JP4273225B2

JP4273225B2 - Preservation of silkworm fertilized eggs

Info

Publication number: JP4273225B2
Application number: JP2003057940A
Authority: JP
Inventors: 哲也飯塚; 啓介間瀬; 俊雄山本
Original assignee: National Institute of Agrobiological Sciences
Current assignee: National Institute of Agrobiological Sciences
Priority date: 2003-03-05
Filing date: 2003-03-05
Publication date: 2009-06-03
Anticipated expiration: 2023-03-05
Also published as: JP2004267007A

Description

【０００１】
【発明の属する技術分野】
本発明は、カイコ受精卵の保存法に関し、特に孵化サイクルがほぼ２カ年となり、孵化率が高いカイコ受精卵保存法に関する。
【０００２】
【従来の技術】
カイコには実用品種の他に、多くの保存系統と育種素材系統がある。我が国では大学や（独）農業生物資源研究所などを合わせると、遺伝資源として１０００種を越える保存系統があるほか、５００種余りの実用品種と育種素材が維持されている。それらの品種を系統保存するためには毎年一回飼育する必要がある。そのため、系統を維持・保存するためには、多大の労力、経費を要しており、その省力化が求められてきた。
【０００３】
休眠性卵（越年蚕種）は産卵後休眠に入り、翌年になって孵化してくるものである。この産卵直後から翌年孵化するまでの期間の蚕卵の取扱いを蚕種の保護と呼んでおり、この期間の保護の良否は、卵の孵化に重要な影響を与えるのみならず、交雑種では作柄や繭糸質にも影響するので、極めて重要な作業である。
【０００４】
従来の確立された蚕種保存技術としては、休眠を覚醒した活性卵の長期冷蔵法として、採種から１５ヶ月間は保護できる複式冷蔵法（例えば、非特許文献１参照。）がある。複式冷蔵法とは、図１にそのプロセスを示すように、採卵後５０〜６０日間２５℃、３０日間２０℃、約１５０日間自然温度で受精卵を保護した後、９０日間−２.５℃に置き、次いで保護中の卵をいったん高温に曝して胚子の発育段階を少し進める中間手入れを一回施し、その後２.５℃で出庫まで保護する方法であり、現在広く実用化されている。
【０００５】
卵の胚子の冷蔵に対する抵抗性は、発育段階によって異なり、最長期（丙Ｂ）の胚子が最も抵抗力が強いので、休眠から覚醒した卵を冷蔵し続けるためには、胚子の発育段階をこの丙Ｂの時期まで進め、再度冷蔵する方法を取るのが良いとされている。このように、冷蔵中の受精卵を所定の温度に一定期間接触させて、胚子の発育を丙Ｂ、好ましくは丙Ｂの少し前まで促進し、卵の冷蔵に対する抵抗性を増すため操作を中間手入れという。
【０００６】
また、いまだ研究段階ではあるが、第１代目の孵化から第２代目の孵化までが２カ年サイクルとなる受精卵の長期貯蔵で高い孵化率(交雑種1品種(宝鐘×春月)を得ることができるた方法（例えば、非特許文献２参照。）が提案されている。即ち、図２に示すように、産卵直後の高温(２５℃)保護を９０日間行い、２０℃、１５℃、１０℃、５℃の各温度にそれぞれ５日間、段階的に移して保護し、次いで２.５℃で４０日間保護し、その後−２.５℃で冷蔵する方法である。この方法では、次いで２.５℃に２０日間、５℃に３０日間置いた後、１５℃で中間手入れを６回行う。この中間手入れの開始日は、保護開始日から４３０、４７０、５１０、５５０、５９０、６１０日目であり、これらの中間手入れの各段階とも、受精卵が破壊されないようにするために初めに各中間手入れ温度よりも低い温度で予備手入れを行っている。この手入れ後の冷蔵温度は、１回目及び２回目の手入れ後は−２.５℃、３回目及び４回目の手入れ後は０℃、５回目及び６回目の手入れ後は２.５℃である。なお、上記方法において、中間手入れを１回のみ施した場合での孵化率は、最高でも保護開始後５５０日目に１回施した場合の７３.１％である。
【０００７】
【非特許文献１】
蚕種の保護取扱い指針、協同組合全国蚕種研究会発行、昭和52年11月10日、pp. 14-16
【非特許文献２】
清水・青木、蚕糸研究、1988年9月(142号)、pp. 45-51
【０００８】
【発明が解決しようとする課題】
上記従来技術の複式冷蔵法では、第１代目の飼育から次世代の飼育開始（催青着手）まで１年半程度が可能であるが、桑葉による飼育は５月中旬から１０月中旬までの時期に限られているので、実際には、晩秋に採種した卵を翌々年の春まで貯蔵・保存するのは無理であるという問題がある。
また、上記非特許文献２記載の受精卵の保存を２カ年間近く保存する方法では、細かく温度を変えたり、中間手入れを６回施すなど、貯蔵工程が極めて煩雑で手間がかかって熟練者でないと実施が困難であるばかりでなく、必ずしも一定の高い孵化率が得られていないという問題がある。
【０００９】
そのため、現在、カイコ系統保存では１年に１回は飼育して継代しているのが実情である。しかしながら、受精卵を２カ年間保存しても高い孵化率を得ることができる簡便な保存法があれば、２年に１回の飼育で系統保存が可能になり、労力も経費も半分に減少することになり、系統保存の省力化に直結する。
本発明の課題は、カイコ受精卵を冷蔵により長期間保護しても高い孵化率を有する、少なくとも２カ年孵化サイクルを有する簡便なカイコ受精卵保存法を提供することにある。
【００１０】
【課題を解決するための手段】
本発明のカイコ受精卵の保存法は、産卵したカイコ受精卵を２５℃で３０〜６０日間保護し、この受精卵を２０〜５℃の間で温度を複数回段階的に下げて各温度でそれぞれ２日間又は５日間の間段階的に保護し、その後さらに０℃で１０日間保護し、次いで０〜−２ . ５℃で３０８〜４１０日間冷蔵した後、５℃で９０日間保護して胚子を活性化させ、この胚子が活性化された受精卵に対して産卵後４８８日目から５４８日目までの期間が経過した後に、始め１０℃次いで１５℃の一連の中間手入れを１回だけ施し、その後０〜−２ . ５℃で１２０〜１８０日間再冷蔵し、最後に出庫、催青を行うことを特徴とする。
【００１１】
上記再冷蔵後に、出庫のために温度を１０℃に上げて３日間維持し、１５℃の中間温度に２日間維持し、次いで２５℃で１１日間催青を行うことを特徴とする。
【００１２】
上記したように産卵後所定の時期に中間手入れを１回施しただけでカイコ受精卵を長期にわたって冷蔵保存することができ、ほぼ２カ年サイクルで系統保存が可能となる。中間手入れをこの期間外に施すと、高い孵化率を維持したままでの２カ年サイクルの系統保存が困難となる。また、上記保護温度及び保護期間の範囲を外れると、高い孵化率を維持したままでの２カ年サイクルの系統保存が困難となる。
【００１３】
【発明の実施の形態】
以下、本発明の実施の形態を説明する。
本発明の実施の形態によれば、カイコ受精卵をほぼ２カ年保存する方法は、産卵後に採卵した受精卵を２５℃で３０〜６０日間保護し、この受精卵を２０℃、１５℃、１０℃、５℃の温度に４回段階的に移して各温度でそれぞれ２日間又は５日間、合計２０日間以下の間段階的に保護し、次いで０〜−２ . ５℃で３０８〜４１０日間保護・冷蔵した後、５ . ０℃で９０日間保護して胚子を活性化させ、この胚子が活性化された受精卵に対し、産卵後４８８日目から５４８日目までの期間が経過した後に、始め１０℃で次いで１５℃で一連の中間手入れを１回施して冷蔵に対する受精卵の抵抗性を増し、その後、０〜−２ . ５℃で１２０〜１８０日間再冷蔵する。
【００１４】
この場合、中間手入れにおいて、受精卵が破壊されないようにするためには、初めに低い温度、例えば１０℃で２日間予備手入れを行い、次いで１５℃で４日間中間手入れを行うことが好ましい。再冷蔵後、例えば、出庫のために温度を１０℃に上げて３日間維持し、１５℃の中間温度に２日間維持し、次いで２５℃で１１日間催青を行うことが好ましい。
【００１５】
本発明の保存法では、上記したように、産卵直後の高温（２５℃）保護期間を短くし、冷蔵への移行も短時間で行い、休眠打破することなく低温貯蔵している。また、低温貯蔵は０〜−２.５℃で行うことができ、中間手入れも１回とすることができるので、従来報告されている方法に比べて作業を著しく単純・簡易化することができる。
本発明によれば、受精卵の産卵後から出庫前までの上記の日数に、第１世代の孵化から産卵までの保護期間４０日間及び出庫から第２世代の孵化(催青期間)までの期間１６日間を加えれば、第１世代の孵化から第２世代の孵化までの期間がほぼ２カ年となり、２年サイクルでの系統保存が可能となる。
【００１６】
【実施例】
以下、本発明の実施例を図面を参照して説明する。
【実施例１】
表１に示す各種品種の蚕について、産卵後に、図３に示すようなプロセスを経て保護・貯蔵し、第１世代の孵化から第２世代の孵化まで系統保存を行った。即ち、第１世代の孵化から産卵までの幼虫・蛹の期間が４０日間であり、平成１１年７月５日に産卵した卵を採種し、産卵後から９月２日まで２５℃で６０日間保護し、９月３日から９月２２日まで、２０℃、１５℃、１０℃、５℃の各温度にそれぞれ５日間段階的に移して保護し、次いで１０月２日まで０℃で１０日間保護した後、平成１２年１０月４日まで−２.５℃で３６８日間冷蔵した。次いで、胚子の活性化を図るために平成１３年１月２日まで５℃で９０日間保護した後、１月８日まで１０℃で２日間及び１５℃で４日間の中間手入れを１回施し、胚子の発育を丙Ｂの少し前まで進めて受精卵の冷蔵に対する耐性を高めた。中間手入れ後、５月８日まで０℃で１２０日間再冷蔵した。その後、出庫のため１０℃で３日間維持し、１５℃の中間温度で２日間維持し、２５℃で１１日間催青を行った。出庫から中間温度を経て第２世代の孵化までの卵の催青の期間は１６日間であった。
【００１７】
実施例１の場合、第１世代の孵化から第２世代の孵化までの期間は７３０日であった。
上記プロセスにより貯蔵した後の蚕卵の孵化率は、各種品種において、以下の表１に示すような結果が得られた。
（表１）

【００１８】
表１から明らかなように、各種品種で９０％前後の高い孵化率が得られ、２カ年サイクルでの系統保存が可能となった。
また、孵化した幼虫を通常の方法で飼育して、長期貯蔵による生育や計量形質（繭重、繭層重）への影響を調べた。その結果、生育や計量形質への影響は認められず、長期貯蔵による障害等は現れなかった。
【００１９】
上記飼育の際の温度は、１〜３齢期は２７℃、４〜５齢期は２５℃を目標とし、給桑回数は１日２回とした。対照区に飼育前年の春採り蚕種を用い、飼育日数、繭重、繭層重を比較した結果、有意な差は認められなかった。
【００２０】
【実施例２】
実施例１と同様にして、第１世代の孵化から第２世代の孵化まで系統保存を行った。
平成１１年７月４日に産卵した卵を採種し、産卵後から９月１日まで２５℃で６０日間保護し、９月２日から９月２１日まで、２０℃、１５℃、１０℃、５℃の各温度にそれぞれ５日間段階的に移して保護し、次いで１０月１日まで０℃で１０日間保護した後、平成１２年８月４日まで−２.５℃で３０８日間冷蔵した。次いで、胚子の活性化を図るために１１月２日まで５℃で９０日間保護した後、１１月８日まで１０℃で２日間及び１５℃で４日間の中間手入れを１回施し、胚子の発育を丙Ｂまで進めて受精卵の冷蔵に対する耐性を高めた。中間手入れ後、平成１３年５月７日まで０℃で１８０日間再冷蔵した。その後、出庫のため１０℃で３日間維持し、１５℃の中間温度で２日間維持し、２５℃で１１日間催青を行った。出庫から中間温度を経て第２世代の孵化までの卵の催青に至る期間は１６日間であった。
【００２１】
実施例２の場合も、第１世代の孵化から産卵までの幼虫・蛹の期間が４０日間あるので、第１世代の孵化から第２世代の孵化までの期間は７３０日であった。
上記プロセスにより貯蔵した後の蚕卵の孵化率は、以下の表２に示すような結果が得られた。
また、孵化した幼虫を実施例１の場合と同様に通常の方法で飼育した結果、生育や計量形質への影響は認められず、長期貯蔵による障害等は現れなかった。
【００２２】
（参考例１）
実施例１と同様にして、第１世代の孵化から第２世代の孵化まで系統保存を行った。
平成１１年７月４日に産卵した卵を採種し、産卵後から９月１日まで２５℃で６０日間保護し、９月２日から９月２１日まで、２０℃、１５℃、１０℃、５℃の各温度にそれぞれ５日間段階的に移して保護し、次いで１０月３日まで０℃で３７８日間保護した。次いで、胚子の活性化をはかるために平成１３年１月１日まで５℃で９０日間保護した後、１月７日まで１０℃で２日間及び１５℃で４日間の中間手入れを１回施し、胚子の発育を丙Ｂの少し前まで進めて受精卵の冷蔵に対する耐性を高めた。中間手入れ後、５月７日まで０℃で１２０日間再冷蔵した。その後、出庫のため１０℃で３日間維持し、１５℃の中間温度で２日間維持し、２５℃で１１日間催青を行った。出庫から中間温度を経て第２世代の孵化までの卵の催青期間は１６日間であった。
【００２３】
参考例１の場合も、第１世代の孵化から産卵までの幼虫・蛹の期間４０日間を加えて、第１世代の孵化から第２世代の孵化までの期間は７３０日であった。
上記プロセスにより貯蔵した後の蚕卵の孵化率は、以下の表２に示すような結果が得られた。
また、孵化した幼虫を実施例１の場合と同様に通常の方法で飼育した結果、生育や計量形質への影響は認められず、長期貯蔵による障害等は現れなかった。
【００２４】
【実施例３】
実施例１と同様にして、第１世代の孵化から第２世代の孵化まで系統保存を行った。
平成１１年７月４日に産卵した卵を採種し、産卵後から８月２日まで２５℃で３０日間保護し、８月３日から８月１０日まで、２０℃、１５℃、１０℃、５℃の各温度にそれぞれ２日間段階的に移して保護し、次いで８月２０日まで０℃で１０日間保護した後、平成１２年１０月３日まで−２.５℃で４１０日間冷蔵した。次いで、胚子の活性化を図るために平成１３年１月１日まで５℃で９０日間保護した後、１月７日まで１０℃で２日間及び１５℃で４日間の中間手入れを１回施し、胚子の発育を丙Ｂまで進めて受精卵の冷蔵に対する耐性を高めた。中間手入れ後、５月７日まで０℃で１２０日間再冷蔵した。その後、出庫のため１０℃で３日間維持し、１５℃の中間温度で２日間維持し、２５℃で１１日間催青を行った。出庫から第２世代の孵化までの卵の催青期間は１６日間であった。
【００２５】
実施例３の場合も、第１世代の孵化から産卵までの幼虫・蛹の期間４０日間を加えて、第１世代の孵化から第２世代の孵化までの期間は７３０日であった。
上記プロセスにより貯蔵した後の蚕卵の孵化率は、以下の表２に示すような結果が得られた。
また、孵化した幼虫を実施例１の場合と同様に通常の方法で飼育した結果、生育や計量形質への影響は認められず、長期貯蔵による障害等は現れなかった。
【００２６】
（表２）

【００２７】
上記実施例１〜３で行ったカイコ受精卵の保存法が、複式冷蔵法等の従来の方法と最も大きく異なるところは、産卵直後からの高温(２５℃)保護期間を３０〜６０日と短くし、高温保護から冷蔵に至る期間を著しく短くし(合計２０日間以下)、胚子のエネルギー消費が少ないうちに冷蔵したことであり、また、貯蔵中の温度変化及び中間手入れ回数を格段に少なくしたことである。
【００２８】
かくして、実施例１〜３から明らかなように、中間手入れ日数、冷蔵温度、冷蔵期間、再冷蔵期間等を所定の範囲内で変動させても、産卵直後からの高温保護期間及び高温保護から冷蔵に至る期間を短くし、また、中間手入れを産卵から４８８日目から５４８日目が経過した後に施すことにより、実用的な孵化率をもって２カ年の保存期間が達成でき、系統保存上問題がないことが分かった。
また、上記実施例では、休眠打破することなく低温貯蔵し、また、低温貯蔵を０℃〜−２.５℃に固定して行い、中間手入れも１回としたので、従来報告されている方法に比べて作業を著しく単純・簡易化することができた。その結果、貯蔵工程は単純化・簡易化され、作業が容易になった。
【００２９】
【発明の効果】
本発明によれば、産卵から一定の期間経過後に中間手入れを１回だけ施すことにより、また、産卵直後からの高温保護期間を短くしかつ高温保護から冷蔵に至る期間を短くすることにより、カイコ受精卵を長期にわたって冷蔵保存することができ、ほぼ２カ年サイクルで系統保存が可能となった。そのため、現在我が国が保有するカイコの遺伝資源及び実用品種とその素材系統を維持・保存に要する労力、経費を半減できる。
【図面の簡単な説明】
【００３０】
【図１】従来の複式冷蔵法のプロセスを説明するためのグラフ。
【図２】別の従来の長期冷蔵法のプロセスを説明するためのグラフ。
【図３】本発明の実施例１の保存法のプロセスを説明するためのグラフ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preserving silkworm fertilized eggs, and particularly to a method for preserving silkworm fertilized eggs having a hatching cycle of approximately 2 years and a high hatching rate.
[0002]
[Prior art]
In addition to practical varieties, silkworms have many conservation lines and breeding material lines. In Japan, together with universities and the National Institute for Agrobiological Sciences, there are over 1000 species of conserved lines as genetic resources, and over 500 types of practical varieties and breeding materials are maintained. In order to preserve these varieties, it is necessary to raise them once a year. Therefore, in order to maintain and preserve the system, much labor and cost are required, and labor saving has been demanded.
[0003]
Dormant eggs (year-old pupa) enter dormancy after spawning and hatch in the following year. The treatment of incubation during the period from immediately after egg laying to the next year's hatching is called protection of pupae, and the quality of protection during this period not only has an important impact on egg hatching, but This is an extremely important task because it affects the quality of the silk thread.
[0004]
As a conventional established seed preservation technique, there is a double refrigeration method (see, for example, Non-Patent Document 1) as a long-term refrigeration method for active eggs that have awakened dormancy, which can be protected for 15 months after seeding. As shown in FIG. 1, the compound refrigeration method is a method of protecting a fertilized egg at a natural temperature for 50 to 60 days at 25 ° C., 30 days at 20 ° C. for about 150 days after egg collection, and then for 90 days to 2.5 ° C. This is a method in which the protected egg is once exposed to a high temperature and subjected to intermediate care once to advance the developmental stage of the embryo a little, and then protected at 2.5 ° C. until delivery, and is now widely used.
[0005]
The resistance of egg embryos to refrigeration varies depending on the stage of development, and the longest-term embryos (） B) have the strongest resistance. Therefore, in order to continue refrigeration of eggs that have been awakened from dormancy, It is said that it is better to proceed until 丙 B and refrigerate again. In this way, the fertilized egg that is being refrigerated is brought into contact with a predetermined temperature for a certain period of time, so that the development of the embryo is accelerated to 丙 B, preferably just before 丙 B, and the operation is intermediated to increase the resistance to refrigeration of the egg. It is called maintenance.
[0006]
In addition, although it is still in the research stage, a high hatching rate is obtained by long-term storage of fertilized eggs in which the hatching from the first generation to the second generation is a two-year cycle (one hybrid (various bell x spring month) is obtained) (For example, see Non-Patent Document 2.) That is, as shown in Fig. 2, high temperature (25 ° C) protection immediately after spawning is performed for 90 days, and 20 ° C, 15 ° C, It is a method of transferring to each temperature of 10 ° C. and 5 ° C. for 5 days stepwise and protecting, then protecting at 2.5 ° C. for 40 days and then refrigerated at −2.5 ° C. In this method, After 20 days at 2.5 ° C. and 30 days at 5 ° C., intermediate care is performed 6 times at 15 ° C. The start date of this intermediate care is 430, 470, 510, 550, 590, 610 from the start date of protection. It is the day, and at each stage of these intermediate cares, the fertilized egg will not be destroyed. In order to achieve this, preliminary maintenance is first performed at a temperature lower than each intermediate maintenance temperature, and the refrigeration temperature after this maintenance is −2.5 ° C. after the first and second maintenance, the third and fourth times. After the maintenance, the temperature is 0 ° C., and after the fifth and sixth times, the temperature is 2.5 ° C. In the above method, the hatching rate when the intermediate care is performed only once is 550 after the start of protection. It is 73.1% when applied once a day.
[0007]
[Non-Patent Document 1]
Species protection handling guidelines, issued by the Cooperative National Species Research Group, November 10, 1977, pp. 14-16
[Non-Patent Document 2]
Shimizu and Aoki, Sericultural Research, September 1988 (No. 142), pp. 45-51
[0008]
[Problems to be solved by the invention]
With the above-described conventional refrigeration method, it is possible to take about a year and a half from the first breeding to the start of the next generation breeding (starting blueprinting), but breeding with mulberry leaves is from mid-May to mid-October. Since it is limited in time, there is actually a problem that it is impossible to store and preserve eggs collected in late autumn until the spring of the following year.
Further, in the method of preserving fertilized eggs described in Non-Patent Document 2 for nearly two years, the storage process is extremely complicated and time-consuming, such as changing the temperature finely and performing intermediate care six times. Not only is the implementation difficult, but there is a problem that a certain high hatching rate is not always obtained.
[0009]
Therefore, the current situation is that the silkworm strains are bred and passaged once a year. However, if there is a simple preservation method that can obtain a high hatching rate even if the fertilized egg is stored for 2 years, it becomes possible to preserve the strain by breeding once every 2 years, reducing labor and cost by half. As a result, it is directly linked to labor saving of system preservation.
An object of the present invention is to provide a simple silkworm fertilized egg preservation method having a hatching cycle of at least two years, which has a high hatching rate even if the fertilized egg is protected for a long time by refrigeration.
[0010]
[Means for Solving the Problems]
The silkworm fertilized egg preservation method of the present invention protects a fertilized silkworm fertilized egg at 25 ° C. for 30 to 60 days, and lowers the temperature of the fertilized egg between 20 and 5 ° C. in a stepwise manner at each temperature. each stepwise protected during the two-day or 5 days and then further protected 10 days at 0 ° C., then was refrigerated 308-410 days 0 to-2. 5 ° C., protected at 5 ° C. 90 days embryo After a period from the 488th day to the 548th day after the laying, the fertilized egg in which the embryo has been activated is subjected to a series of intermediate care at 10 ° C and then 15 ° C only once. , then 0-2. at 5 ° C. re-refrigerated 120-180 days, finally issuing, and performs 催青.
[0011]
After the re-refrigeration, the temperature is raised to 10 ° C. and maintained for 3 days for delivery, maintained at an intermediate temperature of 15 ° C. for 2 days, and then subjected to blueing at 25 ° C. for 11 days .
[0012]
As described above , the silkworm fertilized egg can be refrigerated for a long period of time only by performing intermediate care once at a predetermined time after egg laying, and the system can be stored in a cycle of almost two years. If intermediate care is performed outside this period, it becomes difficult to preserve the system for a two-year cycle while maintaining a high hatching rate. Further, if the protection temperature and the protection period are out of the range, it becomes difficult to preserve the system for a two-year cycle while maintaining a high hatching rate .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below .
According to the embodiment of the present invention, a method for preserving silkworm fertilized eggs for approximately 2 years is to protect the fertilized eggs collected after laying eggs at 25 ° C. for 30 to 60 days. ° C., 2 days or 5 days, respectively 4 times stepwise transferred to the temperature to a temperature of 5 ° C., to protect the following during stepwise total of 20 days, followed by 0-2. protection 5 ° C. at 308-410 days · after refrigeration, 5. 0 ° C. in to activate the protection to the embryo 90 days, to embryo this embryo is activated, after a period of up to 548 days from 488 days after laying has elapsed, series of intermediate care to increase the resistance of the embryo for refrigeration subjected once with a beginning 10 ° C. then 15 ° C., then, 0-2. at 5 ° C. 120 re refrigerated to 180 days.
[0014]
In this case, in the intermediate care, in order to fertilized egg is not destroyed, initially low temperature, for example for 2 days pre-clean at 10 ° C., then it is preferable to carry out 4 days intermediate care at 15 ° C.. After re-refrigeration, for example, it is preferable to raise the temperature to 10 ° C. and maintain it for 3 days, maintain it at an intermediate temperature of 15 ° C. for 2 days, and then perform blanching at 25 ° C. for 11 days.
[0015]
In the preservation method of the present invention, as described above, the high temperature (25 ° C.) protection period immediately after egg laying is shortened, the transition to refrigeration is also performed in a short time, and low temperature storage is performed without breaking dormancy. In addition, low-temperature storage can be performed at 0 to −2.5 ° C., and intermediate care can be performed once, so that the work can be remarkably simplified and simplified as compared with a conventionally reported method. .
According to the present invention, the above-mentioned number of days from the time the eggs are laid until the time of delivery, the period from the first generation hatching to the time of egg laying for 40 days and the time from the delivery to the second generation hatching (tidal period). If 16 days are added, the period from the first generation hatching to the second generation hatching is almost two years, and the system can be stored in a two-year cycle.
[0016]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[Example 1]
The varieties of varieties shown in Table 1 were protected and stored through the process shown in FIG. 3 after laying eggs, and the strains were preserved from the first generation to the second generation. That is, the period of larvae and pupa from the first generation hatching to egg laying is 40 days, eggs laid on July 5, 1999 are collected, and from egg laying to September 2 at 25 ° C for 60 days Protect and protect from 3 September to 22 September at 20 ° C., 15 ° C., 10 ° C., 5 ° C. for 5 days, then at 10 ° C. until 2 October After protecting for days, it was refrigerated at -2.5 ° C for 368 days until October 4, 2000. Next, in order to activate the embryos, it was protected at 5 ° C. for 90 days until January 2, 2001, and then subjected to one-time intermediate maintenance for 2 days at 10 ° C. and 4 days at 15 ° C. until January 8. Then, the development of embryos was advanced a little before 丙 B to increase the resistance of fertilized eggs to refrigeration. After intermediate care, it was refrigerated at 0 ° C. for 120 days until May 8. Then, it was maintained at 10 ° C. for 3 days for delivery, maintained at an intermediate temperature of 15 ° C. for 2 days, and subjected to bluening at 25 ° C. for 11 days. The period of egg bluening from the delivery through the intermediate temperature to the second generation hatching was 16 days.
[0017]
In the case of Example 1, the period from the first generation hatching to the second generation hatching was 730 days.
As for the hatching rate of the eggs after storage by the above process, the results shown in Table 1 below were obtained for various varieties.
(Table 1)

[0018]
As is clear from Table 1, a high hatching rate of about 90% was obtained for various varieties, and the system could be stored in a two-year cycle.
In addition, hatched larvae were bred in the usual manner, and the effects of growth on long-term storage and metrological traits (spider weight, spider layer weight) were examined. As a result, no effects on growth and metrological traits were observed, and no damage due to long-term storage appeared.
[0019]
The temperature at the time of the breeding was 27 ° C. for the 1st to 3rd ages and 25 ° C. for the 4th to 5th ages, and the number of mulberry feeding was twice a day. As a result of comparing the number of days of breeding, the weight of the pupae, and the weight of the cocoon layer, no significant difference was found.
[0020]
[Example 2]
In the same manner as in Example 1, the system was preserved from the first generation hatching to the second generation hatching.
Eggs laid on July 4, 1999 are collected and protected for 60 days at 25 ° C. from egg laying to September 1; from 20 September to 21 September, 20 ° C., 15 ° C., 10 ° C. Protected by moving to 5 ° C stepwise for 5 days, then protected for 10 days at 0 ° C until October 1st, then refrigerated at -2.5 ° C for 308 days until August 4th, 2000 did. Next, in order to activate the embryos, the cells were protected at 5 ° C. for 90 days until November 2nd, and then subjected to intermediate care once at 10 ° C. for 2 days and 15 ° C. for 4 days until November 8th. Development was advanced to 丙 B to increase the resistance of fertilized eggs to refrigeration. After intermediate care, it was refrigerated for 180 days at 0 ° C. until May 7, 2001. Then, it was maintained at 10 ° C. for 3 days for delivery, maintained at an intermediate temperature of 15 ° C. for 2 days, and subjected to bluening at 25 ° C. for 11 days. The period of time from delivery to intermediate temperature and egg bluening from the second generation to hatching was 16 days.
[0021]
Also in Example 2, the period from the first generation hatching to egg laying was 40 days, so the period from the first generation hatching to the second generation hatching was 730 days.
As shown in Table 2 below, the hatching rate of the eggs after storage by the above process was obtained.
Further, as a result of breeding the hatched larvae by the usual method in the same manner as in Example 1, no effects on growth and quantification traits were observed, and no damage due to long-term storage appeared.
[0022]
( Reference Example 1 )
In the same manner as in Example 1, the system was preserved from the first generation hatching to the second generation hatching.
Eggs laid on July 4, 1999 are collected and protected for 60 days at 25 ° C. from egg laying to September 1; from 20 September to 21 September, 20 ° C., 15 ° C., 10 ° C. Protection was achieved by stepping to each temperature of 5 ° C. for 5 days, and then protecting at 0 ° C. for 378 days until October 3. Next, in order to activate the embryos, it was protected for 90 days at 5 ° C. until January 1, 2001, and then subjected to one-time intermediate treatment for 2 days at 10 ° C. and 4 days at 15 ° C. until January 7. Then, the development of embryos was advanced a little before 丙 B to increase the resistance of fertilized eggs to refrigeration. After intermediate care, it was refrigerated at 0 ° C. for 120 days until May 7. Then, it was maintained at 10 ° C. for 3 days for delivery, maintained at an intermediate temperature of 15 ° C. for 2 days, and subjected to bluening at 25 ° C. for 11 days. The egg-bluening period from delivery to intermediate temperature to second generation hatching was 16 days.
[0023]
In the case of Reference Example 1 as well, the period from the first generation hatching to the egg-laying period was 40 days, and the period from the first generation hatching to the second generation hatching was 730 days.
As shown in Table 2 below, the hatching rate of the eggs after storage by the above process was obtained.
Further, as a result of breeding the hatched larvae by the usual method in the same manner as in Example 1, no effects on growth and quantification traits were observed, and no damage due to long-term storage appeared.
[0024]
[Example 3 ]
In the same manner as in Example 1, the system was preserved from the first generation hatching to the second generation hatching.
Eggs laid on July 4, 1999 were collected and protected for 30 days at 25 ° C. from egg laying until August 2, and from August 3 to August 10, 20 ° C., 15 ° C., 10 ° C. Protected by transferring to each temperature of 5 ° C stepwise for 2 days, then protected for 10 days at 0 ° C until August 20, then refrigerated at -2.5 ° C for 410 days until October 3, 2000 did. Next, in order to activate the embryo, it was protected at 5 ° C. for 90 days until January 1, 2001, and then subjected to one-time intermediate maintenance for 2 days at 10 ° C. and 4 days at 15 ° C. until January 7. Then, the development of embryos was advanced to 丙 B to increase the tolerance of the fertilized eggs to refrigeration. After intermediate care, it was refrigerated at 0 ° C. for 120 days until May 7. Then, it was maintained at 10 ° C. for 3 days for delivery, maintained at an intermediate temperature of 15 ° C. for 2 days, and subjected to bluening at 25 ° C. for 11 days. The egg bluening period from shipping to second generation hatching was 16 days.
[0025]
In the case of Example 3 as well, the period from the first generation hatching to the second generation hatching was 730 days, with the addition of the 40th larvae / pupil period from the first generation hatching to egg laying.
As shown in Table 2 below, the hatching rate of the eggs after storage by the above process was obtained.
Further, as a result of breeding the hatched larvae by the usual method in the same manner as in Example 1, no effects on growth and quantification traits were observed, and no damage due to long-term storage appeared.
[0026]
(Table 2)

[0027]
The place where the preservation method of the silkworm fertilized eggs carried out in Examples 1 to 3 is most different from the conventional methods such as the double refrigeration method is that the high temperature (25 ° C.) protection period immediately after egg laying is as short as 30 to 60 days. However, the period from high temperature protection to refrigeration was significantly shortened (20 days or less in total), and the embryos were refrigerated while the energy consumption was low, and the temperature change during storage and the number of intermediate care were greatly reduced. That is.
[0028]
Thus, as is clear from Examples 1 to 3 , even if the intermediate maintenance days, refrigeration temperature, refrigeration period, re-refrigeration period, etc. are varied within a predetermined range, refrigeration from the high temperature protection period and high temperature protection immediately after spawning By applying the intermediate care after the 488th to 548th days after egg laying , a two-year preservation period can be achieved with a practical hatching rate, and there is no problem in system preservation. I understood that.
Moreover, in the said Example, since it carried out low-temperature storage without breaking dormancy, and low-temperature storage was fixed to 0 degreeC--2.5 degreeC, and the intermediate care was also carried out once, the method reported conventionally Compared to, work has been remarkably simplified and simplified. As a result, the storage process has been simplified and simplified, and the work has become easier.
[0029]
【The invention's effect】
According to the present invention, by performing intermediate care only once after a certain period of time has elapsed since egg laying, and by shortening the high temperature protection period immediately after egg laying and shortening the period from high temperature protection to refrigeration, Fertilized eggs can be stored refrigerated for a long period of time, and strains can be stored in almost two-year cycles. Therefore, the labor and cost required for maintaining and preserving silkworm genetic resources and practical varieties and their material lines currently owned by Japan can be halved.
[Brief description of the drawings]
[0030]
FIG. 1 is a graph for explaining a process of a conventional double refrigeration method.
FIG. 2 is a graph for explaining another conventional long-term refrigeration process.
FIG. 3 is a graph for explaining the process of the preservation method according to the first embodiment of the present invention.

Claims

The fertilized silkworm fertilized eggs are protected at 25 ° C. for 30 to 60 days, and the temperature of the fertilized eggs is gradually decreased between 20 to 5 ° C., and each temperature is gradually increased for 2 or 5 days. protected, then further protective 10 days at 0 ° C., then was refrigerated 308-410 days 0~-2. 5 ℃, embryo to activate the protected at 5 ° C. 90 days, the embryos are activated and after a period of up to 548 days from 488 days after laying has elapsed relative fertilized, subjected only once a series of intermediate care began 10 ° C. then 15 ° C., thereafter 0~-2. 5 ℃ 120 A method for preserving silkworm fertilized eggs, which is re-refrigerated for 180 days, and is finally shipped and bluish .

2. The method for preserving silkworm fertilized eggs according to claim 1, wherein after the re-chilling, the temperature is raised to 10 ° C. and maintained for 3 days for delivery, maintained at an intermediate temperature of 15 ° C. for 2 days and then at 25 ° C. for 11 days. A method for preserving silkworm fertilized eggs characterized by performing day-to-day treatment .