Classification of Peruvian highland maize races using plant traits

The maize of Latin America, with its enormous diversity, has played an important role in the development of modern maize cultivars of the American continent. Peruvian highland maize shows a high degree of variation stemming from its history of cultivation by Andean farmers. Multivariate statistical methods for classifying accessions have become powerful tools for classifying genetic resources conservation and the formation of core subsets. This study has two objectives: (1) to use a numerical classification strategy for classifying eight Peruvian highland races of maize based on six vegetative traits evaluated in two years and (2) to compare this classification with the existing racial classification. The numerical classification maintained the main structure of the eight races, but reclassified parts of the races into new groups (Gi). The new groups are more separated and well defined with a decreasing accession within group × environment interaction. Most of the accessions from G1 are from Cusco Gigante, all of the accessions from G3 (except one) are from Confite Morocho, and all of the accessions from G7 are from Chullpi. Group G2 has four accessions from Huayleño and four accessions from Paro, whereas G4 has four accessions from Huayleño and five accessions from San Geronimo. Group G5 has accessions from four races, and G6 and G8 formed small groups with two and one accession each, respectively. These groups can be used for forming core subsets for the purpose of germplasm enhancement and assembling gene pools for further breeding.     

玉米自交系穗部性状对播期的反应

通过７个玉米自交系在５个播期下穗部性状的变化及各性状间相关性分析,提出了选育高自身繁殖力的优良玉自交系,在适宜的生育期下,对穗部性状应依次注意重行粒数、千粒重,出籽率和穗长的选育,可适当放宽穗粗和穗行数的选择要求。     

Morphological quality of sweet corn (Zea mays L.) ears as response to soil moisture tension and phosphate fertilization in Campeche, Mexico

In Mexico, corn production, part of which is sweet corn, is mainly destined for human consumption. In the present work, the morphological quality of sweet corn ears was assessed in response to four levels of soil moisture tension indicating irrigation start (−5, −30, −55, and −80 kPa) and three levels of phosphate fertilization (60, 80 and 100 kg ha⁻¹) in carstic soils in the south-east of Mexico. A factorial experimental design with three replicates was used. The following variables were determined: fresh weight (SCFWh), dry weight (SCDWh), diameter (SCDh), and length (SCLh) of sweet corn ears, all without husk, as well as number of kernels (NKxE), number of unfilled kernels (NUK), number of rows (NRxE), and dry kernel weight per ear (DKW). Yield of fresh (YFSCh) and dry (YDSCh) sweet corn ears, both without husk, and the harvest index (HI) were also determined. HI did not show significant statistical differences among irrigation or fertilization treatments. Regarding the other variables, the effect of the more humid treatments (−5 and −30 kPa) and the effect of the higher phosphorus doses (80 and 100 kg ha⁻¹) were statistically equal (P ≤ 0.01) with the lowest NUK and the highest values of all other variables; therefore, irrigation start at soil moisture tension of −30 kPa and phosphate fertilization application of 80 kg ha⁻¹ are recommended. At this level of soil moisture, the mean values over the three fertilization levels and all the replicates, obtained for SCFWh, SCDh, SCLh and NKxE were 198.5 g, 4.39 cm, 26.72 cm and 467 grains, respectively. According to the regression models, moisture tensions from −11.8 to −24.0 kPa, and phosphate fertilization doses from 87.7 to 102.2 kg ha⁻¹ minimize NUK and maximize the values of the rest of the variables. The highest irrigation water use efficiency was found in the moisture tension treatment of −30 kPa with an increase of 27 kg ha⁻¹ ears for each millimeter of applied irrigation water.     

玉米DH系15D969、D1279株高、穗位高的遗传育种效应研究

利用2份低穗位高DH系(15D969、D1279)、5份自交系(A6、PHB1M、B20、PH4CV、PH6WC)进行杂交、回交试验,对株高、穗位高效应进行研究分析。结果表明,DH系15D969所具有的低株高、低穗位高由隐性基因控制。相对于PH6WC×A6,15D969与PH6WC杂交效应不表达;DH系D1279同时具有高株高隐性基因和低穗位高部分显性基因,杂交组合PH6WC×D1279株高、穗位高显著低于先玉335(PH6WC×PH4CV),改良效果显著。     

水分胁迫对不同倍性小麦穗部干物质积累和分配及转运的影响

为了进一步挖掘小麦穗部的干物质生产潜力,以野生一粒小麦（Triticum boeoticum,二倍体）、野生二粒小麦（T.dicoccoides,四倍体）、碧蚂1号（T.aestivum Bima 1,六倍体）3种不同染色体倍性小麦为材料,在干旱和灌水两种水分处理下,比较不同倍性小麦品种穗部干物质分配规律、转运特性及对产量的贡献率。结果表明,在两种水分条件下,不同倍体小麦穗部各器官干物质分配规律存在差异,与六倍体和二倍体小麦相比,四倍体小麦的穗轴、颖壳干物质分配率最低,其花前干物质转运量、转运效率及对籽粒的贡献率最高。六倍体的花后干物质积累量及其对籽粒的贡献率均大于其他两种小麦。水分胁迫由于降低了营养器官开花前贮藏同化物向籽粒的再分配及花后干物质的积累与转运,从而降低了产量。水分胁迫下,四倍体小麦的产量下降幅度最小,可能与四倍体小麦穗部干物质分配率低、转运效率高有关,其穗部器官干物质能更多地向籽粒转运分配,滞留物最少,使得千粒重增加。因此,水分胁迫下,四倍体小麦表现出更强的耐旱性。     

水稻茎生叶生长对植株和穗部性状的影响

[目的]研究茎生叶和水稻生产相互关系。[方法]2014、2015年对江苏省农垦农业发展股份有限公司江心沙分公司水稻进行调查,分析水稻最长叶与植株性状、穗部性状、叶片总长度的相互关系,以及不同叶长序对水稻穗部性状的影响。[结果]倒2叶最长时穗下节和穗长较长、穗部性状较好;叶长序为213(45)时单穗重最高。[结论]生产上可通过相关措施促进倒2叶生长,构建合理的茎生叶叶长序来实现水稻高产。     

水稻穗部性状与产量的关系

[目的]研究水稻穗部性状与产量形成的关系。[方法]以36个水稻品种为材料,田间试验采用随机区组设计,分别测定抽穗期叶面积指数,成熟期穗茎角,穗长、一次枝梗数、二次枝梗数、每穗成粒数、空秕粒数、千粒重等穗部性状,研究水稻穗部性状之间的关系及其与产量、产量构成因素、源库等之间的关系。[结果]每穗颖花数、一次枝梗数、二次枝梗数、着粒密度之间呈极显著或显著的正相关,二次枝梗数对增加每穗颖花数和着粒密度的作用较大。着粒密度与穗茎角、穗长呈二次曲线关系。穗茎角、穗长与产量呈极显著负相关。着粒密度、粒叶比与产量呈抛物线关系,当着粒密度为9—12粒／cm、粒叶比在1．1—1．2粒／cm^2时水稻产量较高。[结论]该研究为水稻理想株型育种提供理论依据。     

云南省几个骨干玉米自交系穗部性状的利用价值预测

采用包括胚、胚乳、细胞质和母体植株遗传效应以及环境互作效应的禾谷类种子遗传模型,预测10个云南骨干玉米自交系在穗长、穗粗、穗行数、百粒重性状上的利用价值。结果表明,ZNL-1、自330、素湾1611、云147和ZOL-5可显著增加杂交后代穗长,增加效果为素湾1611>自330>云147>ZOL-5>ZNL-1;ZNL-1、素湾1611和云147能显著增加后代穗粗,增加效果为云147>素湾1611>ZNL-1;增加穗行数的亲本是素湾1611;增加后代百粒重的亲本是ZNL-1、1072、ZOL-1、ZOL-2和ZOL-5,增加效果为ZOL-2>ZOL-1>ZOL-5>1072>ZNL-1。     

张杂谷3号的解剖学结构与生物学特性的关系

针对张杂谷3号具有抗性强、产量高的特征,对其叶片解剖结构、叶表皮特征、茎的解剖结构以及穗分化特性进行综合研究,探讨了张杂谷3号与抗旱性、抗逆性以及高产有关的结构特征。结果表明,张杂谷3号为C4植物,叶片具有大维管束、叶绿体浓绿和密集、气孔密度高,叶片表皮毛密集,特化细胞多,气孔内陷的特征。茎具有维管束面积大,穗茎淀粉含量高的特征。谷子穗分化阶段枝梗原基数量多、密集,发育成的谷穗大、穗码密集,以上研究为其抗旱、高产能力的评价以及机理研究提供形态解剖学方面的依据。     

小麦品种(系)不同穗部位种子活力比较研究

[目的]确定小麦种子活力测定的较好方法,探讨小麦品种不同穗部位种子活力的差异。[方法]选用皖麦33、皖麦48、烟农19、扬麦158和W1032(糯小麦)5个小麦品种(系)种子为材料,设置上部穗位、中部穗位、下部穗位和整穗(CK)4种处理,通过种子大小测定、幼苗生长测定、加速老化试验、冷浸试验、电导率测定、模拟田间出苗率测定以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、脂肪氧化酶(LOX)、过氧化氢酶(CAT)和脱氢酶(ADH)5种酶活性测定等方法,综合评价种子活力,并进行整穗(CK)种子的主要活力指标间相关分析以及对5个小麦品种(系)不同穗部位种子主要活力指标平均值的比较。[结果]幼苗生长测定、加速老化试验以及5种酶活性等指标均与模拟田间出苗率呈显著相关;小麦品种(系)不同穗部位种子活力存在明显差异。[结论]幼苗生长测定、加速老化试验以及5种酶活性测定均是小麦种子活力测定的较好方法;小麦中部穗位种子活力较高,下部穗位种子活力次之,上部穗位种子活力较低。