory silos. Herbage from the sward with the intermediate‐heading cultivar had a higher (P < 0·001) dry‐matter (DM) content and buffering capacity than that from the late‐heading cultivar, whereas water‐soluble carbohydrate concentrations increased (P < 0·001) with more frequent grazing in spring. Later harvesting enhanced herbage ensilability through an increased (P < 0·001) DM content and reduced (P < 0·001) buffering capacity and pH. Fermentation profiles of the silage were not markedly influenced by the cultivar mixture used but grazing in both late March and late April resulted in a more extensive fermentation with the acids produced increasingly dominated by lactic acid. The concentrations of acetic acid, and to a lesser extent, ethanol declined as silage harvest date was delayed. Overall, the relative effects of grass cultivar mixture were smaller than those of spring‐grazing treatment or silage‐harvesting date although on any given harvest date the herbage from the intermediate‐heading cultivar mixture was easier to preserve as silage than herbage from the late‐heading cultivar mixture. Delaying the harvesting of the late‐heading swards by 8 d removed the differences related to growth stage in buffering capacity, pH and DM content.     

Irrigated cotton in the tropical dry season. I: Yield,its components and crop development

Growing cotton during the dry (winter) season avoids many insect pests endemic in the wet season (summer) and could permit the reintroduction of cotton to the semi-arid tropics in Australia. This research addressed the questions: (1) what yield is possible given the lower mid-season radiation and temperature of the dry season, (2) the prediction and management of crop development using a range of sowing months to assess whether cotton can be grown and picked within the dry season. Over three seasons two Gossypium hirsutum L. (upland) cultivars and one Gossypium barbadense L. cultivar were sown from March, to June at the Ord River (15.5°S) in Western Australia. For the upland cultivars, lint yields of 1900–2300 kg/ha for March and April sowings were at the high end of Australian and International benchmarks. High lint yields were linearly correlated with a greater proportion of bolls that were located on outer sites on fruiting branches than for high yielding crops in temperate climates (∼30°lat.). The change in boll position increased the length of the growing season which was also linearly correlated with yield. Future research needs to confirm if low minimum temperatures early in flowering caused the change in boll position and to measure the impact of extreme temperature seasons on yield and time to maturity. The lint yield of the G. barbadense cultivar was highest at a March sowing, at least 87% of the upland cultivars, which is comparable with temperate climates. The frequency of temperatures >35 °C and <11 °C affected time to squaring, requiring modification of existing development models derived in temperate climates. It was concluded sowing during March to April should achieve the dual objectives of high yields and avoidance of rain at maturity. The wide temperature range observed in these experiments improved the prediction of boll period from mean temperature; this function should be applicable outside the semi-arid tropics.     

Occurrence of rice blast (Magnaporthe oryzae) and identification of potential resistance sources in Uganda

Rice blast caused by Magnaporthe oryzae continues to be the most destructive disease of rice worldwide, and is a number one disease of rice in Uganda. We present the footprints of M. oryzae importance, distribution, incidence and severity in the rice growing agro-ecologies of Uganda for 2009/2010, and the potential mitigation measures. Our data show that rice blast affects more than 50% of the cultivated rice area on average, and ranks as the most important disease encountered in the field. Between and within agroecologies, both incidence and severity varied (P < 0.05) reflecting the contribution of different cropping practices on rice blast epiphytotics. The highest blast incidence and severities were recorded in Bugiri, Butaleja, Mbale and Lira farmlands, which are the ancestral rice cultivation areas in Uganda. These areas showed mean yield reductions of >30% relative to other locations, suggesting that rice production history played a significant role in rice blast outbreaks. Broadcasting and drill seeding yielded 42.4% less than transplanted rice. Growing two rice crops per year is one of the methods suggested to increase rice production in Uganda, but there was a higher disease incidence in the late season than in the early season, indicating the need for improved resistant varieties. Four blast resistance genes (Pi9, Piz-t, Pi19 and Piz-5) and the cultivar Tetep had the lowest (≤4) blast severity scores in all the test locations. It could be suggested that these genes are potential resistance sources for developing varieties, which would be more relevant for the double cropping systems.     

山区单季稻和再生稻早播气候效应观察

为探寻山区单季稻和再生稻高产气象技术,在尤溪县高山区和低山区分期播种5个杂交稻品种。结果明确,不论低山区或高山区于3月中旬早播种,将产量物质形成期调整在强光适温的季节,结实率高,比迟播田增产5%～10%。其中2个具有较强再生力的品种在低山区早播种,再生季安全开花结实,比迟播田成倍增产。结果表明早播种趋利避害利用气候资源,充分发挥了气候生态的生产潜力。     

Effect of sowing date on the growth and seed yield of common bean (Phaseolus vulgaris L.) in highland environments

Evaluations of common bean cultivars in the highlands of Mexico indicated that land races from that region experience less reduction in seed yield and seed size in late sowings than do lines from other regions. Introduced materials are of interest as sources of increased disease and pest resistance and tolerance to edaphic constraints, however. To quantify effects of sowing date and determine possible underlying causes, germplasm of diverse origins was evaluated at two sites in the highlands using multiple sowing dates. In all trials, seed yield, seed weight, harvest index and canopy dry weight decreased with late sowings. Large effects of sowing date, cultivar and their interaction were found for the four traits. The possible importance of phenology per se and of weather conditions was first examined using regression analyses. Variation in seed yield, seed weight, harvest index and canopy dry weight was more closely associated with time to maturity than with time to flowering. Of three weather variables examined, minimum temperature during seed filling revealed the strongest relations with the four traits. Few interactions of any parameter with line were significant, indicating that the cultivars did not have a strong differential response to a specific weather condition such as night temperature. Simulation analyses comparing photoperiod-sensitive and day-neutral cultivars indicated that radiation and temperature explained part of the yield reduction with late sowings. Daylength also had an influence, however, even in the day-neutral cultivar. Given that phenology had a strong effect on yield and that its inheritance is better understood than that of other physiological traits, priority should be given to understanding the genetic basis of the response of cultivar phenology to sowing date in the region.     

双季杂交稻“肥促水调”栽培技术的应用

选用优势强、品质优的杂交组合,早季中熟搭配晚季迟熟组合,培育壮秧,控制分蘖肥用量,增大后期施肥量,超前搁田控制苗峰,在一定穗粒基础上,实现总粒数、实粒数和经济系数的大幅度提高,从而提高产量．     

Establishment of rice determined by interaction between cultivar,sowing depth,and time between irrigation and sowing,in north west Australia

The influences of cultivar, depth of sowing, and time between pre-irrigation and sowing, on rice crop establishment were investigated by drilling into moist soil during the dry season in N.W. Australia.As the time between pre-irrigation and sowing increased, median seedling emergence was delayed, and spread of the population's emergence rate and final percentage emergence decreased, particularly for shallow sowing depths. Delayed sowing also resulted in less-vigorous growth of some seedlings. Stomatal conductance was generally lowest in seedlings emerged from shallow depths although leaf-air temperature differentials and measurements of stomatal conductance, usually regarded as reliable indices of plant water status, failed to distinguish between cultivars or sowing treatments.Delaying sowing, with attendant cultivation, for more than 10 days after pre-irrigation resulted in negligible weed populations. The tall, vigorous-growing cultivar Pelde (ex N.S.W.), sown at 6–8 cm depth between 10 and 15 days after pre-irrigation reached sufficient height for permanent flooding within 50 days after sowing. A semi-dwarf cultivar IR661-1-170-1-3 (ex IRRI) proved more sensitive to depth and time of sowing following irrigation; because of its slower growth rate and additional irrigation requirements it was less adapted to this method of establishment.     

江苏射阳地区红皮小麦品种不同播期筛选试验

在江苏射阳县新洋农场进行16个红皮小麦品种不同播期的筛选试验,对参试品种早晚2个播期下的生育期、农艺性状、抗性及产量进行汇总分析。结果表明:早播组全生育期变幅在221~225 d,晚播组全生育期变幅在213~217 d,扬麦23全生育期均最短,华麦6号全生育期最长。早播组产量变幅为591.67~739.67 kg/667 m₂,华麦6号最高,扬麦15最低;晚播组产量变幅为637.00~707.67 kg/667 m₂,扬麦23最高,扬麦27最低。未防治条件下,锈病早播组发病明显重于晚播组,早播情况下华麦7号、扬江麦580-1、宁麦13(CK)锈病发生极重,华麦6号锈病早、晚播发生均轻,锈病抗性突出。总之,早播组平均产量水平低于晚播组,产量变幅明显高于晚播组,品种间产量差异较大。扬麦23、华麦1430表现最为突出,在早播组、晚播组产量均居于最前列,赤霉病、锈病均发生较轻。     

迟播对冬小麦灌浆后期高温胁迫下旗叶光合能力和产量的影响

为了解迟播对冬小麦灌浆后期高温胁迫下旗叶光合的调控效应,在大田条件下设置2个播期(常规播期10月8日、推迟播期10月22日)和2种灌浆期温度(开放式增温、自然温度),分析了迟播小麦旗叶光合能力的变化及其对灌浆后期高温胁迫的响应。结果表明,灌浆期高温降低了小麦旗叶光合速率、花后干物质生产量、粒重和产量。与常规播期相比,迟播提高了高温胁迫下小麦旗叶叶绿体类囊体膜不饱和脂肪酸指数,保持类囊体膜相对稳定,减轻高温对旗叶光合机构的损伤;增强了旗叶活性氧清除能力,保障能量传输,减少热耗散,提高光化学反应中可利用能量的分配比例,保持较高的光合系统同化力;提高了气孔导度和胞间CO_2浓度,增加光合作用底物供应。总之,迟播小麦的旗叶可在灌浆期高温胁迫下保持较高的光合能力,有利于提高粒重和产量。     

不同播期对天优8012产量及经济性状的影响

不同播期试验结果表明,天优8012在浙江省作单季晚稻种植,5月20日至6月9日播种均可正常抽穗结实,但随着播种期的推迟,齐穗期、成熟期也相应推后。该组合千粒重和结实率较高,但必须掌握适宜秧龄才能实现高产稳产。在本试验条件下,以5月25日播种、秧龄35 d的处理单位面积产量和日产量较高,均极显著高于其他4个播期处理。