利用游离小孢子培养育成早熟大白菜新品种‘豫新5号’

 ‘豫新5号’是采用游离小孢子培养双单倍体育种技术选育的一代杂种，该品种生育期60 d，单球质量23 kg，球形指数1.35，高抗病毒病、霜霉病和软腐病，净菜产量56.7 t·hm^-2，可兼作早熟、晚熟栽培。     

变叶海棠种群多样性的形成与分化研究

 采用杂种指数和形象化散点图法, 探明了变叶海棠以兼性无融合生殖方式与陇东海棠和花叶海棠产生渗入杂交变异, 又以无融合生殖方式保持新产生变异的遗传, 经过数千万年的世代繁衍,形成现今这样极其复杂多样的渗入杂交群体, 该群体为3 个种的杂交复合体。由于杂种的全部或部分能育子代中发生的基因重组和增加基因的突变, 丰富了物种的基因库, 从而深入的揭示了变叶海棠具有多种高抗性的遗传机理。在变叶海棠居群内保护或栽植适量的陇东海棠和花叶海棠, 对于保持和促进变叶海棠多样性的形成与分化具有重要意义。     

适宜设施栽培番茄新品种——渝红6 号

 ‘渝红6号’番茄是新育成的一代杂种, 自封顶类型, 生长势强, 叶片肥大, 叶色浓绿, 不卷叶, 不早衰; 果面光滑, 无绿果肩, 成熟果红色, 平均单果质量230 g; 可溶性固形物含量5. 24%, 维生素C 含量0. 181 mg / g; 皮厚, 耐贮运; 中抗TMV, 抗枯萎病; 耐低温, 耐弱光; 适宜长江流域早熟大棚栽培和春秋露地栽培。     

杜鹃花新品种‘朝晖’和‘红晕’

 ‘朝晖’杜鹃花是由大白花杜鹃和马缨花杂交选育而成, 叶面灰绿色, 顶生圆锥伞房花序, 有花10～12 朵, 花冠紫红色。‘红晕’杜鹃花是由露珠杜鹃和马缨花杂交选育而成, 叶浅绿色, 花冠漏斗状钟形, 花冠上部粉红色, 下部乳黄色, 有紫红色斑点。     

Inconspicuous restraint of rice seedling growth by root-infecting fungi in soil of a rice paddy field

 Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could occur in soils of rice paddy fields. Received: May 20, 2002 / Accepted: October 16, 2002 Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance.     

优质白菜新品种‘暑绿’

 ‘暑绿’系白菜一代杂种，亲本为SW-13和SU-124(矮×苏)。该品种株型直立、束腰，叶片近圆形、翠绿色，叶柄半圆、绿白色。品质佳，株型美观，叶片与叶柄质量比值为0.67，单株质量0.40 kg。高抗炭疽病，抗TuMV、霜霉病和黑斑病。适宜在喜食青梗菜的地区作夏菜、秋菜和秋冬菜栽培。     

利用雄性不育两用系配制的辣椒一代杂种‘冀研8号’

 ‘冀研8号’是利用甜椒雄性不育两用系AB91-8为母本，以优良辣椒自交系L16-2为父本配制成的杂交一代辣椒新品种。该品种早熟，果实牛角形，商品性好，单果质量70 g，味辣，抗病毒病，较抗疫病，适宜华北地区春季塑料大拱棚和露地地膜覆盖栽培，产量49．6～63．6 t／hm 。     

披碱草和野大麦杂种F1与BC1F1代的生物学及农艺特性研究

对披碱草和野大麦及其杂种F1与BC1F1代的生物学及农艺特性进行了分析比较。结果表明,亲本野大麦生长发育节律较快,较早地开花结实,果后营养期较长,生育期74d,生长天数达206d,具有很强的分蘖能力;披碱草生长发育节律较慢,生育期124d,生长天数193d;杂种F1的生长天数介于双亲之间,生长动态偏向亲本披碱草,分蘖能力介于双亲之间;BC1F1代生长发育节律较F1代提早,不同株系生长天数不同,生长动态偏向轮回亲本野大麦,分蘖能力有较大的变异。杂种F1代表现出较强的杂种优势,BC1F1代产草量较F1代有所降低,不同株系间存在明显的差异。总体上,BC1F1代的生产性能倾向于轮回亲本野大麦。     

Wind-mediated spread of Rice yellow mottle virus (RYMV) in irrigated rice crops

A study was carried out to demonstrate that Rice yellow mottle virus (RYMV), a virus known to be transmitted by beetles, can spread between rice plants by direct leaf contact caused by wind. Almost all healthy plants surrounding an infected plant became infected when exposed to a fan blowing for 15 min at a distance of 50 cm. Spread of RYMV by plant contact, mediated by wind, was also demonstrated in field experiments, the extent of spread depending on plant density. Infection was almost 10 times higher in plots with a density of 33 plants m⁻² than in plots with 16 plants m⁻². Less spread was observed in plots protected by 1·5 m high windscreens. It is suggested that wind-mediated spread of RYMV may result from abrasive contact between leaves of plants.     

施肥和刈割日期对杂交狼尾草钙、磷、镁含量的影响及其与家畜需要的关系

研究了不同施肥处理和刈割日期对杂交狼尾草Ca、P和Mg含量的影响及其与家畜营养的关系,结果表明,有机肥的施用显著降低了植株Ca含量,对植株P和Mg含量无显著影响;随无机氮施用水平的提高,杂交狼尾草植株Ca和Mg含量显著提高,P含量显著降低;植株Ca、Mg含量均随刈割日期的推迟而显著提高,植株磷含量随刈割日期的推迟呈先降后升的规律;根据NRC推荐的饲养标准(奶牛、肉牛和绵羊),所有处理杂交狼尾草植株Mg含量均能满足家畜的需要,Ca:P为(0.95～2.67):1;利用杂交狼尾草饲喂高产奶牛时,应注意日粮中Ca、P的添加.