Analysis of sugar cane variety trials. I. Components of variance and genotype-environment interactions

Summary Surgarcane variety trial data from Barbados and Jamaica were analysed by the analysis of variance. From these analyses, components of variance were estimated in an attempt to quantify genotype x environment interactions. Sixteen sets of trials from Barbados and eight from Jamaica were analysed. The results show that GE effects in both countries were small. It is suggested, on the basis of these analyses that variety trials could use resources more efficiently by growing them at fewer sites, since the absence of site x variety interaction makes each site equally effective for identifying the best genotypes.     

Family selection in plant breeding

Summary Plant breeding programmes rarely take explicit practical account of the two sources of genetic variance, namely between and within full-sib families, even though existence of these two sources of variation has long been recognised. This paper refers to inbred and clonal crops, not to outbred, seed-propagated species. Theory suggests that the two variances should be of similar size, sometimes very similar. Good comparisons have never been made because variance within families is laborious to estimate. It is proposed that sets of families be assayed as to means in formal trials and only the best few, judged against standards as having potential for superior segregates, should be exploited thoroughly. The calculation as to approximate equality of genetic variances between and within families is important. The vast majority of families should probably be discarded without further ado, and at considerable economy. Sensible decision-making requires an economic component in order to exploit the trade-off between the cost of the initial trial and families discarded without further cost. The object of this paper is a critical review of practical principles, not a general review of a large and diffuse literature.     

甘蔗杂交后代主要经济性状的变异分析

对用于构建甘蔗抗黑穗病基因连锁标记群体 15 0个杂交后代的追踪研究结果表明 ,其株高、茎径、锤度、有效茎数、蔗茎重和锤重 6个主要经济性状变异系数为 9.92 %～ 39.6 8% ,其中丛蔗茎重变异系数最大 ,锤度变异系数最小。有性和单系世代 6个性状间两两相关分析表明 ,除茎径与有效茎数间呈显著负相关 ,茎径与锤度间相关系数很小外 ,其余均呈正相关且相关系数值较大 ,其中仅锤度与有效茎数间相关性 2个世代均达显著水平 ,株高与茎径、株高与有效茎数间显著相关仅出现于单系世代 ;6个性状的 2个世代值存在显著差异 ,同一性状在世代间相关性均达显著水平。并指出不同世代的选择策略。     

Biochemical Evaluation of Fungal Disease Resistance in Sugarcane

Two methods are proposed to evaluate rust and eye spot disease resistance in sugarcane using biochemical criteria. Eye spot disease resistance is easily evaluated by a fast conductimetric bioassay of high sensitivity. If desired, the conductimetric values may be converted into grades of field resistance by means of a regression graph based on standard varieties. The main advantages of this method art it's complete objectivity, reproducibility and independence of climatic conditions. It was also found that susceptibility of sugarcane to rust can be recognized very early in the infection process by a striking increment of peroxidase activity. The simplicity of this enzyme reaction, which can easily be automated and the speed of detection during infection are discussed as an option for rust resistance evaluation.     

Soil tillage systems and forms of lime application on soil attribute enhancements in ratoon sugarcane

Combining deep tillage (DT) with lime application at greater depths may improve sugarcane yield. The objective of this study was to evaluate the impact of conventional tillage (CT) and DT systems and liming on sugarcane productivity and soil physical attributes. The experiment was conducted in a clayey-textured Rhodic Hapludox soil cultivated with sugarcane for two growing seasons (first and third ratoons) using a randomized block design with four treatments and four repetitions. The treatments consisted of DT without liming (DT0), DT with liming (DT2), CT without liming (CT0) and CT with liming (CT2). In addition to sugarcane stalk and sugar yields, macroporosity (MA), microporosity (MI), total soil porosity (TP), weighted average diameter (WAD), aggregate stability index (ASI), soil penetration resistance (SPR), pH, potential acidity (H + Al), total soil organic carbon (SOC), particulate organic carbon (POC), mineral-associated organic carbon (MOC), calcium (Ca) and magnesium (Mg) were analysed. DT2 promoted the best soil conservation effect on sugarcane. In general, DT, regardless of lime application, reduced SOC and POC in soil surface layer. Nevertheless, in the long term, localized lime addition resulted in significant reductions in compaction, reaching values below 2 MPa. The soil fertility improvement provided by DT2 promoted increased sucrose concentrations and stalks yield. Considering that there was an improvement in the physical quality and fertility of soil for better plant development, the deep tillage with localized lime addition can be considered an effective alternative for sugarcane cultivation.     

甘蔗种质资源的研究

对 2 64个国内外栽培甘蔗品种及福建省内野生甘蔗“割手密”的特征特性等进行了研究 ,结果表明 :“割手密”的体细胞染色体数有 2n =72、80、84、88、92、96、1 0 2等 7种类型 ,酯酶同工酶有 1 9种类型 ;印度培育的甘蔗品种产量高 ,澳大利亚培育的甘蔗品种锤度高 ;从国外引进的品种中筛选出 3个生长特快的高产品种 (“C1 55-76”、“My5462”和“My5770”)和 2个高纤维含量的高产品种 (“FCP86-2 61”和“FCP86-2 63”)。对上述甘蔗种质资源进行了创新利用 ,已初步选育出特高糖品种“闽糖 91 -2 2 1”及高生物量品系“闽糖 92 -1 1 7”和“闽糖 92 -2 2 5”等     

甘蔗×斑茅远缘杂种的鉴别

本试验采用染色体Giemsa—C带分带和过氧化物酶同工酶电泳频谱分析方法对野生种斑茅(Saccharum arundinaceum Retz.)与甘蔗的远缘杂交后代进行鉴别分析。结果表明,F_1代崖城73/07(2n=68)、崖城75/283(2n=68)染色体数组成为n+n型,染色体带型和同工酶谱均表现为父、母本综合型,崖城57/25(2n=110)、崖城73/512(2n=110)则分别与其母本相似。据此认为,4个待定材料中,仅前二者是真实的斑茅远缘杂交后代。 根据上述结果分析了斑茅对甘蔗育种尚无实质性贡献的原因,认为该野生种之育种性能与其染色体带型有关。最后,讨论了同工酶分析及染色体分带作为杂种鉴别方法的意义及其局限性。     

甘蔗与蔗茅属间杂交F1代真实性的鉴定

采用体细胞染色体计数和RAPD分子标记的方法鉴定“甘蔗×蔗茅”属间杂交种F1代的真实性。结果表明:杂种F1代材料“01/47,01/85,01/120”的2n=80～82,染色体遗传方式为“n 2n”;用110个随机引物进行RAPD扩增,63个引物可获得双亲的RAPD多态性,其中3个引物(OPC-19,OPE-2,OPF-4)可在杂种F1代材料01/64和01/120的RAPD扩增标记中显示出双亲的特征谱带,分别为父本3500bp和母本1300bp、父本1350bp和母本900bp、父本550bp和母本900bp。     

西双版纳割手密血缘DTOPSIS综合评价与分析

通过对现有44份云南西双版纳割手密血缘材料进行DTOPSIS法分析,结果表明：（1）排名前10位的材料是：F202-3、F304-87、F304-41、F203-76、F203-73、F304-47、F203-13、F304-84、F201-394、F203-6;（2）有22份材料超过对照种ROC10;（3）分析结果与材料性状表现较一致,说明DTOPSIS分析不失为一种简便、有效的亲本评价方法.     

割手密遗传作图最适分离群体的选择

[目的]筛选适合用于构建割手密遗传连锁图谱的分离群体,为后续的遗传连锁图谱构建和基因定位及遗传育种提供理论依据.[方法]基于“双假测交“理论,利用DNA水平上遗传差异较大且蔗糖分和分蘖率差异极显著的不同割手密无性系进行杂交获得3个不同杂交组合,对3个备选作图群体的分蘖率和蔗糖分进行变异、正态分布拟合分析及分子多态性分析.[结果]组合3（GXS85-12×GXS87-16）和组合13（云割①×田林）的分蘖率呈偏态分布,而组合5（GXS85-30×GXS87-16）的分蘖率呈近似正态分布;组合3和组合5的蔗糖分呈偏态分布,而组合13的蔗糖分呈近似正态分布.在分子多态性水平上,组合5亲本的遗传相似系数略高于组合3和组合13,而其后代平均遗传相似系数略低,但变幅较高.[结论]组合5（GXS85-30×GXS87-16,群体大小为245株）的分蘖率、蔗糖分遗传性相对稳定,群体来源比较广泛,分子多态性丰富,遗传多样性高,可作为分离群体用于构建遗传图谱.