光敏核不育水稻选育与利用的几个问题讨论

对现有光敏核不育材料进行了分类,分为４种遗传类型;其中,温光弱感到光敏核不育系是最为理 想的遗传工具,并就其选育途径和选择“粳不籼恢”繁殖制种技术体系进行了论证．     

暗期间断对光敏感雌性不育苎麻活性氧代谢的影响

在短日照(10 h/d)处理的光敏感雌性不育苎麻的暗期进行红光和远红光间断暗期的处理,并对叶片和雌性花器官的活性氧相关酶的活性和膜脂过氧化产物丙二醛(MDA)含量测定。结果表明,红光处理诱导雌性败育,远红光处理则雌性可育。败育株叶片的过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性均高于可育株,但败育节位的MDA含量较低;败育株各节花蕾中POD活性较高,正在发育雌蕾的SOD和CAT活性亦高于可育株,但在败育节位下降到可育株水平,MDA含量则升高并超过可育株。暗示光敏色素调节了雌花活性氧代谢的失衡,而且与诱导雌性败育相关。     

光敏小麦雄性不育系A31的育性变异及遗传研究

通过不同生态点的育性试验,观察了光敏小麦雄性不育系A31的育性变异,并结合各试验点的光温条件,分析了A31在7个不同生态点的自交结实率。结果表明,A31雄性育性随日长增加有明显的下降趋势,日长是影响其育性的主导因素,在相近日长条件下,温度对A31育性也有一定的影响;A31育性转换的临界日长约为14.5h。对光敏雄性不育系A31与恢复系1376杂交F2分离群体育性的研究表明,582株F2分离群体的平均结实率为42.16%,变异范围为0～86.67%,由于受异源胞质的影响,F2群体中可育株的平均自交结实率低于恢复系1376的平均结实率。卡方测验表明,F2群体的育性分离符合1对基因的分离比例,所以A31光敏育性可能是由1对基因所控制。     

粳型短光敏核不育系5021S育性基因的定位

以育性转换表现为"长光高温下可育,短光低温下不育"反(向)光、温敏核不育种质5021S为材料,5021S与轮回422杂交组合F2作为遗传群体进行育性相关基因的QTL定位,利用124对SSR标记构建了一张全长1 912.3 cM平均图距为14.98 cM的饱和分子连锁图谱。利用Windows QTLCartographer2.5软件,在全基因组范围内检测到4个控制育性相关性状的QTLs位点,分别位于第2、第3、第5、第7染色体上,单个QTL可解释4.5%～32.5%表型变异。其中位于第2染色体上RM5804与RM425之间的qpms-2贡献率为32.5%,第3染色体RM130与RM3405之间的qpms-3贡献率为16.1%。表明5021S的核不育性受2对隐性主基因控制,同时受微效基因调控。     

Factors responsible for levels of male sterility in photoperiod-sensitive cytoplasmic male sterile (PCMS) wheat lines

A `two-line system' using photoperiod-sensitivecytoplasmic male sterility (PCMS) caused by Aegilops crassa cytoplasm has been proposed as a newmeans of producing hybrid wheat. The PCMS line ismaintained by self-pollination under short-dayconditions (14.5 h light period), and F<sub>1</sub> seedscan be produced by outcrossing of the PCMS line witha pollinator under long-day conditions (15 h lightperiod). As the levels of male sterility in PCMSlines under the long-day conditions is a crucialfactor in determining hybrid purity of the F<sub>1</sub>seeds, a study was conducted into the effect ofseeding rate on male sterility in PCMS lines. Threedifferent density levels were tested using analloplasmic line of Japanese wheat cultivar `Norin 26'which exhibits PCMS. Levels of male sterility of thePCMS line increased at sparse planting, because tiller(ear) number per plant increased at low seedingdensity and late-appearing ears tended to exhibithigher levels of male sterility than early-appearingears. On the other hand, male sterility levels of thePCMS lines depended on genotype, e.g., the PCMS`Fujimikomugi' was completely male sterile, whereasthe PCMS `Norin 26' showed partial male sterility. APCMS line showing complete male sterility, such as thePCMS `Fujimikomugi', should produce F<sub>1</sub> seeds withhigh purity. However, the PCMS `Fujimikomugi' showeda lower female fertility. For practical use, it isnecessary to produce PCMS lines having high malesterility with high female fertility under long-dayconditions.     

苎麻光敏感雌性不育性的遗传分析初报

光周期敏感雌性不育苎麻(PFSR)的4个姊妹系自交或相互杂交,后代不育株和可育株呈13S押3F分离,符合两对基因遗传规律,其中一对为抑制基因,雌性不育基因为隐性,假定PFSR基因型为IiF-phfph。但光钝感雌雄同株苎麻(NM)与PFSR杂交F1代呈3S押5F的分离,而不是所预测的1S押1F的分离,说明与光周期钝感有关的质基因和核基因存在互作。本研究对PFSR及其有关子代的基因型作了初步分析。     

关于植物各种光温反应现象的统一模型

本文提出了一个统一的植物光温反应理论模型。它把植物的各种光温反应现象,包括短日植物的光温反应与长日植物的光温反应,定性的光温反应与定量的光温反应,光周期反应与温度反应,以及温度反应中的低温反应(包括春化反应)与积温反应等统一了起来。应用这一模型可对小麦生长发育中常见的各种光温反应现象和水稻光敏不育系的低温可育现象作出统一的解释。