亚种间杂交稻籽粒充实率表现及其配合力

以５个典型的粳型广亲和材料和５个典型籼稻品种为亲本，按ｐ×ｑ模式配组出２５个亚种间杂交组合，分析亚种间杂交稻籽粒充实率和受精率，结果表明：（１）亚种间杂交稻不同基因型籽粒充实率和受精率间不存在显著相关，是２个独立表现的性状。（２）籽粒充实不良的表现具有全穗性，但籽粒充实率在不同粒位间存在一定的差异，上位＞中位＞下位。（３）供试各父母本的籽粒充实率的一般配合力效应具有显著差异，各供试组合的特殊配合力效应亦达显著水平。在亚种间杂交稻的籽粒充实率的遗传中，加性效应和非加性效应相互独立，共同决定其性状表现。试验证明通过遗传改良提高亚种间杂交稻的籽粒充实率是完全可能的，选配得当可得到籽粒充实率和受精率俱高的优良亚杂组合。     

氮素水平对不同基因型小麦旗叶光合特性和子粒灌浆进程的影响

在池栽条件下，研究了不同施氮水平对强筋小麦8901和弱筋小麦1391生育后期旗叶叶绿素含量、光合速率、灌浆速率和产量的影响。结果表明，两品种表现为随施氮量的增加，叶绿素含量、光合速率都有增加的趋势，但是过量氮肥又使它们降低。在本试验条件下，两品种均以中氮处理(240kg／hm^2)光合速率大，灌浆进程合理，产量水平高。研究发现，强筋和弱筋小麦生育后期叶光合特性和子粒灌浆进程差异显著；旗叶光合速率和叶绿素含量及子粒产量呈正相关。     

化杀杂种小麦灌浆规律及粒重优势

对化杀杂种小麦灌浆特性及播期、密度、灌水效应的研究表明，其灌浆规律与常规（亲本）品种相同，籽粒增重遵循慢—快—慢的节律变化，同时具有自己的特性。杂种的快速增重期较对照早１～３天，灌浆速度峰值超对照优势达２４．７１％～４６．３４％，且持续时间长，灌浆速度的峰面宽，因而单粒重比对照高６～１１ｍｇ，但不同部位小穗间的粒重差异依然存在，且较对照大。杂种的灌浆特性与亲本有关，但仍表现出明显的超亲优势。播期、密度、灌水等影响灌浆进程，因而可通过亲本选配、强优势组合筛选及农艺措施调节进一步发挥杂种的粒重优势     

Development of common bean (Phaseolus vulgaris L.) lines resistant to the bean pod weevil,Apion godmani Wagner,in Central America

Summary The larva of the bean pod weevil (BPW), Apion godmani Wagner (Coleoptera: Curculionidae), causes serious yield losses in common bean (Phaseolus vulgaris L.) in Mexico and Central America, by consuming the seed as it develops in the immature pod. Resistance to the BPW was identified in bean germplasm of highland Mexican origin, and these sources of resistance were incorporated into a pedigree breeding program to recover locally adapted lines resistant to Bean Common Mosaic Virus and BPW, with commercial grain for Guatemala, Honduras and El Salvador. These lines yielded as well as or better than local cultivars in the absence of the insect, and better than local cultivars when the BPW was present. Resistance appeared to be governed by several genes, and was stable across geographic areas, seasons and planting systems.     

用Richards方程模拟三个典型小麦品种的灌浆过程

Richards方程能较好地模拟小麦子粒的灌浆过程.大粒饱满品种鄂恩1号子粒灌浆活跃期长,灌浆后期子粒增重势头旺盛;大粒不饱满品系“95A-10“子粒灌浆活跃期短,光合产物供应不足,“流“不通畅是限制子粒增重的主要因素;小粒饱满品种华麦8号的灌浆特性介于二者之间.鄂恩1号、“95A-10“为强、弱势子粒灌浆同步型品种;鄂恩1号的灌浆曲线偏左,“95A-10“的灌浆曲线偏右.华麦8号为强、弱势子粒灌浆异步型品种.     

产量15 000 kg·ha-1以上夏玉米灌浆期间的光合特性

【目的】探讨产量15000kg·ha-1以上夏玉米籽粒灌浆期的光合特性及其与产量形成的关系。【方法】在多年高产试验基础上,选用3个具有高产潜力的玉米杂交种,采用78000株/ha的密度大田种植。以地上生物量及其分配、果穗叶的光合特征参数来评价产量15000kg·ha-1以上的夏玉米光合生理活性;以Richards模型拟合籽粒灌浆过程。【结果】3个玉米杂交种均可实现15000kg·ha-1以上的高产,以先玉335(XY335)产量最高。对籽粒产量形成的Richards解析表明,籽粒灌浆启动快且高灌浆速率持续时间和生长活跃期(50d以上)长的杂交种更容易实现高产。产量15000kg·ha-1以上3个杂交种表现出灌浆前期净光合速率、PEPCase活性和RuBPCase活性较高,后期净光合速率、叶面积指数和可溶性蛋白含量下降缓慢的特点,整个灌浆期间叶绿素a/b比值始终较高。3个杂交种中XY335叶片光合生理活性最高,净光合速率和叶面积的高值持续期分别达50d和60d以上。【结论】在玉米高产高密度栽培条件下,重视叶片的光合生理活性的改善可提高光能利用效率,维持较高灌浆速率和较长活跃生长期,实现15000kg·ha-1以上的高产目标。     

花生播种机内侧充种式排种器设计与试验

花生播种机核心部件排种器是影响花生播种质量的关键,在很大程度上决定花生的产量。针对播种过程中空穴、漏播率较高的不足,通过分析花生排种器的排种过程,研究设计了内侧充种垂直圆盘排种器。基于课题组自主研发的排种器试验台进行了排种性能、护种板排种器及伤种试验。通过优化排种器结构参数,提升了排种器的排种性能。     

Manipulation of ruminal fermentation and methane production by supplementation of rain tree pod meal containing tannins and saponins in growing dairy steers

Four rumen‐fistulated dairy steers were used in a 2 × 2 factorial arrangement in a 4 × 4 Latin square design. The main factors were two roughage‐to‐concentrate ratios (R:C, 60:40 and 40:60) and two supplementation levels of rain tree pod meal (RPM) [0 or unsupplemented and 60 g/kg of total dry matter (DM) intake]. Chopped 30 g/kg of urea‐treated rice straw was used as a roughage source. All animals received dietary according to respective R:C ratios at 25 g/kg body weight. The RPM contained condensed tannins and crude saponins at 84 and 143 g/kg of DM respectively. It was found that total volatile fatty acids (VFAs) and propionate concentrations were increased (p < 0.01), while acetate concentration, acetate‐to‐propionate ratio, CH₄ production and protozoal numbers were decreased (p < 0.01) when steers were supplemented with RPM and 600 g/kg of concentrate. Allantoin excretion was found different by both R:C ratio and supplementation of RPM, with the highest value at R:C of 40:60 with 60 g/kg RPM (123.6 mmol/day) (p < 0.05). Allantoin absorption and microbial crude protein were increased (p < 0.05) with an increasing concentrate ratio. Moreover, efficiency of microbial protein synthesis was increased (p < 0.05) by feeding a higher ratio of concentrate (R:C 40:60) and supplementation of RPM. Based on this study, it is suggested that supplementation of RPM was beneficial for dairy cows fed on high roughage ratio, which could improved rumen fermentation by reducing fermentation gas loss, thus improving VFA profiles and thus enhancing efficiency of microbial protein synthesis.     

不同种植方式和密度对玉米子粒灌浆速率的影响

以紧凑型品种郑单958为试验材料,在2种不同种植形式(传统小垄、大垄双行)和不同播种方式(一穴单株和一穴双株)及4种种植密度(6.0万、7.5万、9.0万、10.5万株/hm2)条件下,研究不同种植方式和密度对玉米(Zea may L.)光合特性、子粒干重及灌浆速率的影响.结果表明,大垄双行比传统小垄更能创建有利的群体结构,改善植株间的竞争关系,提高子粒灌浆速率.一穴双株在低密度下表现较好.不同种植密度对玉米光合特性、子粒干重及灌浆速率的影响随种植密度的增加呈下降趋势.种植方式和密度间的互作达极显著水平,说明在适宜的种植密度下,合理的种植方式可以改善群体结构,合理分配光资源.其中,低密度条件下种植方式C表现较好,高密度条件下种植方式E的光合能力保持较高水平,对提高子粒的干重和灌浆速率有显著影响.     

行距配置对紧凑型冬小麦品种灌浆特性的影响

为探明行距配置对紧凑型冬小麦品种粒质量的影响,在大田条件下,设置15 cm、20 cm、25 cm 3种行距处理,研究了其对紧凑型冬小麦品种新麦26灌浆特性的影响。结果表明,新麦26的粒质量增加动态、灌浆速率、灌浆持续期和最终粒质量受行距的影响。15 cm 处理的籽粒干物质累积增长量在灌浆前期较低,但后期增加速度较快,至花后31 d 分别比20 cm 处理、25 cm 处理增加1％、5％。籽粒灌浆速率在灌浆前期表现为20 cm 处理＞25 cm 处理＞15 cm 处理,灌浆后期表现为15 cm 处理＞20 cm 处理＞25 cm 处理。相对灌浆速率随行距增大而上升,最大灌浆速率和平均灌浆速率受行距的影响较小。灌浆持续期随行距增大而缩短;最终粒质量和理论粒质量随行距增大而下降,下降幅度分别为4％和8．5％。因此,缩小行距能延长灌浆持续期,提高粒质量。