Phenotypic Expression of Whitebacked Planthopper Resistance in the Newly Established japonica/indica Doubled Haploid Rice Population

A new doubled haploid (DH) rice population was established from a cross between WBPH-resistant japonica Chunjiang 06 (CJ-06) and susceptible indica TN1. Sucking inhibitory and ovicidal resistance of the DH rice lines were evaluated on the basis of non-preference response of WBPH immigrants and honeydew excretion by WBPH females, and appearance of watery lesions in the necrotic discoloration of leaf sheaths ovipositied by WBPH,respectively. Both the major gene resistance to WBPH, sucking inhibitory and ovicidal resistance, showed 1 (resistant): 1 (susceptible) segregation ratio in the DH population. Relative density of WBPH populations and damage scores in the DH population indicated combined functions of both the major resistance genes as well as QTLs affecting the host plant response to WBPH infestations. Thus, the newly developed CJ-06/TN1 DH population could be a useful material to analyze major genes and QTLs for WBPH resistance in japonica rice.

Differential Expression of Whitebacked Planthopper Resistance in the japonica/indica Doubled Haploid Rice Population under Field Evaluation and Seedbox Screening Test

Whitebacked planthopper (WBPH) -resistance in a japonica / indica doubled haploid (DH) rice population established from a cross between WBPH-resistant japonica Chun]iang 06 and susceptible indica TN1, was comparatively evaluated through a field experiment based on the WBPH immigrant density and standardized seedbox screening test (SSST). All the susceptible DH lines in the field experiment behaved accordingly in SSST. However, 35 of resistant 66 lines (53%) in the field, were categorized to susceptible groups in SSST. Likewise, there were no significant differences in WBPH immigrant densities among 70 DH lines that were highly resistant to susceptible in SSST. The results revealed that SSST could not evaluate properly WBPH resistance in the DH lines. Four QTLs for WBPH-resistance phenotyped by the immigrant density were detected on chromosomes 2, 3, 4, and 11. Of them, the QTL on chromosome 4 was the most effective (LOD 21.8, variance 78%). Five QTLs associated with seedling mortality were mapped on chromosomes 2, 3, 4, 5 and 6. In addition to the QTL (LOD 10.5, variance 68%) on chromosome 4, there was another major QTL (LOD 12.7, variance 71%) located on chromosome 5, which was SSST-specific but might be irrespective of the WBPH resistance traits.

Study on the Funcitonal Peptides in Low Salt Sufu Making

Sufu in this project was prepared with Actinomucor elegans (CICC-3318)as the starter and with soybean as the material.Different with the sufu with 10% salt produced by traditional process,a sufu product with 6% salt was produced in this project by reducing the salt content in salting process.To determine peptides,the water-soluble extracts obtained saparetly from frozen dried powders of soybean,tofu,pehtze pehtze and sufu ripening for 50 days were analyzed by high-pressure lipid chromatography (HPLC).Antioxidative activity and antihypertensive activity of the extract due to the peptides contained were evaluated respectively by radical scavenging ability and angiotensin converting enzyme (ACS) inhibitory activity.According to the HPLC patterns,the peptides content was nearly zero in soybean and tofu,but increassed gradually during maturing in the further process of making pehtze,salted pehtze and final product sufu,Correspondingly,the antioxidative and antihypertensive activities of the extracts strengthened with maturing.For our product,sufu with 6% salt,the antioxidative and antihypertensive activities reached peak values at about 30 d maturing,and still remained medium values in final product sufu.In comarison,the antioxidative and antihypertensive activities for the sufu with 10% salt reached peack values at 40 d maturing,but remained medium values inferior to those for the sufu with 6% salt.

Virulence of the Populations of the Whitebacked Planthopper, Sogatella furcifera Reared on Different Resistant Rice Varieties

ARC and ND colony were obtained by rearing the whitebacked planthopper (WBPH), Sogatella furcifera (Horvath), exclusively on ARC10239 (ARC, carrying resistance gene Wbph2) and N'Diang Marie (ND, carrying resistance gene Wbph5) till 15 generations. Taichung Native 1 (TN1) and Rathu Heenati (RHT) served as susceptible and resistant check, respectively. The results of electronic recording revealed that duration of salivation and X-waveform of the two colonies on their corresponding hosts was short while the duration of phloem ingestion was long. The amount of honeydew excreted by ARC and ND colony did not differ on their corresponding host varieties from TN1 and was much higher than that of RHT. The number of eggs laid on their host varieties and TN1 were significantly higher than that on RHT. No distinct change was observed for these two colonies in term of percentage of developed eggs. The nymph survival rate of ND colony on its selection host was 45.0%, significantly different from that on TNI(71.4%) and RHT(21.0%), while that of ARC colony was 68.3%, not significantly different from that on TN1 (77.5%), but much higher than that on RHT(22.6%). The nymphal development duration of these two colonies on the corresponding hosts was not different from that on TN1, but significantly shorter than that on RHT. In brief, these two colonies had almost adapted to their corresponding host varieties based on feeding and oviposition, but the nymphal survival rate of ND colony was still low.

农业研究与推广对尼日利亚农业增长的影响（1981-2002）

本文根据农业研究与推广等一系列指标分析了尼日利亚农业增长的影响因素。作者运用主成分分析方法从22个指标中筛选出农业推广服务经费、农业占财政预算支出的比重、农业人口、耕地及多年生作物用地面积和农业人口人均经费等5个指标用于分析农业增长。根据多元回归分析结果，作者提出增加农业推广服务经费并进行适当监督、促进财政预算向农业的有效分配、增加农业人口人均经费等措施将有助于尼日利亚的农业增长。