Influence of irrigation and nitrogen management on potato yield and quality

The effects of irrigation, water and nitrogen management on yield and quality of the Russet Burbank cultivar are discussed relevant to developmental stages of growth. Recent research on the interactions of irrigation and nitrogen management on total and U.S. No. 1 yields and specific gravity are presented. Total and U.S. No. 1 yields decline with increasing soil moisture stress. Yield of U.S. No. 1 potatoes is particularly sensitive to short periods of irrigation deficit during tuber initiation. Total yield appears most sensitive to short periods of irrigation deficit during tuber bulking. Allocation of longer term irrigation deficits during years of limited water supply should be either a) avoided during mid-season tuber bulking, or b) uniformly distributed over the entire tuber bulking growth period. Yield increases with higher total available soil nitrogen under deficit irrigation, but the yield response diminishes as the amount of total seasonal water decreases. The influence of irrigation and nitrogen availability is also discussed for specific gravity and tuber maturity. Seasonal (split) nitrogen management is proposed as a method to improve yield, quality and nitrogen fertilizer use efficiency of indeterminant cultivars.     

Effects of drip irrigation regimes on potato tuber yield and quality under plastic mulch in arid Northwestern China

Field experiments were conducted to study the effects of drip irrigation regimes on potato (Solanum tuberosum L.) growth, tuber yield and quality, and water use efficiency (WUE) when grown under plastic mulch in an arid area of Northwestern China in 2008, 2009 and 2010. The 2008 experiment consisted of a drip irrigation check without plastic mulch and four different drip irrigation frequency treatments with plastic mulch: once every day, once every 2 days, once every 4 days, and once every 8 days. In 2009 and 2010 the drip check treatment without mulch was irrigated at −25 kPa soil matric potential (SMP) during three potato development stages and four different SMP drip irrigation strategies were compared during the potato development stages (using plastic mulch): S1 (−25 kPa SMP during the three development stages), S2 (−25 kPa SMP during tuber initiation and bulking and −35 kPa SMP during maturation), S3 (−25 kPa SMP during tuber initiation and maturation and −35 kPa SMP during bulking), S4 (−35 kPa SMP during the three development stages). Plastic mulch negatively affected tuber yield, WUE, and tuber quality. In the presence of plastic mulch, tuber yield, specific gravity, starch content, and vitamin C content seemed to be enhanced as the irrigation frequency increased, although the differences were not statistically significant. Irrigation frequency did not affect WUE for potato grown under plastic mulch. Analysis of plant height, tuber yield and WUE showed that a drip irrigation threshold of −35 kPa SMP led to obvious water stress for potato growth in this arid area. Under plastic mulch in 2010, S2 was the optimum drip irrigation regime because of the significantly higher yield than S3 and S4, the highest WUE and significantly firmer tubers than any of the other irrigation regimes tested.     

测墒补灌条件下不同穗型小麦耗水特性和同化物积累与分配研究

为了解测墒补灌对小麦水分利用和干物质积累与分配的影响及与品种类型的关系,在田间条件下,以中穗型品种青农2号和济麦22、大穗型品种山农23和山农30为材料,设置小麦全生育期不灌水(W0)、节水灌溉(W1)和充分灌溉(W2)3个水分处理(W1处理拔节期和开花期0～40 cm土层土壤相对含水量分别补灌至65%和70%,W2分别补灌至85%和90%),研究了不同土壤水分下两种穗型小麦耗水特性和同化物积累与分配。结果表明,两种穗型小麦的W1处理灌水量及其占总耗水量的比例显著低于W2处理;60～140 cm土层土壤贮水消耗量显著低于W0处理,高于W2处理。W1处理开花前营养器官贮藏干物质在开花后向籽粒的转运量和对籽粒产量的贡献率均低于W0处理,而开花后干物质对籽粒产量的贡献率及成熟期干物质在籽粒中的分配量和分配比例均高于W0处理,W2处理的上述指标与W1处理均无显著差异。两种穗型小麦W1处理的籽粒产量高于W0处理,与W2处理无差异;W1处理水分利用效率和灌水利用效率高于W2处理。W1处理下两中穗型品种灌水量及其占总耗水量的比例和土壤贮水消耗量及其占总耗水量的比例的平均值分别比两大穗品种的平均值低4.95%、2.77%、7.15%和3.54%;两个中穗型品种开花前营养器官贮藏干物质向籽粒的转运量和贡献率比两个大穗型品种平均值分别高61.68%和70.33%,开花后干物质向籽粒的转运量、贡献率和成熟期干物质在籽粒中的分配量的平均值比两大穗型品种的平均值分别低13.88%、9.97%和18.08%。     

马铃薯旱作栽培干物质积累与分配

对内蒙古呼盟与乌盟旱作马铃薯优化栽培下的干物质积累状况进行了研究。结果表明 :马铃薯全生育期植株干物质积累量呈“S”型曲线变化 ,干物质积累速率呈单峰曲线 ,峰值出现在块茎快速增长期 ,干物质积累百分率以块茎增长后期至淀粉积累期较高 ;马铃薯生育期间不同器官干物质积累中心依次为叶片、地上茎、块茎 ;两地区不同品种优化栽培下的各项栽培生理指标均优于一般生产田和不施肥处理 ,其产量差异达显著或极显著水平     

Cultivar and seasonal effects on the contribution of pre-anthesis assimilates to safflower yield

In crops grown under Mediterranean environments, translocation of pre-anthesis assimilates to the seed is of great importance for seed growth, because hot and dry conditions during the seed filling period diminish photosynthesis and crop nitrogen uptake. This field study was conducted to assess the genetic and seasonal variation in the amount of pre-anthesis dry matter and nitrogen accumulated and translocated to seed by safflower (Carthamus tinctorius L.) plants, and the possible N losses occurring between anthesis and maturity. Ten genotypes, 4 hybrids and 6 open pollinated cultivars, were grown for 2 growing seasons without irrigation, on a silty clay (Typic Xerorthent) soil. The proportion of dry matter and N content at anthesis that was translocated to seed differed among genotypes and ranged from 14.9 to 39.6 and from 24.8–59.3%, respectively. Genotypic differences in dry matter and N translocation were mainly associated with dry matter and N accumulated during the vegetative growth of the plants. Greater amounts of dry matter and N content at anthesis resulted in a greater dry matter and N translocation to seed during the filling period. When the N contents of aboveground plant parts at anthesis and maturity were compared, both gains and losses were observed, and were mainly related to the sink size. No N losses were detected when yield was high. When yield was low, N losses depended on N content at anthesis; high N content resulted in N losses, otherwise no N losses were observed. The contribution of pre-anthesis accumulated reserves to seed weight ranged from 64.7 to 92.2%, indicating the importance of pre-anthesis storage of assimilates for attaining high safflower yield.     

Tuber growth and biomass partitioning of two potato cultivars grown under different n fertilization rates with and without irrigation

Nitrogen and water deficiencies are known to affect potato yield, but much less is known of their effect on tuber growth and biomass partitioning. The objective of this on-farm study conducted at two sites in each of three years, 1995 to 1997, was to determine the effects of supplemental irrigation and N fertilization rates on tuber growth and biomass partitioning of the cultivars Shepody and Russet Burbank. The N fertilization rates were 0,100, and 250 kg N ha^-1in 1995, and 0, 50,100, and 250 kg N ha_?1 in 1996 and 1997. The highest bulking rate observed in our study (7.3 g fresh tubers m^-2 °C^-1) can be considered near the potential bulking rate in New Brunswick. The water deficit in the absence of supplemental irrigation reduced this potential bulking rate by as much as 40%, but this reduction was much less at five of six sites and negligible at two of six sites. Nitrogen deficiency reduced the bulking rate at two of six sites. This negative effect of N deficiency on bulking rate was greater with irrigation than without irrigation at two of six sites; the tuber bulking rate with irrigation was reduced by as much as 50% with no N applied at one site. Shepody had a greater bulking rate than Russet Burbank. The tuber bulking of Russet Burbank, however, started earlier and lasted longer than that of Shepody. Water and N deficiencies increased biomass partitioning to tubers and large roots. Shepody partitioned a greater proportion of its biomass to large roots and had a greater root biomass than Russet Burbank. Our results demonstrate the ability of potatoes to modify biomass partitioning when grown under water and/or N stresses. As a result of this compensation, the reduction in tuber yield due to limited N and water stresses is minimized.     

不同水分管理模式和播后镇压对小麦干物质积累及产量的影响

为明确不同水分管理模式和播种后镇压对小麦干物质积累及产量形成的影响,以烟农19为材料,在大田条件下设置雨养(RI)、雨养+播后镇压(RC)、传统漫灌(TI)、传统漫灌+播后镇压(TC)、微喷灌(MI)和微喷灌+播后镇压(MC)处理,研究不同处理对小麦干物质积累及产量的影响。结果表明,与RI和TI处理比较,MI处理产量分别提高了44.2%和11.0%;RI处理产量最低,是由于穗数、穗粒数和粒重的显著下降所致,而TI处理产量较MI处理下降是由穗粒数和粒重显著降低导致。雨养和传统漫灌下播后镇压较其未镇压处理显著提升了产量,分别提高14.1%和6.2%。与TI和RI处理比较,MI处理开花期和灌浆期具有较高的群体叶面积指数(LAI)、旗叶叶绿素含量(SPAD值),籽粒平均灌浆速率和成熟期干物质积累量;相比未镇压处理,镇压后,雨养和传统漫灌下LAI提升,雨养和微喷灌处理下灌浆期旗叶SPAD值显著增加,籽粒灌浆速率提高,从而促进了粒重增加和群体干物质积累。总之,微喷灌+播后镇压能促进小麦群体的形成,延缓叶片衰老,提高小麦的穗粒数及千粒重,从而增加小麦产量,为试验区推荐小麦栽培模式。     

Optimal allocation of limited water supplies for Russet Burbank potatoes

Water shortages in many potato-producing regions have increased the demand for information on irrigating potatoes with limited water supplies. Field studies were conducted at Aberdeen, Idaho in 1988 and 1989 to determine the optimal allocation of limited water supplies for Russet Burbank potatoes. Irrigation amounts equal to 60 or 80% of estimated seasonal evapotranspiration (ET) were applied using various patterns of water allocation. Irrigation deficits were either partitioned evenly over the entire tuber bulking period, or were imposed during two of three designated growth stages (early, mid or late bulking) corresponding to the periods from 0 to 3, 3 to 6, and 6 to 9 weeks after tuber initiation, respectively. A well-watered, 100% ET check was included for comparison. Total yield reductions were greater when irrigation deficits were imposed during the early-mid and midlate bulking sequences than when they were imposed evenly over the entire tuber bulking period or during the early-late bulking sequence. Results relating U.S. No. 1 yields to seasonal water allocation patterns were similar to those for total yield. However, U.S. No. 1 yield reductions were proportionately greater. Irrigation deficits imposed during the early-mid bulking sequence resulted in the lowest specific gravities and the highest percentages of dark ends.     

施用硫酸钾对马铃薯生物性状的影响

钾素对马铃薯的生长发育、结薯、薯块膨大和干物质的积累具有十分重要的作用。凉山州马铃薯主产区土壤普遍缺钾少磷,试验选用马铃薯品种凉薯97,研究在凉山州不同地区不同海拔高度施用硫酸钾对马铃薯生物性状的影响,结果表明:马铃薯施用一定量的硫酸钾能适当延长生育期、显著增产、增加薯块干物质和淀粉含量。667 m2施用硫酸钾15 kg的平均全生育期比对照增加2 d;667 m2施用硫酸钾10 kg的平均产量最高,达到1 819 kg,较对照高28.26%,差异达极显著水平;施用硫酸钾对提高干物质、淀粉含量有一定的作用,综合考虑产量、品质、效益等因素,667 m2硫酸钾施用量以5.0～10.0 kg为宜。     

适雨灌溉下氮肥运筹对水稻光合特性、氮素吸收及产量形成的影响

【目的】为合理利用水稻生长期间的降雨，改善江汉平原地区稻田氮肥管理。【方法】采用田间小区试验，研究了常规淹灌(FI)和适雨灌溉(RAI)条件下，农民习惯施肥(FFP)、30%尿素+70%控释掺混肥(30%N+70%CRF)和优化减氮施肥(OPT-N)对降雨利用率、水稻产量、光合特性、干物质积累及氮吸收利用的影响。【结果】1)RAI能在节省水资源同时提升稻田对雨水的储蓄和利用能力，与FI相比可减少田间灌溉水量41.7%，各生育阶段水稻叶片净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr)、干物质积累、氮素吸收以及产量均有不同程度的增加；2)两种水管理方式下，与FFP处理相比，OPT-N处理水稻在分蘖期的Pn、Gs、Ci、Tr、干物质积累和氮素吸收显著降低，但在孕穗期-灌浆期有所增加，对最终产量形成影响不大；RAI结合30%N+70%CRF处理有利于水稻生育前期Pn、Gs、Ci、Tr的增加，提升生育中后期干物质积累量，氮素吸收量在分蘖期显著高于OPT-N和FFP，在齐穗期和成熟期显著高于FFP，有效穗数、穗长、千粒质量和结实率在各处理间表现最高，实际产量相较常规水肥管理可增产10.4%。【结论】适雨灌溉条件下，OPT-N不会显著影响水稻的生长及产量，30%N+70%CRF有助于水稻光合作用、氮素吸收及产量的增加。     

适雨灌溉下氮肥运筹对水稻光合特性、氮素吸收及产量形成的影响

【目的】为合理利用水稻生长期间的降雨,改善江汉平原地区稻田氮肥管理。【方法】采用田间小区试验,研究了常规淹灌(FI)和适雨灌溉(RAI)条件下,农民习惯施肥(FFP)、30%尿素+70%控释掺混肥(30%N+70%CRF)和优化减氮施肥(OPT-N)对降雨利用率、水稻产量、光合特性、干物质积累及氮吸收利用的影响。【结果】1)RAI能在节省水资源同时提升稻田对雨水的储蓄和利用能力,与FI相比可减少田间灌溉水量41.7%,各生育阶段水稻叶片净光合速率(P_n)、气孔导度(G_s)、胞间CO₂浓度(C_i)和蒸腾速率(T_r)、干物质积累、氮素吸收以及产量均有不同程度的增加;2)两种水管理方式下,与FFP处理相比,OPT-N处理水稻在分蘖期的P_n、G_s、C_i、T_r、干物质积累和氮素吸收显著降低,但在孕穗期-灌浆期有所增加,对最终产量形成影响不大;RAI结合30%N+70%CRF处理有利于水稻生育前期P_n、G_s、C_i、T_r的增加,提升生育中后期干物质积累量,氮素吸收量在分蘖期显著高于OPT-N和FFP,在齐穗期和成熟期显著高于FFP,有效穗数、穗长、千粒质量和结实率在各处理间表现最高,实际产量相较常规水肥管理可增产10.4%。【结论】适雨灌溉条件下,OPT-N不会显著影响水稻的生长及产量,30%N+70%CRF有助于水稻光合作用、氮素吸收及产量的增加。     

Influence of irrigation regimes on growth and yield of potato cv. Spunta

Summary The effect of furrow and drip irrigation giving 0, 33, 66, 100 and 133% of the maximum evapotranspiration (ETM) was studied on leaf transpiration, stomatal resistance, tuber growth, yield and yield response of cv. Spunta. The research was carried out in Sicily in 1988 and 1989 on early potato crops grown during the winter/spring cycle. Increased water supply increased leaf transpiration, plant fresh weight, tuber growth rate, yield and earliness, and decreased stomatal resistance and tuber dry weight. A higher yield response was obtained at the lower water regimes (ETM of 33 and 66%). There were no significant differences between the two methods of irrigation.     

灌水模式对春小麦光合性能和干物质生产的影响

为探寻宁夏引黄灌区春小麦节水栽培的适宜灌水模式,比较分析了6个不同灌水处理(W1:二棱水+开花水;W2:二棱水;W3:拔节水;W4:二棱水+孕穗水;W5:二棱水+拔节水+孕穗水+开花水+灌浆水;W6:二棱水+拔节水+孕穗水+开花水)下春小麦光合性能、物质积累与转运、产量性状及水分利用的差异。结果表明,灌二棱水、孕穗水或开花水的W1、W4、W5、W6处理明显增加春小麦花后旗叶光合速率、蒸腾速率和气孔导度,灌二棱水和生育后期少灌水的W1、W2、W4处理明显增加花后旗叶胞间CO2浓度。灌水次数减少会显著增加旗叶SPAD值,并降低叶面积系数,其中以缺少二棱水的W3处理最为明显。灌有二棱水和孕穗水的W4处理明显降低抽穗至开花旗叶SPAD值,增加开花至灌浆旗叶SPAD值和抽穗至开花叶面积系数,灌开花水明显增加开花至灌浆旗叶面积。灌二棱水、拔节水、孕穗水、开花水明显促进了干物质积累,灌水次数增加明显增加了叶干物质积累量,并降低茎鞘干物质比例;缺少二棱水的W3处理最不利于叶、穗干物质积累,但提高了开花至成熟叶干物质比例;灌浆水对各器官干物质积累影响不明显。二棱期至开花期缺少灌水的W1、W3、W2处理促进了开花前贮藏同化物在花后向籽粒的转运。籽粒产量随灌水次数的增加而增加;缺少二棱水明显降低穗粒数、收获指数,但增加千粒重;增加灌水次数降低了灌水利用效率,且以灌二棱水影响最为明显。综上所述,缺少二棱水对春小麦产量影响最明显,孕穗水、开花水影响次之,灌浆水影响不明显。     

Effects of soil water deficit at different growth stages on rice growth and yield under upland conditions. 2. Phenology,biomass production and yield

Phenological development, shoot dry matter production, grain yield and yield components of rice were examined in relation to drought occurring at various stages of growth. Rice was sown three or four times at three-week intervals in the field in each of two years, and performance in three stress trials was compared with that in corresponding irrigation trials, with the aim of quantifying the response of the crop to water stress of 23–34 days' duration developing at different growth stages. When drought occurred during vegetative stages, it had only a small effect on subsequent development and grain yield. The reduction in yield of up to 30% was due to reduced panicle number per unit area in one trial, and reduced number of spikelets per panicle in another. The effect of water stress on yield was most severe when drought occurred during panicle development. Anthesis was delayed, the number of spikelets per panicle was reduced to 60% of the irrigated control and the percentage of filled grains decreased in one crop to zero. This decrease in grain yield to less than 20% of the control was associated with low dry matter production during the drought period as well as during the recovery period following the drought. When drought occurred during grain filling, the percentage of filled grains decreased to 40% and individual grain mass decreased by 20%. The effect of stress was also related to its severity during grain filling. Stress at this stage hastened maturity. The results suggest that variation in yield components due to water availability is related to the variation in dry matter production at particular growth stages. Results of a supplementary shading experiment show that the relationship between spikelet number per panicle or single grain mass and crop growth rate was the same, whether growth rate was varied by availability of soil water or solar radiation. Filled-grain percentage, however, was more sensitive to drought stress than shading when comparison was made at a similar crop growth rate.     

引进日本甘薯品种在昆明适应性的初步探讨

以日本引进的6个甘薯品种为材料,对其农艺性状、经济特性及茎蔓和叶片叶绿素含量在不同生育期的动态变化进行了初步分析。结果表明:鲜薯产量在1159.3~2505.1 kg/667m2;干物质量在24.19%~30.92%;可溶性糖含量在2.78%~8.50%;淀粉含量的变幅是从12.47%~22.05%。茎蔓的生长与叶面积的增加并不是平行的,生育期中叶绿素含量除了在阴雨时期明显升高外,一般相对稳定。     

灌水对强筋小麦籽粒产量及营养品质的影响

为明确水地强筋冬小麦高产、优质、高效的灌溉技术,试验设3个灌水时期8个灌溉处理［越冬期灌1水（W₁）,拔节期灌1水（W₂）,孕穗期灌1水（W₃）,越冬期和拔节期灌2水（W₁₂）,越冬期和孕穗期灌2水（W₁₃）,拔节期和孕穗期灌2水（W₂₃）,越冬期、拔节期和孕穗期灌3水（W₁₂3）,全生育期不灌水处理（CK）］,于小麦成熟期测定籽粒产量、总蛋白及其组分含量和淀粉含量。结果表明,与不灌水的CK比较,所有灌水处理的籽粒产量、有效穗数、穗粒数、千粒重、蛋白质产量以及籽粒淀粉含量均显著增加,但籽粒的总蛋白及其组分含量均呈不同程度降低（W₁处理除外）。越冬期灌水对有效穗数、籽粒产量、总蛋白及其组分含量、淀粉含量的提升作用较大;拔节期灌水对穗粒数的提升作用较大,但对淀粉含量的提升作用较小,对总蛋白及其组分含量的降低作用较大;孕穗期灌水对千粒重的提升作用较大,对蛋白质产量的提升作用较小。随着灌水次数增加,小麦籽粒产量显著提高,淀粉含量先显著提高后基本不变,而籽粒总蛋白及其组分含量降低。W₁₂3处理籽粒产量最高,其次是W₁₃处理;W₁处理籽粒蛋白质及其组分含量最高,其次是W₁₂及W₁₃处理;W₂₃处理淀粉含量最高,其次是W₁₂或W₁₃处理。综合各项指标,最好的灌水组合是越冬期和孕穗期灌2水（W₁₃）。     

播后镇压和冬前灌溉对冬小麦干物质转移和氮素利用效率的影响

为明确播后镇压和冬前灌溉对高产冬小麦干物质和氮素转移及氮素利用效率的影响,以冬小麦品种石新828和石麦12为材料,采用裂区田间试验,于开花期和成熟期,测定不同器官的干物质和氮积累量和转移量、籽粒产量、蛋白质产量、氮吸收效率和氮肥生产效率。结果表明,冬灌和镇压处理下,2个品种开花期和成熟期的干物质积累量下降,开花前各营养器官干物质的转移量、转移率及对籽粒的贡献率均降低,但开花后籽粒中的干物质积累量增加。冬灌处理小麦成熟期的总干物质积累量和产量下降。冬灌处理下,石新828开花后籽粒中的氮积累量增加,开花后氮素对籽粒的贡献率提高,但各器官的氮转移量显著降低,籽粒氮积累总量显著减少,氮吸收效率下降;冬灌对石麦12成熟期籽粒氮素积累量影响不显著。与不镇压相比,镇压处理下,2个品种开花期的氮积累总量和不同器官中的氮积累量均降低,而成熟期各器官氮积累量及分配比例的差异均不显著。镇压处理与不镇压处理相比,2个品种开花前营养器官中的氮转移量、转移率和贡献率均降低,但是开花后的氮积累量及其对籽粒氮的贡献率提高,其中,镇压的石麦12开花前氮转移量、贡献率和开花后氮积累量、贡献率与不镇压的差异达显著水平;成熟期籽粒氮素积累量的差异不显著。建议在足墒播种条件下不必进行冬灌,应根据播种前后土壤和水分条件确定是否需要镇压。     

Analysis on Dry Matter Production Characteristics of Super Hybrid Rice

Six middle-season indica hybrid rice combinations,including five super hybrid rice combinations with the high yield about 10.5 t/ha and a check hybrid rice combination Shanyou 63 with a yield potential about 9.5 t/ha,were used as materials to study the dry matter production characteristics.The super hybrid rice showed a high ability in dry matter production and accumulation and its yield enhanced with the increase of dry matter accumulation.The advantage period of dry matter production in the super hybrid rice was mainly at the middle and late growth stages compared with the check.The grain yield had no significant correlation with the dry matter accumulation before the elongation stage while had a significantly positive correlation with the dry matter accumulation from the elongation to maturity stages in super hybrid rice.There were more dry matter in vegetative organs at the heading stage in the super hybrid rice but its contribution to yield (apparent conversion percentage) was averagely 4.3 percent points lower than that in the check.For crop growth rate (CGR),the comparative advantage of super hybrid rice was at the middle and late stages,especially after flowering.Moreover,as the rising of leaf area index (LAI) and leaf area duration (LAD),CGR enhanced.The total LAD and the mean of LAD per day of super hybrid rice was about 14.79% and 10.31% higher than those of the check,respectively.The results indicate that the high yield of super hybrid rice mostly comes from the products of photosynthesis after heading,which is shown by the increased CGR at middle and later stages.It is suggested that LAD character might be used to better explain the advantage in the dry matter production of super hybrid rice than LAI.     

孕穗期冷水胁迫对寒地水稻干物质生产的影响

以黑龙江省30份主栽水稻品种或品系为试材,在孕穗期设置17℃冷水灌溉处理(20d),以常规栽培管理为对照,分析冷水胁迫对水稻干物质生产的影响。结果表明,冷水胁迫导致所有试材每穴实粒数、结实率、千粒重和产量下降,并根据相对结实率将试材耐冷性分为1、3、5、7和9级,以7和9级最多,1级最少,分别占总材料的30%和10%。在冷水处理下,全部材料抽穗期至成熟期干物质积累量及比例、群体生长率、净同化率、粒叶比、收获指数、叶面积指数、剑叶叶基角、剑叶和倒2叶与倒3叶披垂度均下降,但高效叶面积率增加。相关分析表明,冷水处理的相对结实率与收获指数(r=0.96**)、产量(r=0.91**)、粒叶比(r=0.84**)和干物质积累量(r=0.48**)的冷水反应指数(CRI)呈极显著正相关,与群体生长率(r=0.44*)、净同化率(r=0.44*)和干物质积累比例(r=0.43*)的CRI显著正相关。综上,孕穗期冷水胁迫对水稻干物质生产的影响在品种间存在很大差异,在冷水胁迫下耐冷性极强品种(系)干物质积累量及比例、群体生长率、净同化率、粒叶比和收获指数对冷水反应迟钝,这是耐冷性极强品种(系)保持较高产量的重要形态特征和生理原因。     

几个马铃薯品种产量及品质形成的差异

以3个马铃薯品种为供试材料,在块茎增长期进行分期取样,对不同品种的产量和品质形成状况进行比较,以摸清不同品种的块茎形成特性,为特定品种配套适宜栽培技术的实施提供参考。结果表明：供试3个品种的单株产量存在显著差异,延薯4号的产量最高,薯块膨大早,商品薯率高;东农309的产量其次,薯块膨大较早,商品薯率较高;克新13号的产量最低,薯块膨大偏晚,商品薯率中等;但3个品种的单株结薯数量和干物质含量相近,均为结薯数量适中、干物质含量中等的中晚熟鲜食型品种。在生产上应根据品种特性配套栽培技术,以保证各品种获得较好的产量和品质。