几种杀菌剂防治甜菜褐斑病效果分析

１９９８ 年在内蒙古林西进行了３ 种杀菌剂防治甜菜褐斑病药效比较试验, 结果表明： 以三苯基醋酸锡效果为最好,褐斑病罹病率较对照低２８ 个百分点, 甜菜根产量、含糖率、产糖量分别比对照提高２２ ．３％ 、１．１ 度、２２ ．６％ 。可在甜菜生产中试用     

苜蓿对褐斑病抗性筛选研究

在实验条件下,就国内外收集的250份苜蓿种质材料幼苗对褐斑病的抗性进行了筛选和评价。结果表明,苜蓿种质材料的抗病性存在很大差异,幼苗发病率为11.1%～100%,病情指数为4.1～73%。有45份（占总数18%）的病指数低于20%,且全部为国外品种。大部分材料（78%）的病指数为：20%～60%。病指数大于60%的10份最敏感的材料中有6份来自国内,4份来自国外。     

Inheritance of reaction to Pseudomonas lachrymans in pickling cucumber

Summary Cucumber (Cucumis sativus) lines resistant to angular leafspot caused by Pseudomonas lachrymans react to an infection by developing necrotic lesions that lack the chlorotic halo characteristic of the susceptible reaction. The inheritance of the non-halo lesion reaction was studied in all possible crosses between resistant lines MSU 9402 and Gy 14A, and susceptible cultivars Wisc. SMR 18 and National Pickling. Genetic analysis of the F₁, F₂, backcross and F₃ populations revealed that the non-halo lesion type, associated with resistance, was controlled by a single recessive gene, pl. This character appears to be an important component of resistance to P. lachrymans.     

Field and greenhouse evaluation of the components of partial resistance to early leafspot in peanut

Summary Ten peanut (Arachis hypogaea L.) genotypes were evaluated fro components of partial resistance to Cercospora arachidicola Hori in the field and in two detached leaf tests in the greenhouse. The relationships among the resistance components in the two environments were examined by computing rank correlations among the components measured in the greenhouse and among those measured in the field. A comparison of field and greenhouse testing for partial resistance was made by determining the correlations between components measured in the two testing methods. The genotypes were significantly different for all the components of resistant measured in the field and for most of the components measured in the greenhouse. In the field study necrotic area/10 cm² leaf area was moderately correlated (r=0.58) with lesion number/10 cm² leaf area and highly correlated (r=0.71–0.76) with total lesion number, predicted number of days after planting (X) to reach a standard lesion count, and defoliation. In the greenhouse only the correlation between necrotic area (mm²)/10 cm² leaf area and sporulation/leaf was highly significant (r=0.71–0.83) in both greenhouse tests. Necrotic area (mm²)/10 cm² leaf area measured in the field was significantly correlated with that measured in the greenhouse (r=0.66). Sporulation/leaf measured in the greennhouse was significantly correlated (r=0.66) with lesion increase in the field (measured as predicted X). It should thus be possible to evaluate and select for components of partial resistance in the greenhouse to develop resistant lines for the field.     

花生晚斑病抗性与产量性状的相关研究

采用43份材料研究了花生晚斑病抗性与产量性状的关系,结果表明,单株产量与抗病性呈二次抛物线关系,抗病性对丰产性的制约程度接近20％;出仁率与抗病性近于呈负的直线关系;单株饱果数、百果重与抗病性之间表现曲线相关趋势,但相关系数远不显著。从研究结果预测,通过对抗病性、单株饱果数、百果重的选择,可选育出抗病高产品系;通过对早熟一丰产性的选择,可选育出耐病高产品系。     

禾本卡克防治甜菜褐斑病的效果

以500倍液的禾本卡克喷施2～3次防治甜菜褐斑病有明显的防治效果。病情指数降低22．6-26．1，甜菜产量提高8．1％-10．6％．含糖率增加0．7～1．1度。     

Variation in progenies of an Arachis hypogaea x diploid wild species hybrid

Summary Derivatives of a cross between cultivated peanuts, Arachis hypogaea L. (2n=40), and the wild species collection GKP 10017 (2n=20) were compared morphologically, for leafspot resistance and for yield. The objective of the study was to determine the effects of wild species germplasm on the A. hypogaea genome. The sterile F₁ hybrid which resulted from crossing the two species was treated with colchicine to restore fertility at the 6x ploidy level. The resulting hexaploid was cytologically unstable and progeny lost chromosomes until stability was regained at the 2n=40 chromosome level. Forty-seven characters were used to analyze the variation among plants in the tetraploid interspecific hybrid population. The plants were compared to four cultivated lines plus GKP 10017. Many hybrids were intermediate to the two parents in morphology. Individual traits such as growth habit, pod and seed size, elongation of the constricted area between pods, nodulation and leaflet size were altered by the presence of GKP 10017 germplasm in many of the hybrid plants. Cercospora arachidicola Hori and Cercosporidium personatum (Berk. & Curt.) Deighton resistances were evaluated for all plants. Several hybrids had few lesions due to either leafspot pathogen. In addition, 24 largeseeded interspecific hybrid selections were compared to the cultivated variety NC 5 for yield. Five selections were superior to both parents at p=0.01. Morphology, disease resistance and yields appeared to be greatly influenced by the wild species GKP 10017 germplasm in plants of the interspecific hybrid population. The potentials of using wild species for improvement of the cultivated peanut are discussed.Paper number 5948 of the journal series of the North Carolina Agricultural Research Service, Raleigh, NC 27650. The investigation was supported in part by ICRISAT and SEA-CR grant no. 701-15-51.     

花生叶斑病抗性与产量性状的相关研究

用43份材料研究了花生叶斑病抗性与产量性状的关系,结果表明单株产量与抗病性呈二次抛物线关系,抗病性对丰产性的制约程度接近20%;出仁率与抗病性近于呈负的直线关系;单株饱果数、百果重与抗病性之间表现曲线相关趋势,但相关系数远不显著.从研究结果预测通过对抗病性、单株饱果数、百果重的选择,可选育出抗病高产品系;通过对早熟-丰产性的选择,可选育出耐病高产品系.     

Cytology and leafspot resistance in Arachis hypogaea x wild species hybrids

Summary Introgression of germplasm from diploid wild Arachis species to A. hypogaea has great potential for improving pest resistance in cultivated peanuts. This investigation evaluated methods for incorporating exotic germplasm into cultivated peanuts, especially for Cercospora arachidicola Hori resistance. Interspecific hybrids between A. hypogaea (cvs. NC 2 and NC 5) and the wild species A. cardenasii Krap. et Greg. nom. nud. and A. chacoense Krap. et Greg. nom. nud. were analyzed cytologically and for leafspot resistance. All F₁ hybrids were sterile, had irregular meiosis, and very few multivalents. They were highly resistant to C. arachidicola in field tests and had a 10-fold reduction of conidia per lesion in the greenhouse as compared to A. hypogaea cultivars. After colchicine treatments of F₁ hybrids, hexaploids (2n=60) and aneuploids (2n=54, 56, 63) were observed. The hexaploids had up to 18 univalents per pollen mother cell and very few multivalents, indicating a low frequency of intergenomic chromosome pairing. For C. arachidicola resistance, significant differences were not found among wild species parents, F₁ hybrids and two generations of hexaploids. Most hexaploids were stable at 2n=60 and embryos aborted when backcrosses with the respective wild species were attempted. However, when hexaploids were backcrossed to A. hypogaea, several fertile pentaploid (2n=50) offspring were obtained. Use of self-pollinating pentaploids is believed to be the quickest method to recover 40-chromosome hybrid derivatives in these hybrids.     

Utilizing Arachis cardenasii as a source of Cercospora leafspot resistance for peanut improvement

Summary Advanced generation 40-chromosome hybrids between A. hypogaea (2n=4x=40) and a wild diploid species. A. cardenasii were evaluated for early leafspot, Cercospora arachidicola resistance and agronomic potential. The objective of this investigation was to determine if early leafspot resistance derived from a wild species could be incorporated into the A. hypogaea genome. Interspecific hybrid selections were made and then compared in the field and greenhouse to susceptible cultivars and to A. hypogaea lines which are reported to be resistant to early leafspot. Significantly higher levels of resistance were found in five hybrid selections than in cultivated lines based on numbers of lesions per leaf. In a greenhouse study, several hybrid selections also had greatly reduced sporulation from lesions as compared to A. hypogaea. Several mechanisms of resistance are believed to be present. Although hybrid selections had small seeds and low yields as compared to A. hypogaea, a new and valuable source of early leafspot resistance derived from the species A. cardenasii is present.Paper no. 8814 of the journal series of the North Carolina Agricultural Research Service, Raleigh, NC 27695. This research was partially funded by AID-Peanut CRSP grant DAN-4048-G-SS-2065-00.