Higher crop performance of rice hybrids than of elite inbreds in the tropics: 2. Does sink regulation,rather than sink size,play a major role?

Higher harvest index, widely reported as a main trait supporting major improvements in rice yield potential, also supports the higher performance of hybrids over inbreds. Although higher sink size is generally claimed for being the driver of higher grain filling in hybrid rice, it is relevant to question whether efficient sink regulation, that is timing and magnitude of the successive sink activities over crop growth from early stage, plays a role in supporting higher harvest index and is a key feature ensuring higher performance of hybrid rice. The partitioning coefficient (PC), as the increase in dry matter of one single organ over that of shoot, was calculated over short and successive periods to quantify the dynamics of dry matter partitioning. Four hybrid and four inbred genotypes of similar crop duration were grown under the same cropping management on the IRRI farm during a wet and a dry seasons. While PC to blade and sheath was similar for both plant types in both seasons at the early stage, PC to culm of hybrids was higher than that of inbreds, and PC to blade was lower, in the late vegetative and early reproductive phases. During the late reproductive phase, PC to panicle of hybrids was higher than that of inbreds, and PC to culm was lower whereas culm elongation was similar for both plant types. During grain filling, PC to culm was significantly more negative with hybrids which indicated stronger remobilization with hybrids. Specific culm length before anthesis, as low as 40 cm g⁻¹, accounted for storage ability, and at maturity, as high as 130 cm g⁻¹, for remobilization ability. Sink strength index, as a better indicator of dry matter partitioning efficiency than harvest index, and unfilled grain size, as an indicator of assimilate wastage, were suggested as key indices to account for the better sink regulation in hybrid rice and to improve screening protocols for increasing yield potential and tolerance to lodging.     

实心小麦86-741茎秆的解剖分析及壁厚特性的SSR标记

以实心小麦86-741、新疆稻麦及其杂种F₁为材料, 利用石蜡切片和SSR标记方法对86-741的实心特性进行了分析。结果表明, 实心小麦86-741茎内仅有极小髓腔, 髓腔中有髓, 机械组织中有维管束的分布; 杂种F1偏向实心亲本86-741, 有髓腔, 但髓腔的直径小于新疆稻麦, 机械组织所占的比例小于亲本86-741; 86-741维管束数最多, F₁代其次, 新疆稻麦最少。遗传分析与SSR标记结果表明, 86-741髓的有无是由双隐性基因控制的; 而其壁厚性状由位于3BL染色体上的单显性基因控制, 与SSR标记Xgwm-547的遗传距离为5.3 cM。暂将该壁厚基因定名为Cwt-1。Xgwm-547可用于辅助转育壁厚特性, 提高小麦品种的抗倒伏能力。     

陕西卫矛夏季嫁接试验

试验表明:陕西卫矛用丝绵木为砧木,在生长季节截头插皮枝接比芽接成活率高出24%,冠形好,成型更快,是一种高效的好方法.     

Genetic difference in adventitious rhizogenesis in <Emphasis Type="Italic">Albizia procera</Emphasis> Benth. with IBA treatment

Variable adventitious rhizogenesis of juvenile shoot cuttings was observed in seven half-sib families (TP-1, BAN-1, AN-3, JR-3, SL-16, UM-3, and UM-5) of Albizia procera Benth. Treatment with IBA invariably promoted sprouting by 8%, adventitious rooting by 218%, root number by 869%, and root length by 36.4% compared with the control. Interaction between families and IBA treatment significantly enhanced sprouting and root length in BAN-1, JR-3, UM-3, and UM-5, and root number in all families, but had a significant suppressive effect on sprouting in AN-3. Treatment with IBA increased family heritability (h _f ²) 1.38-fold for sprouting, 2.86-fold for adventitious rooting, and 10.86-fold for root number, but reduced family heritability by a factor of 8.25 for root length. Thus, direct genetic effects seem to have strongly affected sprouting and adventitious rooting, with IBA playing an auxiliary role, but had little effect on root number and length, for which IBA had a dominant regulatory role.     

青刈黑麦产草量与营养动态分析

青刈黑麦在黄淮海地区具有广阔的发展前景。本文针对棉花冬闲田,对青刈黑麦在不同生育阶段的产草量、营养成分含量、刈割时间及刈割次数进行研究。结果表明,一次利用时,刈割时间不能超过抽穗后期。两次利用时,头茬刈割时间不能超过拔节期,二茬应在抽穗后期刈割。后者草的质量优于前者,但产草量较低,因此在实践中可根据需要决定刈割次数。     

湿加松扦插繁殖配套技术

文章从扦插繁殖基地建设和技术环节两方面来阐述湿加松扦插繁殖配套技术。在基地建设方面,提出分区建设思路,将基地区分为生产区和配套设施两大部分,其中生产区包括采穗圃、扦插圃、炼苗圃,配套设施包括7个部分,并就基地总体布局、各区建设要点和使用设施等作了详细说明。以年产100万株扦插苗的规模为例,对基地的建设投资进行了概算。在技术方面,重点介绍了采穗母株培育技术、采穗圃营建技术、扦插繁殖技术和出圃苗木的管理技术。并对营建湿加松扦插繁殖基地的投资收益与风险作了分析。对新建湿加松扦插繁殖苗圃具有指导意义。     

常态下景天科室内观赏植物释放负离子的研究

目的为景天科拟石莲花属植物规模化繁殖和生产提供依据。方法以景天科拟石莲花属植物雪莲种子、红边月影、女雏、花乃井和小蓝衣叶片以及3种播种基质(V_{泥炭土422#}∶V_珍珠岩=3∶2、V_{泥炭土680#}∶V_珍珠岩=3∶2和V_{本地红壤土}∶V_珍珠岩=3∶2)为试材,测定了3种基质的理化性质及其对红边月影、女雏、花乃井和小蓝衣叶插生根率、新芽直径以及对雪莲种子发芽率的影响。结果3种基质的容重、总孔隙度、通气孔隙度、持水孔隙度、有机质和有效氮磷钾元素均存在差异,pH值和EC值均符合拟石莲花属植物的生长要求。3种基质对拟石莲花属植物叶插生根率影响不显著(P>0.05),对新芽直径和种子发芽率影响显著(P<0.05),拟石莲花属植物物种间的叶插生根率和新芽直径存在显著(P<0.05)或极显著(P<0.01)差异,拟石莲花属植物物种和基质间存在互作效应。基质理化性质中,对拟石莲花属植物发芽率和生根率均为显著影响的共性因素为基质中有机质含量、氮元素含量和持水孔隙度,而对生长速度有极显著影响的因素为通气孔隙度。结论泥炭和珍珠岩复配较适宜作为拟石莲花属植物的叶插和播种繁殖基质,针对不同拟石莲花属植物品种筛选不同性质的泥炭,并且在不同生长期选用不同理化性质的基质,可获得更好的繁育效果。     

黑龙江西部农林复合经营区欧李嫩枝扦插试验初报

欧李是一种重要的、极具推广价值的生态经济型小灌木.为了在气候条件较为干旱的黑龙江西部农林复合经营区推广这一树种,提高该区农林复合经营的生态经济功能,以扦插时间、不同浓度生根粉处理、不同带叶情况处理为因素,采用正交试验设计开展了欧李嫩枝扦插试验.结果表明3个因素对欧李嫩枝扦插愈伤组织的形成、生根的影响都是显著的,其中,对愈伤组织的形成,3个因素影响大小依次为带叶情况〉扦插时间〉生根粉处理,对于生根率,则是带叶情况〉生根粉处理〉扦插时间;3个因素最佳处理组合为带2片子的插穗、采用200mgL-1ABT1号生根粉浓度处理、5月30日扦插,可使扦插生根率达到90%以上.     

梅营1号红薯高产栽培技术

红薯究竟能达到多高产量,众多的栽培研究没有一个准确的定论。笔者连续3年,通过不同扦插方式,科学施肥,采取不同化控手段进行栽培技术研究,取得了平均产量9356.00kg/667m2的记录,创当地红薯历史最高水平,个别小区产量超过了1.00万kg/667m2,对红薯夺取高产有着一定的指导意义。     

5种忍冬嫩枝扦插繁殖研究

对具有较强适应性和抗性的5种忍冬,采用嫩枝扦插法,以不同浓度的IBA作为生长调节剂对插穗进行处理,分析药剂浓度对插穗生根率和植株生长状况的影响.结果表明：这5种忍冬的扦插生根率为14.4％～87.6％,蓝叶忍冬扦插平均生根率最高,达到了87.6％.低浓度药剂100 ppm、200 ppm利于忍冬插穗的生根和株高的生长,高浓度500 ppm药剂能刺激忍冬根系分根数的增加,药剂的浓度对忍冬根系长度的生长影响不大.