南江黄羊体重性状的微卫星标记研究

通过10个微卫星位点，对周岁体重差异较大的南江黄羊极端个体基因组DNA进行扩增检测，方差分析寻找与体重性状显著相关的微卫星标记。然后，利用该引物对随机群体进行检测，应用线性模型计算含有相应标记个体体重性状的标记效应和替代效应。结果发现，BM3413位点的186bp和190bp等位基因、MFA70位点的109bp等位基因、INRA063位点的178bp和184bp等位基因、MB066位点的110bp等位基因、MB3501位点的176bp等位基因，这些标记基因与南江黄羊周岁体重呈极显著正相关，相关系数在0.5180～0.7375之间。BM3413位点的182bp等位基因、MFA70位点的115bp等位基因、MB066位点的98bp等位基因，这些标记与南江黄羊周岁体重呈显著（极显著）的负相关，相关系数在-0.6539～-0.388之间。     

福建北部山区南江黄羊消化道寄生虫病控制技术的建立

用粪便寄生虫虫卵检查法,调查福建北部山区南江黄羊体内寄生虫的优势类群,并通过对羊群寄生虫药物驱除后跟踪虫卵检测,分析用药后粪便寄生虫虫卵消长变化。结果表明,虫卵有胰吸虫、前后盘吸虫、扩张莫尼茨绦虫、食道口线虫、乳突类圆线虫、捻转血矛线虫和羊肺丝虫3个纲7个种,线虫纲虫卵检出率为70.2%,为当地的优势类群;用丙硫苯咪唑以20mg/kg体重剂量口服,吸虫和线虫的虫卵阳性率在用药后的第15d降至最低,分别为20%、10%,第30d-60d达到或超过用药前的水平。试验针对福建北部山区潮湿气候条件下,提出南江黄羊消化道寄生虫定期药物驱虫措施,即2-6月龄育成羊每30d驱虫一次,成年羊每60d驱虫一次的新技术措施,其应用效果与常规技术措施相比,2-6月龄育成羊的成活率提高28.3%。     

哲罗鱼生长速度相关性状的微卫星标记筛选

利用22个微卫星标记对随机交配的野生哲罗鱼F1176个个体的生长速度相关性状(体质量、全长、体高、体宽、头长、头宽和眼间距)进行分析,22个微卫星标记共检测到67个等位基因,各座位的等位基因2～6个,片段大小为109～452 bp,平均观测杂合度和期望杂合度分别为0.583 5和0.564 0,22个位点均有不同程度的偏离Hardy-Weiberg平衡。利用SPSS软件对7个性状正态分布检测发现,7个性状都显示出连续变异的特点,属典型的数量性状或者多基因遗传,符合正态分布;同时用GLM程序对22个微卫星标记与生长速度相关性状进行相关性分析,并将与性状显著相关的标记进行基因型之间的多重比较,结果显示,22个微卫星座位中,有11个标记与至少一种性状显著相关,其中与全长相关的标记最少为4个,与体高和体宽相关的标记最多的为7个;多重比较可知每个标记中同一性状均有部分基因型差异达到显著水平,不同标记所代表均值也有些差异。上述这些标记为进一步的分子标记辅助育种提供了基础。     

植物生长季热量资源趋势变化与气候突变

为了调整沈阳市植物结构,对低温冷害进行监测研究,保障粮食生产安全提供依据,采用气候统计诊断分析方法,对近60年沈阳市植物生长季热量资源变化趋势及突变进行研究。结果表明：近60年沈阳市植物生长季平均气温和≥10℃活动积温均呈显著上升趋势,气候倾向率分别为0.164℃/10 a和51.52℃·d/10 a。近30年植物生长季平均气温升高0.6℃;≥10℃活动积温增加180℃·d。应用信噪比诊断1951—2010年长序列气候突变不明显。经滑动平均和年际逐渐延长,植物生长季平均气温和≥10℃活动积温保持持续上升的正相关。研究结果对合理利用热量资源,调整农植物种植结构,合理安排农业生产工程具有参考价值。     

奶牛次级性状的微卫星标记与QTL定位研究进展

本文对奶牛繁殖性状（产犊容易度、排卵数）、体型性状（乳房性状、肢蹄性状、体型性状）、健康性状（体细胞和乳房炎抗性）和生产效率性状（生产寿命、泌乳速度等）等四类次级性状QTL定位的研究进展进行了综述。     

不同生长环境下水稻结实率数量性状位点的检测

以籼稻密阳23与粳稻吉冷1号配制所获得的F_2:3群体200个家系作为作图群体，在北京、昆明、三亚、公主岭和韩国春川等5个点进行水稻结实率的鉴定，并利用SSR标记对水稻结实率数量性状位点进行检测。结果表明，水稻结实率表型值及其在F₃家系群中的分布以及所检测到的QTL数目因生长环境不同而有较大差异，说明QTL与环境有明显的互作效应。水稻结实率在F₃家系群中呈接近正态或偏态的连续分布，是多个基因所控制的数量性状。共检测到与水稻结实率相关的QTL 14个，分布于第1、2、3、4、6、7、8、10和12染色体上，对表型变异的贡献率为4.9%～15.3%。分别位于第1、2、6和12染色体RM1~RM259、RM263~RM6、RM340~RM30、RM270~RM17区间的qSSR1、qSSR2、qSSR6和qSSR12至少在2种生长环境下均检测到，对表型变异的贡献率分别为4.9%～8.4%、4.8%～7.2%、7.6%～10.7%和7.4%～10.4%。以上多数QTL增效等位基因均来自吉冷1号，基因作用方式主要为部分显性或显性或超显性。     

甜菜生长与气象条件的关系

一、当土壤水分得到满足时,甜菜播种至出苗持续时间与平均气温的关系,近似反相关关系。平均温度为10—15℃时,影响出苗速度非常显著,出苗日数为10—20天,随着温度的升高对加速出苗的效应就相对减低了。二、甜菜播种期的农业气象指标,当土壤水分维持在21—26%,平均气温和5厘米地温达7—8℃,为最适宜的条件。在黑龙江南部地区,最早播种期为4月11—15日,最适播种期为4月16—25日,最晚播种期为4月26—30日。三、甜菜不同生长时期,要求不同的气象条件。甜菜叶片抽生速度以6月下旬至8月份最快,平均两天抽生一片,需有效积温30—40℃。需较高的温度和充足的降水有利于茎叶生长,此期的气象条件为平均气温22.4℃,土壤水分25—27%,相对湿度71%。块根膨大时期需较高的地温:20厘米深度为22.5℃,平均气温21.8℃,土壤水分在22—25%。在收获前30—40天糖分形成积累时期,需比较低的温度:平均气温10—14℃,昼夜温差大于10℃,在此时期对水分反应极为敏感,有的年分收获时的含糖率比收获前含糖率降低的原因,主要是秋雨过多,致使块根组织中水分增多含糖率降低,此时期比中期需要较低的土壤水分,土壤水分维持在20—22%,对糖分形成积累是有利的。四、甜菜在整个生育期以茎叶繁茂和块根膨大时期需水量最大,在茎叶繁茂时期生长基本     

8种植物挥发物和浸提液对三七根腐病菌的抑制活性研究

试验测定了8种植物的挥发物和浸提液对引起三七根腐病的恶疫霉菌和腐皮镰孢菌的抑制活性。结果显示,葱属作物大蒜、洋葱、葱及韭菜的挥发物和浸提液对恶疫霉菌和腐皮镰孢菌均具有显著的抑制效果,且大蒜挥发物和浸提液的抑菌活性最强;生姜、鱼腥草、香菜茎和薄荷的挥发物抑菌效果不明显,甚至在低浓度下出现促进菌丝生长的现象,而生姜、香菜根和叶的浸提液对恶疫霉菌和腐皮镰刀菌表现出明显的抑菌活性。本研究结果可为利用作物轮作控制三七根腐病提供科学依据。     

利用极端材料定位水稻粒形性状数量基因位点

利用极端大粒材料GSL156(千粒重71.9 g)与特小粒材料川七(千粒重12.1 g,轮回亲本)杂交、回交获得的BC₂F₂ 216个个体为作图群体,在北京进行稻谷粒长、粒宽、粒厚、长宽比、千粒重等粒形性状的鉴定。采用单标记分析和复合区间作图法,利用SSR标记对粒形性状进行数量性状基因座检测。结果表明,上述粒形性状在BC₂F₂群体均呈正态连续分布,表现为由多基因控制的数量性状;共检测到与粒形性状相关的QTL 28个,分布于第1、2、3、4、5、6和12染色体上。其中qGL3-2、qGL3-3、qGT12-1、qGT2-1、qGT5-1、qGW1-1、qGW12-1、qGW2-1、qGW5-1、qRLW3-1、qTGW12-1、qTGW2-1、qTGW3-3和qTGW5-1对表型变异的贡献率分别为13.70%、52.51%、21.13%、18.79%、20.92%、14.59%、18.33%、30.03%、20.05%、24.53%、13.47%、11.43%、21.30%和15.68%,为主效QTL。其中,第3染色体上检测出来的QTL最多。在所有检测到的28个QTL中,6个QTL的增效等位基因来源于小粒亲本川七,而其余QTL的增效等位基因均来源于大粒亲本GSL156,基因作用方式主要表现为加性或部分显性。第3染色体RM7580~RM8208区间是分别与粒宽、长宽比和千粒重相关的3个主效QTL的共同标记区间,第2染色体的RM7636~RM5812区间、第5染色体的RM3351~RM26区间和第12号染色体的RM1103~RM17区间是分别与粒宽、粒厚和千粒重相关的3个主效QTL的共同标记区间,这些区间对粒形贡献率较大,为进一步精细定位或克隆这些新的粒重或粒形QTL奠定了基础。同时大粒亲本对稻谷粒长、粒宽、粒厚和千粒重等性状的增效作用显著。     

发掘人工合成小麦中千粒重QTL的有利等位基因

以人工合成小麦Am3为供体亲本,普通小麦莱州953为轮回亲本,经5次回交然后自交,培育出含85个株系的F_2:3群体。以该群体为材料,用348对多态性SSR标记,进行全基因组扫描,发掘人工合成小麦中千粒重QTL的有利等位基因。利用复合区间作图法检测到3个千粒重QTL,其对表型变异的贡献率为10.9%~33.79%。其中,Am3的等位基因能够增加千粒重2.3~4.8 g。相关分析表明,该导入系群体的千粒重与穗粒数、穗数和株高无显著相关性。千粒重QTL与穗粒数、穗数性状的QTL不在同一位置,这有利于高千粒重基因与其他产量性状基因的聚合。采用混合线性模型作图法检测到1个千粒重QTL(QGw.caas-3D),该QTL与环境互作效应小,而且与复合区间作图法在3个环境中都检测到的QTL相同,表明QGw.caas-3D是一个稳定的主效QTL。     

宁南山区苜蓿与羊草混播技术效果研究

结合宁夏南部山区的生长条件,在梯田和坡耕地两种地势条件下,设置不同比例的牧草混播组合,测定牧草群体的生长性状、地上生物量和营养成分等指标,对宁南山区苜蓿和羊草混播种植进行研究。结果表明：梯田种植的紫花苜蓿和羊草的株高和茎叶比均高于坡耕地;坡耕地的地上生物量高于梯田;梯田条件下紫花苜蓿与羊草混播比例为3∶2时紫花苜蓿的饲用价值较好,坡耕地条件下紫花苜蓿与羊草混播比例为2∶1时羊草的饲用价值较好。本研究筛选出最适宜宁夏南部山区种植牧草的混播比例,为宁南地区紫花苜蓿和羊草人工混播草地的改良建植积累基础数据。     

The influence of organic and conventional fertilisation and crop protection practices,preceding crop,harvest year and weather conditions on yield and quality of potato (Solanum tuberosum) in a long-term management trial

The effects of organic versus conventional crop management practices (fertilisation, crop protection) and preceding crop on potato tuber yield (total, marketable, tuber size grade distribution) and quality (proportion of diseased, green and damaged tubers, tuber macro-nutrient concentrations) parameters were investigated over six years (2004–2009) as part of a long-term factorial field trial in North East England. Inter-year variability (the effects of weather and preceding crop) was observed to have a profound effect on yields and quality parameters, and this variability was greater in organic fertility systems. Total and marketable yields were significantly reduced by the use of both organic crop protection and fertility management. However, the yield gap between organic and conventional fertilisation regimes was greater and more variable than that between crop protection practices. This appears to be attributable mainly to lower and less predictable nitrogen supply in organically fertilised crops. Increased incidence of late blight in organic crop protection systems only occurred when conventional fertilisation was applied. In organically fertilised crops yield was significantly higher following grass/red clover leys than winter wheat, but there was no pre-crop effect in conventionally fertilised crops. The results highlight that nitrogen supply from organic fertilisers rather than inefficient pest and disease control may be the major limiting factor for yields in organic potato production systems.     

Settlement,abundance, growth and mortality of juvenile flatfish in a subtropical tidal estuary (Georgia,U.S.A.)

The population dynamics of juveniles of some flatfish species were studied in the Duplin River, a tidal creek in a subtropical salt-marsh area in Georgia, U.S.A. from April until September 1990. Seven species were found. Paralichthys dentatus, Paralichthys lethostigma, Paralichthys oblongus and Trinectus maculatus were relatively rare. Etropus crossotus, Citharichthys spilopterus and Symphurus plagiusa were abundant and settled during the period studied. E. crossotus was the most abundant species with a mean abundance of 18 ind·10⁻² m⁻² (max. 287). Demersal settlement of E. crossotus took place in shallow areas and over sandy bottoms from mid-May to August. Prolonged settlement hampered the calculation of growth rate and instantaneous mortality rate. However, laboratory growth experiments indicated a mean growth of about 0.50 mm·d⁻¹ at 24–28°C. Juveniles of C. spilopterus were already present in the Duplin River in March. Settling continued until the end of April with a mean abundance of 3.5 ind·10⁻² m⁻² (max. 183). With increasing size the juveniles of this species tended to migrate to deeper waters and to the mouth of the river, possibly as a reaction to increasing water temperatures. Maximum growth rate was 1.4 mm·d⁻¹ at about 26°C. The mean instantaneous mortality rate (z) was estimated at 0.03·d⁻¹. Settling of S. plagiusa occurred from mid-May onwards. The mean abundance was 10.3 ind·10⁻² m⁻² (max. 98.3). Newly settled juveniles were most abundant on muddy sediments in the shallow river areas. The maximum growth rate was 1.3 mm·d⁻¹ at about 28°C. The mean instantaneous mortality rate (Z) decreased from 0.04·d⁻¹ in April to 0.01·d⁻¹ in August. At all sites the abundance of juveniles of this species decreased with increasing water depth. Predation experiments indicated that blue crabs (Callinectes similis and C. sapidus) and sea robins (Prionotus sp.) are potential predators on juvenile flatfish. The high abundances of juvenile flatfish indicate that the tidal creeks are an important nursery area. The correspondence between growth rates estimated from field data and those observed in the laboratory suggests that growth in the nursery is mainly related to water temperature and not food limited.     

The influence of environmental conditions on settlement,distribution and growth of 0-group sole (Solea solea (L.)) in a macrotidal estuary (Vilaine,France)

In the Vilaine estuary, the environmental conditions at the onset of the settlement of metamorphosing sole have been surveyed for 5 years. The inshore migration occurs either in early or in late April depending on the hydroclimatic conditions: sole are observed in the estuary when bottom water salinity varies between 25 and 30 S and water temperature is up to 11°C. During spring, their distribution pattern is similar in all years: first, accumulation at the entrance of the estuary, then concentration in the upper parts and finally, colonization of the whole estuarine area by juveniles. Interannual variations in growth rates were observed during their first estuarine phase, in particular when the estuary is transformed into a ‘ria’ with high water temperature and salinity. These biological features are discussed according to ontogenic changes occurring during these early life stages. From field and experimental data and from literature information on sole and other pleuronectiform species, a conceptual model on relationships between environmental parameters and metamorphosis processes in estuarine areas is proposed.     

Effects of harvest management on growth dynamics, forage and seed yield in berseem clover

Berseem clover (Trifolium alexandrinum L.) is an annual forage crop widely grown in Mediterranean environments. However, there is little information available on the patterns of accumulation and partitioning of assimilate in berseem and how this varies with harvest management, plant ontogeny or is influenced by genotype. Field experiments were conducted in Foggia (Italy) during three growing seasons (1991–92, 1992–93 and 1993–94), with the aim of evaluating the effects of different harvest managements on growth dynamics, forage yield and seed yield of one population of Egyptian (cv. ‘Giza 10’) as well as Italian (cv. ‘Sacromonte’) origin. Cutting treatments were applied at three different plant ages: sixth internode elongation (A), early flowering (B), and uncut control (C). The growth and development of the shoot and root systems were followed by destructive harvests made at about 5-day intervals during 9 weeks in spring in all treatments. Seasonal growth pattern, determined as dry matter accumulation, forage yield and seed production were greatly influenced by harvest management. The maximum value (20.5 g per plant on average) of dry weight was reached at about 250 days after sowing for treatment C. Defoliation induced a decrease of crown and root dry matter, however, as shown by the allometric relationships, the growth of roots and shoots was closely correlated and in most cases, shoot growth was higher than root growth and stem relative growth rate (RGR) was higher than leaf RGR. Berseem clover is a defoliation-tolerant species because after cutting, regrowth was accompanied by higher values of leaf-stem ratio (LSR), RGR and stem elongation rate (SER) than in control plants. The highest value for total forage yield (1.6 Kg m⁻²) and seed yield (60.5 g m⁻²) were obtained in treatment B and A, respectively. Plants cut at the sixth internode elongation showed a good seed yield and a small decrease (15%) in total forage yield as regards treatment B. Therefore, treatment A appeared the most favourable for obtaining double utilization (forage and seed yield) in a berseem crop. Berseem plants were greatly influenced by harvest treatments applied, but the response did not vary according to the genetic characteristics of the two cultivars examined.     

Effects of controlled irrigation and drainage on growth,grain yield and water use in paddy rice

Rice is subjected to excessive waterlogging and flash-flooding on large areas in south China. A study on water use, growth and yield effects of controlled irrigation and drainage (CID) of paddy rice at four stages was conducted in specially designed experimental tanks. The treatments were (1) CID during Stage I of tillering stage (CID-Stage I), (2) CID during Stage II of booting stage (CID-Stage II), (3) CID during Stage III of heading to flowering stage (CID-Stage III), (4) CID during Stage IV of milky stage (CID-Stage IV), (5) alternate wetting and drying irrigation during the whole stage (CK). Compared with CK, CID reduced drainage volume with 15.8–31.3% in 2008, and 13.5–28.3% in 2009, and increased the efficiency of available rainfall and irrigation by 1.98–3.46% in both years. Irrigation water application during the whole growing season across the 2 years, on average, was only 81.8%, 91.1%, 93.9%, and 94.5%, respectively, of that applied to CK. A strong reduction in root length, root weight, root-shoot ratio and harvest index were observed, however, shoot weight and total dry mass is increased from the treatments of CID-Stage II, CID-Stage III and CID-Stage IV. The highest radiation use efficiency values were for CID-Stage IV. The responses of CID from vegetative plants at Stage I and Stage II were greater than in generative plants at the latter two stages. CID-Stage II had only a small effect on subsequent development and grain yield. This decrease in grain yield to less than 7.88% and 5.72% of CK was due to reduced number of spikelets per panicle in one trial, and reduced panicle number per unit area in another. The CID-Stage I treatment showed the lowest grain yield among the treatments and reduced it by 23.3% in 2008 and by 17.3% in 2009, due to the decreases in the percentage of filled grains and total number of panicles. The effect of stress was associated with low dry matter production during the flooding stress period as well as during the stress withdrawal period following the stress. With regards to irrigation water use efficiency, it was increased under the first two treatments, and by from a minimum of 101% to a maximum of 110%.     

Functions of time for growth characters,their evaluation and approximation to examine differences between genotypes

Summary As a follow up to a previous paper on growth curves (Keuls & Garretsen, 1982) a procedure is described to derive functions of time for growth characters from elementary growth curves which are suited for statistical analysis.For each plot from the parameters , , of the second degree growth curves of type + (t–t) + (t–t)², corresponding functions of time (of harvest) are obtained for the derived growth characters: relative growth rate (of dry weight per plant), net assimilation rate, leaf area ratio, specific leaf area, leaf weight ratio. The elementary growth curves concern ln W, ln LA and ln LW, where W = dry weight per plant, LA = leaf area per plant, LW = leaf dry weight per plant.Only relative growth rate is a simple linear expression in t, i.e., + 2(t–t), where t represents average harvest time.The functions for the four other growth characters are approximated by quadratic functions in t, such that for each plot a curve is characterized by a triple of parameters f(t), f(t), % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaKabGfaammaalaaaba% Gaaiymaaqaaiaackdaaaaaaa!3946!\[\frac{1}{2}\]f(t), representing respectively mean, slope and curvature for that plot at time t The approximation of the function of time is given by f(t) + (t–t)f(t) + % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaKabGfaammaalaaaba% Gaaiymaaqaaiaackdaaaaaaa!3946!\[\frac{1}{2}\](t–t)²f(t).These sets of parameters per plot: (, , ) for ln W(t) etc.; (, 2, 0) for RGR(t) or (f(t), f(t), % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGak0dh9WrFfpC0xh9vqqj-hEeeu0xXdbba9frFj0-OqFf% ea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr% 0-vqpWqaaeaabaGaaiaacaqabeaadaqaaqaaaKabGfaammaalaaaba% Gaaiymaaqaaiaackdaaaaaaa!3946!\[\frac{1}{2}\]f(t)) for the four other growth characters can be analysed by the MANOVA-procedure for 3 parameters as exemplified by Keuls & Garretsen (1982).     

福建省各县(市、区)经济发展实力评估与分类研究

为了研究福建省各县（市、区）经济发展水平的差异,对福建省各县（市、区）的经济实力进行评价,通过建立具有递阶层次结构的指标体系,运用层次分析-极差正规化综合评价方法、聚类分析法对福建省各县（市、区）的经济实力进行实证评价并分类。研究结果将福建省67个县（市、区）划分为经济发展实力雄厚、经济发展实力较强、经济发展实力较薄弱、经济发展实力薄弱四类地区,并为提升各类地区的经济发展实力分类提出相应的政策建议。     

A comparative investigation of seed germination, metabolism and seedling growth between two polyploid Triticum species

The embryo and seedling growth patterns of two Triticum polyploid species, namely the tetraploid, T. durum (AABB), and the hexaploid, T. aestivum (AABBDD), were compared. Two developmental phases were identified, an initial lag phase during embryo growth and an exponential phase during seedling growth. These developmental phases were distinctly different in the two species. The initiation of mitosis prior to the inception of the exponential phase, occurred at 16 hours after imbibition in the hexaploid and 20 hours after imbibition in the tetraploid. All the growth rates of the hexaploid, except that of the shoot, showed higher activities – food reserves were mobilized much faster, root growth was faster, number of cells in mitosis over 24 hours higher: for the hexaploid primary root (7.0%) and first pair of lateral roots (6.5%), while for the tetraploid it was found to be 5.9% in the primary root and 5.7% in the first pair of lateral roots. The primary root and first pair of lateral roots of the hexaploid emerged respectively six hours and four hours earlier in comparison to those of the tetraploid. The inception time of the exponential phase in seedling growth and mobilization of food reserves were observed 12 hours earlier in the hexaploid although no differences were observed in the inception times for the shoot growth and respiration rate. It can therefore be concluded that the genomic composition of the hexaploid promotes a higher growth rate and therefore a higher metabolic rate than the tetraploid. This revised version was published online in July 2006 with corrections to the Cover Date.