Estimating Combining Ability of 4x-2x Crosses in Cultivated Potatoes

Progenies derived from crosses between Solarium tuberosum and 2n pollen-Producing diploid hybrids, exhibit obvious hybrid vigor. The 2n pollen-producing clone can act as a bridge in crossing S. tuberosum and S. andigena with S. phureja. Populations from 4x-2x crosses show more unifomity and less segregation compared with that of 4x-4x crosses. The parent-offspring correlation for the traits, starch content and tuber number, is significant at 0.01 level. The regrssion equations are Y (mp-F1)=1.0 1.2x and Y (mp - F1) = 5.3 0.8x, respectively. The 2n pollen-producing clones play an impotant role in increasing tuber stach content. Estimates of the combining ability for the main yield components indicate that additive effect prodominatcs for such trais as plot yield, tuber weight per plant and starch content, whereas both additive and non-additive effects lay equal stress on mean tuber weight and non-additive effect is important for tuber number. In general, non-additive effect appears to be important in     

Correlation between hydrolytic enzyme activities measured in bean seedlings afterTrichoderma koningii treatment combined with pregermination and the protective effect againstPythium splendens

An experimental protocol consisting in the colonisation of pregerminated bean seeds dressed withTrichoderma sp. was used in order to study the mechanisms correlated with the protective effect againstPythium splendens. Seed dressed with TH-11 (T. koningii) for 24 h presented a higher protective effect and a higher level of seed colonisation as compared to those dressed with TH-13 (T. longibranchiatum). The levels of seed coat colonisation by TH-11 and TH-13 was shown to be correlated with the carboxymethylcellulase activity, as measured in the seed coats retreived from germinating dressed bean seeds. The seed coat colonisation was also associated with an increased activities of endo-1,3--glucanase and endochitinase measured in seed extracts, and an inhibitory effect of seed extracts onPythium sporangia germination. Pretreatment of TH-13-dressed seeds with a commercial cellulase improved all parameters mentioned above, thus suggesting a role of cellulase activity in the colonisation process and the linked protective effect. The possible role of hydrolytic enzymes in the protective effects is discussed.     

Dynamics ofRhizoctonia solani (black scurf) in successive potato crops

The position of plants withRhizoctonia solani sclerotia (black scurf) on progeny tubers was mapped for an experimental field at Haren where potatoes were grown continuously and in rotation with other crops for five successive years, and for another field at Borgercompagnie with a 12 frequency of potatoes during three potato crops. Initially, the distribution of plants with black scurf on both fields was rather dense and homogeneous. In the following years the distribution became heterogeneous and patchy. The local decline ofR. solani AG 3 (the common potato pathogen) in Haren was apparently caused by an unknown factor selectively suppressingR. solani AG 3, while simultaneouslyR. solani AG 5 increased in mass. This AG 5 type proved to be an inferior competitor of AG 3 on the potato plant in a laboratory experiment. The specificR. solani antagonistVerticillium biguttatum did not play a role. A similar factor could have reduced the formation of black scurf in the experimental field at Borgercompagnie, whereV. biguttatum was also too infrequent to account for the decline.R. solani AG 5 was not present here and could not indicate the presence of a selective factor against AG 3.     

Characterisation of energy-dependent efflux of imazalil and fenarimol in isolates of Penicillium italicum with a low,medium and high degree of resistance to DMI-fungicides

Differential accumulation of [¹⁴C]imazalil and [¹⁴C]fenarimol by germlings of wild-type and DMI-resistant isolates ofPenicillium italicum was studied at various pH values. At pH 7 and 8 the low-resistant isolate E_300–3 accumulated 22% and 35%, respectively, less imazalil than the wild-type isolate W₅. Imazalil accumulation at pH 5 and 6 was similar. Isolate E_300–3 also accumulated less fenarimol as compared with the wild-type isolate. This difference was much more obvious than for imazalil and was observed at all pH values tested. Differences in accumulation of both imazalil and fenarimol between low (E_300–3), medium (H₁₇) and high resistant (I₃₃) isolates were not observed. These results suggest that decreased accumulation of DMIs is responsible for a low level of resistance only and that additional mechanisms of resistance might operate in isolates with a medium and high degree of resistance. With all isolates fenarimol accumulation was energy-dependent. This was not obvious for imazalil.The wild-type and DMI-resistant isolates had a similar plasma membrane potential as determined with the probe [¹⁴C]tetraphenylphosphonium bromide ([¹⁴C]TPP⁺). Various test compounds, among which ATPase inhibitors, ionophoric antibiotics and calmodulin antagonists, affected the accumulation of [¹⁴C]TPP⁺, [¹⁴C]imazalil and [¹⁴C]fenarimol. No obvious correlation between the effects of the test compounds on accumulation levels of the fungicides and [¹⁴C]TPP⁺ could be observed. These results indicate that the plasma membrane potential does not mediate the efflux of DMI fungicides byP. italicum.     

香蕉ACC氧化酶基因(MAO3)的克隆及其表达特性分析

 根据同源扩增得到香蕉(Musa acuminata) ACC氧化酶基因(MAO3) 的核心部分, 再通过3'和5'RACE扩增上、下游序列以及Genome-Walker的方法得到启动子部分, 共获得3 718 bp长度的序列。将所得结果进行聚类分析, 发现香蕉中ACC氧化酶的氨基酸序列非常保守, 各序列间的同一性高达99% ,与单子叶植物和双子叶植物中ACC氧化酶的氨基酸序列的同源性在66.7%～71.8%之间。组织原位杂交试验表明MAO3基因的表达具有组织特异性, 初步认为是在韧皮部筛管组织中特异表达。运用实时荧光定量PCR技术, 实时监测到了MAO3基因和香蕉乙烯受体基因ERS2受机械伤诱导的定量变化。     

硝酸钙和IAA对温州蜜柑果实钙含量及其品质的影响

在花期、花后1周、3周、采前2周对龟井蜜柑进行Ca(NO3)2、IAA和IAA+Ca(NO3)2喷布处理,同时测定了不同发育时期各处理果实钙含量及其采后果实的主要品质,并与采后浸钙处理和完熟采收果实品质进行了对比分析,结果表明:1)各处理的果皮钙含量在花后51d和112d均有所提高,但此期整个果实钙含量并无显著性差异,采收时各处理整个果实和果肉钙含量均显著高于对照;2)采收时各处理果实的可溶性固形物和可滴定酸均显著低于对照,可溶性糖、单果重、果皮色差值和相对电导率与对照无显著性差异,各处理糖酸比显著高于对照;3)采后30d时IAA+Ca(NO3)2喷布和采后浸钙处理果实的维生素C及完熟采收果实的可溶性固形物和可溶性糖均显著高于对照和其他处理。     

大蒜新品种成蒜早2号和成蒜早3号的选育

成蒜早2号和成蒜早3号是从温江蒜的自然变异株中,经系统选育而成的早熟新品种.成蒜早2号从播种到蒜薹始收需153～180 d(天),平均单薹质量12.7 g,单头质量10.7 g,多数蒜头由6～9瓣组成,蒜瓣紧密抱握蒜薹轴,一般蒜薹和蒜头产量分别为340和350 kg·(667 m2)-1,抽薹比温江蒜早,抗寒力比温江蒜弱;成蒜早3号从播种到蒜薹始收需153～186 d(天),平均单薹质量和单头质量分别为14.5和12.0 g,多数蒜头由5～8瓣组成.一般蒜薹和蒜头产量分别为320和410kg·(667 m2)-1,抽薹比温江蒜早,抗寒力与温江蒜相当.     

辣椒新品种镇江3号的选育

中晚熟杂交一代辣椒镇研3号是以江苏本地羊角椒自交系Y9007为母本,由甘肃酒泉引进的甜椒自交系T9218为父本配制的一代杂交组合。镇研3号为中熟辣椒品种,果形为牛角形,纵径15cm,肩横径5.0cm、肉厚0.40cm,单果平均重42g。果面光滑,青熟果绿色、味微辣,风味佳,适宜在长江流域或南方保护地栽培种植,667m2产量约为4200～5000kg。     

日光温室黄瓜济杂3号的选育

母本88001来源于津杂2号,父本88010来源于津研2号与新泰密刺的杂交后代。其一代杂种济杂3号,瓜条顺直,长30～35 cm,单瓜质量约180 g,瓜把短,瓜皮深绿,密瘤白刺,品质优,商品性好,对霜霉病、白粉病、枯萎病抗性强。每667m~2产量7000～14000 kg,适合日光温室越冬茬和早春茬栽培。     

一株新的化能无机营养菌——聚积碳酸镁的细菌

从新疆吐鲁番盆地分离了一株新的化能无机营养菌Tp892 4,其主要特征是聚积碳酸镁 ,只在镁盐和碳酸钠的培养基中迅速生长繁殖。细胞球形 ,成串而有规则地排列在碳酸镁的晶体中。菌落白色、坚硬、中间隆起向外散射形成雪花状。细菌能在 10～ 75℃的温度范围和 8～ 14的 pH范围内生长。致死温度 10 0℃ 5 0′ ,平均代时 0 .5hr。这与“伯杰细菌鉴定手册”和“伯杰系统细菌手册”中描述的化能无机营养菌有明显的差别 ,至今国内外尚未见过报道。根据这些特性 ,作者认为该菌是一种新的聚积碳酸镁的化能无机营养菌 ,暂命名为吐鲁番聚镁球菌Polymagcoccusturpanensissp .nov .