品种与播量对直播早稻群体质量和产量的影响

采用两因素随机区组试验设计,研究不同品种和播量对直播早稻群体质量和产量性状的影响。结果表明,双季直播早稻品种间出苗率、成苗率、成穗率和结实率差异不显著;最高苗和单位面积有效穗数差异显著;单产以中早39最高,中早35与之差异不显著,而湘早籼6号与之差异极显著。单位面积出苗数、同期茎蘖数、有效穗数随播量的增加而增加,出苗率、成苗率、分蘖率、成穗率及每穗总粒数随播量的增加而下降,单产以播量112.5 kg/hm²处理最高,播量90.0 kg/hm2处理与之差异不显著,而播量67.5 kg/hm²处理与之差异极显著。在本试验条件下,中早35和湘早籼6号直播的适宜播量为112.5 kg/hm²,而中早39直播的适宜播量为90.0 kg/hm²。     

播量对宽幅条播冬小麦群体结构和干物质积累分配的影响

为明确宽幅条播的适宜播量,于2017-2018年在山西省闻喜县（冬小麦试验示范基地）开展大田试验,采用宽幅条播,设150、225、300、375和425  kg·hm^-2共5个播量处理,研究播量对小麦群体结构、干物质积累和分配的影响。结果表明,播量从150  kg·hm^-2增加至300  kg·hm^-2,可增加冬小麦越冬期、拔节期群体分蘖数、越冬-拔节阶段群体分蘖增加量;增加各生育时期地上部干物质积累量,尤其生育中、后期;提高开花期和成熟期叶片、穗轴+颖壳干物质积累量所占比例;增加花前叶片、穗轴+颖壳中干物质积累量,显著提高花后干物质积累量及其对籽粒贡献率,从而提高了穗数（5%~13%）、千粒重（0.3%~5.0%）,并显著提高产量（4%~19%）,但播量超过300  kg·hm^-2则趋势相反。相关分析表明,冬小麦成熟期穗数与生育前期群体分蘖数密切相关,千粒重与花前干物质积累量和花后干物质积累量密切相关,尤其是花后干物质积累量。总之,山西南部冬小麦采用宽幅条播,播量为300  kg·hm^-2时,利于冬小麦前期形成较多的有效分蘖,增加中后期干物质积累量,尤其叶片、穗轴+颖壳积累比例;利于增加花前叶片、穗轴+颖壳干物质转运量;促进花后干物质积累及其对籽粒的贡献,提高穗数和千粒重,实现增产。     

冬小麦新品种晋麦86号播期和播量试验研究

采用单因素随机区组排列试验设计,通过比较不同播期和播量对晋麦86号生育期变化、群体动态、产量构成要素及单产水平等的影响,总结提出晋麦86号适宜的播期为9月25-30日,适当的播量是基本苗25万/667m2。     

播期播量对国审小麦新品种漯麦9号产量的影响

为探明小麦品种漯麦9号的最佳播期和适宜播量,进行了播期、播量双因子裂区试验。结果表明,漯麦9号的最佳播期为10月14日,适宜播期为10月7～14日;最佳播量为基本苗210万/hm2,适宜播量为165万～255万/hm2。     

水稻机抛栽培的适宜群体探讨

适宜的水稻群体是实行机抛栽培成功的关键技术之一．在育好塑盘矮壮秧的条件下掌握适当的落田苗数和大田施肥量是形成高产群体的基本条件。通过本试验的分蘖消长、叶面积系数、经济性状及实际产量的考查测定，结果表明，早晚稻每667m~2抛60～80盘（每盘播量为60～70g），施纯氮11.5kg及一定量的磷钾肥，并严格掌握搁田时间与搁田程度，可望组成高产不倒、适宜机割的合理群体。     

秀水09作单季直播晚稻适宜播期播量的探讨

【目的]为明确浙北稻区直播单晚水稻的适宜播期和播量提供理论参考。【方法】以常规中熟晚粳秀水09为试材,在桐乡市龙翔街道和乌镇针对不同播期和播量开展研究,分析播期和播量对生育特性、穗粒结构和产量的影响。[结果]不同播期和播量对苗峰出现期、齐穗期、成熟期以及株高、总叶龄均有明显影响。随着播期的推迟和播量的增加,有效穗数增加,每穗总粒数和实粒数显著减少,千粒重也略有降低,产量下降明显。[结论】秀水09作当地直播单晚栽培的最佳播期为5月底至6月初,最佳播量为30．0～37．5kg／hm^2。     

宽幅播种条件下行距对小麦产量及干物质积累和转运的影响

为了确定小麦宽幅播种的适宜行距,在高产地块以高产小麦品种泰农18为材料,设置20 cm、25 cm、30 cm三个行距处理,研究了宽幅播种条件下行距对小麦产量、群体动态、干物质积累与分配的影响。结果表明,相同行距下,宽幅播种的小麦产量较常规条播提高11.0%。在宽幅播种条件下,行距过大时小麦群体数量较小,成穗不足,干物质积累减少,产量降低;缩小行距可提高群体数量和干物质积累;但行距过小时穗粒数、千粒重下降,群体边际效应减弱,产量降低;适宜行距可协调产量构成因素,提高群体在花后维持较高光合能力,提高花后干物质同化量和对籽粒的贡献度。在本试验的条件下,泰农18以宽幅播种、行距25 cm、播量120 kg·hm~(-2)为宜。     

不同播量下的早稻秧田群体动态及其对秧苗素质的影响

壮秧是高产的基础,播量是影响秧苗素质的重要因素。我们于1981～1982年进行了早稻秧田播量的试验,试从秧田群体动态的角度,分析不同播量对秧苗素质的影响,以为确定合理播量提供一些依据。 试验方法 试验于1981～1982年在本所进行,试验田为四纪红壤发育的粘质土,在我县属中上肥力     

播期和播量对冬小麦尧麦16群体性状和产量的影响

为确定高产小麦尧麦16的适宜播期和播量,采用田间裂区设计,研究不同播期和播量对该品种群体性状、产量结构及产量的影响。结果表明,随着播期的推迟,小麦营养生长期缩短,成熟期却不推迟。同一播期下,播量对小麦生育进程无影响;早播增加冬前至拔节期总茎数,而对生育后期总茎数无影响。增加播量可显著增加各生育时期总茎数;随着播期推迟,同一播量水平的干物质积累量明显降低。相同播期下,干物质积累量、叶面积指数随播量的增加而递增;相同播量下,随着播期的推迟叶面积指数降低。小麦叶面积指数随生育时期的推进先升高后下降,在抽穗期达到最大。随着播量增加,产量和有效穗数逐渐增加,穗粒数和千粒重呈下降趋势;与播量相比,播期对尧麦16产量及产量结构的影响较大。尧麦16的最佳播期为10月7日,播量为300×10~4粒·hm~(-2);9月27日至10月2日播种,播量为225×10~4粒·hm~(-2),10月12日至10月17日播种,播量为375×10~4粒·hm~(-2),也可以获得较高的产量。     

粮棉轮作模式下播期播量对棉茬小麦生长发育和产量的影响

为明确粮棉轮作两年三熟模式下棉茬小麦适宜的播期和播量,采用田间裂区试验,研究了不同播期(10月15日、10月25日和11月5日)和播量(187.5kg·hm~(-2)、225.0kg·hm~(-2)、262.5kg·hm~(-2)和300.0kg·hm~(-2))对小麦生长发育、产量及其相关性状的影响。结果表明,在拔节期,小麦叶面积随着播期的推迟而下降;在孕穗期,10月25日播期时,播量过大(300.0kg·hm~(-2))会降低小麦叶面积;在扬花期,11月5日播期时,播量过小(187.5kg·hm~(-2))会降低小麦叶面积。随着播期的推迟,小麦生物量逐渐降低,且随小麦生长发育推移,播期对小麦生物量的影响程度逐渐降低。晚播可以提高小麦灌浆期旗叶叶绿素含量,延缓叶片衰老。播期推迟会降低小麦拔节期、扬花期和成熟期的茎蘖数,播量增加会提高小麦的茎蘖数。随着播期的推迟,小麦的成穗数下降,从而导致产量降低。穗数对小麦的产量贡献最大。增加播量使小麦穗粒数和千粒重下降,但穗数增加,所以相同播期时,播量对小麦的产量没有显著影响。本试验中,以播期10月15日、播量262.5kg·hm~(-2)产量最高。建议棉茬小麦适当早播,如果播期推迟,则应适量提高播量以保证产量。     

北方旱作水稻研究现状及发展前景

阐述了我国北方旱稻研究现状,分析了旱作条件下水稻生物学性状、生理生化变化规律及旱作水稻产量及其构成因素与其它性状、品质与其它性状的相关关系,指出产量的提高与品质的改良并不存在矛盾,育种工作者完全可以培育出集高产、优质于一身的旱稻品种。评价了旱作水稻各抗旱性鉴定指标,指出综合抗旱力指数K值法作为一种鉴定水稻品种的综合抗旱能力研究方法较为客观、准确,且易于掌握利用。并从旱作水稻研究现状、生产实际出发,结合我国北方气候特点、水资源情况,分析了我国北方发展旱稻的可行性及其广阔的发展前景。     

北方旱作水稻研究现状及发展前景

阐述了我国北方旱稻研究现状,分析了旱作条件下水稻生物学性状、生理生化变化规律及旱作水稻产量及其构成因素与其它性状、品质与其它性状的相关关系,指出产量的提高与品质的改良并不存在矛盾,育种工作者完全可以培育出集高产、优质于一身的旱稻品种。评价了旱作水稻各抗旱性鉴定指标,指出综合抗旱力指数K值法作为一种鉴定水稻品种的综合抗旱能力研究方法较为客观、准确,且易于掌握利用。并从旱作水稻研究现状、生产实际出发,结合我国北方气候特点、水资源情况,分析了我国北方发展旱稻的可行性及其广阔的发展前景。     

水、陆稻在水田、旱地栽培的生态适应性研究：II．稻株碳、氮代谢的生态适应性观察

 旱种条件下，不论水稻还是陆稻，全糖、全氮含量均高于水种条件，醇溶糖占全糖的比例较高，碳／氮比低：陆稻的醇溶糖占全糖的比例远远高于水稻，这一特性很少随种植条件的改变而产生很大的变化，这可能是其对旱地适应性较强的生理原因之一。同时发现，贮藏性物质的增加是水稻旱种条件下的重要生理表现。     

不同旱稻品种产量与性状的主成分分析

为了明确旱稻品种的生长发育规律,以及与产量形成的主要因素,为旱稻育种与栽培研究提供理论依据。本试验以10个参试旱稻品种(系)为试材,采用随机区组设计,通过对旱稻品种的主要农艺性状进行主成分分析,研究结果表明:参试品种在不同性状间差异较大,尤其在有效穗数、穗实粒数等高产育种性状上存在较大差异。吉林省旱稻主栽品种粒数因子较为重要,贡献率为40.428%,并以穗粒数、每穗实粒数的分量值较高,而产量的提高应进一步提高株高,同时提高有效穗。因此,在旱稻高产育种中,应适度增加材料的株高和选择多穗的材料,可增加选育材料的单株产量。     

吉林省的旱稻研究及其发展前景

从历年研究课题和取得的科研成果两方面回顾了吉林省旱稻研究的历史过程;客观地分析了旱稻研究的现状,从承担国家旱稻品种试验到旱稻栽培和新品种选育研究,并介绍了旱稻研究存在的主要问题;种植旱稻是实现节水农业的有效途径之一,研究领域和前景十分广阔。     

Growth and Yield of Six Rice Cultivars under Three Water-saving Cultivations

Abstract

We evaluated the genotypic differences in growth, grain yield, and water productivity of six rice (Oryza sativa L.) cultivars from different agricultural ecotypes under four cultivation conditions: continuously flooded paddy (CF), alternate wetting and drying system (AWD) in paddy field, and aerobic rice systems in which irrigation water was applied when soil moisture tension at 15 cm depth reached ?15 kPa (A15) and ?30 kPa (A30). In three of the sixcultivars, we also measured bleeding rate and predawn leaf water potential (LWP) to determine root activity and plant water status. Soil water potential (SWP) in the root zone averaged ?1.3 kPa at 15 cm in AWD, -5.5 and -6.6 kPa at 15 and 35 cm, respectively, in A15, and ?9.1 and ?7.6 kPa at 15 and 35 cm, respectively, in A30. The improved lowland cultivar, Nipponbare gave the highest yield in CF and AWD. The improved upland cultivar, UPLRi-7, and the traditional upland cultivar, Sensho gave the highest yield in A15 and A30, respectively. The yields of traditional upland cultivars,Sensho and Beodien in A30 were not lower than the yields in CF. However, the yields of the improved lowland cultivars, Koshihikari and Nipponbare, were markedly lower in A15 and A30. Total water input was 2145 mm in CF, 1706 mm in AWD, 804 mm in A15, and 627 mm in A30. The water productivity of upland rice cultivars in aerobic plots was 2.2 to 3.6 times higher than that in CF, while those of lowland cultivars in aerobic plots were lower than those in CF. The bleeding rate of Koshihikari was lower in A15 and A30 than in CF and AWD, and its LWP was significantly lower in A15 and A30 than in CF and AWD, but Sensho and Beodien showed no differences among the four cultivation conditions. We conclude that aerobic rice systems are promising technologies for farmers who lack access to enough water to grow flooded lowland rice. However, lowland cultivars showed severe growth and yield reductions under aerobic soil conditions. This might result from poor root systems and poor root function, which limits water absorption and thus decreases LWP. More research on the morphological and physiological traits under aerobic rice systems is needed.     

Historical Changes in Urban Rice Production Systems in Tokyo,Japan

Abstract

Historical changes in planting area, yield improvements, and production of both paddy and upland rice (Oryza sativa L.) in Tokyo and the whole of Japan from 1877 to 2003 were reviewed. The area of rice in Tokyo was at its peak (17,000 ha) at the beginning of the 20th century but dramatically reduced thereafter except for the period of 1950s, to200 and 30 ha for paddy and upland rice, respectively, in 2003, due to urbanization. After the 1950s, the land-use efficiency rate in Tokyo was reduced from 180 to 100% and rice self-sufficiency rate from 4 to 0.1%. There was historical yield improvement of paddy rice in Tokyo particularly after 1960s in the Southern and Northern Tama regions, but the current yield level in Tokyo (ca. 400 g m-²) is lower than that in the whole of Japan (more than 500 g m-²) eventhough crop damage due to low temperatures is not serious.The reasons were discussed from the viewpoints of (1) less agricultural inputs and agronomic management, (2) declining rice research after the 1970s, (3) higher elevating air temperature(e.g. 1.4°C for the last 40 years), in Tokyo, and (4) yield component differences. Upland rice in Tokyo has a planting area comparable with paddy rice (ca. 7,000 to 8,000 ha) during the 1950s, but yield improvement during the last 50 yearsis not noticeable (ca. 150 g m-²) with no development of cultivars, and with greater fluctuation of crop situation index due to drought compared with paddy rice. This review paper discusses the importance of urban rice production system, along with a proposal of the alternatives.     

Yield potential and water use efficiency of aerobic rice (Oryza sativa L.) in Japan

Intensive rice farming in aerobic soil, referred to herein as aerobic rice, can greatly reduce the water input compared to that of flooded rice cultivation. The objective of this study was to compare the potential productivity of aerobic rice and flooded rice using high-yielding varieties at two locations in Japan in two successive years. In aerobic fields, the total amount of water supplied (irrigation plus rainfall) was 800–1300 mm. The soil water potential at 20-cm depth averaged between −15 and −30 kPa each growing season, but frequently reached −60 kPa. The average yield under aerobic conditions was similar to or even higher than that achieved with flooded conditions (7.9 t ha⁻¹ in 2007 and 9.4 t ha⁻¹ in 2008 for aerobic versus 8.2 t ha⁻¹ for flooded). The average water productivity under aerobic conditions was 0.8–1.0 kg grain m⁻³ water, slightly higher than common values in the literature. The super-high-yielding cultivar Takanari achieved yields greater than 10 t ha⁻¹ with no yield penalty under aerobic conditions in 3 out of 4 experiments. The favorable agronomic characteristic of Takanari was its ample sink capacity (grain number × grain weight). In conclusion, high-productivity rice cultivation in aerobic soil is a promising technology for water conservation. With continued breeding, future aerobic rice varieties will possess large numbers of spikelets and sufficient adaptation to aerobic conditions such that they will consistently achieve yields comparable to the potential yield of flooded rice.     

Anatomy of Nodal Roots in Tropical Upland and Lowland Rice Varieties

abstract

Nodal root anatomy was compared among twelve upland and lowland rice (Oryza sative L.) varieties with tropical origin which were grown in hydroponic culture and under field conditions. The traditional upland japonica varieties showed the largest diameter of root, stele, and xylem vessel followed by modern upland varieties. There was a clear varietal difference in the ratio of stele to root diameter, which was associated with the genetic group rather than with the ecosystems. The japonica varieties had a significantly larger stele diameter relative to the root diameter than indica and aus varieties. The indica and aus varieties displayed more xylem vessels per unit area of stele than the japonica varieties, but the diameter of xylem vessel was smaller. Equivalent xylem vessel diameter (De) was more dependent on the number of xylem in the indica varieties than in the japonica varieties. Distinctly different types of sclerenchyma anatomy were identified among the varieties. The development of sclerenchyma was classified into four different types based on thickening of cell wall in the outer cortical parenchyma and the number of sclerenchymatous cell layers. Like the xylem anatomy, the varietal differences in sclerenchyma development were more associated with genetic group rather than the ecotype. The japonica varieties had higher frequency of the types which have a doubled cell layer in sclerenchyma with thick cell wall than indica and aus. The difference among the genetic groups was nearly consistent across growing conditions, aerobic and submerged soils. These results indicated that sclerenchyma development is controlled by a genetic factor.     

Differences in the Rate of Seedling Emergence among Rice Cultivars under Low Soil-Moisture Conditions

Abstract

The objective of this study was to identify rice cultivars with high emergence ability under low soil-moisture conditions using a large number of rice cultivars, and to clarify the differences between the rates of emergence in lowland and upland, white- and red-kerneled, and non-glutinous and glutinous cultivars. First, 30 cultivars with a high emergence rate at 14 days after sowing (DAS) were selected at a soil water potential of -1.17 to -0.89 MPa from 382 cultivars through fourscreening experiments. In these experiments, the emergence rate was significantly higher in the upland cultivars than in the lowland cultivars. The red-kerneled cultivars also had a significantly higher emergence rate than the white-kerneled cultivars. However, no difference in emergence rate was observed between the non-glutinous and glutinous cultivars. Second, the emergence rates of various cultivars were examined at a soil water potential of -1.62, -1.23, and -1.07 MPa. The higher the soil water potential, the higher the emergence rate at 28 DAS and the shorter the time to the emergence. The order of cultivars in their emergence rate at 13 DAS at -1.07 MPa was similar to that at 28 DAS at -1.62 MPa. Therefore, the dataat 13 DAS at -1.07 MPa were used to compare the selected 30 cultivars for their emergence ability under low soil-moisture conditions. Moulla Topa showed the highest emergence rate (78.1%) and Gaiya Rate Bhasunamathe the shortest time to 50% emergence (11.1 d) under these conditions.