控制种子发芽技术对玉米抢墒早播后出苗率和粉种率的影响

通过在玉米顶凌播种的条件下,运用控制种子发芽技术,对玉米种子粉种和保全苗情况进行研究。结果表明,运用高分子包衣剂处理的种子与同期裸种相比有较强的抗″粉种″和提高出苗率作用。

Application Effects of Ultra-fine Powder Shaped Maize Seed Coating Agent in Spring Sowing areas in northeast China

The research explored adaptability maize seed coating agent in spring sowing and effects of ultra-fine powder shaped areas in northeast China. The results showed that germination potential and rate both improved around 5% and the num- ber of root increased by 4% in the treatments with ultra-fine powder shaped maize seed coating agent compared with the control group without seed coating. What＇s more, the treatments with ultra-fine powder shaped maize seed coating agent took advantages in terms of fresh weight of seeding, stem diameter, and dry weight. It is notable that control effects on underground insects performed the best, with per- centage over 94%, which is more excellent relative to other agents in markets. Therefore, ultra-fine powder shaped maize seed coating agent can be widely applied in spring sowing areas in northeast China, without side effects.

Analysis of Fertility Differences of Peiai 64S in Hunan and Hainan

[Objective] The purpose was to study and analyze the difference of Peiai 64 S fertility expression in two different climatic regions, Hainan and Hunan in 2010, and confirm the suitable region for its production of hybrid seeds. [Method] Eight sowing times were designed, March 20 and 30, April 10 and 30, May 15, June 1, 10 and 20, respectively in Changsha of Hunan. Thirteen sowing times were designed in Hainan, January 28, February 12 and 27, March 14 and 29, April 13 and 28, May 13 and 28, June 12, July 1, 12 and 27, respectively. Peiai 64S was gradually managed and recorded heading stage during cultivation, and the effects of different climate influencing factors, such as daily mean temperature, daily maximum temperature, daily minimum temperature, duration of day at 0-25 d before heading （namely pollen mother cell meiophase）, on pollen fertility were analyzed to confirm sensitive periods of light and temperature. [ResuLt] There was a big difference in sensitive period among the same cytoplasmic male sterile （CMS） in different climatic regions. The sensitive period of Peiai 64S was in first four phases, phases V, VI, VII, VIII （0-13 d） in Changsha of Hunan, which was in last four phases, phases I, II, III, IV （13-25 d） in Haikou of Hainan. Under natural conditions, Peiai 64S pollen sterility rate were all more than 99.5% and seed-setting rates all less than 0.5% in Haikou, so production of hybrid seeds was safe. Its pollen sterility rate was 21.3%- 100.0% in Hunan, so its security coefficient of hybrid seeds production was lower than that in Hainan. [Conclusion] The security coefficient of hybrid seeds production of CMS Peiai 64S is lower than that in Hainan.

Replacement of Fish Meal with Graded Levels of Earthworm Meal in the Diet of Fingerlings： Effect on Feed and Growth Parameters

The study was aimed at evaluating growth response of Heteroclarias fingerlings fed diet in which fish meal was substituted with graded levels of earthworm meal. The replacement levels were 0.00%, 25%, 50%, 75% and 100% designated as Eo, E25, Es0, E75 and El00, respectively. Fingerlings used for the work were obtained through artificial insemination of brood stock （purchased from local farmers） with ovaprim in the laboratory. The resulting fry were reared and fed with cultured plankton for 2 weeks followed by 100% fish meal for another two weeks. Thereafter sixteen fingerlings weighing 4.73 g and measuring 6.512 mm standard length （on the average） were starved over night and reared in five indoors tanks （0.8 ~ 0.5 ~ 0.5 m） in duplicate for eight weeks. Fingerlings were fed on graded earthworm meals of 40% protein twice daily at 08：00 and 16：00. The highest mean weight （6.77 g）, specific growth rate （0.86） and protein efficiency ratio （0.6） were obtained at 50% replacement level. Also, Food conversion ratio was the highest at 50% substitution level and lowest at 0.00% substitution, indicating that fingerlings use earthworm containing meal more efficiently. Furthermore, cost benefit analysis revealed that the profit index for 50% inclusion of earthworm meal was the highest （1.71） and the highest net profit of N374.32 （circa $2.3） was achieved at this level. Water quality parameters observed were within tolerable values for the fingerlings well being. Consequently, farmers are advised to use 50% earthworm meal in place of fish meal for formulation of Heteroclarias fingerlings diet. This will drastically reduce production cost, increase farmers profit and enhance the biological value of our menu.

EFFECT OF TEMPERATURE ON THE DEVELOPMENT AND REPRODUCTION OF BEMISIA TABACI B BIOTYPE (HOMOPTERA:ALEYRODIDAE)

The development, survivorship and reproduction of Bemisia tabaci B bi otype on eggplant at seven constant temperatures (17, 20, 23, 26, 29, 32 and 35℃) were studied. The developmental periods from egg to adult varied from 48.7 days at 17℃ to 13.9 days at 29℃ and the develo pmental threshold estimated for a generation by linear regression was 12.4℃. The optimum temperature for B. tabaci population growth was 26℃, both extremely low (<17℃) and high temperature (>32℃) delayed the de velopment. Survivorships from egg to adult was 67.3 % at 26℃, 27.6 % and 29.0 % at 35℃ and 17℃ resp ectively. The average longevity of females ranged from 39.6 days at 20℃ to 12.8 days at 35℃. Ovipo sition per female varied from 164.8 eggs at 20℃ to 78.5 eggs at 32℃. Both the longevity and oviposition of B. tabaci females at different temperatures were significantly different ( P < 0.05), and the intrinsic rate of natural increase ( r m ) for B. tabaci at 29℃ was the highest.