Genotypic Variation of Sweetpotatoes Grown Under Low Potassium Stress

Abstract

Ninety‐four sweetpotato (Ipomoea batatas L.) genotypes were compared under low potassium (K) stress (35 mg kg^?1 dry soil) over two growing seasons. Potassium utilization efficiency ratio (KER), defined as the dry matter weight/K content, was significantly different among genotypes. Genotypes were divisible into four KER categories: high efficient, efficient, fairly efficient and inefficient with most of the genotypes falling in the efficient and fairly efficient groups. The K contents varied significantly within individual plants. Potassium concentration on a dry weight basis was greatest in the petioles followed by leaves, stems, and roots. On a total plant basis, K content in roots was greatest followed by stems, leaves, and petioles. Several genotypes (including 602 × 81‐3, Zhe15‐47 and Xushu18) were selected as most suitable for growth on soils low in available K due to their appreciable yields and higher KER under low K stress.     

Performance of Broiler Chickens Fed Sweet Potato Meal (Ipomoea batatas L.) Diets

Day-old Lohman broiler chicks (n = 120) were fed on five starting diets for 4 weeks in groups of 24 birds. The starting diets contained 0%, 9%, 18%, 27% and 36% sweet potato tuber as a replacement for maize. From the fifth week, the 120 birds were tested in groups of 30 on four finishing diets containing 0%, 15%, 30% and 45% sweet potato tuber as a replacement for maize. The carcass quality was significantly (p>0.05) improved due to a significant (p>0.05) reduction of abdominal fat in the birds fed on the 45% sweet potato finisher diets. However, the birds on the sweet potato diet continually passed wet dropppings, resulting in a significant (p>0.05) reduction in body weight and feed conversion efficiency. The optimum levels of inclusion of sweet potato in the diets were considered to be 27% and 30% for starting and finishing broiler chickens, respectively. Sweet potato diets may be a remedy for fatty broilers.     

水体表面浮植水蕹菜养鱼

随着草食性鱼类养殖的迅速发展,青饲料供不应求和青饲料地十分紧缺等问题日益突出。为寻求解决这些问题,作者于1985—1988年进行了水体表面浮植水蕹菜养鱼的研究工作。现将主要研究结果报道如下。     

薏米对含铬污水的净化作用

[目的]研究铬胁迫下薏米对含铬污水的净化作用及铬胁迫对薏米生理生化的影响,为人工湿地净化含铬污水提供理论支持.[方法]开展桶栽模拟人工湿地试验,以薏米为材料,定期浇灌不同浓度的Cr（Ⅵ）生活污水（0、5、20、40、60mg/LK2Cr2O7）,定期测定进出水的化学需氧量（COD）和总磷（TP）,并检测薏米叶片过氧化物酶（POD）、超氧化物歧化酶（SOD）、丙二醛（MDA）等指标.[结果]薏米对含铬污水中COD的去除率随Cr（Ⅵ）浓度增大而降低,5mg/L的Cr（Ⅵ）处理在对总磷的去除率在90％以上,并随Cr（Ⅵ）浓度的升高而下降;薏米叶中的MDA含量随Cr（Ⅵ）浓度和处理时间的增加而呈增加趋势;叶片SOD、POD活性均随处理时间的延长而呈先上升后下降的趋势.[结论]薏米能耐受一定浓度的Cr（Ⅵ）胁迫,且对水质净化有较好的作用.     

蕹菜Cd-PSC根际土壤酶和微生物特征的研究

[目的]为了研究在2种不同镉浓度的农田上蕹菜Cd-PSC和non-Cd-PSC 2个品种根际土壤酶和微生物的特征。[方法]采用自制根箱试验。[结果]蕹菜根际土壤5种酶(脲酶、转化酶、酸碱磷酸酶、蛋白酶)活性和三类微生物(细菌、真菌、放线菌)数量都显著大于非根际土壤(P0.01)。在同一土壤上,蕹菜品种间酶活性和微生物数量均存在基因型差异(P0.05);在2种土壤上,脲酶、转化酶、蛋白酶在2个品种间表现不一致,而酸碱磷酸酶则一直表现为Cd-PSC的根际酶活性小于non-Cd-PSC的活性。[结论]Cd-PSC的根系细菌、放线菌的数量显著小于non-Cd-PSC的根系土壤中的数量(P0.01),而真菌数量显著大于non-Cd-PSC的数量(P0.05)。     

巴西牵牛组织培养技术初探

以巴西牵牛试管苗的茎尖为外殖体,对巴西牵牛组织培养技术进行研究,结果表明：巴西牵牛组培苗腋芽生长增殖的最佳培养基为MS＋NAA 0.5 mg/L。     

不同浓度硒对蕹菜产量和品质的影响

采用水培研究了不同浓度硒（0尧0.05尧0.5尧1尧2尧4 mg/L）对蕹菜产量和品质的影响。结果表明、硒浓度为1 mg/L 时、蕹菜生长状况最佳、产量最高;而当硒浓度大于2 mg/L 时、蕹菜生长受阻、产量下降、且产生中毒现象。随着 硒浓度的增加、蕹菜硒含量尧可溶性糖含量均不断增加、而维生素C 含量先降低后增加、蛋白质和硝酸盐含量均先增 加后降低。与对照相比、硒浓度为0.05尧0.5尧1尧2尧4 mg/L 的各处理、蕹菜硒含量增加幅度分别为108.35%尧1 706.23%尧 3 097.99%尧5 920.38%尧12 308.82%、蕹菜蛋白质含量增加幅度分别为20.09%尧12.50%尧11.61%尧3.57%尧6.25%;硒浓 度臆2mg/L 的各处理、蕹菜可溶性糖含量增加幅度分别为34.74%尧41.91%尧48.32%尧57.30%。低硒浓度（0.05尧0.5 mg/ L）使蕹菜维生素C 含量略有降低、而高硒浓度（逸1 mg/L）显著增加了蕹菜维生素C 含量、硒浓度臆2 mg/L 的处理使 蕹菜硝酸盐含量增加、而硒浓度为4 mg/L 时、蕹菜硝酸盐含量显著下降。综合考虑、硒浓度为1 mg/L 的处理显著增 加了蕹菜产量、提高了蕹菜品质、是蕹菜水培最适合的硒施肥水平。     

Diallel analysis of sweetpotatoes for resistance to sweetpotato virus disease

Sweetpotato virus disease (SPVD) is due to the dual infection and synergistic interaction of Sweetpotato feathery mottle potyvirus (SPFMV) and Sweetpotato chlorotic stunt crinivirus(SPCSV), and causes up to 98% yield loss in sweetpotato in East Africa. This study was conducted to determine the inheritance of resistance to SPVD in sweetpotato and to estimate the nature of genetic variance. Ten parental clones varying in reaction to SPVD were crossed in a half diallel mating design to generate 45 full-sib families. The families were graft-inoculated with SPCSV and SPFMV to induce SPVD and evaluated for resistance in a randomized complete block design at two sites in Namulonge, Uganda during 1998–2000. In serological assays for SPFMV and SPCSV,resistance to symptom development and recovery from initial systemic SPVD symptoms, characterised resistant genotypes. Genetic component analysis showed significant effects for both general combining ability (GCA) and specific combining ability (SCA) for resistance to SPVD. GCA to SCA variance component ratios were large (0.51–0.87), hence GCA effects were more important than SCA effects. Resistant parents exhibited high GCA indicating that additive gene effects were predominant in the inheritance of resistance to SPVD and recovery. Narrow-sense heritability (31–41%) and broad-sense heritability (73–98%) were moderate to high, indicating that rapid genetic gains for SPVD resistance could be accomplished by mass selection breeding techniques. Two genotypes, New Kawogo and Sowola, had high negative GCA effects and had several families in specific crosses,which exhibited rapid recovery from SPVD,and are promising parents for enhancement of SPVD resistance and recovery. This revised version was published online in August 2006 with corrections to the Cover Date.     

Interactions of Glomus clarum with Acetobacter diazotrophicus in infection of sweet potato (Ipomoea batatas), sugarcane (Saccharum spp.), and sweet sorghum (Sorghum vulgare)

Summary Spores of the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus clarum obtained from sweet potatoes grown in soil inoculated with this fungus and with an enrichment culture of Acetobacter diazotrophicus contained A. diazotrophicus and several other bacteria, including a diazotrophic Klebsiella sp. Inoculation of micropropagated sweet potatoes with G. clarum and A. diazotrophicus enhanced spore formation in soil compared to VAM inoculation alone. Plants inoculated with VAM spores containing the bacteria showed additional increases in the number of spores formed within roots. A. diazotrophicus infected aerial plant parts only when inoculated together with VAM or when present within VAM spores. Micropropagated sugarcane seedlings inoculated with the same VAM spores containing the diazotrophs also contained much higher numbers of A. diazotrophicus in aerial parts than seedlings inoculated in vitro with the bacteria alone. When grown in non-sterile soil, the sugarcane seedlings again showed the greatest infection of aerial parts after inoculation with VAM spores containing the diazotrophs. This treatment also increased VAM colonization and the numbers of spores formed within roots. Similar effects were observed in sweet sorghum except that the aerial plant parts were not infected by A. diazotrophicus.     

甘薯早代品系部分数量性状的遗传相关分析

选用12个甘薯杂交组合的136个品系的无性1代和2代的7个农艺性状与鲜重进行相关分析和通径分析,并估算其遗传率。结果表明,大中薯重在两代的选择中都是重点考虑的因素。鲜薯重、大中薯重、地上部重等经济性状的遗传率不高,在早代品系选择时要综合其他性状。