玉米籽粒突变体dek101的表型分析和精细定位

As the storage organ of maize, kernel development and accumulation of storage production directly determines maize yield and quality. In this study, a stable defective kernel mutant, named as defective kernel 101 (dek101), was identified during the development of double haploid (DH) lines in maize. The dek101 kernels displayed severely shrunk kernel appearance, significantly reduced kernel weight, lethal embryo, defective endosperm and were incapable of germinating. The dek101 showed obvious developmental abnormalities at 12 days after pollination (DAP). The fresh weight, dry weight and volume of the kernels were no longer increased after 21 DAP. Scanning electron microscopy (SEM) observation revealed that the starch granules of dek101 were significantly smaller compared with wild-type kernels. Genetic analysis demonstrated that the mutant trait was controlled by a recessive single gene. Using 441 F₂ individuals and 1648 F₃ individuals, dek101 was narrowed down to a genomic region of about 300 kb between the InDel marker IDP2182 and IDP4600 on chromosome 1, which contains five predicted genes. These results laid the foundation for mining functional genes related to maize kernel development and deciphering the mechanism of grain development.     

翻耕复种防治核桃举肢蛾的初步研究

核桃树下翻耕复种对核桃举肢蛾有明显的防治效果。覆土模拟试验证明，覆土４ｃｍ时，成虫羽化出土率仅为１８％，在８ｃｍ以上时，则全部不能出土。大田防治采用翻耕复种技术可使黑果率下降到１０％以下，防效高达８９．２９％。     

Changes of the Methionine Content During Maize Grain Maturation

The changes in the amounts of dry matter, total nitrogen and methionine during maturation of normal maize hybrids grown under the same topographical and agrotechnical conditions on two consecutive vegetation years were examined.
Total nitrogen was determined by Kjeldahl's method and methionine spectrophotometrically from papain hydrolysate by the method of McCarthy and Sullivan. Analysis of variance was applied to assess the significance of the changes in particular components during grain maturation.
A significant increase (p = 0.01) in amounts of the all investigated components in original grain matter up until a late stage of dough maturity in both vegetation years was determined. The increase was mostly expressed by the end of milky maturity. The correlation between these components during maturation is positive and highly significant (p = 0.001). The methionine content in dry matter attained in stage of milky maturation the value being characteristic for mature grain. On a total-proteins basis, the methionine content is significantly the least (p = 0.01) at the early stage of milky maturation and increases up until dough maturity reaching a value that does not significantly differ from the value in full maturity of grain.     

阿荣旗旱作丘陵区春玉米配方施肥的研究

春玉米是内蒙古自治区呼伦贝尔盟岭南旱作丘陵区的重要粮食作物。施肥不足,氮、磷配比不合理是该地区玉米低产的重要影响因素。1987～1989年在该地区的中部阿荣旗25个试验点上进行了测土配方施肥的研究,经统计分析,提出了不同土壤肥力条件下氮,磷效应函数;并根据碱解氮、速效磷的土测值确定最佳施肥量的推荐,为岭南旱作丘陵区春玉米丰产栽培提供了施肥依据。     

新垦地覆盖稻草春玉米高产机理分析

试验结果表明:本项技术方法简便,保土、保肥、保水效果好,既能达到地膜玉米的产量,又能就地取材,降低成本,增加土壤有机质投入,改良土壤结构,且无环境污染,有较高的推广价值.     

Comparative Analysis of Photosynthetic Parameters and its Evaluation in Pearl Millet Hybrid and its Parents

Fully expanded leaf occupying topmost position in a field grown pearl millet hybrid (BJ-104) and its parents (J-104 and 5141-A) were analysed at weekly intervals for chlorophylls, Hill activity and phosphoenolpyruvate carboxylase activity. Large ontogenic drifts in these parameters, made the actual comparison between hybrid and parents, difficult. However, up to 52 d the hybrid leaf possessed considerably higher chlorophyll pigments than its parents. Amongst the inbreds, the male parent was initially better than the female parent while at later stages, the trend was reversed. Hill activity and PEPcase were more in the male than in the female parent and the hybrid followed the better parent. Rate limiting steps for productivity, measured as NAR (g dry weight)⁻¹, were worked out in the female parent, using multiple regression and correlation analysis, and the significance of such an analysis is discussed in relation to plant productivity.     

Undesired Self-Pollination of the Parent Plant Decreases Dry Matter Yield of Silage Maize

A proportion of the maize seed sold in the Netherlands is genetically impure. The most common form of genetic impurity in hybrid seed production is the accidental self-pollination of the female parent. Varying quantities of selfed seeds were added to certified seedlots of three-way cross hybrids. These mixtures were tested in nine field experiments, in 1985 and 1986.
Whole plant dry matter yield decreased by 40 to 45 kg/ha per percent of selfed seed added. The effect of selfed seed on dry matter yield did not differ significantly in the hybrids studied.     

Maize Smut Induced by Ustilago maydis (D. C.) Corda – Reaction of Maize Hybrids and Lines to Smut Disease

A field experiment was carried out during the growing seasons 1982, 1983 and 1984 to evaluate the reaction of different maize hybrids and lines to smut disease and to give further informations on the effect of environmental factors on smut incidence.
The kernels of 17 different maize hybrids and 17 inbred line were planted in the field and the stand was maintained constant of 30 plants per row during the respective years. Each plant was subjected to an artificial infection by dropping 2 ml of U. maydis -spore suspension into the leaf whorl at 6–8 leaf stage. Field observations, concerning the number, the size and location of smut galls were recorded for each individual plant whenever the symptoms appeared. The reaction of maize genotypes was evaluated on a new classified system and the differential response was correlated with the changes ol meteorological data.
The results indicated that hybrids: Circe LG9, E1, Kaceplns, Limac-LG11 and RA 94A x RA 320 as well as lines: F2, L1, L2, L8, RA 94A, RA 320, W33 and W401 were highly resistant; while the hybrids E2, F7 x EP1.J and Giga as well as lines: EP1J, F115, L5 and L6 were highly susceptible. The reaction of these genotypes exhibited an identical behaviour during the 3 years. The remaining genotypes were unstable and showed differential response to degree of infection and location of smut galls. The increase of smut infection in 1982 relative to that recorded in 1984, under the same wet weather conditions, was attributed to the increase of air temperature and sunshine duration. Under dry weather condition, as in 1983, increasing temperature and sunshine duration had little effect on smut incidence.     

Influence of grain type on the insecticidal efficacy of two diatomaceous earth formulations against Rhyzopertha dominica (F) (Coleoptera: Bostrychidae)

Laboratory bioassays were carried out in order to evaluate the effectiveness of two diatomaceous earth (DE) formulations, Insecto and SilicoSec, against adults of Rhyzopertha dominica (F) in eight different grain commodities. The adherence of the two DEs to each grain was also measured. The eight grains tested were wheat, whole barley, peeled barley, oats, rye, triticale, rice and maize. These commodities were treated with the DEs at three rates, 0.75, 1.0 and 1.5 g DE kg(-1) grain. The mortality of R dominica adults was measured after 24 h, 48 h, 7 days and 14 days of exposure in the treated grains at 26 degrees C and 55% RH. After the 14-day mortality count, all adults were removed and the treated grains retained under the same conditions for a further 60 days. The treated grains were subsequently examined for F1 progeny. Significant differences were recorded among the eight grain types as well as between the DE formulations tested. After 14 days of exposure, even at the lowest DE rate for both formulations, adult mortality was high (>90%) in wheat and triticale. In contrast, adult mortality was significantly lower in peeled barley. Increasing the rate improved the efficacy of the DEs significantly in only some of the grains tested. Reproductive capacity in all the treated grains was significantly suppressed when compared with untreated grains. Generally, more F1 individuals of R dominica were noted in the treated peeled barley than in the other commodities. Significant differences in the percentage of DE retention were noted among the eight grains. The highest retention level was noted in rice (>87%) and the lowest in maize (<6%). However, the degree of DE adherence to a given grain was not always indicative of the effectiveness of DE against R dominica.