Transmission of bacterial wilt resistance by First Division Restitution (FDR) 2n pollen via 4x×2x crosses in potatoes

Summary Resistance to bacterial wilt (Pseudomonas solanacearum) found in tuber-bearing Solanum species was transferred into a diploid potato breeding population. Simultaneous selections were made for agronomic characters, production of first division restitution (FDR) 2n pollen, and resistance. Diploid resistant genotypes were identified via inoculation with a virulent isolate (CIP-204) of race 3 of Pseudomonas solanacearum. These resistant diploid genotypes were crossed to susceptible tetraploid potatoes. An investigation was made to assess whether resistant diploid genotypes transmit resistance to bacterial wilt, which is a quantitatively inherited trait, to tetraploid potatoes via FDR 2n pollen. Tetraploid seedlings from 4x×2x crosses were inoculated with the same isolate CIP-204, and the percentage of surviving seedlings was scored. Some 4x×2x families from resistant diploid genotypes demonstrated a high level of survival rate. The transmission of bacterial wilt resistance was achieved by the use of FDR 2n pollen. It was speculated that a female x male interaction effect on the survival rate of the evaluated progeny may exist. Selecting proper 4x and 2x parents would be important for obtaining a higher frequency of transmission of resistance to bacterial wilt in the progeny.     

A biosystematic study of the origin of the cultivated diploid potato,Solanum x Ajanhuiri Juz. et Buk.

Summary The origin and nature of the diploid cultivated potato species S. ajanhuiri Juz. et Buk. was studied. Several lines of evidence indicate that S. ajanhuiri might be derived from natural crosses between primitive cultivars of the diploid species S. stenotomum and the wild species S. megistacrolobum. Morphological comparisons were made between S. stenotomum x S. megistacrolobum F₁ hybrids and naturally occurring S. ajanhuiri to investigate this hypothesis. Comparisons were also made between S. ajanhuiri x S. stenotomum crosses and the F₂ generation of the first-mentioned cross.Crosses between the two major groups of S. ajanhuiri cultivars, Ajawiri and Yari, showed not only genetic breakdown but also a wide range of phenotypic variation similar to those of artificial F₂ families of S. stenotomum x S. megistacrolobum. Furthermore, there was strong evidence showing that the Yari group of S. ajanhuiri could almost certainly be an F₁ S. stenotomum x S. megistacrolobum hybrid, whereas the Ajawiri group could be a backcross of an F₁ hybrid to S. stenotomum. These results added further support to the hypothesis of a hybrid origin of S. ajanhuiri, as well as indicating its putative parents. It is suggested that this hybridogenic taxon be retained at the species level under the name Solanum x ajanhuiri.     

甘薯淀粉白度的研究

用石灰水调整磨浆液ｐＨ值至７．５～８．５，（３０００－４０００ｒ／ｍｉｎ）离心分离和沉淀，能有效改善甘薯淀粉白度。     

紫甘薯初加工产品糊化过程中花青素的浸出特性

[目的]探索紫甘薯高效开发利用的方法。[方法]对2种特定温度下烘干的紫甘薯初加工试样进行模拟糊化,测定糊化不同阶段糊化醪中花青素的浸出量。[结果]紫甘薯粉在糊化时,90℃程序升温至95℃过程,花青素的浸出速率最大。95℃保温结束时,达到最大浸出量。相比110℃烘干,紫甘薯60℃烘干试样花青素保留量大,最大浸出量大,最大浸出率高。[结论]紫甘薯通过较低温度烘干加工,同时适当缩短90℃程序升温前的糊化程序有利于花青素的保留与浸出。     

长期施肥条件下旱作农田土壤水分剖面分布特征

利用黄土高原旱地长期定位施肥试验,通过比较不同施肥方式和施肥量对土壤剖面水分分布的影响,研究了施肥与土壤水分的关系,并对深层土壤水分消耗引起的水分生态效应进行了分析。试验期间,0300.cm土壤水分虽在雨季得到降水补充,但是播种期的土壤贮水量仍处于亏缺状态。结果表明,不同施肥方式和施肥量的试验处理中,100300.cm土层作物耗水剧烈,土壤水分含量均较低。与对照相比,单施磷肥对作物利用土壤水分没有显著影响;单施氮肥和氮磷配施均促进了作物对下层土壤水分的利用。在相同的施氮量下,施用磷肥加大了作物对深层土壤水分的利用,100300.cm土层的土壤含水率在磷肥用量达到45.kg/hm2后不再随施磷量的增加而降低;在同样的施磷条件下,作物对下层土壤水分的利用随施氮量的增加而增加,当施氮量增加到90.kg/hm2后,100300cm土层的土壤含水率达到一个稳定的值。在同样的氮磷用量情况下,施钾对土壤水分没有显著影响。     

Potassium isotherm partitioning based on modified quantity‐intensity relation and potassium buffering characterization of soils of North India

Background : Potassium (K) availability in soil and plant uptake is restrained by the dynamic interactions among the different pools of K. Aims : To understand these interactions, a study was undertaken to assess the quantity–intensity (Q/I) and buffering characteristics of rainfed maize (Zea mays L.) growing soils. Ten contrasting soils were evaluated for K partitioning changes in exchangeable K (ΔEK) and non‐exchangeable K (ΔNEK) pools in the soil‐solution phase and buffering characteristics using a modified version of Q/I approach. Results : The partitioned Q/I isotherms showed strong adsorption with the increase in K concentration ratio (CR^K) and the changes due to ΔEK were higher than changes due to ΔNEK. Total buffering capacity (PBC^K) significantly correlated (r = 0.92, p <0.01) with clay content with a major share contributed by buffering capacity owing to non‐exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{NEK}}^K$) rather than exchangeable K ( ${\mathrm{PBC}}_{\Delta \mathrm{EK}}^K$). The fixation capacity (β) factor, the magnitude of added K converted into a non‐exchangeable pool, ranged from 41 to 63%, whereas release (α) factor, the magnitude of added K converted to the exchangeable pool, ranged from 19 to 36%. Both threshold solution K (CK_r) and threshold exchangeable K (EK_r) values were found to be high in Satran clay loam (S2) and lower in Doon silty clay loam (S3) soils. The equilibrium exchangeable K (EK_o) was found close to minimum exchangeable K (E_min) in Doon silty clay loam (S3) and Babaweyl sandy clay loam (S1) soils and overall E_min constituted about 8.94 to 0.57% of the EK_o. Conclusion : It may be concluded that K Q/I isotherm partitioning provides a valuable insight to assess the dynamic relations. The ratio of α/β (K recharge index) could be used to evaluate the K enrichment capacity of soil to K additions while EK_r and E_min can be potentially useful in the elucidation of exchangeable K as K fertility index especially in soils with poor K fertilizer management.     

不同采摘期甘薯茎尖中的硝酸盐 亚硝酸盐和VC含量分析

测定了鲜甘薯茎尖4个品种(胜利100号,卢选1号,一窝红,红腿)不同采摘期的硝酸盐、亚硝酸盐及VC含量。结果表明,4种甘薯茎尖不同采摘期的硝酸盐和亚硝酸盐含量均较低。其中亚硝酸盐含量低于4.0mg/kg,符合我国无公害蔬菜亚硝酸盐的限量标准,硝酸盐含量符合一级蔬菜限量标准,VC含量丰富,均为品质上乘的蔬菜。     

淀粉型甘薯施用烟茎生物有机肥部分替代化肥试验

以渝薯27为材料,采用田间试验方法,研究烟茎生物有机肥部分替代化肥对甘薯的生长和鲜薯产量的影响。以不施肥F1和常规施肥F2作对照,生物有机肥设置8个梯度,生物有机肥从2400 kg·hm-2-1000 kg·hm-2每一梯度递减200kg·hm-2,对应8个梯度的复合肥0-1067 kg·hm-2,复合肥从F4开始每一梯度增加133·hm-2。结果表明：施用烟茎生物有机肥替代22.3%的复合肥,即F9施复合肥933kg·hm-2+生物有机肥1200 kg·hm-2的鲜薯产量最高达39759.7kg·hm-2,鲜薯蔓产量最高达31555.kg·hm-2,淀粉产量9464.7kg·hm-2,是最佳的搭配施肥组合。     

渭北旱塬土壤养分时空变异与养分平衡研究

利用20世纪80年代第二次全国土壤普查资料和2010—2012年耕地地力调查与质量评价项目数据,运用经典统计学、地统计学结合GIS技术,分析了渭北旱塬近30年来土壤养分变化;并通过对该区测土配方施肥项目农户施肥调查数据的分析,明确了该区农户施肥现状及主要种植体系养分平衡状况。结果表明,渭北旱塬当前土壤有机质、碱解氮和有效磷含量平均分别为12.9 g/kg、59.4 mg/kg和15.4 mg/kg,与20世纪80年代相比,分别提高了22.0%、37.9%和129.8%;速效钾基本保持不变。该区氮、磷肥过量投入现象严重,小麦、玉米和苹果的氮肥、磷肥投入过量农户分别占总调查农户的89%、69%、74%和75%、49%、52%;76%和67%的农户在小麦和玉米田间的钾肥投入不足,苹果钾肥投入过量和不足的农户比例均较高,分别为40%和48%。小麦、玉米和苹果三大主要种植体系土壤氮、磷均处于盈余状态,氮盈余量平均分别为116、111和655 kg/hm2,磷盈余量平均分别为88、56和357 kg/hm2,其实际盈余率均大大超出短期内允许的盈余范围。小麦和玉米种植体系钾素均为亏损状态,其亏损量平均分别为73和93 kg/hm2,在允许亏损范围内;而苹果种植体系钾素年盈余量高达283 kg/hm2,实际盈亏率较允许平衡盈亏率高出145个百分点。因此,为实现渭北旱塬粮食安全和环境安全的双重目的,今后该区域应适量减少氮、磷肥的投入,尤其是苹果园区;增加粮食作物的钾肥投入,以保证作物稳产、高产,保持地力。     

不同玉米品种在陇东旱塬区适应性试验初报

为筛选出适合陇东旱塬区种植的优质高产玉米品种,于2019年在甘肃庆阳对12个玉米品种的农艺性状和抗逆性(倒伏率、对茎腐病的抗性)等进行了田间比较。结果表明,供试12个玉米品种在当地均可正常成熟,生育期为128～143 d。产量以先玉1321最高,为15 400.5 kg/hm2;新玉108次之,为14 785.5 kg/hm2;兴贮88居第3位,为14 448.0 kg/hm2。在抗逆性方面,九圣禾2468、新玉108、陕单650、迪卡519、松科106、兴贮88倒伏率均为0,表现出良好的抗倒伏性;九圣禾2468、新玉108和陇单9号对茎腐病表现出良好的抗性。从农艺性状和抗性等综合考虑,新玉108、九圣禾2468和兴贮88表现最佳,适宜在陇东旱塬区种植。